Yates

Historical Biology, 2006; 1–31, iFirst article

Solving a dinosaurian puzzle: the identity of Aliwalia rex Galton

ADAM M. YATES Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, Private Bag 3, WITS 2050, South Africa

Abstract Eucnemesaurus fortis Van Hoepen 1920 from the Late Triassic of South Africa is demonstrated to be the senior synonym of the puzzling dinosaur taxon Aliwalia rex Galton 1985. A new specimen of this poorly-known taxon is described. Eucnemesaurus is clearly a sauropodomorph and increases the diversity of sauropodomorph taxa in the South African Late Triassic to six. It shares a number of femoral synapomorphies with Riojasaurus from the Late Triassic of Argentina and Riojasauridae tax. nov. is erected to accommodate them. These conclusions are supported by a comprehensive cladistic analysis of 46 sauropodomorph and other basal dinosauriform taxa using 353 osteological characters. This analysis also supports the paraphyletic nature of the traditional ‘prosauropod’ assemblage.

Keywords: Aliwalia, Eucnemesaurus, Late Triassic, Sauropodomorpha, South Africa, Riojasauridae

Introduction Alfred “Gogga” Brown discovered the first Triassic dinosaurs from South Africa sometime during the early 1860’s. His early collections were all made at “Barnard’s Spruit, Ward, 15 miles south of Aliwal North” (Galton and Van Heerden 1998) and were collected from a unit that is now called the lower Elliot Formation. The fossils were sent in five shipments to various museums in Europe (Seeley 1894; Broom 1911). The bulk of these collections consisted of moderately large sauropodomorph dinosaurs, which are the commonest fossils in the lower Elliot Formation. However the shipment that went to the Naturhistorisches Museum in Vienna contained a peculiar dinosaur femur that is from a decidedly rare taxon. Indeed, until now, this femur was thought to be unique, although it has been suggested that a maxilla of a carnivorous archosaur, included amongst the bones that Brown sent to London, might also belong to the same taxon as the femur (Galton 1985).

Von Huene was the first to describe this particular femur and he tentatively placed it in the genus Euskelosaurus (Huene 1906). Euskelosaurus browni

Huxley 1866 was the name given to the large sauropodomorph bones in the first shipment that Brown had sent to London (Huxley 1866). The name is no longer regarded as valid since the lectotype of E. browni displays no diagnostic characters beyond Sauropodomorpha (Yates 2003; Yates and Kitching 2003). Cooper went further than Huene and suggested that the Vienna femur was part of the same individual that included the type series of E. browni (Cooper 1980). Galton pointed out that it was quite distinct from the lectotype femur of E. browni and indeed appeared to be quite distinct from all other sauropodomorphs (Galton 1985). Consequently he erected Aliwalia rex Galton 1985 to accommodate it (Galton 1985). The systematic position of A. rex has always been uncertain. Galton suggested that it belonged to an herrerasaurid which was the position taken by Paul (1988). The belief that A. rex represented a large, carnivorous dinosaur, whether or not it was an herrerasaurid, was the part of the basis for referring a maxilla of a large carnivorous archosaur to this taxon (Galton 1985; Galton and Van Heerden 1998). This referral was also supported by the fact that the maxilla was part of the Brown’s London

Correspondence: A.M. Yates, Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, Private Bag 3, WITS 2050, South Africa. E-mail: yatesa@geosciences.wits.ac.za ISSN 0891-2963 print/ISSN 1029-2381 online q 2006 Taylor & Francis DOI: 10.1080/08912960600866953

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shipment of bones and had therefore been found at the same locality as the lectotype femur. Sues commented that there were no shared derived characters that link A. rex to Herrerasaurus and that it was best classified as Dinosauria incertae sedis (Sues 1990), a position that was agreed upon by later workers (Galton and Van Heerden 1998; Langer 2004a).

In 2003 a party of geologists and palaeontologists from the University of Witwatersrand found a small assemblage of dinosaur bones in the lower Elliot Formation, on the farm Spioenkop, Rosendal District, Free State South Africa. This assemblage included the proximal and distal end of a femur that was quickly recognised as Aliwalia rex, the second specimen recognised since the initial discovery over 130 years previously. It was with anticipation of solving the riddle of the identity of A. rex that the associated bones were prepared. Unexpectedly the dorsal vertebra had diagnostic synapomorphies of Sauropodomorpha and did not differ any noticeable way from the large basal sauropodomorphs common in the lower Elliot Formation. Examination of the numerous scrappy holotypes of dinosaurian taxa named from the lower Elliot Formation over the years has revealed that this is not the first time an ‘Aliwalia-type’ femur has been found associated with sauropodomorph vertebrae.

Specifically the long-forgotten Eucnemesaurus fortis Van Hoepen 1920 which had been dismissed as either a synonym of Euskelosaurus browni or a nomen dubium, is a third example of an ‘Aliwalia-type’ femur, once again associated with typical basal sauropodomorph vertebrae (Van Hoepen 1920). In this case it appears that the accumulation represents the fragmentary remains of a pelvis, hind leg and tail of a single individual. This paper outlines the evidence that Aliwalia rex is a junior synonym of Eucnemesaurus fortis and that the species is a sauropodomorph with close affinities to Riojasaurus incertus from the Late Triassic of Argentina.

Institutional abbreviations: BP, Bernard Price Institute, University of the Witwatersrand, Johannesburg; NMW, Naturhistorisches Museum, Vienna; PVL Instituto Miguel Lillo, Tucuman; SMNS, Staatliches Museum fu¨r Naturkunde, Stuttgart; TM, Transvaal Museum, Pretoria.

The synonymy of Eucnemesaurus fortis and Aliwalia rex Although much of TM 119 (the holotype of Eucnemesaurus fortis) could not be located during a visit to the Transvaal Museum (the distal end of the pubis, a section of the femur and the tibia were missing), the morphology of the material is well recorded by photographs and accurate (if minimalist) line drawings in Van Hoepen (1920) (Figure 1). These show clearly that, like NMW 1889-XV-39 (the

holotype femur of Aliwalia rex), the femoral head is elongate for a basal sauropodomorph, that there is a large proximal tubercle on the posterior surface, the lesser trochanter is developed into a tall crest and the long axis of the base of the fourth trochanter extends obliquely from a position against the medial margin of the shaft in posterior view, at its proximal end, to a position more centrally placed on the posterior surface of the shaft, distally. The large posterior tubercle is an especially unusual character that represents a reversal to the non-dinosaurian condition (Novas 1996). The only other dinosaur to exhibit one is Riojasaurus incertus. Points of dissimilarity between the two holotypes are probably caused by damage to one, or the other, of the specimens. In TM 119 the proximal end of the lesser trochanter ends abruptly whereas the proximal end slopes more gradually toward the shaft in NMW 1889-XV-39. However the proximal end of the lesser trochanter of both specimens has been damaged and the tip of the trochanter could simply have been lost in the latter specimen. The wellpreserved lesser trochanter of BP/1/6111 demonstrates that the proximal end terminates abruptly. In TM 119 and NMW 1889-XV-39 the fourth trochanter is relatively proximally placed although it is more extreme in NMW 1889-XV-39. In TM 119 the first rise of the proximal end of the fourth trochanter was placed 175 mm from the proximal end of the bone according to Van Hoepen (1920). This distance is 1.13 times the length of the proximal head of the bone, whereas in NMW 1889-XV-39 this distance is only 0.95 of the length of the proximal head. This difference may be simple individual variation but there are reasons to suspect that the fragment of NMW 1889-XV-39 has not been correctly attached to the proximal end of the bone. There is a large obvious repaired join between the two pieces and the medial margin of the piece bearing the fourth trochanter is strongly deflected medially relative to the long axis of the femoral head. Since the medial margin of the femur in the vicinity of the fourth trochanter is more or less vertical in other dinosaurian femora it would imply that the head of NMW 1889-XV-39 would be angled strongly downwards. Such an arrangement is not impossible but seems unlikely in a moderately derived sauropodomorph. It is more likely that the two pieces are mismatched and the head of the femur was angled medially as in other sauropodomorphs (Figure 2). The base of the fourth trochanter in TM 119 is figured (in posterior view) as starting at the medial edge at its proximal end and curving in away from it at its distal end (Van Hoepen 1920). This is less apparent in NMW 1889-XV-39 but it is still somewhat obliquely oriented and, as explained above, the fragment that bears the fourth trochanter in this specimen is probably displaced. The new femur, BP/1/6111, clearly displays a medio-distally curving fourth trochanter as well as a rounded profile of the

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Figure 1. Unlocated bones from the holotype of Eucnemesaurus fortis as figured by Van Hoepen (1920). Distal fragment of the left pubis in proximal view showing a section through the pubic blade (A) and distal view (B). Proximal end of the left femur in lateral (C), and posterior (D) views. Left tibia in lateral (E), posterior (F), proximal (G) and distal views (H). Scale bar represents 100 mm.

Figure 2. Proximal ends of the femora of Plateosaurus engelhardti and Eucnemesaurus fortis in posterior view. A, Plateosaurus engelhardti, SMNS 13200. B, Eucnemesaurus fortis, TM 119, redrawn from Van Hoepen (1920). C, Eucnemesaurus fortis, NMW 1889-XV-39, as restored.

D, Eucnemesaurus fortis, NMW 1889-XV-39, with the position of the distal fragment shifted to bring the specimen into line with A and B. Each figure displays the angle between the medial margin of the shaft and the axis running from the proximolateral corner of the femur to the peak of the femoral head. Numbers below each figure indicate the distance between the proximal end of the bone and the proximal end of the fourth trochanter divided by the proximal length of the femoral head. Grey areas represent restored areas, black areas represent broken bone surfaces. Scale bars represent 100 mm.

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fourth trochanter and a notched (‘semi-pendant’) distal end. The latter two characters are present in NMW 1889-XV-39 but cannot be determined in TM 119 because the fourth trochanter is broken off at its base.

The occurrence of this constellation of unusual characters (where they can be determined) in all three specimens from the same stratigraphic unit is good evidence that they belong to a single taxon. The only major difference between NMW 1889-XV-39 and TM 119 is the relative position of the fourth trochanter but this may well be an artefact of restoration in the holotype of Aliwalia.

Diagnosis: Large, robust sauropodomorphs with the following synapomorphies: a tall, crest-like lesser trochanter that is higher than wide in cross-section; a large tubercle on the posterior side of the proximal femur (this is a reversal to a non-dinosaurian character-state); and a rounded, convex profile of the fourth trochanter (versus a subrectangular profile). The presence of a shallow embayment on the distal margin of the fourth trochanter (giving the trochanter a semi-pendant shape) might also diagnose this clade but the presence of this character in Massospondylidae renders its distribution ambiguous.

Eucnemesaurus fortis Van Hoepen 1920

Systematic palaeontology Sauropodomorpha Huene, 1932 Massopoda taxon nov.

Definition: The most inclusive clade containing Saltasaurus loricatus but not Plateosaurus engelhardti. As it currently stands this taxon is a homodefinitional synonym of Sauropoda but as explained below the content of Sauropoda in the phylogeny supported here (and elsewhere) is radically expanded beyond all traditional usage of the name Sauropoda and a redefinition of this taxon is required.

Etymology: Massa (Latin), lump and pous (Greek), foot. Also a contraction of Massospondylidae and Sauropoda, two well-known and disparate subordinate taxa within Massopoda.

Riojasauridae taxon nov.

Definition: The most inclusive clade containing Riojasaurus incertus but not Plateosaurus engelhardti, Massospondylus carinatus, or Anchisaurus polyzelus. As undesirable as multiple anchor taxa may be, it is necessary to use them here to preserve the intent of the name across the widely differing hypotheses of sauropodomorph phylogeny that have been proposed recently. It is important to note that Melanorosaurus readi was deliberately left out of the list of exclusive anchors. This is because it makes little sense to differentiate Riojasauridae from Melanorosauridae in situations where these taxa form a small low-diversity clade within Sauropodomorpha such as in Galton and Upchurch (2004). In cases like these Riojasauridae simply becomes a heterodefinitional junior synonym of Melanorosauridae as defined by Galton and Upchurch (2004). However, in the phylogenetic hypothesis favoured here, Riojasauridae and Melanorosauridae are distinct and distantly related taxa amongst basal sauropodomorphs.

Included Taxa: Riojasaurus incertus and Eucnemesaurus fortis

1906 ? Euskelosaurus Huene (1906), pp. 131 – 132, Figures 41 – 42, pl. 16, Figure 2, pl. 17, Figure 1 1920 Eucnemesaurus fortis Van Hoepen (1920), pp. 93 – 102, Figures 1 –7, pl. 11 – 13 1979 cf. Euskelosaurus Van Heerden (1979), p. 69, Figures 19 – 20, pl. 52 – 55 1985 Aliwalia rex Galton (1985), pp. 15 –16, Figure 5d –i, pl. 5 Diagnosis: A sauropodomorph with: a small accessory lamina branching off of the paradiapophyseal lamina and dividing the middle chonos in the middle dorsal vertebrae; an abrupt proximal end of the lesser trochanter; a fourth trochanter with a curved and oblique long axis .

Holotype: TM 119 a fragmentary posterior postcranial skeleton including two incomplete dorsal neural arches, a dorsal centrum, distal and proximal fragments of the left pubis, the proximal end of the left femur, the left tibia and four incomplete proximal to mid caudal vertebrae. From Farm Zonderhout, near Slabberts, Free State, South Africa, lower Elliot Formation (Norian, Late Triassic).

Referred Material: NMW 1889-XV-39 and 1876-VIIB124. Proximal and distal ends of a left femur.

Holotype of Aliwalia rex. From Barnard’s Spruit, Aliwal North District, Eastern Cape, South Africa, lower Elliot Formation.

BP/1/6107, 6110 –6115, 6220. Incomplete postcranial skeleton including a posterior dorsal vertebra (6107), left coracoid (6113), a ventral fragment of a left scapula (6114), a fragment of the dorsal end of a left scapula? (6115), a proximal caudal vertebra (6220), fragments of a right proximal femur (6111), distal end of a right femur (6110) and two rib shaft fragments (6112). The bones have been catalogued individually because the remains were disarticulated (although in close proximity to one another) and the association cannot be proven. Nevertheless it

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Figure 3. Dorsal vertebrae of Eucnemesaurus fortis. A, Middle dorsal neural arch (TM 119) in left lateral view. B, Posterior dorsal neural arch (TM 119) in posterior view. Posterior dorsal vertebra (BP/1/6107) in left lateral (C), anterior (D) and posterior (E) views. Scale bars represent 50 mm. Abbreviations: a.l.mc, accessory lamina of middle chonos; a.l.pc, accessory lamina of the post chonos; c, centrum; dp, diapophysis; hs, hyposphene; n.c, neural canal; n.sp, neural spine; pcd.l posterior centrodiapophyseal lamina; pp, parapophysis; pod.l, postzygapophyseal lamina; poz, postzygapophyses; ppd.l, paradiapophyseal lamina; prz, prezygapophysis; t.p, transverse process.

seems likely that these bones come from a single skeleton because of the lack of duplication, and the similarity in size, and state of preservation. In addition several weathered pieces were found downstream from the site (BP/1/6151). These may, or may not, belong to the specimen. They include fragmentary mid and distal caudal vertebrae and two phalanx fragments. From the dongas (erosional gullies) at the base of Spioenkop, Heelbo farms, Rosendal District, Free State South Africa.

The specimens were collected in dark purple-grey silts in the lower Elliot Formation.

Description Van Hoepen (1920) described the holotype specimen so this description concentrates on the new material in the BP collections. Nevertheless certain aspects of the holotype are described here in light of recent advances in our knowledge of characters significant to sauropodomorph phylogeny. The Vienna specimen has been described elsewhere (Galton 1985; Galton and Van Heerden 1998).

