Plesiodipsas perijanensis

Herpetological Monographs, 22, 2008, 106–132 E 2008 by The Herpetologists’ League, Inc.

SYSTEMATICS OF THE ENIGMATIC DIPSADINE SNAKE TROPIDODIPSAS PERIJANENSIS ALEMA´N (SERPENTES: COLUBRIDAE) AND REVIEW OF MORPHOLOGICAL CHARACTERS OF DIPSADINI MICHAEL B. HARVEY1,5, GILSON RIVAS FUENMAYOR2, JOSE´ RANCES CAICEDO PORTILLA3, JOSE´ VICENTE RUEDA-ALMONACID4

AND

1

Department of Biological Sciences, Broward Community College, 3501 S.W. Davie Road, Davie, FL 33314, USA 2 Museo de Biologı´a, Facultad Experimental de Ciencias, La Universidad del Zulia, Apartado Postal 526, Maracaibo 4011, Estado Zulia, Venezuela 3 Laboratorio de Anfibios, Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogota´, DC, Colombia 4 Coordinador Programa Biodiversidad y Especies Amenazadas, Conservacio´n Internacional Colombia, Bogota´, DC, Colombia, e-mail: jvrueda@yahoo.com ABSTRACT: On the basis of new material from Colombia, we describe external morphology, the hemipenis, osteology, musculature, and visceral morphology of Tropidodipsas perijanensis, a species previously known from the unique holotype and long assigned to Dipsas. Tropidodipsas perijanensis may be the sister species of all other Dipsadini or the sister species of a clade formed by Dipsas and Sibynomorphus. This distinctive South American species cannot be assigned to Tropidodipsas or to any other genus, and we erect a new genus for it. Our study of cephalic musculature identified a previously unreported division of the m. levator anguli oris and new insertion of the m. intermandibularis posterior superficialis. New characteristics of dipsadine hemipenes were visualized by Alizarin staining. Some osteological characters of Dipsadini support synonymization of Sibon and most species of Tropidodipsas, whereas visceral characters and published molecular data suggest that Dipsas, Sibon, and Sibynomorphus form a clade.

RESUMEN: Con base en nuevos ejemplares de Colombia, se describe la morfologı´a externa y visceral, hemipenes, musculatura y osteologı´a de Tropidodipsas perijanensis. Esta especie conocida previamente solo por el holotipo fue por mucho tiempo asignada al ge´nero Dipsas. Posee caracteres especiales que la diferencian de todos los ge´neros descritos, por lo que se describe uno nuevo para la ubicacio´n de esta especie.

El estudio sobre su musculatura cefa´lica identifico´ una divisio´n del m. levator anguli oris y una nueva insercio´n del m. intermandibularis posterior superficiales, no indicados previamente para la familia Colubridae. Nuevas caracterı´sticas de los hemipenes de Dipsadini fueron visualizadas por medio de tincio´n con Alizarina. Algunos caracteres osteolo´gicos soportan la sinonimia de Sibon y la mayorı´a de las especies de Tropidodipsas, mientras que los caracteres de la morfologia visceral y datos moleculares ya publicados sugieren que Dipsas, Sibon y Sibynomorphus forman un clado.

Key words: Dipsas perijanensis; Dipsas sanctijoannis; Lung morphology; Musculature; Osteology; Plesiodipsas new genus; Sibon; Sibynomorphus; Tropidodipsas.

IN RECENT years, several careful studies have revisited the systematics of Dipsas. Herpetologists discovered two new species (MacCulloch and Lathrop, 2004; Reynolds and Foster, 1992) and redescribed poorly known species such as D. neivai (Porto and Fernandes, 1996), D. alternans (Passos et al., 2004), and D. albifrons (Passos et al., 2005). Several species were revalidated in the D. oreas (Cadle, 2005), D. pratti (Harvey and Embert, 2008), and D. variegata (Cadle and Myers, 2003) groups. Perhaps most importantly, these studies defined a suite of new morpho5

CORRESPONDENCE: e-mail, mharvey@broward.edu

logical characters that can reliably establish species boundaries and be used to infer relationships within Dipsas and other Dipsadini.

Alema´n (1953) described Tropidodipsas perijanensis on the basis of a single female from 1700 m on the Venezuelan slopes of the Serranı´a de Perija´. When Peters (1960) reviewed the Dipsadini, he did not consider T. perijanensis. Later, Peters (1970) verified Alema´n’s report of 19–17 dorsal scale rows and referred this species to the D. polylepis group. As Peters (1970) acknowledged, the members of the D. polylepis group were a heterogenous assemblage of seemingly unrelated snakes sharing 17 or more scale rows at 106

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midbody, whereas species in his other groups have 15 or 13 scale rows at midbody, usually without reduction. After Peters’ (1960) revision, the D. polylepis group was systematically dismembered. Its species were referred to other genera (Downs, 1961; Hoge, 1964; Fernandes et al., 1998) or shown to normally have 15 dorsal scale rows (Fernandes et al., 2002; Harvey and Embert, 2008). Tropidodipsas perijanensis remained an enigma since no new specimens were collected, and Peters (1970) and Alema´n (1953) were the only authors to examine and comment on the unique holotype.

Lying along the politically unstable border of Colombia and Venezuela, the Serranı´a de Perija´ has remained largely unexplored until very recently. The Sociedad de Ciencias Naturales La Salle, Caracas, conducted limited herpetological surveys in the late 1940s and early 1950s (Alema´n, 1953). Then from 1989 to 1991, three expeditions led by the Museo de Biologı´a de la Universidad del Zulia discovered new species of Anolis and Atractus (Barros, 2000; Barros et al., 1996). Finally, in the late 1990s, field parties from the Museo de la Estacio´n Biolo´gica de Rancho Grande discovered species previously recorded from the Colombian side of the Serranı´a, but unreported for Venezuela (Harvey et al., 2004; Manzanilla et al., 1998, 1999; Rivas et al., 2002). Meanwhile, herpetologists began surveying lower slopes on the Colombian side of the Serranı´a (Herna´ndez-Ruz et al., 2001) and two new species of Eleutherodactylus were discovered (Lynch, 2003).

While reviewing South American Dipsas (Harvey and Embert, 2008), Harvey discovered a specimen of Tropidodipsas perijanensis in the California Academy of Sciences and several additional specimens were collected around Bucaramanga, Santander, Colombia.

External anatomy of these snakes immediately suggested to us that T. perijanensis had been wrongly assigned to Dipsas. We take this opportunity to revisit the species’s systematics and provide a more thorough description based on the holotype and new specimens from Colombia.

Content of the subfamily Dipsadinae and tribe Dipsadini has changed over time and usage of these names has been inconsistent.

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Although Peters (1960) narrowly defined the Dipsadinae as containing only the genera Dipsas, Sibon, and Sibynomorphus, recent authors usually considered it to include genera referred to as ‘‘Central American xenodontines’’ by Cadle (1984a, b, c; Cadle and Greene, 1994). Other authors (e.g., Fernandes, 1995; Ferrarezzi, 1994), prefer to recognize this entire clade as a tribe (‘‘Dipsadini’’), considering that it is likely part of a larger clade of xenodontine snakes. Wallach (1995) proposed that the tribe Dipsadini include only Dipsas, Sibon, and Sibynomorphus. Nonetheless, he appreciated that Tropidodipsas is the sister group of his more restricted tribe. More recently, Zaher (1999) included all four genera in the Dipsadini. Our use of these terms is equivalent to that of Zaher (1999) in recognizing Dipsadinae as a large subfamily containing the genera of Cadle’s ‘‘Central American xenodontines’’ and Dipsadini as a tribe containing Dipsas, Sibon, Sibynomorphus, Tropidodipsas, and a new genus described herein. The Dipsadinae is nested within a larger radiation of xenodontine snakes and its formal recognition renders Xenodontinae paraphyletic (Lawson et al., 2005). Both Zaher (1999) and Lawson et al. (2005, their table 5) list genera included in the Dipsadinae.

MATERIALS AND METHODS Morphological characters.—We measured snout-vent length (SVL) and tail length with a string and meter stick to the nearest 1 mm.

With a dial caliper, we measured head length (from the posterior tip of the last supralabial to the center of the rostral), eye-nostril distance (from the anterior border of the orbit to the center of the nostril), eye-diameter, loreal length (along its ventral margin), greatest loreal height, greatest chinshield length, greatest chinshield width, length of the heart, snout-heart interval (from the tip of the snout to the posterior tip of the heart), heart-liver gap (from the posterior tip of the heart to the anterior edge of the liver), length of the liver, and distance between the posterior tip of the liver and anterior edge of the gall bladder.

We include the nuchal blotch in counts of body blotches, whereas we include a blotch

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straddling the vent in counts of caudal blotches. When characterizing relative blotch length on the anterior body, we counted dorsal scales along the sixth dorsal row. We then generated a blotch-interblotch ratio (Harvey and Embert, 2008) by averaging counts from the second and third blotches and dividing the average by an average of counts from the second and third interblotches. We counted ventrals using Dowling’s (1951) method. We use the term ‘‘chinshields’’ to refer to the large paired, subequal scales between the preventrals and first few infralabials in medial contact. Our definition includes scales sometimes referred to as gulars or divided preventrals and is consistent with Peters’ (1960) use of the term.

In the species account, ranges are separated by a dash, whereas a backslash (/) is used to separate counts from different sides of the same specimen. Where appropriate, means 6 standard deviation and sample size follow ranges and character frequencies. When tabulating descriptive statistics, each count was treated as a separate observation. Therefore, sample sizes given for paired characters of pholidosis (e. g., supralabials, preoculars, etc.) refer to the number of sides examined for all specimens, whereas sample sizes given for other (non-paired) characters (e. g., dorsals, ventrals, etc.) refer to the number of snake specimens examined.

Sex was determined by subcaudal incision or by inspection of the viscera in specimens with open abdominal cavities. We routinely used methylene blue in 70% ethanol to reversibly stain muscle fibers and some structures such as tiny spines at the base of the hemipenis, tracheal cartilages, and buccal epithelia when counting maxillary teeth.

Our description of hemipenial morphology uses the terminology of Dowling and Savage (1960), Harvey and Embert (2008), and Myers and Campbell (1981). For Tropidodipsas perijanensis (UIS 1243), a distorted and only partially everted organ was removed, softened in 1% KOH, filled with petroleum jelly, and returned to ethanol for storage (Pesantes, 1994; Myers and Cadle, 2003). When softening the organ, we added Alizarin Red to the KOH solution (see Harvey and Embert, 2008, for a discussion of this procedure). Harvey

[No. 22,

and Embert (2008) reviewed hemipenial morphology of Dipsadini. We compared the hemipenis of UIS 1243 to Dipsadini described

by Harvey and Embert (2008) and to more distantly related Dipsadinae in the genera Adelphicos (4 species examined), Coniophanes (1), Geophis (5), Hydromorphus (1), Imantodes (1), Leptodeira (1), and Ninia (2) (Appendix 1).

UIS 1243 was used for a more detailed study of this species’s morphology. Prior to this study, the right maxilla, ectopterygoid, pterygoid, and palatine had been removed and both of its mandibles had been broken. We did not undertake an exhaustive study of the muscles of Tropidodipsas perijanensis. Nonetheless, we scored characters used in earlier studies of dipsadine systematics (Fernandes, 1995; Savitzsky, 1972) and comment on a few other characters of musculature that vary among colubrids and may be useful in future studies of dipsadine evolution. We use the nomenclature of Haas (1973) for the jaw adductors and the nomenclature of Langbartel (1968) for hyoid muscles. After studying the cephalic musculature and glands, we removed the skull, and cleared and stained it with Alizarin using a modification of the procedure of Taylor and Van Dyke (1985).

We compared UIS 1243 to partially dissected heads and skeletal material of Dipsas (9 species examined), Sibon (4), Sibynomorphus (1), and Tropidodipsas (2) (Appendix 1).

We describe the viscera of UIS 1243 and compare it to that of other dipsadines described by Wallach (1995) and Harvey and Embert (2008). When a left lung and bronchus were absent, we considered the right bronchus to begin at the posterior tip of the heart, following the arguments of Wallach (1998). We estimated total number of tracheal rings by counting the number of rings in a 10 mm strip of the trachea just in front of the heart, then multiplying this ratio by the distance from the posterior tip of the trachea to the tip of the snout. This method minimizes damage to the specimen and is preferable to opening the coelom up to the glottis. However, it assumes that tracheal spacing is uniform throughout and does not account for the short distance from the glottis to the tip of the snout. In many species spacing usually chang-

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es throughout the length of the specimen (Wallach, unpublished data), and our estimates may best be viewed as an index.

Except for CBF (Coleccio´n Boliviana de Fauna, La Paz, Bolivia), MCNC (Museo de Ciencias Naturales de Caracas, Caracas, Venezuela), MHNLS (Museo de Historia Natural La Salle, Caracas, Venezuela), MIZA (Museo del Instituto de Zoologı´a Agrı´cola, Maracay, Venezuela), NK (Museo Noel Kempff Mercado, Santa Cruz, Bolivia), UIS (Coleccio´n de Reptiles, Museo de Historia Natural, escuela de biologı´a, Universidad Industrial de Santander, Bucaramanga, Colombia), and ULABG (Laboratorio de Biogeografı´a, Universidad de Los Andes, Venezuela), museum abbreviations are those of Leviton et al. (1985).