Dorsal vertebrae (Figure 3). There are two incomplete middle to posterior dorsal neural arches of TM 119 that are available for study, with the middle dorsal being the more informative of the two. It has a laterally directed transverse process on the right side from which arise three diapophyseal lamiae: the postzygodiapophyseal, posterior centrodiapophyseal and paradiapophyseal laminae. These laminae bound the posterior and middle chonae. A unique accessory lamina branches off of the paradiapophyseal lamina and extends ventrally for a short distance. It does not reach the neurocentral suture but does divide the middle chonos into two compartments. As in all other early sauropodomorphs the prezygodiapophyseal lamina and its associated anterior chonos are absent, although there is a weak horizontal ridge extending from the diapophysis to the base of the prezygapophysis. The zygopophyses have simple rounded margins in dorsal view and are horizontally oriented. The posterior dorsal neural arch preserves the base of a shallow, triangular hyposphene that extends ventrally from between the two postzygapophyses. The position of the ventral margin

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Figure 4. Caudal vertebrae of Eucnemesaurus fortis. Proximal caudal vertebra (BP/1/6220) in anterior (A), posterior (B), left lateral (C), dorsal (D) and ventral (E) views. F, Middle caudal vertebra (TM 119) in right lateral view. Scale bars represent 50 mm. Abbreviations: a.t, anterior tubercle; c.f, chevron facet; p.r, parasagittal ridge; s.r sagittal ridge, other abbreviations as in Figure 2.

Figure 5. Left pectoral girdle of Eucnemesaurus fortis. Ventral end of the scapula (BP/1/6114) and complete coracoid (BP/1/6113) in lateral (A), medial (B) and ventral (C) views. D, Dorsal fragment of left scapula (BP/1/6115) in lateral view. Scale bar represents 50 mm.

Abbreviations: a.f, acromial fossa; c.f, coracoid foramen; c.t, coracoid tubercle; g, glenoid; s.b, scapula blade; s.m.t, scar for scapula head of m. triceps.

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Figure 6. Pelvic and hindlimb bones of the holotype of Eucnemesaurus fortis (TM 119). Proximal end of left pubis in lateral (A) and anterior (B) views. Proximal end of left femur in lateral (C) anterior (D) and proximal (E) view. Scale bars represent 50 mm. Abbreviations: f.h, femoral head; i.a.s, ilial articular surface; l.t, lesser trochanter; o.f, obturator fenestra; p.b, pubic blade; p.t, posterior tubercle.

indicates that the size of the articular surfaces of the hyposphene would have been much smaller than the postzygapophyseal facets. Only the lower part of the neural spine is preserved but it is enough to show that the spine was a simple, transversely compressed laminar structure.

There is a posterior dorsal vertebra in the Spioenkop assemblage. It probably represents the thirteenth or fourteenth dorsal based on the position of the parapophysis. Unfortunately the prezygapophysis, postzygapophyses, diapophyses, neural spine and hyposphene have all broken off at their base. The centrum is massive, amphicoelous and lacks pleurocoels, or even pleural fossae, on each side. It is 98 mm long, which is slightly less than its maximum height of 106 mm. The anterior and posterior centrum faces are also slightly higher than they are wide. The neural arch is low with the height from the postzygapophyseal facets to the neurocentral sutures is much less than the height of the centrum. The middle and posterior chonae are impressed below the base transverse process and are separated by a well-developed posterior centrodiapophyseal lamina. The paradiapophyseal lamina is not present because the parapophysis abuts the base of the transverse process. There

is a smooth surface between the parapophysis, the base of the transverse process and the base of the prezygapophysis, which lacks both an anterior chonos and the prezygodiapophyseal lamina. A well-developed hyposphene is present below the postzygapophyseal facets and is 75% of the height of the subcircular neural canal. The base of the neural spine is anteroposteriorly elongate and transversely compressed.

Caudal vertebrae (Figure 4). A proximal caudal vertebra is present in the Spioenkop collection, while there are two proximal caudals, a middle caudal and a distal caudal present in TM 119. The Spioenkop proximal caudal (BP/1/6220) is well preserved, although it is missing the right transverse process, the dorsal tip of the neural spine and the tips of both prezygapophyses. The gently amphicoelous centrum is very slightly wedge shaped in lateral view, with a length of 75 mm at the ventral end and 80 mm dorsally. It is also taller than it is long with a maximum height of 90 mm. The mid-length cross-section is ovoid and dorso-ventrally tall, with a transversely rounded ventral surface. The central faces are also

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Figure 7. Right femoral fragments of Eucnemesaurus fortis from Spioenkop. Proximal end and mid section (BP/1/6111) in anterior (A), lateral (B), posterior (C), and medial (D), views. A, includes cross sections from the distal end of each of the two pieces. Distal end (BP/1/6110) in anterior (E), lateral (F), posterior (G), and distal (H) views. Scale bar represents 50 mm. Abbreviations: f.c, fibular condyle; f.t, fourth trochanter; g.t, greater trochanter; i.f, intercondylar fossa; l.c, lateral condyle; l.s, lateral sulcus; m.c, medial condyle, other abbreviations as in Figure 5.

dorsoventrally taller than they are wide with the anterior face being 82 mm high and 67 mm wide and the posterior face being 90 mm high and 68 mm wide.

The ventral portion of this (16 mm deep at the midline) forms a convex chevron facet that is oriented posteroventrally. The transverse processes have flatly elliptical bases that are oriented horizontally. The flattened process is backswept and slightly dorsally directed. The neural spine is a simple, transversely flattened rod. Its anteroposterior length (measured above the postzygapophyseal buttresses is more than half the length of the neural arch at its junction with the centrum. A midline keel begins at the base of the anterior margin of the neural spine and extends forwards to the interprezygapophyseal space, where it terminates in a small raised tubercle. There are shallow paramedian fossae on each side of this keel that are flanked by short, low ridges. The postzygapophyses project posterior to the neural spine and there is a small notch developed between them.

The ventral margins of the postzygapophyseal facets are separated and there is no hyposphenal ridge.

The proximal caudal from TM 119 is less completely preserved and differs only in that the anterior central face is not as strongly laterally compressed as in BP/1/6220. In the former specimen

the width of the anterior centrum face is 94% of its height while it is 82% in the former. This is probably due simply to individual variation. The other proximal caudal is from a more distal position in the tail and has a centrum that is longer than high (80 mm long and 65 mm high) The ventral surface of the centrum is broad and rounded and lacks any trace of a midline sulcus. The anterior centrum face is as wide as it is high. The anterior median ridge is poorly developed and there are no paramedian fossae or ridges. The more distal caudals do not record any significantly different features other than the reduction in the size of the neural spine and transverse processes, and the relative elongation of the centrum, although the length of the centra remain less than twice their height.

Coracoid (Figure 5). An almost complete left coracoid is preserved in the Spioenkop assemblage (BP/1/6113). It is a roughly oval plate with its long axis measuring 236 mm and oriented subparallel with the scapula suture and perpendicular to the long axis of the scapula. The anterior margin is not gently convex for its entire length but bears a shallow embayment dorsally. The plate, which is gently convex laterally and concave medially, is much thinner at the end furthest from the glenoid (the anterodorsal end).

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Figure 8. Strict consensus tree of 60 most parsimonious trees (tree length Âź 1094) produced by the analysis of 43 basal dinosaur and sauropodomorph taxa and 3 outgroup taxa. Taxon labels follow the phylogenetic taxonomy proposed in the text. Arrows represent stem-based taxa, dots represent node-based taxa.

The coracoid portion of the glenoid is a flattened oval surface that is slightly turned out so that it can be viewed laterally but not medially. The coracoid reaches its maximum mediolateral thickness of 67 mm immediately dorsal to the glenoid. A broad, indistinct, buttress supports this thickening medially and the medial opening of the coracoid foramen pierces the dorsal side of this buttress. This opening lies close to the scapula suture, whereas on the lateral side it opens closer to the centre of the bone. The scapula suture is strongly kinked on the dorsal side of the medial buttress.

At the posteroventral end of the coracoid, on the lateral side, there is a prominent laterally projecting

coracoid tubercle. The coracoid tubercle is connected to the rim of the glenoid by a low, rounded lateroventral ridge. This ridge and the medial margin of the coracoid defines a flattened, posteroventrally facing surface.

Scapula (Figure 5). A fragmentary left scapula in the Spioenkop assemblage articulates perfectly with the left coracoid, leaving no doubt that they belong to the same individual. There are two non-contacting parts: a ventral fragment (BP/1/6114) and a dorsal fragment (BP/1/6115). The ventral fragment preserves the glenoid, part of the coracoid articular surface, the base of the acromion and the base of

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the scapular blade. The glenoid is a slightly concave oval surface (78 mm long and 67 mm wide) with its transverse axis angled slightly with respect to the long axis of the scapula, so that the glenoid surface is visible laterally but not medially. A rugose patch of low ridges and striations on the posteroventral surface, adjacent to the lip of the glenoid, marks the origin of scapula head of the m. triceps. The medial side of the base of the scapula blade shows that there was no ridge or groove extending parallel to the posteroventral margin. On the lateral surface there is a broad shallow fossa, the acromial fossa, above the glenoid region. The dorsal scapula fragment is too limited to be of much value. Its width (136 mm) and the orientation of the bone fibres indicate that like most sauropodomorphs, the dorsal end was flared.

Pubis (Figures 1a, b, 6a, b). The proximal end of the left pubis is preserved in TM 119. The proximal body of the pubis, which bears the iliac articular surface dorsally, projects anterior to the plane of the pubic apron. This anterior projection creates a concave anterior margin, below the iliac articulation, when the pubis is viewed laterally. The lateral surface of the proximal body lacks a pubic tubercle. Ventral to the proximal pubic body is the base of the pubic apron.

It shows that the apron was flattened, transversely oriented and not much narrower than the distance between the iliac peduncles in anterior view. Van Hoepen (1920) also described a distal fragment of the pubis of TM 119 that could not be located. However his description makes it clear that there was a moderate distal swelling that at least as twice as thick in the anteroposterior dimension than the shaft of the apron (taken from the minimum measurement on the proximal pubic fragment).

Femur (Figures 1c, d, 6c, d, 7). The femur is the most distinctive bone of Eucnemesaurus. Unlike most other dinosaurs, except Riojasaurus (PVL 3805), a large rounded tubercle protrudes from the posterior surface of the proximal end, immediately below the proximal articular surface. This tubercle is present in TM 119 and NMW 1889-XV-39. It is present as a low mound in BP/1/6111 but its surface is abraded and the original tubercle may have been higher. The proximal surface bears a longitudinal sulcus like most other early dinosaurs. The medially projecting head is subrounded in anterior view and lacks a distinct distal edge where the ligaments of the caput femoris would have been inserted. It is oriented subhorizontally though it appears to be distally deflected in NMW 1889-XV39. The latter condition is probably the result of the medial shaft fragment being incorrectly attached to the head. The proximolateral corner of the femur is rounded in anterior view. The greater trochanter is a

low, proximodistally oriented, anteriorly projecting ridge that is located on the lateral margin of the shaft. It is set some distance from the proximal end of the bone so that its proximal end is approximately level with the distal margin of the femoral head. The tall, crest-like lesser trochanter extends parallel to the greater trochanter, and the proximodistal axis of the bone, on the anterior surface of the proximal shaft. It is situated on the lateral side of the middle of the shaft in anterior view. It does not extend as far proximal as the greater trochanter, and its proximal termination is distal to the distal margin of the femoral head. The proximal end of the crest is well-preserved in BP/1/6111 and it shows that the height of the crest decreases towards the proximal end but the termination is still abrupt as it is in TM 119. Three small, flattened spurs with a rounded profile project proximally from the proximal termination of the lesser trochanter and suggest that it was the site of a strong ligamentous attachment. The flat surface between the lesser trochanter and the greater trochanter bears no trace of a trochanteric ridge. There is no connection between the proximal portion of BP/1/6111 and the segment that bears the fourth trochanter so it is not possible to say how proximally or distally the fourth trochanter was placed. However enough of the shaft is preserved to show that the fourth trochanter cannot be brought as close to the proximal end as it is in NMW 1889-XV-39. Nevertheless the fourth trochanter itself is identical in shape to that of the Vienna specimen.

The proximal end of the trochanter is level with the medial margin of the shaft in posterior view, the proximal half of the trochanter slopes distolaterally relative to the long axis of the femoral shaft. After the midlength of the fourth trochanter its axis curves and extends approximately parallel to the long axis of the shaft. The crest also becomes thicker distal to the midlength. The profile of the fourth trochanter is rounded rather than the subrectangular shape seen in most basal sauropodomorphs, except Riojasaurus (PVL 3805). The distal end of the fourth trochanter is separated from the femoral shaft by a rounded notch.

Distal to the fourth trochanter the femoral shaft is slightly wider transversely (92 mm) than it is anteroposteriorly (83 mm) but this degree of eccentricity is below that seen in derived anchisaurs such as Antentonitrus and Melanorosaurus.

The distal end of what is very probably the same femur (BP/1/6110) was shattered into many pieces and had washed downstream a short distance. It can be assembled into a single piece that consists of the medial, lateral and fibular condyles. A large wedge of bone is missing from the intercondylar area. The medial condyle is roughly equivalent in size to the fibular Ăž lateral condyles. The distal surfaces of the medial and fibular condyles are rather flat but the medial condyle curves proximally at the posterior end so that this part of the condylar surface faces

Solving a dinosaurian puzzle posteriorly. There is no extensor depression on the anterior face of the distal end although the very distal end, immediately adjacent to the condylar surface is missing. The surface proximal to the missing wedge is broad and flattened. A limited, shallow extensor depression may well have been present at the very distal end, as it is in NMW 1889-XV-39 (Galton and Van Heerden 1998), because the anterior margin of the fibular condyle lies slightly ahead of that of the medial condyle to the same degree seen in NMW 1889-XV-39. Posteriorly there is a deep fossa between the medial and lateral condyles. The lateral condyle is small and sub triangular in distal view, with the apex pointing posterolaterally. A vague sulcus separates it from the fibular condyle. This sulcus is continuous with a deep lateral sulcus that extends proximally.

Tibia (Figures 1e, f, g, h). The tibia of TM 119 could not be located in the collections of the Transvaal Museum but it has been well illustrated by Van Hoepen (1920) and Van Heerden (1979). The following observations are based on these illustrations and the measurements given in Van Hoepen (1920). It is a stout bone where the maximum length of the proximal articular surface is 42% of the maximum length of the bone. The cnemial crest is thick and projects forward although the medial surface curves toward the lateral side. The fibular condyle is large and indistinct but is clearly centrally located so that its posterior margin is not level with the posterior end of the proximal articular surface. The distal end is transversely wider than it is anteroposteriorly long. The descending posterolateral process of the distal tibia extends laterally to draw level with the anterolateral corner of the distal tibia.

The lateral margin of this process is straight and is not bevelled or excavated as it is in Plateosauravus cullingworthi.

Comparison with contemporary taxa The unusual high diversity of sauropodomorphs in the lower Elliot Formation warrants detailed comparison between each taxon and Eucnemesaurus fortis to further test the validity of this taxon and to aid in the identification of future specimens.