Cladistic methods and diagnoses.—The evolutionary relationships of the Dipsadini have yet to be resolved and a phylogenetic analysis of this group is beyond the scope of our study. A priori, we did not assume monophyly of any genus of Dipsadini. Fernandes (1995) has already provided evidence that Dipsas is monophyletic only if Sibynomorphus is included within it and that Tropidodipsas fischeri is not likely to be congeneric with other Tropidodipsas. To evaluate possible phylogenetic affinities of T. perijanensis, we compared the species’s morphology to species of Dipsas, Sibon, Sibynomorphus, and Tropidodipsas (Appendix 1).

We generated a relatively small matrix of morphological characters (Table 2, Appendix 2) and use these data to evaluate the most parsimonious placement of T. perijanensis (determined by hand) within the constrained alternative dipsadine phylogenetic hypotheses of Kofron (1985) and Dessauer et al. (1986).

This exercise also allowed us to consider alterantive evolutionary scenarios of the characters described herein.

Character state assignments were based on published accounts (see DISCUSSION) and specimens examined in this study (Appendix 2). To polarize characters, we applied the method of Maddison et al. (1984) to the following hypothesis of outgroup relationships to the Dipsadini: ((((((Dipsadini) Adelphicos, Atractus, Geophis, Ninia) Rhadinaea)((Imantodes, Leptodeira) Tretanorhinus))) Xenodon-

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tinae). This conservative and partially unresolved hypothesis reflects agreement among the phylogenetic hypotheses of Cadle (1984a, b, c), Dessauer et al. (1986), Fernandes (1995), and Vidal et al. (2000). Branch support was not considered, because we did not reanalyze the data used by Kofron (1985) and Dessauer et al. (1986). Two characters (10 and 13) require additional morphological study, have not been described in outgroups, and were excluded from the phylogenetic analysis.

In his seminal revision of dipsadine snakes, Peters (1960) did not formulate diagnoses for most species. Our species level diagnosis follows the numbered format standardized

by Harvey and Embert (2008), whereas the generic level diagnosis includes characters broadly applicable to snakes within the Dipsadinae. Even though the new genus is monotypic, we provide a species level diagnosis since investigators will likely confuse Tropidodipsas perijanensis with Dipsas. The species level diagnosis allows it to be correctly identified without examining internal morphology. Previously, the senior author (Harvey, 1999; Harvey et al., 2003, and Harvey et al., 2005) has discussed reasons for using standardized, numbered diagnoses for large complex genera of Neotropical snakes.

RESULTS Tropidodipsas perijanensis cannot be assigned to Dipsas, because, unlike that genus, it lacks a tracheal lung and has a long heart-liver gap, a large Harderian gland, and usually 17 dorsals reducing to 15. It cannot remain in Tropidodipsas, because it has subrectangular chinshields, has lost the mental groove, lacks an enlarged penultimate supralabial, and lacks a posterior blade-like process on the maxilla.

Since this species cannot be placed in any other genus, we assign it to a new genus.

Plesiodipsas gen. nov.

(Figs. 1, 2) Type species.—Tropidodipsas perijanensis Alema´n, 1953, by monotypy.

Diagnosis and definition.—Robust banded snakes probably not exceeding a meter in length and differing from other Dipsadinae by

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FIG. 2.—Cephalic morphology of Plesiodipsas perijanensis (Holotype, MHNLS 655) from Jamayaujaina, Serranı´a de Perija´, Venezuela.

FIG. 1.—Plesiodipsas perijanensis. Reproduction of original watercolor by Gabriel Ugueto.

the following combination of characters: (1) eyes large, not visible from below, with elliptical pupils; (2) head distinct from neck, with subacuminate snout; (3) chinshields subrectangular and mental groove absent; (4) penultimate supralabial not greatly enlarged; (5) no infralabials greatly enlarged; (6) loreal excluded from orbit by lower preocular; (7) dorsals smooth, without keels or apical pits, usually in 17 rows at midbody reducing to 15; (8) chin tubercles present in males, supra-

cloacal tubercles absent; (9) Harderian gland large and rhomboidal, medial to mm. levator anguli oris and adductor mandibulae externus, pars superficialis; (10) m. levator anguli oris inserting far anteriorly on dentary; (11) maxillary teeth directed inward, lacking grooves, and decreasing in size posteriorly; (12) posterior blade-like process of maxilla absent; (13) teeth extending posterior to notch in dorsolateral maxillary lamina; diastema and enlarged fangs absent; (14) pterygoid teeth numerous, reaching posterior point of divergence of pterygoids; (15) tracheal lung absent; (16) heart-liver gap large; (17) capitulum of hemipenis covered in papillate calyces; (18)

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sulcus spermaticus bifurcating within capitulum; (19) base of hemipenis encircled by rows of large spines separated from pair of basal hooks by asulcate patch; (20) nude basal pocket present on lateral side of hemipenis.

Etymology.—The new name is a feminine noun formed by adding the prefix plesio(derived from the Greek word plesios meaning near) to the generic name Dipsas (derived from the Greek word for thirst).

Content and Range.—Plesiodipsas is a monotypic genus currently known only from the northeastern Andes of Colombia and Serranı´a de Perija´ of Venezuela.

Plesiodipsas perijanensis (Alema´n) Tropidodipsas perijanensis Alema´n, 1953:217.

Holotype female (MHNLS 655) from ‘‘Jamayaujaina, Sierra de Perija´’’ Zulia, Venezuela, 1700 m (10u009010N, 72u559010W), collected

by Ramo´n Urbano.

Dipsas perijanensis (Alema´n): Peters, 1970: 394; Peters and Orejas-Miranda, 1970:88.

Diagnosis and definition.—Plesiodipsas perijanensis is defined by the following characters: (1) dorsals usually 17 (occasionally 15, 18, or 19) reducing to 15; (2) temporals excluded from orbit by postoculars; (3) usually one pair of infralabials in contact behind mental; (4) infralabials broadly contacting third pair of chinshields; not contacting preventrals or ventrals; (5) loreal taller than long, excluded from orbit by lower preocular; (6) prefrontals excluded from orbit by upper preocular; (7) dorsal surface of head black with large yellow spots on most scales; (8) labials barred yellow and black; (9) nuchal region like dorsal surface of head, black scales with yellow markings; first blotch not reaching rictus, separated from parietals by 4–7 vertebrals; (10) dorsum lichinose with both blotches and interspaces heavily stippled with contrasting pigments; bands edged broadly first in yellow then in black; (11) blotches usually not complete ventrally; longer or equal to interspaces; (12) interspaces heavily stippled, large accessory blotches absent; (13) venter cream to yellow with extensive black markings; short black bars interrupting interspaces anteriorly; (14) ventrals 188 in males, 186–195 in females; (15) subcaudals 88–92 in males, 79–83 in females; (16) maxillary teeth 16.

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Comparisons with Dipsas sanctijoannis and Dipsas variegata.—Of the various snakes present in northern Venezuela and Colombia, Plesiodipsas perijanensis is most likely to be confused with Dipsas sanctijoannis. Like P. perijanensis, D. sanctijoannis has a lower preocular excluding the loreal from the orbit.

Among other species of Dipsas, a lower preocular normally excludes the loreal from the orbit only in D. catesbyi, although the lower preocular may appear as a rare scale anomaly in other species.

Inspection of Table 1 reveals considerable similarity between Plesiodipsas perijanensis and Dipsas sanctijoannis. However, unlike D. sanctijoannis (characteristics in parentheses), P. perijanensis lacks presuboculars (usually present), usually has 17 dorsal scale rows reducing to 15 (15 reducing or not to 13), and has more blotches on the body (33–43 compared to 21–28) and tail (18–25 compared to 11–17). Although the anterior blotches are about the same size, the first blotch lies further back on the neck in P. perijanensis than in D. sanctijoannis. In D. sanctijoannis, the anterior blotches are complete ventrally; however, they fail to meet in P. perijanensis.

Peters (1970) suggested that the holotype of Plesiodipsas perijanensis might be an anomalous specimen of Dipsas variegata. Unlike D. variegata (characters in parentheses), P. perijanensis has a subacuminate snout and eyes not visible from below (snout rounded, eyes protruding and visible from below), 17 dorsals usually reducing to 15 (15 dorsal without reduction), one pair of infralabials in contact behind the mental (two pairs), infralabials broadly contacting the second and third chinshields (sublabials usually separating infralabials from second and third pairs of chinshields on one or both sides), and the preocular excluding the loreal from the orbit (loreal usually entering orbit). Dipsas variegata also has very different coloration. Its dorsum is light gray or tan with black or brown streaks and markings. Its labials are light gray with or without narrow dark brown edging, whereas the head and labials of P. perijanensis are black and its labials bear prominent yellow bars.

External morphology.—Plesiodipsas perijanensis is a robust species reaching 812 mm in

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TABLE 1.—Comparison of morphological characters between Plesiodipsas perijanensis and Dipsas sanctijoannis. Mean 6 standard deviation then sample size follow ranges in parentheses.

Plesiodipsas perijanensis

Maximum length

Presuboculars

Male: 812 mm (2) Female: 812 mm (4) Males: 25–27% (2) Females: 21–25% (23 6 2, 4) 3.0–3.6% (3.3 6 0.2, 6) 19–22% (20 6 1, 6) 19–21% (19 6 1, 6) 61–103% (77 6 15, 6) 50–94% (68 6 16, 6) Males: 188 (2) Females: 186–195 (190 6 4, 4) Males: 88–92 (2) Females: 79–83 (80 6 2, 4) 17 – 15 (or 18–16) n 5 5 15 – 15 n 5 1 Absent n 5 12

Blotches on body Blotches on tail Length of first blotch Distance to first blotch Anterior blotch/interblotch ratio Maxillary teeth

33–43 (37 6 4, 6) 18–25 (22 6 3, 5) 4–6 (5 6 1, 6) 4–7 (5 6 1, 6) 1.3–3.5 (2.4 6 0.7, 6) 16 (3)

Tail length/total length Head length/SVL Eye-nostril/head length Eye diameter/head length Loreal length/height First chinshield width/height Ventrals Subcaudals Dorsals

total length. The tail accounts for 21–25% (23 6 2, 4) of total length in females and 25–27% (2) in males; the head (Fig. 2) is weakly distinct from the neck, terminates in a subacuminate snout, and accounts for 3.0– 3.6% (3.3 6 0.2, 6) of SVL in both sexes.

The internasal suture is sinistral (100%, 3) to the prefrontal suture. Sutures above and below the nostril divide the nasal; this scale is distinct from the first supralabial and overlaps its anterior margin. The loreal is higher than long [loreal length 61–103% (77 6 15, 6) of height] and excluded from the orbit by a tall, narrow preocular. A small, square preocular invariably excludes the prefrontals. Presuboculars are absent (100%, 12). The large eye accounts for 19–21% (19 6 1, 6) of head length; its distance from the nostril accounts for 19–22% (20 6 1, 6) of head length. The eye is not visible from below. Behind the eye, 1 (8%, 12) or 2 (92%, 12) primary, 2 (8%, 12) or 3 (92%, 12) secondary, and 2 (20%, 10), 3 (70%, 10), or 4 (10%, 10) tertiary temporals separate the parietals from the supralabials.

Modest shortening of the gape partially excludes the tertiary temporals and one specimen lacks them entirely. Two (100%, 12) postoculars completely exclude the tem-

Dipsas sanctijoannis

Male: 923 mm (6) Female: 701 mm (1) Males: 23–27% (26 6 1, 8) Female: 25% (1) 3.0–3.6% (3.2 6 0.2, 6) 21–26% (22 6 2, 6) 17–25% (22 6 3, 6) 55–77% (66 6 7, 6) 49–147% (108 6 41, 6) Males: 182–187 (185 6 2, 7) Female: 182 (1) Males 74–98 (91 6 9, 8) Female: 80 (1) 15 – 15 n 5 3 15 – 13 n 5 3 Absent n 5 1 Present n 5 9 21–28 (24 6 3, 8) 11–17 (13 6 3, 4) 4–6 (5 6 1, 6) 3–4 (3 6 0, 6) 2.0–2.5 (2.1 6 0.2, 6) 16–17 (2)

porals from the orbit. This species has 8 (100%, 12) supralabials and 10 (8%, 12), 11 (58%, 12), or 12 (33%, 12) infralabials. Two (100%, 12, invariably supralabials 4–5) supralabials enter the orbit. In all specimens (100%, 12), a single pair of infralabials is in contact behind the mental. Usually (67%, 12), infralabials broadly contact the first three of four pairs of chinshields; however, they do not contact the preventrals or ventrals in this species. Less frequently (33%, 12) infralabials fail to reach the third pair; they always contact the first two pairs and sublabials (sensu Harvey and Embert, 2008) are absent.

In Plesiodipsas perijanensis, 186–195 (190 6 4, 4) ventrals and 79–83 (80 6 2, 4) subcaudals in females and 188 (2) ventrals and 88–92 (2) subcaudals in males follow 0–3 preventrals. Dorsal counts in this species are highly variable. UIS 1244 has 15 scale rows without reduction. However, most specimens (67%, 12) have 17 scales at midbody reducing to 15. In two specimens, this fusion occurs far anteriorly (74–75 ventrals in front of the vent), in one specimen relatively far posteriorly (27 ventrals in front of the vent), and in one specimen less than one head length in front of the vent (6 ventrals in front). In several places

Inserting far anterior on dentary Present Turned inward In front of notch Absent Large Unreported Inserting far anterior on dentary Present Turned inward In front of notch Present Small Unreported 8.