Plateosauravus cullingworthi differs from Eucnemesaurus fortis in the following characteristics: absence of an accessory lamina in the middle chonos of the middle dorsal vertebrae; presence of a posteroventral ridge on the medial side of the scapula; absence of a large posterior tubercle at the proximal end of the femur; a low lesser trochanter that is wider than tall; a more distally placed fourth trochanter (first rise is 1.3 – 1.4 times the length of the femoral head from the proximal end); a longitudinally oriented fourth trochanter (not oblique) that is located away from the

11

medial edge in caudal view; presence of a bevelled embayment above the descending posterolateral process of the distal end of the tibia. If a pubic fragment that has been tentatively referred to as Plateosauravus cullingworthi, is correctly identified then this taxon further differs from Eucnemesaurus fortis in the presence of a large oval pubic tubercle on the lateral surface of the proximal end of the pubis.

Melanorosaurus readi differs in the following characteristics: absence of an accessory lamina in the middle chonos of the middle dorsal vertebrae; narrow hyposphenes that are deeper than the neural canal in the dorsal vertebrae; proximal caudal vertebrae with hyposphenal ridges and median ventral fossae; presence of a posteroventral sulcus on the medial side of the scapula; a more abbreviated femoral head; the absence of a large posterior tubercle at the proximal end of the femur; a lower lesser trochanter that is placed laterally so that it is visible in posterior view; a femoral shaft that is close to straight in anterior view; a moderately eccentric cross-section of the femoral shaft with the transverse width below the fourth trochanter exceeding the anteroposterior length; a subrectangular fourth trochanter without a distal notch; a longitudinally oriented fourth trochanter that is situated against the medial edge of the shaft in posterior view and straddles the midlength of the femur.

Blikanasaurus cromptoni differs in having a more robust tibia with a descending posterolateral flange that lies medial to the lateral margin of the bone in distal view.

Antetonitrus ingenipes differs in all of the same femoral characters that differentiate Melanorosaurus readi, as well as in the following characteristics: tall dorsal neural arches with slot-shaped neural canals; deep hyposphenes with median ventral ridges on the dorsal vertebrae; absence of an accessory lamina in the middle chonos of the middle dorsal vertebrae; a descending posterolateral flange of the distal end of the tibia that lies medial to the lateral margin of the bone in distal view.

Lastly the unnamed sauropodomorph from Nova Barletta (Yates 2003) can be distinguished from Eucnemesaurus fortis by the following characteristics: low, thick laminae in the dorsal neural arches; absence of an accessory lamina in the middle chonos of the middle dorsal vertebrae; absence of a large posterior tubercle at the proximal end of the femur; a more abbreviated femoral head; a low lesser trochanter that is wider than tall; a longitudinally oriented fourth trochanter (not oblique) that is located away from the medial edge in caudal view.

Phylogenetic analysis The sauropodomorph affinity of Eucnemesaurus fortis and its sister-group relationship with Riojasaurus

12

A. M. Yates

incertus is supported by a cladistic analysis of a matrix of 46 taxa (including 3 outgroup taxa) and 353 characters (see electronic supplemental material for the character list and character-taxon matrix). The analysis encompasses a broad range of early dinosaurs in order to avoid making an a priori decision regarding the immediate outgroup of Sauropodomorpha. Analysis of the matrix produces 60 most-parsimonious trees that are 1094 steps long. The strict consensus of the 60 fundamental trees is presented here (Figure 7) but the detailed tree description and robustness tests of the various nodes will be presented elsewhere.

Eucnemesaurus and Riojasaurus comprise the Riojasauridae in this tree. The Riojasauridae is the basal branch of a large clade containing all taxa more closely related to Neosauropoda than to Plateosaurus engelhardti. This clade conforms the phylogenetic definition of Sauropoda that is in current use, i.e. the most inclusive clade containing Saltasaurus loricatus (a neosauropod) but not Plateosaurus engelhardti (Wilson and Sereno 1998). However due to the paraphyly of the traditional prosauropod assemblage, in this analysis, and the relatively basal position of Plateosaurus engelhardti amongst that assemblage, this definition ‘captures’ a large number of taxa that have not been included in the Sauropoda before (Riojasaurus, Eucnemesaurus, Massospondylus, Coloradisaurus, Lufengosaurus, Jingshanosaurus and Yunnanosaurus) or taxa that are only rarely considered to be sauropods (Anchisaurus and Melanorosaurus). Thus the content of Sauropoda has departed radically from its original concept and it is simplest to re-define Sauropoda. I propose that Sauropoda be defined as the most inclusive clade that includes Saltasaurus loricatus but not Melanorosaurus readi. This definition is desirable because in phylogenies where the prosauropod assemblage forms a paraphyletic array, Sauropoda is still restricted to the clade of specialised gigantic quadrupeds that form the traditional Sauropoda and their closest outgroups whereas in topologies that have an inclusive, monophyletic Prosauropoda (e.g. Galton and Upchurch 2004) it makes no difference whether Plateosaurus or Melanorosaurus forms the exclusive anchor taxon. One possible objection to this definition of Sauropoda is that Melanorosaurus readi is a poorly known taxon and is likely to be quite labile in phylogenetic hypotheses.

This is no longer the case as there are several highquality specimens that can be referred to this taxon (Galton et al. 2005; Yates 2005). One of these new specimen includes a complete skull as well as an articulated manus and pes, arguably making it a better-known taxon than Saltasaurus loricatus. A new clade name is now required for the most inclusive clade containing Saltasaurus loricatus but not Plateosaurus engelhardti and I propose that it be called Massopoda tax. nov.. Note that Massopoda simply becomes a heterodefinitional synonym of Sauropoda

in phylogenies where Plateosaurus and Melanorosaurus are included in Prosauropoda.

Discussion Far from being a basal dinosaur as is usually suspected, Aliwalia rex, or rather its senior synonym Eucnemesaurus fortis, is a sauropodomorph and not a particularly basal one at that. Synapomorphies of Sauropodomorpha, or less inclusive clades, that are found in E. fortis include absence of the prezygodiapophyseal lamina and its associated anterior chonos in the middle and posterior dorsal vertebrae, stout mid-caudal vertebral centra that are less than twice as long as high (a synapomorphy of sauropodomorphs more derived than Saturnalia tupiniquim and Thecodontosaurus spp.) proximo-distal elongation of the lesser trochanter (a synapomorphy of sauropodomorphs more derived than Saturnalia tupiniquim), a concave anterior margin of the proximal pubis in lateral view (a synapomorphy of sauropodomorphs more derived than Efraasia minor), a distally notched (semi-pendant) fourth trochanter (a derived character with an ambiguous distribution that is found in Riojasauridae and Massospondylidae). In addition Eucnemesaurus fortis shares some characters uniquely with Riojasaurus incertus.

Yates (2003) proposed that an unnamed sauropodomorph specimen (BP/1/4953) from the lower Elliot Formation could represent a sister taxon of Riojasaurus incertus based on the shared derived presence of very thick and low laminae of the dorsal neural arches.

However this specimen lacks all of the femoral synapomorphies of Riojasauridae proposed in this paper while Eucnemesaurus fortis has ordinary tall, thin laminae on its dorsal neural arches. Therefore it now seems rather unlikely that BP/1/4953 shares a close relationship with Riojasaurus incertus, amongst sauropodomorphs. Given the break-up of Prosauropoda sensu Yates and Kitching (2003) in the analysis presented here, BP/1/4953 cannot be classified any further than Sauropodomorpha incertae sedis.

Galton (1985) suggested that an unusual dinosaurian femur, SMNS 51958, from the Norian of Germany belonged to the same family as ‘Aliwalia rex’. The specimen consists of a proximal end of a left femur from the Lo¨wenstein Formation ( ¼ Stubensandstein).

A close relationship between SMNS 51958 and Eucnemesaurus fortis is unlikely because they differ in a number of key points. The proximal end of the fourth trochanter is level with the base of the femoral head whereas it is far distal to this level in all Eucnemesaurus fortis specimens including NM 1886-XV-39 where the fourth trochanter is artificially placed more proximal than it should be. Furthermore the fourth trochanter lacks the rounded profile and notched distal end seen in Eucnemesaurus fortis. The lesser trochanter of SMNS

Solving a dinosaurian puzzle 51958 does not form a proximodistally elongate ridge as it does in all sauropodomorphs, except Saturnalia tupiniquim (Langer 2004b). The identity of SMNS 51958 is obscure but it can be confidently excluded from the clade of Sauropodomorpha more derived than Saturnalia tupiniquim (including Riojasauridae).

The diversity of sauropodomorphs in the lower Elliot Formation now increases to six species (Antetonitrus ingenipes, Blikanasaurus cromptoni, Melanorosaurus readi, Plateosauravus cullingworthi, Eucnemesaurus fortis and an unnamed sauropodomorph Yates 2003), making it the richest known Triassic sauropodomorph fauna. It is frustrating that the carnivores that utilised this rich resource of prey are so poorly known. Isolated teeth and undiagnostic fragments of jaws are not uncommon but no remains that can conclusively identify them even as far as the level of Dinosauria, or Rauisuchia, are known. An isolated tooth crown from the lower Elliot Formation has been referred to Theropoda (Ray and Chinsamy 2002) but the authors’ reasons for excluding this tooth from the Rauisuchia were based on comparisons with just one rauisuchid taxon, Teratosaurus, and another isolated tooth from the lower Elliot Formation that cannot be certainly identified. Furthermore the reported differences between these teeth were the greater size and subrectangular basal cross section of the putative theropod tooth. Both of these characters can vary considerably between species and along a single jaw, consequently the identification of this tooth should be considered highly suspect.

Given that Eucnemesaurus is nested deeply within Sauropodomorpha, it is extremely unlikely that the maxilla tentatively referred to as Aliwalia rex by Galton and Van Heerden (1998) belongs to Eucnemesaurus fortis and the specimen is hereby removed from the hypodigm of that species. Like other fossils of carnivorous reptiles from the lower Elliot Formation, all that can be said of it is that it belongs to a moderately large archosaur.

Acknowledgements Emese Bordy, John Hancox and Paul Dirks found the new Eucnemesaurus specimen while Pepson Mukanela and Doctor Mbense prepared some of the bones. I thank Naude Bremmer and Cobus Visser for allowing us to collect on Spioenkop and for their hospitality during our stay. Deigo Pol and Peter Galton are thanked for their review of the manuscript and their useful comments. I thank Francis Thackeray for access to specimens in the Transvaal Museum. Travel to China for the coding of Chinese taxa used in the phylogenetic analysis was supported by P.A.S.T.

13

References Broom R. 1911. On the dinosaurs of the Stormberg, South Africa.

Ann South African Mus 7:291–308.

Cooper MR. 1980. The first record of the prosauropod dinosaur Euskelosaurus from Zimbabwe. Arnoldia 9:1–17.

Galton PM, Van Heerden J. 1998. Anatomy of the prosauropod dinosaur Blikanasaurus cromptoni (Upper Triassic, South Africa), with notes on other tetrapods from the lower Elliot Formation.

Pala¨ontologische Z 72:163–177.

Galton PM. 1985. The poposaurid thecodontian Teratosaurus suevicus v. Meyer, plus referred specimens mostly based on prosauropod dinosaurs, from the Middle Stubensandstein (Upper Triassic) of Nordwu¨rttemberg. Stuttgart Beitra¨ge zur Naturkunde (B) 116:1–29.

Galton PM, Upchurch P. 2004. Prosauropoda. In: Weishampel DB, Dodson P, Osmo´lska H, editors. The dinosauria. 2nd ed., Berkeley: University of California Press. p 232– 258.

Galton PM, Van Heerden J, Yates AM. 2005. Postcranial anatomy of referred specimens of Melanorosaurus from the Upper Triassic of South Africa. In: Tidwell V, Carpenter K, editors. Thunderlizards. The sauropodomorph dinosaurs. Bloomington: Indiana University Press. p 1 –37.

Huene F von. 1906. Ueber die Dinosaurier der aussereuropa¨ischen Trias. Geol Palaeontologische Abh 8:99–156.

Huxley TH. 1866. On the remains of large dinosaurian reptiles from the Stormberg Mountains, South Africa. Geol Mag 3:563.

Langer MC. 2004a. Basal saurischians. In: Weishampel DB, Dodson P, Osmo´lska H, editors. The dinosauria. 2nd ed.

Berkeley: University of California Press. p 25–46.

Langer MC. 2004b. The pelvic and hindlimb anatomy of the stemsauropodomorph Saturnalia tupiniquim (Late Triassic, Brazil).

Paleobios 23:1–40.

Novas FE. 1996. Dinosaur monophyly. J Vert Paleontol 16:723–741.

Paul GS. 1988. Predatory dinosaurs of the world. New York: Simon and Schuster.

Ray S, Chinsamy A. 2002. A theropod tooth from the Late Triassic of southern Africa. J Biosci 27:295–298.

Seeley HG. 1894. On Euskelosaurus brownii (Huxley). Ann Mag bof Nat Hist 14:317–340.

Sues H-D. 1990. Staurikosaurus and Herrerasauridae. In: Weishampel DB, Dodson P, Osmo´lska H, editors. The dinosauria.

Berkeley: University of California Press. p 143– 147.

Van Heerden J. 1979. The morphology and taxonomy of Euskelosaurus (Reptilia: Saurischia; Late Triassic) from South Africa. Navorsinge Van Die Nasionale Mus 4:21 –84.

Van Hoepen ECN. 1920. Contributions to the knowledge of the reptiles of the Karroo Formation. 6. Further dinosaurian material in the Transvaal Museum. Ann Transvaal Mus 7:7–140.

Wilson JA, Sereno PC. 1998. Early evolution and higher-level phylogeny of sauropod dinosaurs. Soc Vert Paleontol Memoirs 5:1–68.

Yates AM, Kitching JW. 2003. The earliest known sauropod dinosaur and the first steps towards sauropod locomotion. Proc R Soc Lond B 270:1753–1758.

Yates AM. 2003. A definite prosauropod dinosaur from the lower Elliot Formation (Norian: Upper Triassic) of South Africa.

Palaeontologia africana 39:63–68.

Yates AM. 2005. The skull of the Triassic sauropodomorph Melanorosaurus readi from South Africa and the definition of Sauropoda. J Vert Paleontol 25 (supplement to 3):132A.

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Character List 1. Skull to femur ratio: greater than (0), or less than (1), 0.6 (modified from Gauthier 1986).

2. Lateral plates appressed to the labial side of the premaxillary, maxillary and dentary teeth: absent (0) or present (1) (Upchurch 1995).

3. Relative height of the rostrum at the posterior margin of the naris: more than (0), or less than (1), 0.6 of the height of the skull at the middle of the orbit (Langer 2004).

4. Foramen in the middle of the lateral surface of the premaxillary body: absent (0), or present (1).

5. Distal end of the dorsal premaxillary process: tapered (0) or transversely expanded (1) (Sereno 1999).

6. Profile of premaxilla: convex (0) or with an inflection at the base of the dorsal process (1) (Upchurch 1995).

7. Size and position of the posterolateral process of premaxilla: large and lateral to the anterior process of the maxilla (0) or small and medial to the anterior process of the maxilla (1).

8. Relationship between posterolateral process of the premaxilla and the anteroventral process of the nasal: broad sutured contact (0), point contact (1) or separated by maxilla (2) (modified from Gauthier 1986). Ordered.

9. Posteromedial process of the premaxilla: absent (0) or present (1) (Rauhut 2003).

10. Shape of the anteromedial process of the maxilla: narrow, elongated and projecting anterior to lateral premaxilla-maxilla suture (0), short, broad and level with lateral premaxilla-maxilla suture (1).

11. Development of external narial fossa: absent to weak (0) or well developed with sharp posterior and anteroventral rims (1).

12. Size and position of subnarial foramen: absent (0), small (no larger than adjacent maxillary neurovascular foramina) and positioned outside of narial fossa (1), or large and on the rim of, or inside, the narial fossa (2) (modified from Sereno et al. 1993). Ordered.