9.

10.

11.

12.

13.

Posterior blade-like process of maxilla Maxillary teeth Posterior extent of maxillary teeth Tracheal lung Heart-liver gap Left lung

Inserting far anterior on dentary Absent Turned inward Behind dorsolateral notch Present Small Saccular or absent Inserting far anterior on dentary Absent Turned inward Behind dorsolateral notch Absent Large Faveolar

Present Enlarged 13 or 15 Same as at midbody Small Lateral Absent Small 13 or 15 Same as at midbody Small or L-shaped Medial Absent Small 17 Reducing to 15 Large, rhomboidal Medial

Mental groove Penultimate supralabial Dorsals Dorsal count on posterior body Harderian gland Position of Harderian gland relative to m. levator anguli oris 7. m. levator anguli oris 1.

2.

3.

4.

5.

6.

Sibon Dipsas and Sibynomorphus Plesiodipsas perijanensis

TABLE 2.—Characters used in cladistic analysis of Plesiodipsas perijanensis. Derived characters are in bold font.

Present Enlarged 17 Same as at midbody Small Lateral

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Tropidodipsas sartorii

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anterior to the reduction site, only 16 scales are present due to fusion of one of the paravertebral rows to the vertebral scale row.

These counts typically extend for only one or two rows of dorsals, but a count of 16 dorsal rows may extend for up to about 10 segments in some instances. Through loss and fusion of one or both paravertebral rows, the vertebrals are slightly enlarged on the posterior body.

Both Alema´n (1953) and Peters (1970) counted 19 scale rows at midbody on the holotype; one of us (G. Rivas) counted 18 reducing to 16. Peters (1970) called attention to the irregular dorsal counts of the holotype when he remarked, ‘‘the holotype of T. perijanensis has counts of 19 on most parts of the body, often 18, and occasionally 17.’’

The dorsal scales of this species (including those of the neck, body, and tail) are smooth and lack keels or obvious, raised striations.

Apical pits are absent from the neck, body, and tail. In both males and females, lenticular scale organs (sensu Harvey and Gutberlet, 1995) cover scales of the head and are numerous on the chin. In males only, distinct chin tubercles are present, elevating the scale organs above the surface of the surrounding skin. Supracloacal tubercles are absent.

Overall, the cryptic dorsal pattern of Plesiodipsas perijanensis is best described as lichenose (Figs. 1, 3). It is a black snake with yellow to yellowish-green markings; virtually every scale on the body has these two colors in varying amounts. On the dorsal surface of the head, each of the internasals and prefrontals contains a large yellow blotch, an elongate yellow stripe extends obliquely across each parietal, and scattered yellow spots mark the remaining scales. The mostly yellow supralabials have wide black edges. A distinct nuchal band is absent; instead a few rows of yellow and black scales separate the first blotch from the rictus. Four to seven (5 6 1, 6) vertebrals lie between the parietals and the first blotch.

The chin is mostly cream to yellow although most scales have wide black margins. Along the juncture of the chinshields, these margins form a continuous stripe in some specimens, truncated by white scales before the ventrals.

This species has 33–43 (37 6 4, 6) blotches on the body and 18–25 (22 6 3, 5) on the tail.

Each blotch is edged widely in black and has a

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FIG. 3.—Specimen of Plesiodipsas perijanensis (CAS 116319, female, SVL 600 mm) from Socorpa Mission, Ce´sar, Colombia.

lightly pigmented center. In both the interspaces and centers of blotches, the dorsals are yellow and have a black line down their centers. However, within the centers of the blotches, these scales are made darker by additional black edging around each scale.

The blotches fuse dorsally to form bands or are staggered along the midline. Ventrally they are incomplete; although black pigment is so extensive on the posterior body that their ventral edges cannot be discerned. The first blotch extends for 4–6 (5 6 1, 6) vertebrals.

The anterior blotches are about twice as long as the interspaces and extend for about 4–7 dorsal scale rows; the interspaces extend for about 2–4 dorsal scale rows (blotch/interblotch ratio 1.3–3.5, 2.4 6 0.7, 6). Posteriorly, the blotches shorten to 2–3 scale rows and are

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shorter than the interspaces. The interspaces lack accessory blotches of any kind and are interrupted ventrally by black markings.

Ventral pigmentation increases posteriorly and the tail is almost entirely black ventrally.

Hemipenis.—Plesiodipsas perijanensis has a cylindrical, bulbous (i.e., not bilobed), and fully capitate hemipenis (Fig. 4). The capitulum terminates proximally in a free flap interrupted by the sulcus spermaticus; a weak capitular arch is present on the asulcate side.

The sulcus spermaticus bifurcates a short distance into the capitulum and its branches form a widely obtuse angle as they extend to the sides. Each branch gradually terminates into the surrounding calyces, stopping on the sides only about half-way to the distal tip of the organ. Papillate calyces cover the capitulum. Development of the papillae is more or less uniform across the capitulum. About six rows of papillae located proximally are calcified, including all of the papillae proximal to branches of the sulcus spermaticus. A medial band of four additional rows of papillae (i.e., 10 rows total counted from the flap of the capitular arch) are calcified on the asulcate side. Additionally, a few papillae in the first row distal to the bifurcation of the sulcus are calcified.

On the asulcate side of the organ, a single row of relatively long, straight spines with weakly curved tips is followed by about four rows of shorter, strongly curved spines.

Medially, a broad, asulcate patch interrupts the spine rows and separates spines of the capitular arch from a pair of basal hooks. The medial hook is about half again as large as the lateral hook, and both bear sharply curved tips. Small spinules cover the base of the organ, including the asulcate patch. The spines, hooks, and spinules are all calcified, and long, robust calcified struts support them.

Tips of the papillae and the long straight spines are rounded, slightly bulbous, and blunt, whereas tips of the curved spines, basal hooks, and spinules are sharply pointed.

Approaching the sulcus, the number of spines reduces from four to two on the lateral side and to one on the medial side (i.e., one medial and two parasulcal spines are present in this species). Obviously offset parasulcal spines, like those described for other Dipsa-

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HERPETOLOGICAL MONOGRAPHS

FIG. 4.—Sulcate (A) and asulcate (B) surfaces of the hemipenis of Plesiodipsas perijanensis (UIS 1243) with calcified structures revealed by Alizarin staining.

dini (Harvey and Embert, 2008) cannot be discerned, because the spines increase in number along a continuous slope on either side of the sulcus. A proximal spine three rows removed from the sulcus appears to be at

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about the same position as the offset spines in other Dipsadini. In this species, the lateral spine in this position is about the same size as the smaller hook and is slightly larger than its counterpart on the medial side.

A nude pocket flanked by rounded, fleshy walls begins on the lateral side of the organ and curves rather sharply medially to terminate at the edge of the asulcate patch. It only extends for about one-fourth of the length of the everted organ. Three large, curved spines sit atop the sulcate wall of the pouch, whereas only spinules cover the asulcate wall. The floor and lower walls of the pouch are entirely nude. A few spinules appear at the upper reaches of the walls of the pouch.

Visceral morphology.—The trachea consists of about 218 (i.e., 17 cartilages lie within a 10 mm stretch in front of heart) narrowly spaced, cartilaginous rings, very few of which bifurcate or fuse laterally. Right and left bronchi are absent, and a small (5.8 mm, 1.0% of SVL), entirely faveolar left lung (Fig. 5) attaches to a left tracheal orifice just anterior to the apex of the heart. A tracheal lung is absent, although the cartilages do form a trough embracing about one-half to threequarters of the trachea. Thus, as in most snakes, the trachea opens dorsally into a tracheal ‘‘chamber’’ continuous with the right lung. Faveoli extend into the cardiac region, grade into trabeculae, then disappear all together about 3 mm in front of the heart.

The tracheal chamber does not appear to be vascularized (numerous branches of the pulmonary artery and vein are evident on the ventral surface of the right lung, but are absent from the trachea). Unlike the tracheal lungs of Dipsas and Sibon, the walls of the tracheal chamber are not distended and extensible. Within the right lung, faveoli extend for 26.2 mm (4.4% of SVL; extent on either side of liver not asymmetrical) before grading into the saccular portion of the lung.

In this specimen, the snout-heart interval (128 mm) accounts for 21.5% of SVL. The heart is 14.5 mm (2.4% of SVL) long, and a gap of 42.8 mm (7.2% of SVL) separates it from the liver. The liver extends for 168 mm (28.2% of SVL) and lies 50.3 mm (8.4% of SVL) in front of the gall bladder.

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FIG. 5.—Viscera of Plesiodipsas perijanensis (UIS 1243).

Cephalic glands and musculature.—The premaxillary gland (Fig. 6) is triangular and extends dorsally to overlap the anterior edges of the nasal bones; ventrally it fuses with the long, narrow supralabial gland below the naris. A small, oval-shaped gland lies postero-ventral to the naris overlapping the upper edge of the supralabial gland. This structure (presumably the juxtanarial gland described

by Savitzky, 1972, for Chersodromas, Ninia, and Nothopsis) may be part of the supralabial gland; however, it is a shade darker in color and its superficial epithelium contains denser melanophores than does adjacent epithelium of the supralabial gland. A large, rectangular nasal gland edges the naris and the prefrontal, frontal, and nasal bones; ventrally it reaches a line drawn from the center of the naris to the center of the eye and it is widely separated from the supralabial gland. The small, oval rictal gland is an inconspicuous structure closely adhering to extensible skin of the

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rictus, just below the quadratomaxillary ligament. Circular pores in skin overlying the rictal gland may drain this structure, although ducts could not be distinguished with a stereoscope.

The Harderian gland is massive and rhomboidal; at either end, it posses prominent, oval-shaped swellings, each projecting laterally between overlying muscles and, thus, visible externally when the skin is removed. The anterior swelling of the Harderian gland extends into the triangular space between the antero-ventral edge of the m. levator anguli oris and postocular ligament; whereas, the posterior swelling abuts the rictal gland where the swelling extends into the space between the m. adductor mandibulae externus, pars superficialis, and m. levator anguli oris.

Except for these swellings, the Harderian gland lies medial to the m. levator anguli oris and m. adductor mandibulae externus (including pars superficialis and pars medialis), filling most of the concave space between the prootic and orbit. Finally, the Harderian gland has a broad flat anterior expansion, extending into the orbit to encircle the lower two-thirds of the medial side of the eye and cupping the entire ventral surface of the eye between the eye and palatomaxillary arcade. Plesiodipsas perijanensis lacks a Durvenoy gland.

At the corner of the jaw, the m. constrictor colli separates the quadratomaxillary ligament from the skin, and the ligament can no longer be distinguished from the quadrate aponeurosis (sensu Rieppel, 1980) at the level of the quadrate. Nonetheless, the ligament is distinct from the aponeurosis just anterior to the m. depressor mandibulae. Anterior to the m. constrictor colli, the quadratomaxillary ligament adheres closely to skin overlapping the m. adductor mandibulae externus, pars superficialis, and m. levator anguli oris. In fact, several fibers branch off dorsally from the ligament and insert firmly on the basement membrane of the dermis in this region of the head. The ligament then extends medial to the supralabial gland to loop around the m. levator anguli oris and continue under the braincase where it attaches to the posterior edge of the maxilla.

The m. levator anguli oris is unusual in arising by two distinct slips. Except for a few

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FIG. 6.—Subintegumentary, cephalic morphology of Plesiodipsas perijanensis (UIS 1243; m. cervicomandibularis and quadratomaxillary ligament both bisected). Labels identify the quadrate aponeurosis (qa), rictal gland (RG), Harderian gland (HG), supralabial gland (SL), juxtanarial gland (JN), nasal gland (NA), premaxillary gland (PM), m. levator anguli oris (loa), m. cervicomandibularis (cer), m. depressor mandibulae (dm), m. intermandibularis posterior superficialis (int), and m. adductor mandibulae externus, pars medialis (med), pars posterior (pos), pars profundus (prf), and pars superficialis (sup).

fibers attached to the anterolateral (postfrontal) process of the parietal, the anterior slip of the m. l. a. oris arises from the lateral face of the postorbital ligament and postorbital bone.

Fibers accounting for the antero-ventral onesixth of the muscle pass deeply to arise from the medial face of the postorbital bone. The anterior slip edges the m. adductor mandibulae externus, pars superficialis, and passes medial to the quadratomaxillary ligament and rictal gland. The posterior slip might easily be mistaken for the m. a. m. e., pars medialis, because it overlaps the anterior one-half of this muscle’s fan-like origin. Medial to the m. a. m. e., pars superficialis, the fibers of the posterior slip and the fibers of the m. a. m. e., pars medialis, diverge, the latter passing posterior to the lateral expansion of the Harderian gland and those of the posterior slip passing anterior to the lateral expansion.

The two slips of the m. l. a. oris fuse medial to the infralabial gland and insert far anteriorly via a short tendon (beginning between dentary teeth 5–7, counted from the anterior tip of mandible backward) on the ventral edge of the dentary below teeth 3–5.