13. Shape of subnarial foramen: rounded (0) or slotshaped (1).

14. Maxillary contribution to the margin of the narial fossa: absent (0) or present (1).

15. Diameter of external naris: less than (0), or greater than (1), 0.5 of the orbital diameter (Wilson and Sereno 1998).

16. Shape of the external naris (in adults): rounded (0) or subtriangular with an acute posteroventral corner (1) (Galton and Upchurch 2004).

17. Level of the anterior margin of the external naris: anterior to (0), or posterior to (1), the midlength of the premaxillary body (Rauhut 2003).

18. Level of the posterior margin of external naris: anterior to, or level with the premaxilla-maxilla suture (0), posterior to the first maxillary alveolus (1) or posterior to the midlength of the maxillary tooth row and the anterior margin of the antorbital fenestra (2) (modified from Wilson and Sereno 1998). Ordered.

19. Dorsal profile of the snout: straight to gently convex (0) or with a depression behind the naris (1).

20. Elongate median nasal depression: absent (0) or present (1) (Sereno 1999).

21. Width of anteroventral process of nasal at its base: less than (0) or greater than (1) width of anterodorsal process at its base (modified from Sereno 1999).

22. Nasal relationship with dorsal margin of antorbital fossa: not contributing to the margin of the anorbital fossa (0), lateral margin overhangs the antorbital fossa and forms its dorsal margin (1), overhang extensive, obscuring the dorsal lacrimal-maxilla contact in lateral view (2) (modified from Sereno 1999).

23. Pointed caudolateral process of the nasal overlapping the lacrimal: absent (0) or present (1) (Sereno 1999).

24. Anterior profile of the maxilla: slopes continuously towards the rostral tip (0) or with a strong inflection at the base of the ascending ramus, creating a rostral ramus with parallel dorsal and ventral margins (1) (Sereno et al. 1996).

25. Length of rostral ramus of the maxilla: less than (0), or greater than (1), its dorsoventral depth (Sereno et al. 1996).

26. Shape of the main body of the maxilla: tapering posteriorly (0) or dorsal and ventral margins parallel for most of their length (1).

27. Shape of the ascending ramus of the maxilla in lateral view: tapering dorsally (0) or with an anteroposterior expansion at the dorsal end (1) 28. Rostrocaudal length of the antorbital fossa: greater (0), or less (1), than that of the orbit (Yates 2003a).

29. Posteroventral extent of medial wall of antorbital fossa: reaching (0), or terminating anterior to (1), the anterior tip of the jugal (modified from Galton and Upchuch 2004).

30. Development of the antorbital fossa on the ascending ramus of the maxilla: deeply impressed and delimited by a sharp, scarp-like rim (0), weakly impressed and delimited by a rounded rim or a change in slope (1).

31. Shape of the rostral margin of the antorbital fenestra: strongly concave, roughly parallel to the rostral margin of the antorbital fossa, creating a narrow antorbital fossa (0) or straight to gently concave creating a broad, subtriangular antorbital fossa (1) (Galton 1985a).

Solving a dinosaurian puzzle 32. Size of the neurovascular foramen at the caudal end of the lateral maxillary row: not larger than the others (0) or distinctly larger than the others in the row (1) (Yates 2003a).

33. Direction that the neurovascular foramen at the caudal end of the lateral maxillary row opens: caudally (0), rostrally, ventrally or laterally (1) (modified from Sereno 1999).

34. Arrangement of lateral maxillary neurovascular foramina: linear (0) or irregular (1) (modified from Sereno 1999).

35. Dorsal exposure of the lacrimal: present (0) or absent (1) (Gauthier 1986).

36. Shape of the lacrimal: dorsoventrally short and block-shaped (0) or dorsoventrally elongate and shaped like an inverted ‘L’(1) (Rauhut 2003).

37. Orientation of the lacrimal orbital margin: strongly sloping anterodorsally (0) or erect and close to vertical (1).

38. Length of the anterior ramus of the lacrimal: greater than (0), or less than (1), half the length of the ventral ramus, or absent altogether (2) (modified from Galton 1990). Ordered.

39. Web of bone spanning junction between anterior and ventral rami of lacrimal: absent and antorbital fossa laterally exposed (0) or present, obscuring posterodorsal corner of antorbital fossa (1).

40. Extension of the antorbital fossa onto the ventral end of the lacrimal: present (0) or absent (1) (modified from Wilson and Sereno 1998).

41. Length of the caudal process of the prefrontal: short (0), or elongated (1), so that total prefrontal length is equal to the rostrocaudal diameter of the orbit (Galton 1985a).

42. Ventral process of prefrontal extending down the posteromedial side of the lacrimal: present (0) or absent (1) (Wilson and Sereno 1998).

43. Maximum transverse width of the prefrontal: less than (0), or more than (1), 0.25 of the skull width at that level (modified from Galton 1990).

44. Shape of the orbit: subcircular (0) or ventrally constricted making the orbit subtriangular (1) (Wilson and Sereno 1998).

45. Slender anterior process of the frontal intruding between the prefrontal and the nasal: absent (0) or present (1) (modified from Sereno 1999).

46. Jugal-lacrimal relationship: lacrimal overlapping lateral surface of jugal or abutting it dorsally (0), or jugal overlapping lacrimal laterally (1) (Sereno et al. 1993).

47. Shape of the suborbital region of the jugal: an anteroposteriorly elongate bar (0) or an anteroposteriorly shortened plate (1).

48. Jugal contribution to the antorbital fenestra: absent (0) or present (1) (Holtz 1994).

49. Dorsal process of the anterior jugal: present (0) or absent (1) (modified from Rauhut 2003).

15

50. Ratio of the minimum depth of the jugal below the orbit to the distance between the rostral end of the jugal and the rostroventral corner of the lower temporal fenestra: less than (0), or greater than (1), 0.2 (modified from Galton 1985a).

51. Transverse width of the ventral ramus of the postorbital: less than (0), or greater than (1), its rostrocaudal width at mid shaft (Wilson and Sereno 1998).

52. Shape of the dorsal margin of postorbital in lateral view: straight to gently curved (0) or with a distinct embayment between the anterior and posterior dorsal processes (1).

53. Height of the postorbital rim of the orbit: flush with the posterior lateral process of the postorbital (0) or raised so that it projects laterally to the posterior dorsal process (1).

54. Postfrontal bone: present (0) absent (1) (Sereno et al. 1993).

55. Position of the rostral margin of the lower temporal fenestra: behind the orbit (0), extends under the rear half of the orbit (1) or extends as far forward as the midlength of the orbit (2) (modified from Upchurch 1995). Ordered.

56. Frontal contribution to the supratemporal fenestra: present (0) or absent (1) (modified from Gauthier 1986).

57. Orientation of the long axis of the supratemporal fenestra: longitudinal (0) or transverse (1) (Wilson and Sereno 1998).

58. Medial margin of supratemporal fossa: simple smooth curve (0) or with a projection at the frontal/postorbital-parietal suture producing a scalloped margin (1) (Leal et al. 2004).

59. Length of the quadratojugal ramus of the squamosal relative to the width at its base: less than (0) or greater than (1) four times its width (Sereno 1999).

60. Proportion of lower temporal fenestra bordered by squamosal: more than (0), or less than (1), 0.5 of the depth of the lower temporal fenestra.

61. Squamosal-quadratojugal contact: present (0) or absent (1) (Gauthier 1986).

62. Angle of divergence between jugal and squamosal rami of quadratojugal: close to 908 (0) or close to parallel (1).

63. Length of jugal ramus of quadratojugal: no longer than (0), or longer than (1), the squamosal ramus (Wilson and Sereno 1998).

64. Shape of the rostral end of the jugal ramus of the quadratojugal: tapered (0) or dorsoventrally expanded (1) (Wilson and Sereno 1998).

65. Relationship of quadratojugal to jugal: jugal overlaps the lateral surface of the quadratojugal (0), quadratojugal overlaps the lateral surface of the jugal (1), or quadratojugal sutures along the ventrolateral margin of the jugal (2).

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A. M. Yates

66. Position of the quadrate foramen: on the quadrate-quadratojugal suture (0) or deeply incised into, and partly encircled by, the quadrate (1) (Rauhut 2003).

67. Shape of posterolateral margin of quadrate: sloping anterolaterally from posteromedial ridge (0), everted posteriorly creating a posteriorly facing fossa (1), posterior fossa deeply excavated, invading quadrate body (2) (Wilson and Sereno 1998). Ordered.

68. Exposure of the lateral surface of the quadrate head: absent, covered by lateral sheet of the squamosal (0) or present (1) (Sereno et al.

1993).

69. Proportion of the length of the quadrate that is occupied by the pterygoid wing: at least 70% (0) or greater than 70% (1) (Yates 2003a).

70. Depth of the occipital wing of the parietal: less than (0), or more than 1.5 (1) times the depth of the foramen magnum (Wilson and Sereno 1998).

71. Position of vena capitis foramina on occiput: between supraoccipital and parietal (0) or on the supraoccipital (1).

72. Dorsal fenestra between supraoccipital and parietals: absent (0) or present (1).

73. Shape of the supraoccipital: diamond-shaped, at least as high as wide (0), or semilunate and wider than high (1) (Yates 2003b).

74. Orientation of the supraoccipital plate: erect to gently sloping (0) or strongly sloping forward so that the dorsal tip lies level with the basipterygoid processes (1) (Galton and Upchurch 2004).

75. Orientation of the paroccipital processes: slightly dorsolaterally directed to horizontal (0), or ventrolaterally directed (1) in occipital view (Rauhut 2003).

76. Size of the posttemporal fenestra: large fenestra (0) small hole that is no larger than any of the foramina for the cranial nerves (1).

77. Exit of the mid-cerebral vein: through trigeminal foramen (0) or through a separate foramen anterodorsal to trigeminal foramen (1) (Rauhut 2003).

78. Shape of the floor of the braincase in lateral view: relatively straight with the basal tuberae, basipterygoid processes and parasphenoid rostrum roughly aligned (0), bent with the basipterygoid processes and the parasphenoid rostrum below the level of the basioccipital condyle and the basal tuberae (1) or bent with the basal tuberae lowered below the level of the basioccipital and the parasphenoid rostrum raised above it (2) (modified from Galton 1990). Unordered.

79. Shape of basal tuberae: knob-like, with basispenoidal component rostral to basioccipital component (0), or forming a transverse ridge

80.

81.

82.

83.

84.

85.

86.

87.

88.

89.

90.

91.

92.

93.

94.

95.

with the basisphenoidal component lateral to the basioccipital component (1).

Length of the basipterygoid processes (from the top of the parasphenoid to the tip of the process): less than (0), or greater than (1), the height of the braincase (from the top of the parasphenoid to the top of the supraoccipital) (Benton et al. 2000).

Ridge formed along the junction of the parabasisphenoid and the basioccipital, between the basal tuberae: present with a smooth rostral face (0), present with a median fossa on the rostral face (1), or absent with the basal tuberae being separated by a deep caudally opening U-shaped fossa (2).

Unordered.

Deep septum spanning the interbasipterygoid space: absent (0) or present (1) (Galton 1990).

Dorsoventral depth of the parashenoid rostrum: much less than (0) or about equal to the transverse width (1) (Yates 2003a).

Shape of jugal process of ectopterygoid: gently curved (0) or strongly recurved and hook-like (1) (Yates 2003a).

Pneumatic fossa on the ventral surface of the ectopterygoid: present (0) or absent (1) (Sereno et al. 1996).

Relationship of the ectopterygoid to the pterygoid: ectopterygoid overlapping the ventral (0), or dorsal (1), surface of the pterygoid (Sereno et al.

1993).

Position of the maxillary articular surface of the palatine: along the lateral margin of the bone (0) or at the end of a narrow anterolateral process (1) (Wilson and Sereno 1998).

Centrally located tubercle on the ventral surface of palatine: absent (0) or present (1).

Medial process of the pterygoid forming a hook around the basipterygoid process: absent (0), flat and blunt-ended (1) or bent upwards and pointed (2) (modified from Wilson and Sereno 1998). Ordered.

Length of the vomers: less than (0), or more than (1), 0.25 of the total skull length.

Position of jaw joint: no lower than the level of the dorsal margin of the dentary (0) or depressed well below this level (1) (Sereno 1999).

Shape of upper jaws in ventral view: narrow with an acute rostral apex (0) or broad and U-shaped (1) (Wilson and Sereno 1998).

Length of the external mandibular fenestra: more than (0), or less than (1), 0.1 of the length of the mandible.

Caudal end of dentary tooth row medially inset with a thick lateral ridge on the dentary forming a buccal emargination: absent (0) or present (1) (Gauthier 1986).

Height: length ratio of the dentary: less than (0), or greater than (1), 0.2 (modified from Benton et al. 2000).

Solving a dinosaurian puzzle 96. Orientation of the symphyseal end of the dentary: in line with the long axis of the dentary (0) or strongly curved ventrally (1) (Sereno 1999).

97. Position of first dentary tooth: adjacent to symphysis (0) or inset one tooth’s width from the symphysis (1) (Sereno 1999).

98. Dorsoventral expansion at the symphyseal end of the dentary: absent (0) or present (1) (Wilson and Sereno 1998).

99. Splenial foramen: absent (0), present and enclosed (1), or present and open anteriorly (2) (Rauhut 2003). Ordered.

100. Splenial-angular joint: flattened sutured contact (0), synovial joint surface between tongue-like process of angular fitting in groove of the splenial (1) (Sereno et al. 1993).

101. A stout, triangular, medial process of the articular, behind the glenoid: present (0) or absent (1) (Yates 2003a).

102. Length of the retroarticular process: less than (0), or greater than (1), than the depth of the mandible below the glenoid (Yates 2003a).

103. Strong medial embayment behind glenoid of the articular in dorsal view: absent (0), or present (1) (Yates and Kitching 2003).

104. Number of premaxillary teeth: four (0) or more than four (1) (Galton 1990).

105. Number of dentary teeth (in adults): less than 18 (0), 18 or more (1) (modified from Wilson and Sereno 1998).

106. Arrangement of teeth within the jaws: linearly placed, crowns not overlapping (0), or imbricated with distal side of tooth overlapping mesial side of the succeeding tooth (1).

107. Orientation of the maxillary tooth crowns: erect (0) or procumbent (1) (modified Gauthier 1986).

108. Orientation of the dentary tooth crowns: erect (0) or procumbent (1) (modified Gauthier 1986).

109. Teeth with basally constricted crowns: absent (0) or present (1) (Gauthier 1986).

110. Tooth – tooth occlusal wear facets: absent (0) or present (1) (Wilson and Sereno 1998).

111. Mesial and distal serrations of the teeth: fine and set at right angles to the margin of the tooth (0) or coarse and angled upwards at an angle of 458 to the margin of the tooth (1) (Benton et al.

2000).

112. Distribution of serrations on the maxillary and dentary teeth: present on both the mesial and distal carinae (0), absent on the posterior carinae (1), absent on both carinae (2) (Wilson 2002).

Unordered.

113. Long axis of the tooth crowns distally recurved: present (0) or absent (1) (Gauthier 1986).

114. Texture of the enamel surface: entirely smooth (0), finely wrinkled in some patches (1), or

115.

116.

117.

118.

119.

120.

121.

122.

123.

124.

125.

126.

127.

128.

129.

130.

131.

17

extensively and coarsely wrinkled (2) (modified from Wilson and Sereno 1998).

Lingual concavities of the teeth: absent (0) or present (1) (Upchurch 1995).

Longitudinal labial grooves on the teeth: absent (0) or present (1) (Upchurch 1998).

Distribution of the serrations along the mesial and distal carinae of the tooth: extend along most of the length of the crown (0) or are restricted to the upper half of the crown (1) (Yates 2003a).