The m. adductor mandibulae externus, pars superficialis, arises from the edge of the anterolateral process, the lateral edge of the parietal between the origins of the two slips of the m. levator anguli oris, and the surface of the m. l. a. oris itself. On the anterolateral process, the origin is fleshy, although a short, triangular tendon (longest posteriorly) forms most of the origin of this muscle. The muscle is about 60% larger than the anterior slip of the m. l. a. oris with which it runs parallel until the m. l. a. oris curves sharply anterior around the quadratomaxillary ligament and rictus.

Posterior to the rictal gland, the carnose region terminates and its aponeurosis fuses to the quadrate aponeurosis to attach along the lateral face of the quadrate and retroarticular process of the compound bone.

The m. adductor mandibulae externus, pars medialis, arises from the lateral edge of the parietal and fascia covering part of the origin of the m. a. m. e., pars profundus. The broad, fan-like origin of the m. a. m. e., pars medialis, extends anteriorly for a short distance under the posterior slip of the m. levator anguli oris.

Its fibers extend ventrally and deeply to fill the

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space between the Harderian gland and prootic and insert along the medial surface of the compound bone. The posterior portion of the insertion is fleshy, and a short aponeurosis forms the anterior half of the insertion.

The m. adductor mandibulae externus, pars profundus, has a narrow origin on the anterior and dorsolateral face of the prootic, roughly at the level of this bone’s sutures with the parietal and supratemporal. Its fibers extend ventrally, at first paralleling and closely adhering to fibers on the anterior face of the m. a. m. e., pars posterior. About half-way to the mandible, the fibers of the m. a. m. e., pars profundus, curve anteriorly to insert along the dorsomedial edge of the compound bone dorsal to and extending more anteriorly than the m. a. m. e., pars medialis. The fibers of the m. a. m. e., pars profundus, are oriented at about 10u to those of the m. a. m. e., pars medialis, and a small portion of the m. a. m. e., pars medialis, is visible externally through a triangular space between the m. a. m. e., pars profundus and pars posterior.

Two large muscles covering the quadrate are the m. adductor mandibulae externus, pars posterior, and the m. depressor mandibulae.

Both muscles have long fleshy origins from the shaft of the quadrate, extending dorsally to fascia covering the supratemporal. The m. depressor mandibulae does not have a discrete occipital slip. The m. a. m. e., pars posterior, covers the antero-lateral face of the quadrate; it passes medial to the quadratomaxillary ligament and quadrate aponeurosis to form a fleshy insertion along the retroarticular process and compound bone. Its anterior extent abuts the m. a. m. e., pars medialis. The m. depressor mandibulae covers the posterolateral face of the quadrate and inserts on the caudal tip of the jaw.

We reached the jaw adductors by first reflecting the m. constrictor colli, a thin muscle arising from dorsal fascia along the midline. Its origin overlaps the anterior edge of the m. cervicomandibularis, which appears to extend as far anteriorly as the fourth vertebra (its anteriormost fibers arise from just below the fourth vertebral scale when the skin is in place). The origin of the m. cervicomandibularis extends posteriorly to

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the level of the tenth vertebral scales behind the parietal scales. Its fibers converge to insert on the posterior tip of the mandible, ventral to the insertion of the m. depressor mandibulae, and along the posterior edge of the quadratomaxillary ligament. The insertion is oriented at about the same angle as the quadrate and its fibers are oriented along a line drawn between the m. a. m. e., pars posterior, and m. depressor mandibulae.

Although we did not dissect the mandibular and hyoid muscles, we nonetheless noted a peculiar condition of the m. intermandibularis posterior superficialis. This long, strap-like muscle arises from the depressed area ventral to the retroarticular process on the lateral face of the compound bone. In contrast to the condition in most colubrids (Langebartel, 1968), the fibers extend anteriorly to insert by a series of slips across the center of each of the three anterior chinshields. It does not insert on a fourth pair of chinshields.

Osteology.—The skull of Plesiodipsas perijanensis resembles that of other Dipsadini (Fernandes, 1995; Kofron, 1980, 1982, 1985; Scott, 1967). In this section, we focus on characteristics mentioned in other reviews of dipsadine osteology. Previous authors relied heavily on dentigerous bones when making comparisons among Dipsadini, and we describe these bones in detail. During clearing and staining, several bones became disarticulated and the postorbitals were lost. Their description is based on observations made while studying the jaw musculature.

Braincase: The dorsal lamina of the nasal (Fig. 7) is subtriangular and narrowly overlies the frontal; it is widely separated from the prefrontal. The ventral lamina deepens posteriorly so that a wide space separates it from the ascending process of the premaxilla. The frontal is subrectangular and a little more than one-half the length of the parietal. It extends to the posterior one-fourth of the orbit. The relatively small optic fenestra occupies about one-fourth of the height of the fronto-parietal articulation inside the orbit. The fenestra is positioned ventrally in the orbit, closely approximating but not bordering the sphenoid. The parietal has a prominent postorbital process excluding the frontal from the thin, blade-like postorbital bone. The anterior edge

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FIG. 7.—Braincase of Plesiodipsas perijanensis (UIS 1243).

of the parietal is slightly curved where it articulates with the frontal. Low dorso-lateral crests on the parietal extend posteriorly from the postorbital process and demarcate origins of the adductor muscles. The relatively short, wide sphenoid has a trough-shaped anterior process, terminating in a single point.

Palato-Maxillary Arcade: A thin, dorsally rounded ascending process of the premaxilla ends about 1 mm below the nasals. It forms a thin partition between the nasal capsules and extends posteriorly for a short distance between the vomers. Ventrally, the anterior edge (5center and transverse processes) of the premaxilla is shallowly concave. A prominent, acutely pointed process extends below the maxilla-premaxillary articular surface at the ends of each transverse process. The vomers are firmly braced atop a relatively robust vomerine process of the premaxilla.

This process bears an acute V-shaped notch between the vomers, posteriorly.

The maxilla (Fig. 8) is a short bone bearing 16/16 long, curved teeth and three laminae. A

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FIG. 8.—Elements of the palato-maxillary arcade of Plesiodipsas perijanensis (UIS 1243). Abbreviations in figure of pterygoid and ectopterygoid (A, ventral aspect) identify the antero-lateral process of the ectopterygoid (ale) and antero-medial process of the ectopterygoid (ame); abbreviations in figure of maxilla (B, ventro-lateral aspect) identify the palatine articular process (pap), dorsolateral maxillary lamina (dll), lateral maxillary notch (lmn), lateral ectopterygoid articular process (lep), posteromedial maxillary lamina (pml), post-dental maxillary ridge (pdr); and abbreviations in figure of palatine (C, medial aspect) identify the dorso-lateral palatine lamina (dpl) and dorsal process of the palatine (dpp).

robust palatine articular process extends along the anterior extent of the maxilla; it abruptly narrows and terminates between the 10th and 11th maxillary teeth. The dorso-lateral lamina articulates with the prefrontal and is oriented laterally at about 70–80u to the palatine articular process. It begins just behind the seventh tooth and extends to the terminus of the maxilla. It widens gently to the level of the 14th tooth, narrows to form a wide shallow notch (herein referred to as the ‘‘lateral maxillary notch’’), then widens slightly where it articulates with the lateral process of the ectopterygoid. This lateral maxillary notch lies just anterior to the lateral ectopterygoid articular process and between the last two maxillary teeth. Thus, whereas teeth do not extend beyond the notch in many Sibon and Tropidodipsas (Kofron, 1980), one tooth lies

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posterior to it in Plesiodipsas perijanensis. A distinct, blade-like postero-lateral process like that described by Kofron (1980; 1985) and Scott (1967) is absent. A wide, short posteromedial lamina articulates with the medial process of the ectopterygoid and extends from the posterior tip of the maxilla to the anterior edge of the penultimate maxillary tooth. A low ridge of bone (post-dental maxillary ridge) behind the last tooth demarcates the lateral border of the postero-medial maxillary lamina.

The ectopterygoid is a short, edentate, Y-shaped bone. Its anterolateral process is two times as wide as its anteromedial process.

The shaft of this bone is cylindrical. Posteriorly, it bears a tab-like process articulating with the dorsal surface of the pterygoid.

Plesiodipsas perijanensis has a long, welldeveloped pterygoid bearing 18/18 teeth along its medial edge. This bone is concave ventrolaterally and widest posteriorly. The pterygoids are weakly divergent posteriorly (sensu Peters, 1960) and toothed to the point of divergence. They extend to the quadrate but do not articulate with it. The palatine bears 10/11 teeth and is a long, narrow element. It has a robust dorso-lateral lamina firmly articulating with the palatine articular process of the maxilla and a long, narrow, arch-shaped dorsal process extending to the ventral surface of the braincase. At the tip of this process, the palatine bears a short, peg-like articulation with the posterior process of the vomer.

Teeth of the palato-maxillary arcade and dentary are curved and lack grooves. They decrease in size posteriorly; abrupt transitions in size and diastemas are absent. The last dentary tooth is only about one half as long as the first, and teeth of the posterior process of the dentary are rotated inward to about 60u of horizontal, whereas teeth of the anterior half of the dentary are oriented vertically. As in most other Dipsadini, the maxillary teeth of Plesiodipsas perijanensis are directed ventromedially at about 30u to vertical.

Suspensorium and Mandible: The dorsal head of the quadrate is wider than the shaft due mainly to an expanded dorso-posterior crest, which articulates with the supratemporal bone. The greatest width (along the dorsal edge of the quadrate-supratemporal articular surface) of the quadrate is one-half

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FIG. 9.—The quadrate and mandible (both in lateral aspect; mandible broken in half) of Plesiodipsas perijanensis (UIS 1243). Abbreviations identify the angular crest (anc), dorsal head of the quadrate (dhq), dorsoposterior crest (dpc), posterior maxillary process (pmp), retro-articular process (rap), splenial (spl), and ventrolateral ridge (vlr).

its greatest length. The head of the quadrate is slightly larger than the supratemporal bone with which it articulates. On the lateral face of the quadrate, a low, ventro-lateral ridge (Fig. 9) extends for a short distance above the condyle. The supratemporal is reduced relative to other xenodontines (Fernandes, 1995) and extends anteriorly for about threefourths of the length of the prootic, terminating where it abuts the posterior edge of raised bone forming the anterior semicircular canal.

Posteriorly, the supratemporal overlies raised bone of the posterior semicircular canal passing through the exoccipital.

The mandible is very weakly curved in the vertical plane. The dentary is relatively thin;

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its posterior process accounts for 60% (measured from the anterior tip of the compounddentary pivot joint to tip of dentary) of its length. A pivot joint between the dentary and compound bone likely allows some abduction of the dentary, because the joint is open on the lateral face of the mandible. Medially, the angular and splenial border the joint, possibly preventing adduction. The angular forms the posterior edge of the anterior mandibular foramen and sends a short process above it onto the compound bone, just behind its articulation with the dentary. The splenial forms the ventral margin of the mandibular foramen and extends forward to partially enclose the Meckelian fossa for about onehalf its length. The splenial does not contact the low ridge of the dentary forming the dorsal border of the fossa. The surangular crest is slightly larger than the angular crest and flares outward at about 80u to horizontal.

In contrast, the angular crest is oriented vertically. Plesiodipsas perijanensis has a small, subrectangular retroarticular process.

Distribution and natural history.—Most of the new Colombian specimens come from highly disturbed areas between 1400–2100 m in the Andes of Santander Department (Fig. 10). These areas were once covered with humid, upper montane forest, although most of the original habitat has been cleared.

Specimens in the UIS were collected at the edge of pine forests (Pinus patula) or in ecotones between pine forest and secondary growth. Two specimens were found dead either on a road (UIS 1228) or in front of a municipal building (UIS 1211). UIS 1243 was found in a coffee plantation, whereas UIS 1244 was collected while it was crossing a road. J. R. Caicedo P. found UIS 1242 at 2036 hrs in forest, the specimen was at rest about 1.5 m above ground in a bush. UIS R1211 regurgitated a slug when it was killed and preserved.

We do not know if Plesiodipsas perijanensis is arboreal or mostly terrestrial. Enlarged vertebrals and eyes visible from below are two characters usually associated with arboreal Dipsadini; P. perijanensis lacks these characteristics. However, its tail is as long as the tails of arboreal species such as D. sanctijoannis, and J. R. Caicedo’s observation

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FIG. 10.—Known distribution of Plesiodipsas perijanensis along northern border of Venezuela and Colombia.

Areas above 500 m are shaded gray.

of a specimen 1.5 m aboveground in a bush suggests that this species is at least semiarboreal.

DISCUSSION External morphology and hemipenes of Dipsadini.—Alema´n (1953) did not elaborate on his reasons for assigning Plesiodipsas perijanensis to the genus Tropidodipsas.

Familiar with Dipsas variegata and Sibon nebulatus, Alema´n likely realized that this distinctive dipsadine could not be congeneric with either of these species. Peters (1970) examined the holotype and noted the subrectangular chinshields and absence of a mental groove. However, some of his other remarks are misleading or incorrect. As is evident in Alema´n’s (1953) photo of the holotype, the head is somewhat distorted.

The distortion, likely led Peters (1970) to state that in this species, ‘‘the head is blunt and rounded, distinct from neck. The eyes are prominent, positioned laterally, and can be seen from below.’’ These statements would be an accurate description of most Dipsas and Sibon; however, they do not correctly describe

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P. perijanensis. The eyes of P. perijanensis are not visible from below, its head is only slightly distinct from the neck, and its snout is subacuminate.

Occasional specimens of Dipsas, Sibon, and Sibynomorphus have 17 dorsal rows (Fernandes et al., 2002; Harvey and Embert, 2008), and Peters (1970) suspected that this might be the case with Plesiodipsas perijanensis. Noting that D. polylepis might be an aberrant specimen of a species in the D. pratti group, Peters (1970) speculated that P. perijanensis might be an aberrant specimen related to D. variegata. Data from our larger series show Peters’ speculation to be incorrect. Unlike all other Dipsadini, Plesiodipsas perijanensis usually has 17 middorsal scale rows, normally reducing to 15. Seventeen middorsal scale rows normally occur in most species of Tropidodipsas, whereas species of Dipsas, Sibon, and Sibynomorphus have 15 or 13 scale rows. Occasional specimens show reduction on the posterior body, but normally the counts are constant in Dipsas, Sibon, Sibynomorphus, and Tropidodipsas.

Species of Sibon and Tropidodipsas have an enlarged penultimate supralabial, which contacts a postocular and the primary and secondary temporals. These genera retain a relatively well-defined mental groove flanked by pairs of elongate chinshields. In contrast, the penultimate supralabial is not enlarged, the mental groove is lost, and the chinshields are more or less rectangular in species of Dipsas and Sibynomorphus. For each of these characters, P. perijanensis unequivocally has the traits of Dipsas and Sibynomorphus.

The Dipsadinae share three derived hemipenial characters (Myers and Cadle, 1994; Zaher, 1999): (1) reduction or loss of bilobation, (2) capitation, and (3) bifurcation of the sulcus spermaticus within the capitulum. On the other hand, a hemipenial character has yet to be identified as a synapomorphy of the Dipsadini. Every potential character we could think of also occurs in outgroup taxa. A basal pocket on the lateral edge of the hemipenis occurs in several dipsadine genera such as Atractus (Schargel and Castoe, 2003; Myers, 2003) and Geophis, Leptodeira, and Ninia (this study). Spines encircle the base of hemipenes in several dipsadine genera, as

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well as in various Xenodontinae. Basal hooks separated by an asulcate patch occur in Geophis and Ninia. One or two offset parasulcal spines occur in some species of all Dipsadinae examined in this study.

Viscera and musculature.—Wallach (1995) observed that Dipsas, Sibon, and Sibynomorphus share two derived visceral characters: (1) a relatively short heart-liver gap, and (2) a welldeveloped, tracheal lung. Harvey and Embert (2008) examined additional species of Dipsas, confirmed Wallach’s characters for these species, and noted that, when present in Dipsas, the left lung is saccular rather than faveolar.

Tropidodipsas and Plesiodipsas perijanensis lack these derived traits. They have long heart-liver gaps and lack a tracheal lung.

Moreover, the left lung of Plesiodipsas is not saccular, being lined with faveolar parenchyma.

In most snakes, a ‘‘true’’ m. levator anguli oris inserts on the rictal plate, as is the case in lizards (McDowell, 1986; Rieppel, 1980; Zaher, 1994). However, a muscle in some dipsadines referred to by the same name (e.g., Fernandes, 1995; Moro, 1999; Zaher, 1994, 1999) inserts on the mandible. Following the same reasoning voiced by Rieppel (1988) in reference to the Viperidae, the muscle in dipsadines is likely to be a subdivision of the m. adductor mandibulae externus superficialis, which runs parallel to it and inserts next to it in some Dipsadinae such as Adelphicos, Atractus, Chersodromus, Geophis, and Ninia (Fernandes, 1995; Zaher, 1999). This observation further supports suspicions that the muscle has evolved independently in various colubroids (Zaher, 1994). Brongersma (1957), Dunn (1951), Haas (1931), and Peters (1960) all appreciated the significance of this muscle and its forward shift to the dentary in the Dipsadini. Among species with this anterior insertion of the m. l. a. oris, Fernandes (1995) distinguished two different states. He reported that Sibon and Tropidodipsas exhibit his character M01(2) (m. levator anguli oris ‘‘inserting on the anterior extremity of the jaw and a carnose region extending to the anterior third of the jaw’’), whereas Dipsas and Sibynomorphus exhibit his character M01(3) (‘‘inserting on the anterior extremity of the jaw with a small tendon’’). His observations expand on observations of earlier

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authors and firmly establish insertion of the m. l. a. oris as a synapomorphy of Dipsadini.

Unfortunately, Fernandes’ (1995) descriptions of his characters M01(2) and M01(3) are inadequate, and we do not see any difference between them. He failed to use specific landmarks when defining these characters referring to ‘‘the dentary’’ and ‘‘the anterior extremity of the jaw’’ as though these are different locations. From the definitions we quote above, one might conclude that presence or absence of a ‘‘small tendon’’ differs among these groups. However, in the same paragraph, Fernandes writes, ‘‘Sibon posses a more developed muscle, with the tendon reaching close to the anterior extremity of the jaw (state 2).’’ The muscle in Plesiodipsas perijanensis is like other species of Dipsadini in inserting anteriorly on the dentary by a short tendon.

None of the authors mentioned in the preceding paragraph report anterior and posterior slips of the m. levator anguli oris.

Nonetheless, the posterior slip might easily be mistaken for a part of the m. adductor mandibulae externus, pars medialis. We did not correctly identify the posterior slip until we bisected and reflected the m. a. m. e., pars superficialis. These two distinct slips of the m. l. a. oris are not unique to Plesiodipsas perijanensis. Dipsas catesbyi and D. indica lack them, but they are present in Sibynomorphus oneilli and Dipsas pavonina. We were unable to examine this muscle in other species and further study is required to determine how widespread the slips are.

Like species of Chersodromus, Enulius, Enuliophis, Geophis, and Ninia (Savitzky, 1972, his character P[1]; Fernandes, 1995, his character M01[1], Zaher, 1999), Plesiodipsas perijanensis has a very large Harderian gland. Interestingly, the gland is small in most Dipsas, Sibon, and Tropidodipsas. A large gland is present in Dipsas catesbyi, D. pavonina, Sibynomorphus neuwiedi, and S. ventrimaculatus; however, the gland of these species is L-shaped (Fernandes, 1995, his character M01[2]) rather than rhomboidal and does not reach the m. a. m. e., pars posterior.

Among the Dipsadini, only T. fischeri appears to have a relatively large rhomboidal gland similar to P. perijanensis. Savitzky (1972)

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observed that the enlarged Harderian gland of niniaform snakes lies internal to the m. adductor mandibulae externus, pars superficialis, whereas the much smaller gland of most colubrids occupies a triangular space ventral and anterior to this muscle, just behind the orbit. Expanding on these observations, Fernandes (1995) observed that Sibon and Tropidodipsas sartori are unique among xenodontines in having the Harderian gland positioned lateral to fibers of the m. levator anguli oris (Fernandes, 1995, his character M03[1]). In T. fischeri, the gland lies medial to the jaw adductors as it does in P. perijanensis. Also, as in P. perijanensis, the midsection of the m. levator anguli oris is removed from the jaw leaving a space between the muscle and the orbit where the Harderian gland is visible (Fernandes, 1995, his character M02 [0]) in T. fischeri.

Several additional characters of cephalic musculature vary among genera of the Dipsadinae, but do not vary among the Dipsadini.

With other Dipsadini, P. perijanensis shares a lateral origin of the m. adductor mandibulae externus medialis, pars superficialis, on the parietal (Fernandes, 1995, his character M04 [0]; also in all Dipsadinae except Hydromorphus and Tretanorhinus), a lateral origin of the m. a. m. e., pars medialis, on the parietal (M05 [1]; also in many other Dipsadinae), a posterior insertion of the m. a. m. e., pars profundus (M06 [0]; in all Dipsadinae except some Geophis and Ninia), and the origin of the m. cervicomandibularis anterior to the m. neurocostimandibularis (M08 [0]; in all other Dipsadinae except Adelphicos and Atractus; see also Irish, 1981). Although he commented in passing on the m. adductor mandibulae externus, pars superficialis, and the m. levator anguli oris, Savitzky (1972) only considered variation in the m. depressor mandibulae in his analysis of the niniaform snakes. Plesiodipsas perijanensis lacks a discrete occipital head of the m. depressor mandibulae (Savitzky’s, 1972, character R [1]; also found in Chersodromus, Ninia, and Nothopsis).

Plesiodipsas perijanensis lacks several characters of cephalic musculature reported only from some species of Dipsas and Sibynomorphus. In Sibynomorphus and most Dipsas (excluding only D. elegans and D. temporalis

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among species examined by Fernandes, 1995), the m. adductor mandibulae externus, pars profundus, inserts posterior to the level of its origin. The insertion is clearly anterior in P. perijanensis and even further anterior than the insertion of the m. a. m. e., pars medialis.

Several species of Dipsas are the only Dipsadinae that lack a quadratomaxillary ligament (Fernandes, 1995); however, this structure is well developed in P. perijanensis.

Fernandes (1995) mentions fibers of the m. a. m. e., pars superficialis, arising from the lateral surface of m. levator anguli oris in D. brevifacies. The triangular tendon of the m. a. m. e., pars superficialis, does attach to the posterior slip of the m. l. a. oris in P. perijanensis; however, Fernandes (1995) did not distinguish a posterior slip and would have been referring to the portion of this muscle homologous with the anterior slip in D. brevifacies.

Although he briefly describes the hyoids of many dipsadines, Langebartel (1968) included only a single species of Dipsadini (Dipsas catesbyi) in his survey of hyoid musculature.

Frustratingly, this species was neither illustrated nor commented upon in his descriptive section. Although we did not examine these groups of muscles in detail, we describe an unusual condition of the m. intermandibularis posterior superficialis. Langebartel (1968) found this muscle to be variably present in snakes with a parallel hyoid. However, the muscle is usually thin and aponeurotic, whereas it is relatively robust and entirely carnose in Plesiodipsas perijanensis. Interestingly, the muscle inserts laterally by slips on the chinshields in P. perijanensis, whereas it always inserts on the median raphe in other snakes (Langebartel, 1968). This muscle did not attach to a fourth pair of chinshields in our specimen. Peters (1960) describes a muscle extending from the postero-ventral margin of the mandible diagonally across the chin to attach to the opposite dentary, so that the muscle forms a ‘‘chiasma with its counterpart’’ (Peters, 1960). Nothing like this is present in P. perijanensis. Like Peters (1960), we suspect that the muscle he is describing and the m. i. p. superficialis of P. perijanensis are designed to overcome difficulties associated with feeding on snails. Since the fibers of the m. i. p.

[No. 22,

superficialis insert on the distinctive rectangular chinshields of P. perijanensis, it would be interesting to know if evolution of a new insertion is correlated with loss of the mental groove.

Osteology.—Elements of the palato-maxillary arcade have figured prominently in discussions of dipsadine systematics. Scott (1967) first commented on processes of the palatine and maxillary. He reported that Tropidodipsas annulifera entirely lacks the dorsolateral process of the palatine and noted that this process is reduced and probably never makes contact with the ventral surface of the skull in Dipsas gracilis, Sibon nebulatus, T. philippii, Geophis, and Ninia. While examining skulls of various Dipsadini, we noted considerable variation in processes of the palatine and suspect that further study of this bone would provide useful phylogenetic information. We describe two processes, a dorso-lateral lamina articulating with the maxilla and a dorsal process extending to the floor of the braincase. The processes in Plesiodipsas perijanensis are about the same size as those in S. nebulatus and D. indica.

The dorsal process of D. peruana is a much larger shelf of bone, firmly bracing the palatine against the skull. Like T. annulifera, Sibynomorphus ventrimaculatus lacks the dorsal process, although the lateral lamina is well developed and articulates with the maxilla in this species.

Plesiodipsas perijanensis lacks the bladelike posterior process of the maxilla found in some Sibon and Tropidodipsas (Fernandes, 1995; Kofron, 1980, 1985; Scott, 1967).

Although Kofron (1980) reports that both D. brevifacies and D. gaigeae have ‘‘a pronounced lateral process on the maxilla,’’ he is referring to the apex of the dorsolateral lamina located in front of the lateral maxillary notch, whereas the blade-like process of Tropidodipsas and Sibon is located posterior to the notch. The blade-like process is actually a modified ectopterygoid articular process; it provides ventral support to the ectopterygoid and extends laterally as far as the anterolateral process of the ectopterygoid. Kofron (1985; see also Haas, 1931) reported that the quadrato-maxillary ligament inserts on the blade-like process. In P. perijanensis, the

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insertion of the quadrato-maxillary ligament has shifted medially to the posterior edge of the maxilla, with a few fibers also inserting on the basement membrane of the dermis.

Whereas Kofron (1985) remarked that the quadrato-maxillary ligament ‘‘appears to contain muscle fibers,’’ there is no trace of muscle fibers in the ligament of P. perijanensis.

Kofron (1985) considered the blade-like process of the maxilla to be a synapomorphy uniting Tropidodipsas and Sibon. Fernandes (1995) confirmed Kofron’s observations and found this character only in species of Sibon and Tropidodipsas. Wallach (1995) questioned the importance of the character, citing Scott’s (1967) report of the process in Dipsas gracilis. Nonetheless, the character in D. gracilis should be confirmed; Scott (1967) may have been referring to a particularly welldeveloped dorsolateral lamina. The apex of the dorsolateral lamina is considerably pointed and attenuate in some species of Dipsas such as D. gaigeae (Kofron, 1982; his figure 2).