Number of cervical vertebrae: 8 or fewer (0), 9 to 10 (1), 12 – 13 (2) or more than 13 (3) (modified from Wilson and Sereno 1998). Ordered.

Shallow, dorsally facing fossa on the atlantal neurapophysis bordered by a dorsally everted lateral margin: absent (0) or present (1) (Yates and Kitching 2003).

Width of axial intercentrum: less than (0), or greater than (1), width of axial centrum (Sereno 1999).

Position of axial prezgapophyses: on the anterolateral surface of the neural arch (0) or mounted on anteriorly projecting pedicels (1).

Posterior margin of the axial postzygapophyses: overhang the axial centrum (0) or are flush with the caudal face of the axial centrum (1) (Sereno 1999).

Length of the axial centrum: less than (0), or at least (1), 3 times the height of the centrum.

Length of the anterior cervical centra (ce 3 – 5): no more than (0), or greater than (1), the length of the axial centrum.

Length of middle to posterior cervical centra (ce 6 – 8): no more than (0), or greater than (1), the length of the axial centrum.

Dorsal excavation of the cervical parapophyses: absent (0) or present (1) (Upchurch 1998).

Lateral compression of the anterior cervical vertebrae: centra are no higher than they are wide (0) or are approximately 1.25 times higher than wide (1) (Upchurch 1998).

Relative elongation of the anterior cervical centra (ce 3– 5): lengths of the centra are less than 2.5 times the height of their anterior faces (0), lengths are between 2.5 and 4 times the height of their anterior faces (1) or the length of at least ce 4 or 5 exceed 4 times the anterior centrum height (2) (modified from Sereno 1999).

Ordered.

Ventral keels on cranial cervical centra: present (0) or absent (1) (modified from Upchurch 1998).

Height of the mid cervical neural arches: no more than (0), or greater than (1), height of the posterior centrum face.

Cervical epipophyses on the dorsal surface of the postzygapophyses: absent (0), or present (1), on at least some cervical vertebrae.

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A. M. Yates

132. Caudal ends of cranial, postaxial epipophyses: with a free pointed tip (0) or joined to the postzygapophysis along their entire length (1).

133. Shape of the epipophyses: tall ridges (0) or flattened, horizontal plates (1) (Yates 2003a).

134. Epipophyses overhanging the rear margin of the postzygapophyses: absent (0), or present (1), in at least some postaxial cervical vertebrae (Sereno et al. 1993).

135. Anterior spur-like projections on mid-cervical neural spines: absent (0) or present (1).

136. Shape of mid-cervical neural spines: less than (0), or at least (1), twice as long as high.

137. Shape of cervical rib shafts: short and posteroventrally directed (0) or longer than the length of their centra and extending parallel to cervical column (1) (Sereno 1999).

138. Position of the base of the cervical rib shaft: level with, or higher than the ventral margin of the cervical centrum (0) or located below the ventral margin due to a ventrally extended parapophysis (1) (Wilson and Sereno 1998).

139. Postzygadiapophyseal lamina in cervical neural arches 4 – 8: present (0) or absent (1) (Yates 2003a).

140. Laminae of the cervical neural arches 4 to 8: well developed tall laminae (0) or weakly developed low ridges (1) (Wilson and Sereno 1998).

141. Shape of anterior centrum face in cervical centra: concave (0), flat (1) or convex (2) (modified from Gauthier 1986). Ordered.

142. Ventral surface of the centra in the cervico-dorsal transition: transversely rounded (0) or with longitudinal keels (1) (Rauhut 2003).

143. Number of vertebrae between cervicodorsal transition and primordial sacral vertebrae: 15 to 16 (0) or no more than 14 (1) (modified from Wilson and Sereno 1998).

144. Lateral surfaces of the dorsal centra: with at most a vague, shallow depressions (0), with deep fossae that approach the midline (1) or with invasive, sharp-rimmed pleurocoels (2) (Gauthier 1986). Ordered.

145. Oblique ridge dividing pleural fossa of cervical vertebrae: absent (0) or present (1) (Wilson and Sereno 1998).

146. Laterally expanded tables at the midlength of the dorsal surface of the neural spines: absent in all vertebrae (0), present on the pectoral vertebrae (1) or present on the pectoral and cervical vertebrae (2) (Yates and Kitching 2003).

Ordered.

147. Dorsal centra: entirely amphicoelous to amphiplatyan (0) first two dorsals are opisthocoelous (1), or cranial half of dorsal column is opisthocoelous (2) (Wilson and Sereno 1998).

Ordered.

148. Shape of the posterior dorsal centra: relatively elongated for their size (0) strongly axially compressed for their size (1) (modified from Novas 1993).

Various authors have noted that the posterior dorsal vertebrae of some dinosaur taxa, notably Herrerasaurus, are much shorter, than they are tall. This is contrast to the condition in basal dinosauromorphs (e.g. Marasuchus lilloensis) and most basal dinosaurs (e.g. Lesothosaurus diagnosticus; Dilophosaurus wetherilli; Thecodontosaurus antiquus). Thus the shortening of the posterior dorsal vertebral centra, so that the length:height ratio is less than 1.0 has been used as a character in several cladistic analyses. Conversely some analyses take a roughly equant centrum to be the primitive condition and describe the elongation of the posterior dorsal centra as derived.

Regardless of the polarity of this character, these analyses fail to take into account the allometric changes that occur in the posterior dorsal centra with increasing body size. If the length of the posterior dorsal centra of various sized basal sauropodomorphs are plotted against their elongation index (EI Ÿ centrum length/ posterior centrum height) we can see that they plot close to a line with a negative slope. The very largest basal sauropodomorphs have short posterior dorsal vertebrae with EI’s of less than 1 where as small ones approach 1.5. So it would seem that EI is dependant upon size and that simple variation in EI should not be used to discriminate different evolutionary states. However it is clear that there is variation amongst the EI of dinosauromorphs that cannot be accounted for by size alone. When a range of dinosauromorphs are added to the plot, most form a linear cloud that is centred upon the regression line for the basal sauropodomorph data. Early neotheropods like Lilliensternus and Dilophosaurus tend to plot above the line, indicating that they have slightly elongated vertebrae, for their size, compared to other early dinosauromorphs. However this variation is not pronounced, as they still fall within the bounds of the main cloud and either reflect a derived condition within Neotheropoda or a synapomorphy of the group. In either case this variation is not parsimony informative for the present analysis and it is ignored. On the other hand, Herrerasaurus and Staurikosaurus plot well below the main dinosauromorph cloud and are separated by a distinct gap in morphospace.

There it is clear that, for their size they have posterior dorsal centra that are markedly compressed in the anteroposterior dimension and they are coded as having a different character state from other dinosauromorphs.

Solving a dinosaurian puzzle 149. Laminae bounding triangular infradiapophyseal fossae (chonae) on dorsal neural arches: absent (0) or present (1) (Wilson 1999).

150. Location of parapophysis in first two dorsals: at the anterior end of the centrum (0), or located at the midlength of the centrum, within the middle chonos (1).

151. Parapophyses of the dorsal column completely shift from the centrum to the neural arch: anterior (0), or posterior (1) to the 13th presacral vertebra (Langer 2004).

152. Orientation of the transverse processes of the dorsal vertebrae: most horizontally directed (0) or all upwardly directed (1) (Upchurch 1998).

153. Contribution of the paradiapophyseal lamina to the margin of the anterior chonos in mid dorsal vertebrae: present (0) or prevented by high placement of parapophysis.

154. Hyposphenes in the dorsal vertebrae: absent (0), present but less than the height of the neural canal (1), or present and equal to the height of the neural canal (2) (modified from Gauthier 1986). Ordered.

155. Prezygadiapophyseal lamina and associated anterior triangular fossa (chonos): present on all dorsals (0) or absent in mid dorsals (1) (Yates 2003a).

156. Anterior centroparapophyseal lamina in dorsal vertebrae: absent (0) or present (1) (Wilson 2002).

157. Prezygaparapophyseal lamina in dorsal vertebrae: absent (0) or present (1).

158. Accessory lamina dividing posterior chonos from postzygapophysis: absent (0) or present (1).

159. Lateral pneumatic fenestra in middle chonos of middle and posterior dorsal vertebrae opening into neural cavity: absent (0) or present (1) (Wilson and Sereno 1998).

160. Separation of lateral surfaces of anterior dorsal neural arches under transverse processes: widely spaced (0) or only separated by a thin midline septum (1) (Upchurch et al. 2004).

161. Height of dorsal neural arches, from neurocentral suture to level of zygapophyseal facets: much less than (0), subequal to, or greater than (1), height of centrum.

162. Height of the dorsal neural spines: greater than (0), or less than (1), 1.5 times the length of the base of the spine (modified from Bonaparte 1986).

163. Shape of posterior dorsal neural canal: subcircular (0) or slit-shaped (1) (Wilson and Sereno 1998).

164. Height of middle dorsal neural spines: less than the length of the base (0), higher than the length of the base but less than 1.5 times the length of the base (1) or greater than 1.5 times the length of the base (2).

19

165. Shape of anterior dorsal neural spines: lateral margins parallel in anterior view (0) or transversely expanding towards dorsal end (1).

166. Cross sectional shaped of dorsal neural spines: transversely compressed (0), broad and triangular (1) or square-shaped in posterior vertebrae (2) (modified from Bonaparte 1986).

167. Spinodiapophyseal lamina on dorsal vertebrae: absent (0), present and separated from spinopostzygapophyseal lamina (1) or present and joining spinopostzygapophyseal lamina to create a composite posterolateral spinal lamina (Wilson and Sereno 1998).

168. Well developed, sheet-like suprapostzygapophyseal laminae: absent (0), present on at least the caudal dorsal vertebrae (1) (Bonaparte 1986).

169. Shape of the spinopostzygapophyseal lamina in middle and posterior dorsal vertebrae: singular (0) or bifurcated at its distal end (1) (Wilson 2002).

170. Shape of posterior margin of middle dorsal neural spines in lateral view: approximately straight (0) or concave with a projecting posterodorsal corner (1) (Yates 2003c).

171. Transversely expanded plate-like summits of posterior dorsal neural spines: absent (0), or present (1) (Novas 1993).

172. Last presacral rib: free (0) or fused to vertebra (1).

173. Sacral rib much narrower than the transverse process of the first primordial sacral vertebra (and dorso-sacral if present) in dorsal view: absent (0) or present (1) (Yates and Kitching 2003).

174. Number of dorsosacral vertebrae: none (0), one (1) or two (2) (modified Gauthier 1986).

175. Caudosacral vertebra: absent (0) or present (1) (Galton and Upchurch 2004).

176. Shape of the iliac articular facets of the first primordial sacral rib: singular (0) or divided into dorsal and ventral facets separated by a nonarticulating gap (1).

177. Depth of the iliac articular surface of the primordial sacrals: less than (0), or greater than (1), 0.75 of the depth of the ilium (modified from Novas, 1992).

178. Sacral ribs contributing to the rim of the acetabulum: absent (0) or present (1) (Wilson 2002).

179. Posterior and anterior expansion of the transverse processes of the first and second primordial sacral vertebrae, respectively, partly roofing the intercostals space: absent (0) or present (1) (Langer 2004).

180. Length of first caudal centrum: greater than (0), or less than (1), its height (Yates 2003a).

181. Length of base of the proximal caudal neural spines: less than (0), or greater than (1), half the length of the neural arch (Gauthier 1986).

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A. M. Yates

182. Position of postzygapophyses in proximal caudal vertebrae: protruding with an interpostzygapophyseal notch visible in dorsal view (0) or placed on either side of the caudal end of the base of the neural spine without any interpostzygapophyseal notch (1) (Yates 2003a).

183. A hyposphenal ridge on caudal vertebrae: absent (0) or present (1) (Upchurch 1995).

184. Depth of the bases of the proximal caudal transverse processes: shallow, restricted to the neural arches (0), deep extending from the centrum to the neural arch (1) (Upchurch 1998).

185. Position of last caudal vertebra with a protruding transverse process: distal (0) or proximal (1) to caudal 16 (Wilson 2002).

186. Orientation of posterior margin of proximal caudal neural spines: sloping posterodorsally (0) or vertical (1) (Novas, 1992).

187. Longitudinal ventral sulcus on proximal and middle caudal vertebrae: present (0) or absent (1) (modified from Upchurch 1995).

188. Length of midcaudal centra: greater than (0), or less than (1), twice the height of their anterior faces (Yates 2003a).

189. Cross-sectional shape of the distal caudal centra: oval with rounded lateral and ventral sides (0) or square-shaped with flattened lateral and ventral sides (1).

190. Length of distal caudal prezygapophyses: short, not overlapping the preceding centrum by more than a quarter (0) or long and overlapping the preceding the centrum by more than a quarter (Gauthier 1986).

191. Shape of the terminal caudal vertebrae: unfused, size decreasing toward tip (0) or expanded and fused to form a club-shaped tail (1) (Upchurch 1995).

192. Length of the longest chevron: is less than (0), or greater than (1), twice the length of the preceding centrum (modified from Yates 2003a).

193. Anteroventral process on distal chevrons: absent (0) or present (1) (Upchurch 1995).

194. Midcaudal chevrons with a ventral slit: absent (0) or present (1) (Upchurch 1995).

195. Longitudinal ridge on the dorsal surface of the sternal plate: absent (0) or present (1) (Upchurch 1998).

196. Craniocaudal length of the acromion process of the scapula: less than (0), or greater than (1), one and a half times the minimum width of the scapula blade (Wilson and Sereno 1998).

197. Minimum width of the scapula: is less than (0), or greater than (1), 20% of its length (Gauthier 1986).

198. Caudal margin of the acromion process of the scapula: rises from the blade at angle that is less than (0), or greater than (1), 658 from the long

199.

200.

201.

202.

203.

204.

205.

206.

207.

208.

209.

210.

211.

212.

213.

214.

215.

216.

217.

axis of the scapula, at its steepest point (modified from Novas, 1992).

Flat caudoventrally facing surface on the coracoid between glenoid and coracoid tubercle: absent (0) or present (1) (Yates and Kitching 2003).

Coracoid tubercle: present (0) or absent (1) (modified from Pe´rez-Moreno et al. 1994).

Length of the humerus: less than 55% (0), 55 – 65% (1), 65 – 70% (2), or more than 70% (3), of the length of the femur (modified from Gauthier 1986). Ordered.

Shape of the deltopectoral crest: subtriangular (0) or subrectangular (1) (Gauthier 1986).

Length of the deltopectoral crest of the humerus: less than 30% (0), 30 –50% (1), or greater than 50% (2), of the length of the humerus (modified from Sereno et al. 1993). Ordered.

Shape of the anterolateral margin of the deltopectoral crest of the humerus: straight (0) or strongly sinuous (1) (Yates 2003a).

Rugose pit centrally located on the lateral surface of the deltopectoral crest: absent (0) or present (1).

Well-defined fossa on the distal flexor surface of the humerus: present (0) or absent (1) (Yates and Kitching 2003).

Transverse width of the distal humerus: is less than (0), or greater than (1), 33% of the length of the humerus (Langer 2004).

Shape of the entepicondyle of the distal humerus: rounded process (0) or with a flat distomedially facing surface bounded by a sharp proximal margin (1).

Length of the radius: greater than (0), or less than (1), 80% of the humerus (Langer 2004).

Deep radial fossa, bounded by an anterolateral process, on proximal ulna: absent (0) or present (1) (Wilson and Sereno 1998).

Olecranon process on proximal ulna: present (0) or absent (1) (Wilson and Sereno 1998).

Maximum linear dimensions of the ulnare and radiale: exceed that of at least one of the first three distal carpals (0) or are less than any the distal carpals (1) (Yates 2003a).

Transverse width of the first distal carpal: less than (0), or greater than (1), 120% of the transverse width of the second distal carpal (Sereno 1999).

Sulcus across the medial end of the first distal carpal: absent (0) or present (1).

Lateral end of first distal carpal: abuts (0), or overlaps (1), second distal carpal (Yates 2003a).

Second distal carpal: does (0), or does not (1), completely cover the proximal end of the second metacarpal (Yates and Kitching 2003).

Ossification of the fifth distal carpal: present (0) or absent (1).

Solving a dinosaurian puzzle 218. Length of the manus: less than 38% (0), between 38 and 45% (1), or greater than 45% (2), of the humerus þ radius (modified from Sereno et al.

1993). Ordered.

219. Shape of metacarpus: flattened to gently curved and spreading (0) or a colonnade of subparallel metacarpals tightly curved into a ‘u’ shape (1) (Wilson and Sereno 1998).

220. Proximal width of first metacarpal: less than (0), or greater than (1), the proximal width of the second metacarpal (modified from Gauthier 1986).

221. Minimum transverse shaft width of first metacarpal: less than (0), or greater than (1), twice the minimum transverse shaft width of second metacarpal.

222. Proximal end of first metacarpal: flush with other metacarpals (0) or inset into the carpus (1) (Sereno 1999).

223. Shape of the first metacarpal: proximal width less than 65% (0), between 65% and 80% (1), between 80% and 100% (2), or greater than 100% (3), of its length (modified from Sereno 1999). Ordered.

224. Strong assymetry in the lateral and medial distal condyles of the first metacarpal: absent (0) or present (1) (Gauthier 1986).

225. Deep distal extensor pits on the second and third metacarpals: absent (0) or present (1) (Novas 1993).

226. Shape of the distal ends of second and third metacarpals: subrectangular in distal view (0) or trapezoidal with flexor rims of distal collateral ligament pits flaring beyond extensor rims (1).

227. Shape of the fifth metacarpal: longer than wide at the proximal end with a flat proximal surface (0) or close to as wide as it is long with a strongly convex proximal articulation surface (1) (Yates 2003a).

228. Length of the fifth metacarpal: less than (0), or greater than (1), 75% of the length of the third metacarpal (Upchurch 1998).

229. Length of manual digit one: less than (0), or greater than (1), the length of manual digit two (Yates 2003a).

230. Ventrolateral twisting of the transverse axis of the distal end of the first phalanx of manual digit one relative to its proximal end: absent (0), present but much less than 608 (1) or 608 (2) (Sereno 1999). Ordered.

231. Length of the first phalanx of manual digit one: less than (0), or greater than (1), the length of the first metacarpal (Gauthier 1986).

232. Shape of the proximal articular surface of the first phalanx of manual digit one: rounded (0) or with an embayment on the medial side (1) (modified from Sereno 1999).

21

233. Shape of the first phalanx of manual digit one: elongate and subcylindrical (0) or strongly proximodistally compressed and wedge shaped (1) (Wilson 2002).

234. Length of the penultimate phalanx of manual digit two: less than (0), or greater than (1), the length of the second metacarpal (Rauhut 2003).

235. Length of the penultimate phalanx of manual digit three: less than (0), or greater than (1), the length of the third metacarpal (Rauhut 2003).

236. Shape of non-terminal phalanges of manual digits two and three: longer than wide (0) or as long as wide (1) (Yates 2003a).

237. Shape of the unguals of manual digits two and three: straight (0), or strongly curved with tips projecting well below flexor margin of proximal articular surface (1) (Sereno et al. 1993).

238. Length of the ungual of manual digit two: greater than the length of the ungual of manual digit one (0), 75–100% of the ungual of manual digit one (1), less than 75% of the ungual of manual digit one (2) or the ungual of manual digit two is absent (3) (modified from Gauthier 1986). Ordered.

239. Phalangeal formula of manual digits four and five: greater than (0), or less than (1), 2-0, respectively (Gauthier 1986).

240. Strongly convex dorsal margin of the ilium: absent (0) or present (1) (Gauthier 1986).

241. Cranial extent of preacetabular process of ilium: does not (0), or does (1), project further forward than cranial end of the pubic peduncle (Yates 2003a).

242. Shape of the preacetabular process: blunt and rectangular (0) or with a pointed, projecting cranioventral corner and a rounded dorsum (1) (modified from Sereno 1999).

243. Depth of the preacetabular process of the ilium: much less than (0), or subequal to (1), the depth of the ilium above the acetabulum (modified from Gauthier 1986).

244. Length of preacetabular process of the ilium: less than (0), or greater than (1), twice its depth.

245. Buttress between preacetabular process and the supra-acetabular crest of the ilum: present (0) or absent (1) (Gauthier 1986).

246. Medial wall of acetabulum: fully closing acetabulum with a triangular ventral process between the pubic and ischial peduncles (0), partially open acetabulum with a straight ventral margin between the peduncles (1), partially open acetabulum with a concave ventral margin between the peduncles (2) or fully open acetabulum with medial ventral margin closely approximating lateral rim of acetabulum (3) (modified from Gauthier 1986). Ordered.

247. Length of the pubic peduncle of the ilium: less than (0), or greater than (1), twice the craniocaudal width of its distal end (Sereno 1999).

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A. M. Yates

248. Caudally projecting ‘heel’ at the distal end of the ischial peduncle: absent (0) or present (1) (Yates 2003b).

249. Length of the ischial peduncle of the ilium: similar to pubic peduncle (0), much shorter than pubic peduncle (1), or virtually absent so that the chord connecting the distal end of the pubic peduncle with the ischial articular surface contacts the postacetabular process (Upchurch et al. 2004). Ordered.

250. Length of the postacetabular process of the ilium: between 40 and 100% of the distance between the pubic and ischial peduncles (0), less than 40% of this distance (1), or more than 100% of this distance.

251. Well developed brevis fossa with sharp margins on the ventral surface of the postacetabular process of the ilium: absent (0) or present (1) (Gauthier 1986).

252. Anterior end of ventrolateral ridge bounding brevis fossa: not connected to (0), or joining (1) supracetabular crest (1).

253. Shape of the caudal margin of the postacetabular process of the ilium: rounded to bluntly pointed (0), square ended (1) or with a pointed ventral corner and a rounded caudodorsal margin (2) (Yates 2003b). Unordered.

254. Width of the conjoined pubes: less than (0), or greater than (1), 75% of their length (Cooper, 1984).

255. Pubic tubercle on the lateral surface of the proximal pubis: present (0) or absent (1) (Yates 2003a).

256. Proximal anterior profile of pubis: anterior margin of pubic apron smoothly confluent with anterior margin of iliac pedicel (0) iliac pedicel set anterior to the pubic apron creating a prominent inflection in the proximal anterior profile of the pubis (1).

257. Minimum transverse width of the pubic apron: much more than (0), or less than (1), 40% of the width across the iliac peduncles of the ilium.

258. Position of the obturator foramen of the pubis: at least partially occluded by the iliac pedicel (0), or completely visible (1), in anterior view (Galton and Upchurch 2004).

259. Lateral margins of the pubic apron in anterior view: straight (0) or concave (1) (Yates and Kitching 2003).

260. Orientation of distal third of the blades of the pubic apron: confluent with the proximal part of the pubic apron (0) twisted posterolaterally relative to proximal section so that the anterior surface turns to face laterally (1) (Langer 2004).

261. Orientation of the entire blades of the pubic apron: transverse (0) or twisted posteromedially (1) (Wilson and Sereno 1998).

262. Craniocaudal expansion of the distal pubis: absent (0), less than 15% (1), or greater than

263.

264.

265.

266.

267.

268.

269.

270.

271.

272.

273.

274.

275.

276.

277.

278.

15% (2), of the length of the pubis (modified Gauthier 1986). Ordered.

Notch separating posteroventral end of the ischial obturator plate from the ischial shaft: present (0) or absent (1) (Rauhut 2003).

Elongate interischial fenestra: absent (0) or present (1) (Yates 2003b).

Longitudinal dorsolateral sulcus on proximal ischium: absent (0) or present (1) (Yates 2003a).

Shape of distal ischium: broad and plate-like, not distinct from obturator region (0) or with a discrete rod-like distal shaft (1).

Length of ischium: less than (0) or greater than (1) that of the pubis (Salgado et al. 1997).

Ischial component of acetabular rim: larger than (0) or equal to (1) pubic component (Galton and Upchurch 2004).

Shape of the transverse section of the ischial shaft: ovoid to subrectangular (0) or triangular (1) (Sereno 1999).

Orientation of the long axes of the transverse section of the distal ischia: meet at an angle (0) or are coplanar (1) (Wilson and Sereno 1998).

Depth of the transverse section of the ischial shaft: much less than (0) at least as great as (1), the transverse width of the section (Wilson and Sereno 1998).

Distal ischial expansion: absent (0) or present (1) (Holtz 1994).

Transverse width of the conjoined distal ischial expansions: greater than (0), or less than (1), their sagittal depth (Yates 2003a).

Length of the hindlimb: greater than (0), or less than (1), the length of the trunk (Gauthier 1986).

Longitudinal axis of the femur in lateral view: strongly bent with an offset between the proximal and distal axes greater than 158 (0), weakly bent with an offset of less than 108 (1) or straight (2) (Cooper, 1984). Ordered.

Shape of the cross section of the midshaft of the femur: subcircular (0) or strongly elliptical with the long axis oriented mediolaterally (1) (Wilson and Sereno 1998).

Angle between the long axis of the femoral head and the transverse axis of the distal femur: about 308 (0) or close to 08 (1) (Carrano, 2000).

Shape of femoral head: roughly rectangular in profile with a sharp medial distal corner (0) roughly hemispherical with no sharp medial distal corner (1).

This character only applies to taxa with a medially, or anteromedially protruding femoral head. It does not apply to outgroup taxa (Euparkeria or Crurotarsi) with proximally directed femoral heads and is coded as unknown in these taxa.

Solving a dinosaurian puzzle 279. Posterior proximal tubercle on femur: welldeveloped (0) or indistinct to absent (1) (Novas 1996).

280. Shape of the lesser trochanter: small rounded tubercle (0), proximodistally oriented, elongate ridge (1) or absent (2) (modified from Gauthier 1986). Unordered.

281. Position of proximal tip of lesser trochanter: level with (0), or distal to (1) femoral head (Galton and Upchurch 2004).

282. Projection of the lesser trochanter: just a scar upon the femoral surface (0) or a raised process (1).

283. Transverse ridge extending laterally from the lesser trochanter: absent (0) or present (1) (Rowe and Gauthier 1990).

284. Height of the lesser trochanter in cross section: less than (0) or at least as high as basal width (1) (modified from Galton 1990).

285. Position of the lesser trochanter: near the center of the anterior face (0), or close to the lateral margin (1), of the femoral shaft in anterior view.

286. Visibility of the lesser trochanter in posterior view: not visible (0) or visible (1) (Galton and Upchurch 2004).

287. Height of the fourth trochanter: tall crest (0) or a low rugose ridge (1) (Gauthier 1986).

288. Position of the fourth trochanter along the length of the femur: in the proximal half (0) or straddling the midpoint (1) (Galton 1990).

289. Symmetry of the profile of the fourth trochanter of the femur: sub symmetrical without a sharp distal corner (0) or asymmetrical with a steeper distal slope than the proximal slope and a distinct distal corner (1) (Langer 2004).

290. Shape of the profile of the fourth trochanter of the femur: rounded (0) or subrectangular (1).

291. Postion of fourth trochanter along the mediolateral axis of the femur: centrally located (0) on the medial margin (1) (Galton 1990).

292. Extensor depression on anterior surface of the distal end of the femur: absent (0) or present (1) (Molnar et al. 1990).

293. Size of the medial condyle of the distal femur: subequal to (0) or larger than (1) the fibular Ăž lateral condyles (modified from Wilson 2002).

294. Tibia: femur length ratio: greater than 1.0 (0), between 1.0 and 0.6 (1) or less than 0.6 (2) (modified from Gauthier 1986). Ordered.

295. Orientation of cnemial crest: projects anteriorly to anterolaterally (0) or projecting laterally (1) (Wilson and Sereno 1998).

296. Paramarginal ridge on lateral surface of cnemial crest: absent (0) or present (1).

297. Position of the tallest point of the cnemial crest: close to the proximal end of the crest (0) or about half way along the length of the crest, creating an

298.

299.

300.

301.

302.

303.

304.

305.

306.

307.

308.

309.

310.

311.

23

anterodorsally sloping proximal margin of the crest (1).

Proximal end of tibia with a flange of bone that contacts the fibula: absent (0) or present (1) (Gauthier 1986).

Position of the posterior end of the fibular condyle on the proximal articular surface tibia: anterior to (0) or level with posterior margin of proximal articular surface.

Shape of the proximal articular surface of the tibia: ovoid, anteroposteriorly longer than transversely wide (0) or subcircular and as wide transversely as anteroposteriorly long (Wilson and Sereno 1998).

Transverse width of the distal tibia: subequal to (0), or greater than (1), its craniocaudal length (Gauthier 1986).

Anteroposterior width of the lateral side of the distal articular surface of the tibia: as wide (0), or narrower than (1), the anteroposterior width of the medial side.

Relationship of the posterolateral process of the distal end of the tibia with the fibula: not flaring laterally and not making significant contact with the fibula (0), flaring laterally and backing the fibula (1).

Shape of the distal articular end of the tibia in distal view: ovoid (0) or subrectangular (1).

Shape of the anteromedial corner of the distal articular surface of the tibia: forming a right angle (0) or forming an acute angle (1) (Langer 2004).

Position of the ateral margin of descending caudoventral process of the distal end of the tibia: protrudes laterally at least as far as (0), or set well back from (1), the craniolateral corner of the distal tibia (Wilson and Sereno 1998).

A triangular rugose area on the medial side of the fibula: absent (0) or present (1) (Wilson and Sereno 1998).

Transverse width of the midshaft of the fibula: greater than 0.75 (0), between 0.75 and 0.5 (1), or less than 0.5 (2), of the transverse width of the midshaft of the tibia (Langer 2004).

Ordered.

Position of fibula trochanter: on anterior surface of fibula (0), laterally facing (1), or anteriorly facing but with strong lateral bulge (2) (modified from Wilson and Sereno 1998).

Depth of the medial end of the astragalar body in cranial view: roughly equal to the lateral end (0) or much shallower creating a wedge shaped astragalar body (Wilson and Sereno 1998).

Shape of the caudomedial margin of the astragalus in dorsal view: forming a moderately sharp corner of a subrectangular astragalus (0) or evenly rounded without formation of a caudomedial corner (1) (Wilson and Sereno 1998).

24

A. M. Yates

312. Dorsally facing horizontal shelf forming part of the fibular facet of the astragalus: present (0) or absent with a largely vertical fibular facet (1) (Sereno 1999).

313. Pyramidal dorsal process on the posteromedial corner of the astragalus: absent (0) or present (1).

314. Shape of the ascending process of the astragalus: anteroposteriorly deeper than transversely wide (0) or transversely wider than anteroposteriorly deep (1).

315. Posterior extent of ascending process of the astragalus: well anterior to (0), or close to posterior margin (1), of astragalus (Wilson and Sereno 1998).

316. Sharp medial margin around the depression posterior to the ascending process of the astragalus: absent (0) or present (1) (Novas 1996).

317. Buttress dividing posterior fossa of astragalus and supporting ascending process: absent (0) or present (1) (Wilson and Sereno 1998).

318. Vascular foramina set in a fossa at the base of the ascending process of the astragalus: present (0) or absent (1) (Wilson and Sereno 1998).