Having examined UMMZ 155635, Fernandes (1995) thought that T. fischeri lacks a bladelike process. We examined UMMZ 155635 and suspect that Fernandes reached his conclusion after examining the specimen’s left side where the tip of the process has been broken off. However, FMNH 20257 and UMMZ 155635 (on the intact right side) both have short, acutely pointed blade-like articular processes. Sibon carri, and the specimen of T. fischeri (UTA 7715) illustrated by Kofron (1980, his figure 7) have similar short, acutely pointed processes. In contrast, the process is more distinctly differentiated in other Sibon and Tropidodipsas.

Fernandes (1995) argued that Tropidodipsas fischeri belongs in its own genus. This species falls outside the Sibon-Tropidodipsas clade, because it possesses primitive traits for Fernandes’ characters M02–M03 (both describing the relationship of the m. levator anguli oris and the m. adductor mandibulae externus pars superficialis to the Harderian gland and orbit) and O18 (orientation of the maxillary teeth; vertical in T. fischeri, turned inward in other Dipsadini). In front of the lateral ectopterygoid articular process of most Dipsadini, the dorsolateral lamina of the maxilla bears an indentation ranging from a

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shallow depression (e.g., Plesiodipsas perijanensis, T. fischeri, and Sibynomorphus ventrimaculatus) to a deep notch (e.g., most Sibon and Tropidodipsas; Kofron, 1980, 1985). Maxillary teeth extend behind this depression in T. fischeri, P. perijanensis, and at least some species of Dipsas (Kofron, 1982) and Sibynomorphus. Some species of Dipsas (e.g., D. indica, D. peruana) and Sibynomorphus (e.g., S. oneilli) conspicuously lack the notch; the dorsolateral lamina of the maxilla merges seamlessly with the ectopterygoid articular process in these species.

Plesiodipsas perijanensis lacks other derived osteological features common to various subsets of Dipsas such as straight parietalfrontal articular surfaces (Fernandes, 1995, his character O06[1]), a postorbital lateral process located immediately behind the frontal-parietal articulation (O08[2]), an abruptly narrowed quadrate (O13[1]), an enlarged optic fenestra (O16[2]), an enlarged dorsolateral lamina (O17[2]), truncate posterior end of the pterygoid due to loss of its lateral expansion (O23[1]), reduced numbers of pterygoid teeth (O25[1]), and loss of the dorsolateral notch in the maxilla. In addition to the posterior blade-like process, P. perijanensis lacks some derived osteological features of subsets of Sibon and Tropidodipsas such as an enlarged optic fenestra (Fernandes, 1995, his character O16[2]) and loss of the dorsal process of the palatine (Scott, 1967).

Hypotheses of Character Evolution and Relationships of Dipsadini.—Plesiodipsas perijanensis possesses a suite of derived and primitive characters that preclude it from any currently recognized genus of Dipsadini.

However, its relationships to other genera remain obscure, because the morphological characters provide contradictory information.

To facilitate discussion of the morphological characters used in dipsadine systematics, we present three phylogenetic hypotheses (Fig. 11) depicting the most parsimonious placement of P. perijanensis within the constrained dipsadine phylogenetic hypotheses of Dessauer et al. (1986) and Kofron (1985).

Within the dipsadine hypothesis proposed

by Dessauer et al. (1986), Plesiodipsas is most parsimoniously placed as the sister taxon of all

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[No. 22,

blade-like process of the maxilla evolve twice (or be lost secondarily by some Dipsadini).

Within the dipsadine hypothesis proposed by Kofron (1985), Plesiodipsas is most parsimoniously placed as either the sister genus of Dipsas + Sibynomorphus (Fig. 11B) or as sister to all other Dipsadini (Fig. 11C). In both hypotheses, a tracheal lung, short heartliver gap, and reduction to 13–15 dorsals would have to evolve twice (or be lost by Tropidodipsas in Fig. 11C).

Kofron (1985) synonymized Sibon and Tropidodipsas and suggested that T. fischeri be transferred to a new genus. Although subsequent authors generally agreed with his views about T. fischeri, his proposal that Sibon and Tropidodipsas are congeneric was supported by Fernandes (1995), was questioned

by Savage and McDiarmid (1992), and was rejected by Wallach (1995). Genetic distance data (Cadle, 1984b, Dessauer et al., 1986) does not support Kofron’s proposal. The morphological evidence from our study is ambiguous (Fig. 11) with regard to the possible sister relationship of Sibon and Tropidodipsas. These genera share three distinctive apomorphies (an enlarged penultimate supralabial, a posterior blade-like process of the maxilla and, except for T. fischeri, the Harderian gland positioned lateral to the m. levator anguli oris). Except for T. fischeri, the maxillary teeth terminate in front of the dorsolateral notch (Character 10 a, Appendix 2) in Sibon and Tropidodipsas. However, we suspect that this character is not independent of Characters 8. Additional study of the posterior end of the maxilla and its associated musculature might help resolve this question of character independence.

FIG. 11.—Three phylogenetic hypotheses of Dipsadini (L 5 15, CI 5 0.73, RI 5 0.50). Character numbers are those in Table 2 and Appendix 2. Convergent characters are shaded gray. (A) Intergeneric relationships consistent with genetic differentiation (Dessauer et al., 1986). (B and C) Intergeneric relationships consistent with Kofron’s (1985) proposal.

other Dipsadini (Fig. 11A); however, this hypothesis requires that the mental groove, enlarged penultimate supralabial, lateral position of the Harderian gland, and posterior

Acknowledgments.—G. Ugueto prepared a watercolor illustration of Plesiodipsas perijanensis (Fig. 1) and O. Villarreal illustrated the cephalic morphology of the holotype (Fig. 2). For loan of specimens under their care, we thank J. W. Arntzen (RMNH), C. Austin (LSUMZ), J. A. Campbell (UTA), R. Feeney (LACM), D. R. Frost and L. S. Ford (AMNH), J. Hanken and J. Rosado (MCZ), J. McGuire (MVZ) R. Nussbaum and G. Schneider (UMMZ), M. P. Ra´mirez-Pinilla (UIS), S. P. Rogers (CM), R. P. Reynolds (USNM), L. Trueb and W. E. Duellman (KU), and H. K. Voris and A. Resetar (FMNH), and J. Vindum (CAS). T. R. Barros B. (La Universidad de Zulia, Venezuela) kindly sent a specimen of D. praeornata to us. During the course of this study, M. B. Harvey visited three museums in the United States and two museums in Bolivia. For providing him with working

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space and for their many courtesies during his visit, Harvey thanks D. R. Frost and R. Bain (AMNH); J. A. Campbell, E. N. Smith, and C. Franklin (UTA); M. A. Nickerson, K. L. Krysko, and C. Sheehy (UF); L. Gonzales A. (NK); and J. Aparicio E. (CBF). B. Noonan provided advice about cladistic methods.

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PETERS, J. A. 1960. The snakes of the subfamily Dipsadinae. Miscellaneous Publications Museum of Zoology, University of Michigan 114:1–224, plates I– VIII. PETERS, J. A. 1970. Generic position of the South American snake Tropidodipsas perijanensis. Copeia 1970:394–395.

PETERS, J. A., AND B. OREJAS-MIRANDA. 1970. Catalogue of the Neotropical Squamata. Part I. Snakes. Smithsonian Institution Press, Washington D.C., U.S.A. PORTO, M., AND R. FERNANDES. 1996. Variation and natural history of the snail-eating snake Dipsas neivai (Colubridae: Xenodontinae). Journal of Herpetology 30: 269–271.

RIEPPEL, O. 1980. The trigeminal jaw adductors of primitive snakes and their homologies with the lacertilian jaw adductors. Journal of Zoology, London 190:447–471.

RIVAS, G., J. MANZANILLA, R. RIVERO, AND E. LA MARCA. 2002. Lepidoblepharis sanctaemartae (Ruthven, 1916), a lizard new to the Venezuelan fauna. Herpetozoa 15:92–94.

SAVAGE, J. M., AND R. W. MCDIARMID. 1992. Rediscovery of the Central American colubrid snake, Sibon argus, with comments on related species from the region.

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APPENDIX 1 Specimens Examined Adelphicos latifascatum.—MEXICO: OAXACA: Colonia Rodulfo Figueroa (UTA 12246); Cerro Baul (UTA 6213).

Adelphicos nigrilatum.—MEXICO: CHIAPAS: 1.8 km E Tulanca (UTA 8838); 13.7 km (by road) SE San Cristo´bal de las Casas (UTA 12248); Cerro Pij (UTA 51864).

Adelphicos quadrivirgatum.—GUATEMALA: QUETZALTENANGO: S slope Volca´n Santa Marı´a, Finca El Farro (UTA 22655, 22671, 22680).

Adelphicos veraepacis.—GUATEMALA: BAJA VERAPAZ: Cerro Verde (UTA 6542, 6551, 6584).

Coniophanes fissidens.—MEXICO: VERACRUZ: 2.1 m NW Sontecomopan, by road (UTA 3069); SW slope of Volca´n San Martı´n (UTA 51094); 5.6 mi ESE Tebanca (UTA 3067).

Dipsas albifrons.—BRAZIL: SA˜O PAULO: no other data (MCZ 20855); SANTA CATARINA: Corupa (UF 11597).

Dipsas articulata.—COSTA RICA: ALAJUELA: ‘‘vicinity of Muelle San Carlos’’ (LACM 150495); PANDORA: Limo´n (UMMZ 125236); UNKNOWN: ‘‘San Jose´’’ (AMNH 17370). NICARAGUA: UNKNOWN: ‘‘Atlantic slope eastern Nicaragua’’ (LACM 150496). PANAMA´: BOCAS DEL TORO: ‘‘Rı´o Changuinola nr Quebrada El Guabo, 40–100 m’’ (AMNH 124125).

Dipsas bicolor.—COSTA RICA: HEREDIA: ‘‘Rio Frio, Standard Fruit Company 10u209N, 83u539W, 330 ft’’ (UF 31293).

Dipsas brevifacies.—MEXICO: QUINTANA ROO: ‘‘Hwy. 307, 1 km N. of intersection with Puerto Morelos Road’’ (UF 42072); YUCUTAN: ‘‘Mex. 180, 1.9 mi W Valladolid’’ (UF 140801); 2.2 km N Piste (KU 70839 skull and external morphology).

Dipsas bucephala.—BOLIVIA: COCHABAMBA: Campamento Guacharos, 600 m (MHNC-R 890); no other data (AMNH 6780); SANTA CRUZ: Porongo, 400–550 m (NK 3070); Finca Dos Milanos, 260–280 m (UTA 38081); Loma alta, 800–1300 m (NK 160); Aguaclara, 1100–2000 m (NK 1220, 1569, 2156); Barrio Nuevo, 1200–1900 m (NK 856); Becerro, 1300–2000 m (NK 1567); El Millu, 1100–2000 m (NK 3473–3474); El Pacay, 1200–1800 m (NK 2201); Mairana, 1400–2000 m (NK 1277); Pampagrande, 1200–1900 m (NK 557, 586, 684);

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Santa Rosa de Lima, 1500–2200 m (NK 2737, 3516); Buena Vista, 300–400 m (CM 2878, FMNH 16794, 35723; UMMZ 63252–63253, 67902–67905, UMMZ 149728 skull); ‘‘near Buena Vista, Rı´o Colorado’’, 300– 400 m (CM 2954); Lago Caima´n, Parque Noel Kempff Mercado, 200–580 m (UTA 52871–52872); specific locality unknown (CM 2941).

Dipsas catesbyi.—BOLIVIA: BENI: ‘‘Serranı´a Pilon, 27 km by road N Rı´o Quiquilbay’’, 300–1300 m (LSUMZ 45543); Estancia Ojo de Agua, 140 m (UF 68513); Tumi Chucua, 150 m (USNM 280380); ‘‘vicinity of Guayaramerı´n’’, 150 m (AMNH 101824); ‘‘Rio Marmore´, Santa Rosa’’, 160–180 m (AMNH 101825, 101826); Rurrenabaque, 190–300 m (AMNH 22444); no other data (AMNH 2978, 2979, 2980); COCHABAMBA: Altamachi, 930– 1770 m (CBGR 0050); Sajta, 230 m (NK 668); Chimore´, 240 m (NK 439); LA PAZ: Ixiamas, Barraca Santa Rosa, Rio Manuripi, 250–290 m (NK 2123–2124); Ixiamas, Aceradero Bosques del Norte, 250–290 m (CBF 779); Tumupasa, 2500 m (CBF 1903); Valle de Zongo, 1350 m (CBF 1169); Parque Nacional Cotapata, Campamiento Sandillani, 1300–3200 m (CBF 2083, 2085); ‘‘Espia, Bopi River’’, 900–1500 m (AMNH 21245); ‘‘Pelechnes, nordo¨stlich von Titicaca’’ (ZMB 10889); PANDO: Nueva Espan˜a, Manuripi Heath, RNAVS, 200 m (NK 2571); SANTA CRUZ: Angostura, 600–1100 m (NK 548); Santa Rita, 550–700 m (NK 804); Bermejo, 800–1500 m (NK 1562); El Millu, 1100–2000 m (NK 1588); Huachi, 150– 200 m (AMNH 22485, 22486, 22444); ‘‘probably Buena Vista’’, 300–400 m (FMNH 35711–16, 35717–22, AMNH 35995, ZSM unnumbered); San Ramo´n, 250–280 m (NK 420); ‘‘112 km N of Santa Cruz’’, 230–260 m (AMNH 119925); UNKNOWN: locality unknown (ZMB 25929, UMMZ 149727 skull). ECUADOR: NAPO: ‘‘10.9 km. N Rio Tiputini’’ (UF 43170); ‘‘3.1 km. S Rio Tiputini’’ (UF 43171); Rio Yasuni, Campsite 2 (UF 44288, 44289); SUCUMBIOS: Santa Cecilia (KU 146737 musculature and external morphology). SURINAME: ‘‘poisoned forest’’ (RMNH 35958), Silpaliwini (UTA 52875).