319. Transverse width of the calcaneum: greater than (0), or less than (1), 30% of the transverse width of the astragalus (Yates and Kitching 2003).

320. Lateral surface of calcaneum: simple (0) or with a fossa (1).

321. Medial peg of calcaneum fitting into astragalus: present, even if rudimentary (0) or absent (1) (Sereno et al. 1993).

322. Calcaneal tuber: large and well-developed (0) or highly reduced to absent (1).

323. Shape of posteromedial heel of distal tarsal four (lateral distal tarsal): proximodistally deepest part of the bone (0) or no deeper than the rest of the bone (1) (Sereno et al. 1993).

324. Shape of posteromedial process of distal tarsal four in proximal view: rounded (0) or pointed (1) (Langer 2004).

325. Ossified distal tarsals: present (0) or absent (1) (Gauthier 1986).

326. Proximal width of the first metatarsal: is less than (0), or at least as great as (1), the proximal width of the second metatarsal (modified from Wilson and Sereno 1998).

327. Orientation of proximal articular surface of metatarsal one: horizontal (0), or sloping proximolaterally relative to the long axis of the bone (1) (Wilson 2002).

328. Orientation of the transverse axis of the distal end of metatarsal one: horizontal (0), or angled proximomedially (1) (Wilson 2002).

329. Shape of the medial margin of the proximal surface of the second metatarsal: straight (0) or concave (1) (modified from Sereno 1999).

330. Shape of the lateral margin of the proximal surface of the second metatarsal: straight (0) or concave (1) (modified from Sereno 1999).

331. Length of the third metatarsal: greater than (0), or less than (1), 40% of the length of the tibia (Gauthier 1986).

332. Minimum transverse shaft diameters of third and fourth metatarsals: greater than (0), or less than (1), 60% of the minimum tansverse shaft diameter of the second metatarsal (Wilson and Sereno 1998).

333. Transverse width of the proximal end of the fourth metatarsal: less than (0), or at least (1), twice the anteroposterior depth of the proximal end (modified from Sereno 1999).

334. Transverse width of the proximal end of the fifth metatarsal: less than 25% (0), between 30 and 49% (1), or greater than 50% (2), of the length of the fifth metatarsal (modified from Sereno 1999). Ordered.

335. Transverse width of distal articular surface of metatarsal IV in distal view: greater (0), or less (1), than anteroposterior depth (Sereno 1999).

336. Pedal digit five: reduced, non-weight bearing (0), or large (fifth metatarsal at least 70% of fourth metatarsal), robust and weight bearing (1) (Wilson and Sereno 1998).

337. Length of non-terminal pedal phalanges: all longer than wide (0), proximal-most phalanges longer than wide while more distal phalanges are as wide as long (1) or all non-terminal phalanges are as wide, if not wider, than long (2) (modified from Wilson and Sereno 1998). Ordered.

338. Length of the first phalanx of pedal digit one: greater than (0), or less than (1) the length of the ungual of pedal digit one (Yates and Kitching 2003).

339. Length of the ungual of pedal digit one: less than at least some non-terminal phalanges (0) or longer than all non-terminal phalanges (1).

340. Shape of the ungual of pedal digit one: shallow, pointed, with convex sides and a broad ventral surface (0), or deep, abruptly tapering, with flattened sides and a narrow ventral surface (1) (Wilson and Sereno 1998).

341. Shape of proximal articular surface of pedal unguals: proximally facing, visible on medial and lateral sides (0) or proximomedially facing and visible only in medial view, causing medial deflection of pedal unguals in articulation (1) (Wilson and Sereno 1998).

342. Penultimate pahalanges of pedal digits two and three: well developed (0) or reduced disc-shaped elements if they are ossified at all (1) (Wilson and Sereno 1998).

343. Shape of the unguals of pedal digits two and three: dorsoventrally deep with a proximal

Solving a dinosaurian puzzle

344.

345.

346.

347.

348.

articulating surface that is at least as deep as it is wide (0) or dorsoventrally flattened with a proximal articulating surface that is wider than deep (1) (Wilson and Sereno 1998).

Length of the ungual of pedal digit two: greater than (0), between 100% and 90% (1), or less than 90% (2), of the length of the ungual of pedal digit one (modified from Gauthier 1986).

Ordered.

Size of the ungual of pedal digit three: greater than (0), or less than (1), 85% of the ungual of pedal digit two in all linear dimensions (Yates 2003a).

Number of phalanges in pedal digit four: four (0) or fewer than four (1) (Gauthier 1986).

Phalanges of pedal digit five: present (0) or absent (1) (Gauthier 1986).

Femoral length: less than 200 mm (0), between 200 and 399 mm (1), between 400 and 599 mm (2), between 600 and 799 mm (3), between 800 and 1000 mm (4) or greater than 1000 mm (modified from Yates 2004).

References Benton MJ, Juul L, Storrs GW, Galton PM. 2000. Anatomy and systematics of the prosauropod dinosaur Thecodontosaurus antiquus from the upper Triassic of southwest England. J Vert Paleontol 20:77–108.

Bonaparte JF. 1986. The early radiation and phylogenetic relationships of the Jurassic sauropod dinosaurs, based on vertebral anatomy. In: Padian K, editor. The beginning of the age of dinosaurs. Cambridge: Cambridge University Press. p 247– 258.

Galton PM. 1985. Cranial anatomy of the prosauropod dinosaur Sellosaurus gracilis from the middle Stubensandstein (upper Triassic) of Nordwu¨rttemberg, West Germany. Stuttgart Beitra¨ge zur Naturkunde (B) 118:1–39.

Galton PM. 1990. Basal sauropodomorpha—prosauropods. In: Weishampel DB, Dodson P, Osmo´lska H, editors. The dinosauria. Berkeley: University of California Press. p 320 –344.

Galton PM, Upchurch P. 2004. Prosauropoda. In: Weishampel DB, Dodson P, Osmo´lska H, editors. The Dinosauria. 2nd ed.

Berkeley: University of California Press. p 233–258.

Gauthier J. 1986. Saurischian monophyly and the origin of birds.

Memoirs Californian Acad Sci 8:1–55.

Holtz Jr TR. 1994. The phylogenetic position of Tyrannosauridae: Implications for theropod systematics. J Paleontol 68:1100– 1117.

Langer MC. 2004. Basal Saurischia. In: Weishampel DB, Dodson P, Osmo´lska H, editors. The Dinosauria. 2nd ed. Berkeley: University of California Press. p 25–46. ´ AS. 2004. A Leal LA, Azevedo SAK, Kellner AWA, Da Rosa A new early dinosaur (Sauropodomorpha) from the Caturrita Formation (Late Triassic), Parana´ Basin, Brazil. Zootaxa 690:1–24.

Molnar RE, Kurzanov SM, Dong Z. 1990. Carnosauria.

In: Weishampel DB, Dodson P, Osmolska H, editors.

The Dinosauria. Berkeley: University of California Press. p 169– 209.

Novas FE. 1993. New information on the systematics and postcranial skeleton of Herrerasaurus ischigualastensis (Theropoda: Herrerasauridae) from the Ischigualasto

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Formation (Upper Triassic) of Argentina. J Vert Paleontol 13:400–423.

Novas FE. 1996. Dinosaur monophyly. J Vert Paleontol 16:723–741.

Pe´rez-Moreno BP, Sanz JL, Buscalioni AD, Moratalla JJ, Ortega F, Rasskin-Gutman D. 1994. A unique multitoothed ornithomimosaur dinosaur from the Lower Cretaceous of Spain. Nature 370:363–367.

Rauhut OWM. 2003. The interrelationships and evolution of basal theropod dinosaurs. Special papers in palaeontology 69.

London: The Palaeontological Association.

Sereno PC. 1999. The evolution of dinosaurs. Science 284:2137–2147.

Sereno PC, Forster CA, Rogers RR, Monetta AM. 1993. Primitive dinosaur skeleton from Argentina and the early evolution of dinosauria. Nature 361:64–66.

Sereno PC, Dutheil DB, Iarochene M, Larsson HCE, Lyon GH, Magwene PM, Sidor CA, Varricchio DJ, Wilson JA. 1996.

Predatory dinosaurs from the sahara and Late Cretaceous faunal differentiation. Science 272:986–991.

Upchurch P. 1995. The evolutionary history of sauropod dinosaurs.

Philos Trans R Soc Lond B 349:365 –390.

Upchurch P. 1998. The phylogenetic relationships of sauropod dinosaurs. Zool J Linnean Soc 124:43–103.

Upchurch P, Barrett PM, Dodson P. 2004. Sauropoda. In: Weishampel DB, Dodson P, Osmo´lska H, editors. The Dinosauria. 2nd ed. Berkeley: University of California Press. p 259 –322.

Wilson JA. 2002. Sauropod dinosaur phylogeny: critique and cladistic analysis. Zool J Linnean Soc 136:217 –276.

Wilson JA, Sereno PC. 1998. Early evolution and higher-level phylogeny of sauropod dinosaurs. Soc Vert Paleontol Memoirs 5:1–68.

Yates AM. 2003a. A new species of the primitive dinosaur, Thecodontosaurus (Saurischia: sauropodomorpha) and its implications for the systematics of early dinosaurs. J Syst Palaeontol 1:1–42.

Yates AM. 2003b. The species taxonomy of the sauropodomorph Dinosaurs from the Lo¨wenstein Formation (Norian, Late Triassic) of Germany. Palaeontology 46:317–337.

Yates AM. 2003c. The first definite prosauropod dinosaur from the Lower Elliot Formation (Norian: Upper Triassic), South Africa.

Palaeontologia Africana 39:63–68.

Yates AM. 2004. Anchisaurus polyzelus (Hitchcock): the smallest known sauropod dinosaur and the evolution of gigantism amongst sauropodomorph dinosaurs. Postilla 230:1–58.

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Character-taxon matrix Euparkeria 00000000?000?0000000?000?1001000 0000000000000?00000000000010000 0000000000000000000?00?000?0000 00000?1000000000000000000?00000 000000???0000??000000000?00?0?00? ?00000000000000000000000?0?0???? ?????0000020000000000??????000000 00001?0?0?0000??00?0000?0000?001 0000000000010000000000?02?000??0 1000001?000?100000?0000000??0?00 010??0000??0001?000000000?000

26

A. M. Yates

Crurotarsi

Antetonitrus

0 0 0 0 0 0 0 0 0 0 0 0 ? 0 0&1 0 0 0 0 0 0 0 0 0 ? 0 0 0 0 0 0 0 0 0 0&1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0000000000000000000000000000000 0000000000000000000000000000000 00000000000???0000??000002000?00 ?0?00??0000200000000000000000000 0 0 0 0 0 0 0 0&1 0 0 ? 0 0&1 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0&1 0 0 0 0 0 0 0 0 ? 0 0 0 0 ? 0 0&1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00000000?00?0000000000001?00000 00000?0000000??0?000000000000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0&1

?1??????????????????????????????????? ?????????????????????????????????????? ?????????????????????????????????1?10 1 2 0 0 0 ? ? ? ? ? ? ? ? 0 ? 0&1 1 ? ? ? ? ? ? ? ? 0 ? ? 0 0 ? 0 00001??00210010010121001000???? ????10000?01100???0?001??3110001 0110??????0010?3100???1010??????? ?????????????111010001????????????1 110111100111111110100000011011 1 0 1 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1 0 1 1 1 1 0 ? ? ? ? 1&2 1?00?0????3

Marasuchus

Barapasaurus

00???????0?????????????0?00??????????? ???????0???????????????????????????00??

00000???????????????????????00?00000 000?1?100000000010???00?0??00?000 000?00???00??000?00000000?000000 000??01010000000?0000121000?0000 ?????????????????????????????00000100 0000?00000100000000000000010000 0001100010000000000000000100010 0100000?00000000000000000?10?0??

00???10

???????????????????????????????????????? ???????????????????????????????????????? ????????????????????????????1?111211?? ?????????1?1????00??002??100101??00 2 0 1 1 0 1 1 1 1 1 2 0 1 2 1 1 0 0 ? 0 1&2 1 0 0 1 ? 1 0 ? 1 1??1????????10100?1???????11????????? ???????????????????1111003101100001 1110011???11110010????????????????? ??1?1?1?????????1?1???????1?????????0? ??????????1?1??????5

Agnosphitys

Blikanasaurus

?0???????0?????????????11?0?000100?? ???????????????????????????????????????? ?????????????????????????????00?00000 0000?????????????????????????????????? ??????????????????????000?????????????? ???????????1100?00???????????????????? ???????????00000120000100??????????? ?????????????????????????????????????10 ??????011000100??0??????????????????? ????????

???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ??????????????0000?0110111?1?00001 0110101110010111111201211000010 0?2

Anchisaurus 10???00??012?1??11?????111011?010?

01010110001100111101200?10?????2 01?0011011?2002010??????10?10?00? ? 1 0 0 ? 0 0 1 0 1 0 1 ? 1 1&2 ? 0 1 1 1 ? 0 0 1 1 ? ? ? 1 0 0 1001111011?10000?010?001100?000? ?0000000??0100?0??0?01?00?10?????1 1 0&1 ? ? 2 1 1 0 0 1 0 1 1 0 0 ? ? 0 ? ? 1 0 0 1 0 1 1 1 0 0 1 0 0 2 0 1 0 0 0 0 0 2 0 0 0&1 1 0 1 0 3 1 0 0 0 0 0 ? 1 1 11100010011?0010100001011010000 1 0 0/1 1 1 1 0 1 0 0 0 0 0 0 1 1 0 1 1 1 ? 1 ? 0 1 ? 0 1 0 ? ? ?10111?0?01??0011?1010000010011

Camelotia ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ????????1???????????0??0??001??00210 0000000??00?0??????????1???0??011?? ???????????????????????????????????????? ???????????????????????1??????????1??0 0111?111011110111?1??110?000000? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1&2 ? ??000????5

Solving a dinosaurian puzzle

27

Cetiosaurus

Eoraptor

1?????????????????????????????????????? ????????????????01????????????????????? ???????????????????????????????????????

2??0011110111110100100020?2001?1 0 ? 1 0 2 0 ? ? 1 0 1 1 1 0 2 0 1 0 1 0 0 ? ? ? 1&2 ? ? ? ? ? 1 001??00100???011111031100100011? ??????1????????????????????1111003?02 10?0010?1?011??1101?00???211112??

0???010?111210100010010111??????? ????????????????????????????????5

0010?000?0110?00110000010100100 1?00110100000?10110010100001000 001001???0??1???????????????000000?

0?0?0?0?00?100000000??????1000010 10000?10????000??00?0????00?000??0 0000001??10???100??????????????01???

011???0?0????????20?000?1?000?0?01 0000110100?2?001110??0???0?0???10 ?0010?10????0?100??0011??000?0?10?

0110??1????0???????????0?0???00?0010 000000??000

Chindesaurus ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ????100?????????????01?0??0?1??0?1??? ???000??00???????????1??0????1?00???? ???????????????????????????????????????? ????????????0???101?1????0???????????? ??00?0101110000000100??00?101111 00???011110100??1??????????????????? ???????1

Eucnemesaurus ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????0???01??001100 100000??00?0??????????10000?01100? ???????11?????????????????????????????? ????????????????????????110???0??????? ??????001101?1010?1010110??000001 10110????????????????????????????????? ? ? ? ? ? ? ? ? 3&4

Coloradisaurus ?00?1002?012?111111?1??1110?1111 00?10??00?001?01110101?100100100 ?1011011011??110111???0?1?100101 101011102100101010000?1?00?1100 200100011?0110??00?001?100110000 0000000000101110??0100100?0?????? ???011111121?011?????0?????????????? ???????????00100031100?0?111011001 00111110111?0010110100001011110 10000?0110110???011110?000101???