Dipsas chaparensis.—BOLIVIA: COCHABAMBA: Khara Huasi, 1800–2300 m (UTA 38083); ‘‘Paracti, 83.2 km from Cochabamba on road to Villa Tunari’’, 2300–3100 m (USNM 257869, holotype); SANTA CRUZ: Algodonal, 1100–1900 m (NK 1864); Bermejo, 800– 1500 m (NK 2629); El Chape, 1000–2000 m (UTA 38082, 52873–52874); La Hoyada, 1200–2000 m (NK 1997, 3065–3066, 3231); Palmasola, 1400–2000 m (NK 1861); Palmasola, Yunga del Tontal, 1400–2000 m (NK 1732); Santa Rosa de Lima, 1500–2200 m (NK 3360, 2736).

Dipsas copei.—VENEZUELA: AMAZONAS: ‘‘Sierra Parima 3u259N, 64u389W, 1180 m’’ (MHNLS 11972).

Dipsas gaigae.—MEXICO: JALISCO: ‘‘La Huerta, 2 km N Zapata (Municipio La Huerta)’’ (UTACV 52573); ‘‘on Hwy 200, 34 miles NW of Hwy 80’’ (LACM 136910).

Dipsas gracilis.—ECUADOR: ESMERALDAS: ‘‘Hacienda Equinox, 30 km (airline) NNW of Santo Domingo de los Colorados, 1000 ft (5 300 m)’’ (USNM 210945); LOS RIOS: ‘‘Estacio´n Biolo´gica Rı´o Palenque, 56 km N Quevedo, 220 m’’ (KU 152604); PICHINCHA: ‘‘14.1 km SE Patricia Pilar by road’’ (MCZ 156894); Pachijal (USNM 210940); Gualea (USNM 210941); ‘‘Finca La Esperanza, 4 km W of Santo Domingo de los Colorados’’

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(USNM 210942–210944); UNKNOWN: no other data (LACM 2308).

Dipsas elegans.—ECUADOR: PICHINCHA: Tandapi, 1520 m (KU 112264 skull and specimen). UNKNOWN: UNKNOWN: no other data (MCZ 178357).

Dipsas indica ecuadoriensis.—ECUADOR: NAPO: ‘‘6.5 km ESE of Puerto Misahualli at La Cruz Blanca on Jatun Sacha Biol. Res.’’ (MCZ 173881, 173880); ‘‘Baeza’’ (MCZ 164492); 15 km ENE Umbaqui, Bermejo No. 4, 740 m (KU 121871 skull and external morphology); PASTAZA: ‘‘Rı´o Pastaza, 500 m’’ (UMMZ 89028, paratype); SUCUMBIOS: Santa Cecilia (KU 126023 muscles and external morphology). UNKNOWN: UNKNOWN: no other data (MCZ 178356).

Dipsas indica.—BOLIVIA: PANDO: ‘‘Madre de Dios River junction with Rı´o Sena’’, 150 m (UMMZ 59774).

COLOMBIA: AMAZONAS: Leticia (CM 53500–53503).

GUYANA: UPPER TAKUTU-UPPER ESSEQUIBO: ‘‘Marudi’’ (AMNH 60857). PERU: CUSCO: ‘‘Huadquina Andes S. Peru’’ (MCZ 10772); UCAYALI: ‘‘Iparia’’ (MCZ 119409). SURINAME: COMMEWIJNE: ‘‘Wederzorg’’ (RMNH 5349); ‘‘distr. Saramacca, km 11 Loksihatiweg, Coesewijne Hontvesterij LBB’’ (RMNH 35959).

Dipsas nicholsi.—PANAMA´: CANAL ZONE: ‘‘Madden Forest Road, 3.9 mi. S. Transisthmus Highway’’ (UF 44292); ‘‘Madden Forest Madden Road, 100 ft. N George Green’’ (UF 44293); ‘‘Park’’ (44294); ‘‘Madden Forest Road, 3.2 mi SE Transisthmus Hwy’’ (UF 44295); ‘‘Madden Forest Road, 3.3 mi. S Transisthmus Hwy’’ (UF 44296); ‘‘Madden Road’’ (44297); ‘‘Madden Forest Road, 0.9 mi. S Transisthmus Hwy’’ (UF 44298, 44303); ‘‘Chiva-chiva Road’’ (UF 44300); ‘‘Madden Forest Road’’ (UF 44301, 44302); ‘‘Madden Forest Preserve, 100 m’’ (KU 110310, skull and external morphology).

Dipsas oreas.—ECUADOR: LOJA: 13 km E Veracruz (20 km NE Catacocha) 2250 m (KU 142803).

Dipsas pakaraima.—GUYANA: DISTRICT 7: ‘‘Mount Ayanganna, northeast plateau, 05u249N, 059u579W, 1490 m.’’ (ROM 41236).

Dipsas pavonina.—BOLIVIA: LA PAZ: Iturralde: Parque Nacional Madidi, Serranı´a El Tigre, Camino Alto Madidi, 250–340 m (CBF 2139). ECUADOR: SUCUMBIOS: Santa Cecilia (KU 121875 musculature and external morphology). GUYANA: DEMERARA-MAHAICA: ‘‘Dunoon; Demerara River’’ (6u269S, 58u189W) (UMMZ 47747).

Dipsas peruana.—COLOMBIA: BOYACA: ‘‘valley of Rı´o Cusiana, 1700 m’’ (KU 110589). ECUADOR: NAPO: ‘‘Rı´o Napo’’ (UMMZ 88978–79); ‘‘Rı´o Napo watershed’’ (UMMZ 88980); ‘‘immediate environs of Borja, 5600 ft (5 1670 m)’’ (USNM 210957); Borja (USNM 210958–210959); Coca (MCZ 166589–90); El Reventador (MCZ 164510–11); Lumbaqui (MCZ 164674– 75); ‘‘Rio Azuela, where river crosses road from Quito’’ (USNM 286323); Rio Cotopino, Upper Rio Napo (USNM 210960); PASTAZA: ‘‘Rı´o Pastaza, 1800 m’’ (UMMZ 88995); ‘‘Rı´o Pastaza, 500 m’’ (UMMZ 88996–97); TUNGURAHUA: ‘‘W slope Cordillera del Condor, E San Jose´, 1600 m, Morono-Santiago’’ (KU 147196); ‘‘Mapoto, 1300 m’’ (UMMZ 88977); ‘‘Ban˜os, 1800 m’’ (UMMZ 88984–86); ‘‘Yungurahua, N bank Rı´o Pastaza at Rı´o Blanco, Yungilla, 1700 m’’ (UMMZ 92046); ‘‘S bank Rı´o Pastaza near Ban˜os, 1800 m’’ (UMMZ 92047–48); UNKNOWN: Ban˜os Abi Taqua (AMNH 24146, 24149);

[No. 22,

Palmera (not traced)(AMNH 37939); Llangate (FMNH 23532 skull). PERU: AMAZONAS: ‘‘Bongara province, Pomocochas (5Florida), 2150 m’’ (KU 212590); ‘‘28 km SE Ingenio on road to Laguna Pomacocha’’ (LSUMZ 27371–27372); CAJAMARCA: ‘‘Tabaconas, 1892 m, 5u199S, 79u189W’’ (MCZ 17404); CUSCO: ‘‘Hacienda Huyro between Huayopata and Quillabamba; above plantations; Bosque Aputinye’’ (LSUMZ 27369–70); ‘‘Las Ruinas de Machu Picchu, 2400 m’’ (KU 117109); ‘‘Paucartambo, Paucartambo, Mirador, 1810 m, 13u49110S, 71u339190W.’’ (AMNH 147037); ‘‘1 km (airline) W Amaybamba’’ (MCZ 178175); Urubamba, Putukusi, 2050 m (UTACV 51467); Pucyura (USNM 60718); PASCO: ‘‘Playa Pampa, 8 km NW Cushi on trail to Chagalla, 2100 m, 9u579S, 75u429W’’ (LSUMZ 45499, locality amended based on personal communication to Cadle by T. S. Schulenberg as cited by Cadle, 2005); PUNO: ‘‘11 km NNE (airline) of Ollachea, 1880 m’’ (USNM 299232–299234); SAN MARTI´N/LORETO: ‘‘Cumbre Ushpayacu-Mishquiyacu, 975 m, 6u579S, 76u39W’’ (Cadle, 2005, provides additional information about this locality) (AMNH 52444); NOT TRACED: Arubo (FMNH 5597).

Dipsas praeornata.—VENEZUELA: ARAGUA: ‘‘Km 24, Maracay-Ocumare de la Costa rd, 870 m’’ (KU 167574); ‘‘Km 22.3, Maracay-Ocumare de la Costa Road, 0 m’’ (KU 182709); ‘‘Rancho Grande, nr Maracay’’ (AMNH 98245–47); Parque Nacional Henry Pittier (MHNLS 17708); DISTRITO FEDERAL: ‘‘Federal District, on rd to Instituto Venezolano de Investig.

Cientificas (IVIC), 2 km from Pan Amer hwy, 8 km from Caracas’’ (UMMZ 203984); LIBERTADOR: Boca de Tigre, Parque Nacional El Avila, 1800 m (MHNLS 13305); MIRANDA: Curupao, Power Plant (AMNH 59452).

Dipsas pratti.—COLOMBIA: ANTIOQUIA: ‘‘Rı´o Negrito, 15 km E Sonson, 1850 m’’ (FMNH 63758); ‘‘Medellin’’ (AMNH 35553); UNKNOWN: ‘‘New Granada’’ (AMNH 17525, Cotype).

Dipsas sanctijoannis.—COLOMBIA: CALDAS: ‘‘Pueblo Rico, Santa Cecilia, Pacific side, 1700 m’’ (FMNH 54898); CAUCA: ‘‘El Tambo, Munchique, Cauca River side, 2300 m’’ (FMNH 54903–05); ‘‘ca Popayan, 1700 m’’ (KU 140403); ‘‘Valle del Cauca, San Antonio,’’ (MVZ 68694); ‘‘Valle del Cauca. 4 km NW San Antonio,’’ (MVZ 68695); QUINDIO: ‘‘mts. east of Calarca´, 2000 m’’ (AMNH 106650); VALLE: 24 km NW Cali, 1800 m (AMNH 106651); ‘‘vicinity of Cali’’ (AMNH 106652). ´ : ‘‘Agua Dipsas temporalis.—COLOMBIA: CHOCO Clara, Rı´o Tamana´, approximately 4u539N, 76u459W’’ (USNM 267244); Camino de Yupe (LACM 72745–46); Alto de Buey, N slope (LACM 72747). PANAMA´: DARIEN: ‘‘ridge between Rı´o Jacque & Rı´o Imamado´, 800 m, 7u359N, 77u579W’’ (KU 110294–110297; skull and external morphology of KU 110294); ‘‘N ridge Cerro Cituro, Serranı´a de Pirre, 900 m, 8u59N, 77u469W’’ (KU 110298); ‘‘S slope Cerro Cituro, Serranı´a de Pirre, 1000 m’’ (KU 110299–300); PANAMA´: ‘‘S slope Cerro La Campana, 850 m,’’ (KU 110293); ‘‘Pequeni-Chagres ridge, head of Rı´o Limpio and Quebrada Las Tres Honeras (Panama snake census), 9u189N, 79u279W’’ (MCZ 50214).

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Dipsas trinitatis.—TRINIDAD: ST. GEORGE: ‘‘vicinity of milestone 1, Arima–Blanchisseuse Road’’ (10u389N, 61u179W) (USNM 166683); ‘‘at turn-off to Simla, Arima Ward, Arima–Blanchisseuse Road’’ (10u409N, 61u189W) (USNM 194987); ‘‘between Arima bypass and 7.5 mi N of Arima, on Blanchisseuse Road’’ (USNM 252674–252678); ‘‘Arima Valley, 5 mi N of Arima, Arima Ward’’ (10u409N, 61u189W) (UMMZ 125790); UNKNOWN: Port of Spain (10u399N, 61u319W) (AMNH 73124).

Dipsas variegata.—BOLIVIA: COCHABAMBA: ‘‘Reserva Altamachi, Serranı´a de Mosetenes, 1200 m, 16u029270S, 66u389540W’’ (NK uncatalogued); LA PAZ: ‘‘Pro´ximo al rı´o Quiquibeycito en la senda hacia la serranı´a de Muchanes, Territorio Indı´gena Pilo´n Lajas’’, 200– 500 m (CBF 1127); ‘‘ca 1 mile W of Puerto Linares, 360 m’’ (USNM 281210). GUYANA: ESSEQUIBO: Kartaba (AMNH 98194); UNKNOWN: ‘‘Dunoon’’ (UMMZ 47757–47758); ‘‘Demerara River’’ (UMMZ 53900); ‘‘Wismar’’ (UMMZ 76690 [n52], 77504); Kartabo (AMNH 81425, AMNH 21275). PERU: MADRE DE DIOS: ‘‘Cusco Amazo´nico, 15 km E Puerto Maldonado, 200 m’’ (KU 214858). SURINAM: MAROIJNE: Tepoe (UTACV 15772). VENEZUELA: ARAGUA: Parque Nacional Rancho Grande (UMMZ 124243, 124339, AMNH 81423, 98244); BOLIVAR: ‘‘Rio Yuruari, upper basin, 300 m a.s.l.’’ (AMNH 111075); Santa Elena (AMNH 114769–70); CARABOBO: ‘‘San Esteban, Puerto Cabello’’ (MCZ 51477); DISTRITO FEDERAL: ‘‘Laguayra’’ (5La Guaira) (USNM 22531); GUARICO: ‘‘Parque Nacional Guatopo, 15 km NW of Altagracia, 9u589N, 66u259W, 680 m’’ (USNM 217182).

Dipsas vermiculata.—ECUADOR: MORONA-SANTIAGO: Chiguaza (USNM 210973); NAPO: Rı´o Napo Watershed (UMMZ 89029, paratype); PASTAZA: ‘‘1 km W El Puyo’’ (MCZ 14718); ‘‘Rı´o Shilcayacu below Puyo’’ (USNM 210972).

Dipsas viguieri.—PANAMA´: PANAMA´: Pipeline Road, Canal Zone (UMMZ 155717); Chagres River camp #2 (MCZ 3476); CANAL ZONE: ‘‘Madden Rorest Road, 2.0 mi S. Transisthmus highway’’ (UF 44290); ‘‘Madden Forest’’ (UF 44291).

Geophis anocularis.—MEXICO: OAXACA: Sierra Mixe (UTA 8535, 14189, 14191, 12294).

Geophis brachycephalus.—COSTA RICA: CARTAGO: Turrialba (UTA 44973).

Geophis dubius.—MEXICO: OAXACA: 4.5 km N La Cumbre (UTA 38826); Agua Agria (UTA 51842).

Geophis duellmani.—MEXICO: OAXACA: Sierra Juarez (UTA 8433, 14159).

Geophis rhodogaster.—GUATEMALA: GUATEMALA: Guatemala City (UTA 17694).

Hydromorphus concolor.—COSTA RICA: CARTAGO: Turrialba (UTA 44938–44941).

Imantodes cenchoa.—HONDURAS: no other data (UTA 24861, 25041).

Leptodeira annulata.—GUATEMALA: IZABAL: Municipio Los Amantes (UTA 22810, 37352).

Ninia diademata.—GUATEMALA: QUETZALTENANGO: S slope Volca´n Santa Marı´a, Finca El Farro (UTA 21114, 21128).

Ninia sebae.—GUATEMALA: QUETZALTENANGO: S slope Volca´n Santa Marı´a, Finca El Farro (UTA 21214, 21217, 21227, 21231).

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Plesiodipsas perijanensis.—COLOMBIA. SANTANDER: ‘‘Vereda Agua Blanca - Parte alta. Kilometro 23 vı´a Bucaramanaga - Pamplona. Al frente del Centro de Educacio´n Ambiental ‘El Diviso’’’ Municipio Floridablanca (UIS 1211, UIS 1228); Vereda Las Amarillas, Municipio Piedecuesta, 6u58910.60N, 73u01917.50W, 1400 m (UIS 1242); Vereda Guarumales, Finca El Reposo, Municipio Tona, 1700 m (UIS 1243); Vereda Guarumales, Finca La Plazuela, Municipio Tona, 2100 m (UIS 1244); CE´SAR: Socorpa Mission, Sierra de Perija´, 1350 m [this locality is at approximately 9u479N, 73u29W].

VENEZUELA. ZULIA: Jamayaujaina, Sierra de Perija´, 1700 m (MHNLS 655).

Sibon annulatus.—COSTA RICA: CARTAGO: Pavones de Turrialba, 600 m; LIMON: ‘‘Tortuguero’’ (UF 10282); HEREDIA: ‘‘Rio Frio, Standard Fruit Company, 10u209N, 83u539W, 330 ft’’ (UF 30898, 31292); ‘‘Rio Frio, 10u209N, 83u539W, 330 ft’’ (UF 31553).

Sibon anthracops.—COLOMBIA: VALLE: vicinity of Cali (UTACV 18704; this specimen was recovered from a military aircraft that had recently returned to South Carolina from Cali, Colombia. It is not known if the plane spent time at a Central American airport before arriving in Cali. The locality is likely in error because this is a Nuclear Central American species that has otherwise never been found south of Costa Rica.). COSTA RICA: GUANACASTE: Liberia, Santa Rosa National Park (UTACV 4467); Canas (UMMZ 131721 skull). GUATEMALA: GUATEMALA: Palencia (UTACV 5552); El Progreso (UTACV 39185); BAJA VERAPAZ: ‘‘51.7 km S Purulha, CA-14’’ (UTACV 5748); ‘‘23.4 rd km NE El Rancho, CA-14’’ (UTACV 5749). UNKNOWN: no data (UF 117875).

Sibon carri.—GUATEMALA: BAJA VERAPAZ: ‘‘20.6 km NW El Rancho, on road between El Rancho and La Cumbre’’ (UTACV 33070); GUASTATOYA: ‘‘ca 3.0 km SSW El Rancho (Km 81 on Hwy CA-9), 320 m’’ (UTACV 37270); PROGRESO: El Rancho (UTACV 12946); ZACAPA: ‘‘Km 185 on Hwy CA9, Finca Santa Beatriz, near Guala´n, ca 330 m’’ (UTACV 26560); ‘‘Guala´n, 1.0 km al E de Don˜a Maria, por carretera al Atla´ntico’’ (UTACV 44750); ‘‘Guala´n, carretera al Atla´ntico, Aldea Juan de Paz’’ (UTACV 45493).

Sibon dimidiatus.—GUATEMALA: IZABAL: ‘‘Sierra de Santa Cruz, E slope Cerro 1019 (next to Aldea La Libertad), 150 m’’ (UTACV 26314). COSTA RICA: PUNTARENAS: 3.5 mi SW of Rincon, in bushes (UF 30212).

Sibon longifrenis.—COSTA RICA: HEREDIA: Rio Frio, Standard Fruit Company, in banana packing house ´ N: Siquirres (UF 77732).

(UF 31787); LIMO Sibon nebulatus.—COLOMBIA: Cartagena (UF 143444). COSTA RICA: HEREDIA: ‘‘3 km. SE Puerto Viejo, on road 31054; Rio Frio, Standard Fruit Company’’ (UF 30480, 30481, 31014, 31194, 31269, 32341); locality ` N: Tortuguero unknown (UMMZ 138818 skull); LIMO (UF 15669; 10283 (n53), 10284, 10285 (n52), 10512– 10514, 11568, 19549); ‘‘2.0 mi N Tortuguero, Tortuga Lodge’’ (UF 37172, 44305, 40774, 40784); PUNTARENAS: ‘‘N Palmar Sur on Interamerican Hwy’’ (UF 44304). ECUADOR: PICHINCHA: ‘‘47 km S Santo Domingo de los Colorados, Centro Cientifico Rio Palenque, below station building’’ (UF 68033). GUATE-

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HERPETOLOGICAL MONOGRAPHS

MALA: PETEN: ‘‘Peten, Tikal’’ (UF 13847). HONDURAS: OLANCHO: ‘‘12 km SW Catacamas on road to Juticalpa’’ (UF 44334); UNKNOWN: no other data (UF 42970, 87863, 99216, UMMZ 149980 skull). MEXICO: NAYARIT: San Blas (UF 86613); no other data (UF 86612); VERACRUZ–LLAVE: ‘‘Hwy. 180 between Catemaco and Acayucai 8.5 km S Catemaco’’ (UF 44309). PANAMA´: COCLE: El Valle (UF 24916); PANAMA´: UNKNOWN: El Aquacate (UF 44313).

SURINAME: PARAMARIBO: Combe (UF 27051).

TOBAGO: UNKNOWN: ‘‘3.7 mi. ENE Scarborough’’ (UF 44310). TRINIDAD: UNKNOWN: ‘‘Pointe-APierre, West Indies’’ (UF 16528); Port of Spain (UF 44332); ‘‘Port of Spain, St. Ann’s, Fondes Amardes’’ (UF 44333). VENEZUELA: ARAGUA: ‘‘Km 24, MaracayOcumare de la Costa road, 870 m’’ (KU 167575); ‘‘Km 40, Maracay-Ocumare de la Costa road, 100 m’’ (KU 167577– 167578); COJEDES: ‘‘Manrique, Tierra Caliente’’ (UF 44311–44312); Mun. Cojedes, Camoruco, Finca la Coromoto (UF 117876); FALCON: Klm 45 Road UleDabajuro (UF 126467–12668). UNKNOWN: no other data (UF 44306–44307).

Sibon sanniolus.—MEXICO: QUINTANA ROO: 27.9 km NE Felipe Carrillo Puerto (KU 157619 skull and external morphology).

Sibynomorphus lavillai.—BOLIVIA: TARIJA: no other data (UTACV 38080).

Sibynomorphus mikani.—BRAZIL: SA˜O PAULO: Cotia, Granja Viana (UTACV 37711); Osasco, Fazenda Recreio (UTACV 37712); Jundiai (UTACV 37713).

Sibynomorphus neuwiedi.—BRAZIL: PARANA´: Antonina (UTACV 35935); RIO GRANDE DO SUL: Viamao Lombo do Pinheiro (UTACV 43953); SA˜O PAULO: Taubat (UTACV 37714); Igual (UTACV 37715); Mococa (UTACV 37716–17).

[No. 22,

Sibynomorphus oneili.—PERU: CAJAMARCA: Abra Gelic, 13 km E Celendin, 3080 m (KU 212599, cephalic musculature, maxilla, and external morphology).

Sibynomorphus turgidus.—BOLIVIA: SANTA CRUZ: no other data(UTACV 38049, 38067–68). PARAGUAY: ‘‘vicinity of Asuncio´n’’ (UTACV 2585, 5599–600).

Sibynomorphus vagus.—PERU:UNKNOWN: Huancabamba (MCZ 17422).

Sibynomorphus ventrimaculatus.—ARGENTINA: MISIONES: Iguazu´ Falls (FMNH 9259, skull and external morphology). BRAZIL: RIO GRANDE DO SUL: Porto Alegre (UTACV 37708, 41154).

Tropidodipsas fasciata.—MEXICO: OAXACA: Cerro Baul (UTACV 6215–16), Colonı´a Rodulfo Figueroa (UTACV 12538).

Tropidodipsas fischeri.—GUATEMALA: CHIMALTENANGO: Finca Chichivac (FMNH 20257, skull and external morphology); QUEZALTENANGO: ‘‘between San Martı´n and Colomba Finca Lorena’’ (UMMZ 155635 skull). EL SALVADOR: Hacienda Montecristo, 2200 m (KU 63906, skull and external morphology). MEXICO: OAXACA: Cerro Baul (UTACV 5773, 6221–22, 6637, 8785, 12539–40).

Tropidodipsas philippii.—MEXICO: COLIMA: 7.3 mi E Colima, Mex Hwy 110 (UTACV 4398).

JALISCO: 3.3 mi E Puerto los Mazos (UTACV 7916).

Tropidodipsas sartorii.—MEXICO: CHIAPAS: Soconusco, 6 km NE Escuintla, 150 m (UMMZ 155632 skull).

QUINTANA ROO: 14.6 km NE Felipe Carrillo Puerto (KU 171701 skull and external morphology). SAN LUIS POTOSI´: 6.3 mi E Valle de las Fantasmas on Mex. Hwy. 70 (UTACV 8405); 4.0 km S Tamazunchale (UTACV 12542); 5.5 km NE Xilitla (UTACV 16146); 3.1 km E jct.

Mex. Hwy. 57 and 80, Huizache Junction, (UTACV 16155); 4.8 km W El Huizache (UTACV 16156).

APPENDIX 2 Matrix of character state assignments used to evaluate the phylogenetic affinity of Plesiodipsas.

Characters Genera

Plesiodipsas Dipsas and Sibynomorphus Sibon Tropidodipsas sartorii Ancestor of Dipsadini Adelphicos Atractus Geophis Ninia Rhadinaea Imantodes Leptodeira Tretanorhinus Xenodontinae

1

2

3

4

5

6

7

8

9

10

11

12

13

1 1 0 0 0 0 0 0 0 0 0 0 0 0

0 0 1 1 0 0 0 0 0 0 0 0 0 0

0 1 1 0 0 1 0/1 0/1 0 0 0/1 0 0 0/1

1 0 0 0 0 0 0 0 0 0 0/1 1 1 0/1

0 1 1 1 0 0 1 0 0 0 0 0/1 0 1

0 0 1 1 0 0 0 0 0 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 1 1 1 0 0 0 0 0 0 0 0 0 0

a a b b ? ? ? ? ? ? ? ? ? ?

0 1 1 0 0 0 0/1 0 ?

1 0 0 ?

0/1

0 1 1 0 0 ?

0 0 ? ? ? ? ? ?

a b ? ? ? ? ? ? ? ? ? ? ? ?