001110012?101?000021002

Gongxianosaurus 1?????0?????????12???????????????????? ???????????????????????????????????????? ?????????????????????????00???1??2121? ???????????0????????????1??0??001??0?? ????0?0??00000????????????0??0?0?1?0 ?000?011??2110????1?1??????????????? ?????????????0?100????0??????????????? ? ? ? ? ? ? ? ? ? ? 1&2 1 1 1 ? 2 ? ? ? ? ? ? 0 ? ? ? 1 1 0 1 ? ? ? ? ??1?0??1???0?1?1????1?11??010???10?

2?0111000020005

Efraasia 100?1001?01??1?111?112?1110?100?? ?0100100000??0?10??01?1??1??????10 ?000?1????0110100??????10010010??1 1?021001010100001???1?1100110100 1011011010000001??001?000000000 00000000110000101000?0110000?0?

01011212000111001101012010?1100 0001110100010001000310001011000 1000000110010110100001111000010 1100010000001101?001?011010?0?01 ?1110001??0011?1010000010002

Plateosaurus ( 5 Gresslyosaurus) ingens ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ?????????????01??01????????10????????? ???????????????????????????????????????? ???????????????????????????????????????? ????????????????00?010???????????????? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0&1 ? ? ? 0 ? 0 ? ? ? ? 4

28

A. M. Yates

Guaibasaurus

Lufengosaurus

???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????0???01??011001 000000??00000???????0?01100???????

1????1????????????????????????????????? ?????????0?????1?00210110010000000 010?10110?00001001000010?1?10100 00?001111001?0?01????00101??0000? ?10?001000000000011

100???02???211?1?11?1111111111010 001011010000101110101110010?1??? ?0110??011??01010100?011010010??? ?0111?21011010100011?0001110020 0110111?01101000200111001100000 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 1 0 0 1 0 0 0 0 0 0 0 0&1 1 0 0 0 0 0 0 0 0 0 1 1 1 1 1 2 0&1 1 0 1 1 1 0 0 1 1 0 1 1 1 1 0111310010120100010200010003110 0002111011002101100101100001011 0100001021110101000011011001001 1110?0001?111010111001201011000 0 1&2 0&1 0 0 4

Herrerasaurus 00000000?011000000000000?000100 0000000100000010001010101000100 00110100000011?0000000?1000?000 00000?1000000000000000001010001 000000100000?000010000011??0010 0&1 1 0 0 0 0 0 0 2 0 0 0 0 0 0 1 0 0 0 0 0 1 0 1 1 0 0 0 0 0110010100?111??011000000000000 0120000011000001101101010000012 000000010000010???01?01010010000 1011100010110001000010000100010 0100101000000110001000010010000 00000?02

Mamenchisaurus 11000113?11201101200000001011?2 ???11120101010111?1?101201000001 1 1 2 2 1 0 ? ? 0 ? 0 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1 1 0&1 0 0 0 01?0100011111111121113??0011101 210????0111002?11101010?0020?1?0 01?020121000?011??1?11111101?001 011?1???????00??0??????????1????????? ????1??????11110031011?00?11?10011 00?11??00100211112??0???010?11121 010?1??0??????101011111??????1?????

2??2?02?111102??05

Massospondylus Isanosaurus ?????????????????????????????????????? ?????????????????????????????????????? ?????????????????????????????????????? ???????????0??0???????????2??10??0?? ?????????????2?011000??????????????? ????????101?????????????????????????? ?????????????????????????????????????? ?????????????211112??0???001?1?0?? ?????????????????????????????????????? ??????????????3

1001100210121111111112110111110 1000101101000110011011111001000 102?01?01100111010101??101001001 0 1 1 0 1 0 1 0 1 0 2 1 0 0&1 1 0 1 0 1 1 0 0 1 1 1 0 0 ? 1 1100200100111101101000200111001 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 1 0 1 0 0 1 0&1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ? 0 1 0&1 1 1 1 1 2 0 1 0 1 1 1 0 0 1 1011110111210010121100000200010 0031000100111011001001100101110 0010110100001021010100000011011 0010011110100011111000111001201 010000021002

Jingshanosaurus

Melanorosaurus

1001?002??1211111100?0?111011101 10?102001??1?10111011101001000?? ??0110000011?211001000??1?101100 10??11102100101211001????111??01 0??????1???10100??0011100?1???0000 000000000??10??01000000001000000 ?001??11201011100??00??0011?3100 100?010001020001000310000021110 01002??110010110?01001101000010 111101010000110110?12011010?00?? ????0101111012010100000010?4

1001?103?01211111101?1110101111???

010101101011001101011?000000102?0 11011001??2002010010011101?00101?

1000210?10021100110?0101100110110 10010111?0000001??002100000000100 00000?020100110010?001100????000??

2 1 2 0 0 0 0 0 1 1 0 ? ? ? ? ? ? 0 0 ? 0 ? 2 1 0 0 1 0 1 1&2 0 ? 0 00102000100031000001111010001???1 ?010110?1110111100111001110100000 01101100102110101000011100101110 01?111110000110?3

Solving a dinosaurian puzzle Neosauropoda 110001131112011012000001010111 0&2 1 1 1 1 1 1 2 0 1 0 1 0 1 0 1 1 0&1 1 1 1 1 0 1 2 0 1 0 0 0&1 1 0 1 1 2 2 2 1 1 1 0 0 1 0 1 1 1 2 0 0&1 2 0 0 0 0 0 1 0 2 0 1 1 1 0 0 0 0 1 2 0 1 0 0 0 0&2 1 1 1 1 1 1 0&2 1 2 0&1 1 1 2 0&1 0 0 0 0 1 1 1 0 0 1 1 1 1 0 1 0 0 1 1 0 0 2 0 1 2 1 0 1 0 1 0 1 0&1 0 2 0 1 1 1 0 0 1 1 0 2 0 1 2 1 1 0 0 0 0 2 1 0 0 1 1 1 0 0 1 1 1 1 0&1 1 0 0 0 0 1 0 0 1 1 1 0 0 3 1 1 0 0 1 0&1 0 0 1 1 1 1 0 0 0 1 0 1 0 0 0 0 0 0 0 0 1 1 0 0 0 1??1?3011110031021000011110011001 1 1 0 0&1 1 0 0&1 0 0 2 1 1 1 1 2 ? ? 0 ? ? ? 0 1 0 ? 1 1 1 2 1 010?11000011111010111111011??1111 00210200211111021105

Neotheropoda 0 0 0&1 0 0&1 0 0 2 0&1 0 1 2 0 1 0 0 1 1 0 0 0 0 1 0&1 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 0 0&1 1 0 0 0&1 0 1 0 1 0 0 0 1 0&1 0 0 0 1 0&1 0 1 0 0 0 0 0 01110000001110001000000001?00 00000000000000010110011000001 0 0 0 0 0&1 1 0 0 0 0 1 0 2 0 0 0 0 1 0 1 0 1 1 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1&2 1 0 0 0 1 1 0 0 0 0 0 0 0 00101000010010110000010001000 1 2 0 0 0 0 0 0 1 0 ? 0 0 0 1 0 0 1 1 0 1 1&2 1 0 1 0 1 0 03000211111010000111110000110 1 0 0 0 0 1 ? 0 1 1 0 0 0 1 0 0 0 0 0 0 0 0 0&1 0 1 1 0 1 1111002001011000011111000?0?00 00011000000000012

Omeisaurus 11000113111201101200000101011?2 0101112010101011111010120100000 11222111001011???0?00???1???11100 001?0?00021101111121113??0011101 20011010111002?1210101011020110 0011020121100?021??1?10011100100 ?01111110031100100011??????01000 01000110001001?3011110031011000 011110011000111100100211012??0?? ?010?01021010011?0??111?011010?1 1??1????1111021020021111102?105

Ornithischia 001000000000?0000000?000?101100 010100?1000000100100001010000 0&1 0 0 0 1 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0&1 0 1 0&1 0 0 0 0 0 0 1 0 0 1 1 1 0 0 1 1 1 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0&1 0 0 0 0 ? ? 0 1 0 0 0 0 0 0 0 ? 0 0 ? 0 ? 0 0 ? 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1&2 1 0000000000010000100001011111000 0010000000000000000000000000000 000110102100010011??000?0001100

29

00000100001?010111102000000000 0&1 0 1 1 1 1 0 0 0 2 ? 0 1 ? 0&1 1 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0&1 1 0 0 0 0 0 0 0 0 0 0 1 0

Patagosaurus 11????????????????????????????????????? ???????????????????????????????????????? ????????????1?00001??????0??0111012 111??????1100101100000110020?200 1010?00201?01111120121?00?021001 1100?1?0?100???0?11100?1100100?11 ????????????????????????????111100310 1000001111001100111110010?21111 2??0???0011111?101000??0??????????? ?????????????????????????????????5

Plateosaurus engelhardti 1 0 0 1 1 0 0 1 1 0 1 2 0 1 1 0&1 1 1 1 1 1 2 1 1 1 1 0 0 1 0110001001010101100110011010110 0100110110110111111011000101111 0010110101111210010101000011001 1 1 1 0 0 1 1 0 1 0 0 0&1 0 1 1 0 1 1 0 1 0 0 0 2 0 0 1 1 1 0011000000000000001011010001000 0000010000000010111120001110011 0111101011100100201000001000100 0311001021010100011111001011110 0001111000010110001000010111110 0100110101000101110001100011110 10000010004

Plateosaurus gracilis ?00??001?012?110111?1??1110?101??

0?10?1010?0??0?10001101??10??????? ??????????1?????????????0??0110?????1 2100101010?001?????1100??01???011 01101?00?001?100110000000000000 010?1010001010000001000?00???????

1200?11100?1011?10101010000???10 ??????00100031100102101010001111 1001011??00001111000010110?0100 00?0??0110????????????????????0?????? ? ? ? 0 ? 0 ? ? ? ? ? ? ? ? 2&3

Plateosauravus ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ? ? ? ? 1 0 ? ? ? 0 1 0 0 1 0 1 ? 0 1 1 0 1 ? 0 0 1/2 0 0 1 1 ? 0 0110000000001000000??10??011???0 ? ? 1 1 0 ? ? ? ? ? ? ? ? 0 ? ? 2/3 1 1 1 0 0 1 1 1 0 0 ? ? ? ? ? ? ?

30

A. M. Yates

?????1???????????????00100031100101 ?01????????11??10110?000011110000 11110001000000110110??????0??????? ????????11?0????0??????????4

?001?0201210000?11?00?1001110110 01?111?1?00211001100?11000?10110 01?000110000??1?3011110031011000 01111?01100?111100100211112??0?? ?000?01121010?01?0????110?101???1 1011??1111102002?02111?1021105

Riojasaurus 1001?00??012011?110??001110110 1100?100001000?10010?001110010 00001101?0?10011?01011??????1?0 01000?1??101?200010101000010??

11110011010010110110100010011 10011000000000000001011101001 000000011000??0?01011212101111 00111111?01111101100101000102?

00100031100102111010001101100 10110010110111010110201101000 000110110010011010100??011?000 11100121111000001??13

Silesaurus 00?0??00?000?00100000??0?00?0?010 1?????????0010??0????01?????????00?0 ?0?000??000000?????1?00?0?010???0?

0000010001000010?00000000000???0 0100000000000101000011000000000 00000??00000100000?0?0???????1111 110000100000???????????????????????? ????000001000000001000000000?010 100?0?1000011011000101100010001 1000000000?0000000??11?1??00??00 0000?10???000?0011

Ruehleia ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ????10???0????01???101?002001??001 10010000011000000?1100001?00?0?0 110??????0101111200011100?0100??0 1011101000???0??00??001000311000 021??11000110110?10110?101011010 000102100010?00?011011001?00001 0100?????????????????????????????3

Staurikosaurus 00????????????????????????????????????? ???????????????????????????????????????? ???????????0000000001000?00?000000 0000????????00010????00?01001?0000 11?000?00000000020000001??010101 100000110010????1?1????????????????? ????????????????????????000001200110 001110?010?00010?00000100001??00 0?0101?000000001000000001????01? ????????????????????????????????1

Saturnalia 10???????????????????????1??1????0?10 0?0??????????????????10?????1??00???0 ???0?0000??????????01000??????00001 00010000????????00??010010??01101?

000001?000110010000000000?00000 0000101??????????????1111111100010 100????????????????????????????0??0?11 1002102100000001001100100100000 0100110001011000100000001010001 0010010100000001000000001011000 ?000?0010

Tazoudasaurus 11????????????????????????????????????? ???????????010????????????00?1???????? ?????????????00000001???0??20?11110 1210???????????????????????02??1??001 ??102011?001??20111?00????????00?? ??110????11??????????????????????????? ????????????????????????????????111010 0 0 1 ? ? ? ? ? ? ? ? ? ? ? ? 1&2 1 ? ? ? 1 ? 1 0 0 1 ? 0 ? ? ? ? ? ? ?0????0?????????10101?111???????????? ??????1??10?1????5

Shunosaurus

Thecodontosaurus antiquus

11000113?11201101200000001011?2 0101112010101010011010121000110 1112101000101?120020???110200100 000120100011111112121112??01011 ?1001?1?10010012?1100001011021?0

?0???????????????????????1??1??100???? ??0?0?0?0???000????????????10?0?0?10 1??011000???????00?11010??????2100 101010000?1??????000101010?1?0110 1?000001??00110000000000000000?1

Solving a dinosaurian puzzle 000?0101100?01000??00?0101121100 0101001100012010001100001010000 01100000021000001???0?000??011??

01010?0000111100001011000100000 00101100??011010100????110001110 ?1?010??00?0????1

Thecodontosaurus caducus ? 0 ? ? ? 0 ? ? ? ? ? ? ? ? ? ? ? 0&1 0 0 ? 0 ? ? ? 1 ? ? 1 ? ? ? ? 0 0100100000010?100001?10????????00 ?000?1?1??00100011?000?00?01010??

0000?1001010100001001??1100?1010 1001101101?00???1????1?????????????? ?????????0??11?00010000100????11?1?

00??????????????????????????????????00 100021100001?????????0011??10110?

00??????????1?1?000?0000000?01?001 ?????????????????001110011?10000000 1001?

Unaysaurus 100?1001??1?01?111???211110?10110 0????????????0??00001?101100000??0?

10??0?1??010100???????10?10110?????

02?00101010000???0?1?????0?1?0???? ??????0??0?1??00?10000?0??0000????? ?????????0????01000?00?01011?12000 01100??????1????110????211???0??????

31

???????????????????????????????????????? ??????????????????110110???011010??? ???????0?110???0??0??????????1

Vulcanodon ???????????????????????????????????????? ???????????????????????????????????????? ???????????????????????????????????????? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 1/2 ? ? ? ? ????????????????1??????0111?0?00?0?0? ?01??2110?10?011???????????????????? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 3 1 0 1&2 ? 0 0 ? 1 1 1 1 1 0 0 0 1 0 0111110010?111011110010011?1??20 ?10001?0???11?1010110111011??11?0 1010120011110?121?05

Yunnanosaurus 110??002?01?1111110????101?11?010 1 ? 1 0 1&2 ? ? ? ? ? 0 ? ? 0 ? ? ? 0 1 1 1 ? 0 0 ? ? 0 0 0 1 0 ? ?01?0??001???????????????10?00010???

0?011001012121111???111100110110 100?011010000001100011000000000 1000000?010110100000?00?0??0??00 1???11200?11100??01??0011?2101100 2 0 1 0 0 0 0&1 0 2 ? 0 0 1 0 0 0 3 1 0 0 0 0 0 0 1 1 1 0 1 00010?110010111?001011010000101 1010101000010011001?01101010001 1110010111001???11?0000110?2