Marine MOLLUSCS Robert Perry Malibu High School
rev 2012
Question: Where do mollusks “fit� in the evolution of animals on earth?
eukaryotes
ANIMALS
THE ANIMAL KINGDOM
NO TISSUES NO SYMMETRY
porifera
NO ORGANS RADIAL SYMMETRY ORGANS
cnidaria
BILATERAL SYMMETRY
platyhelminthes
bryozoa arthropoda mollusca
annelida echinodermata
cho r
dat a Animal cladogram based on DNA sequencing From National Museum of Natural History
MOLLUSKS:
--COELOMATE
(what is a coelom?)
--CALCAREOUS SHELL (not all mollusks have one)
--85,000+ SPECIES --SW, FW, DAMP TERRESTRIAL
--MOST ABUNDANT INVERT ANIMALS IN OCEAN
Phylum Mollusca Mollusks have a soft, muscular body which may or may not be protected by one or more shells. The 3 body regions are: 1--Headfoot. 2--Visceral Mass. 3--Mantle Cavity.
mollusca “mollis� = soft
(under shell)
visceral mass (under shell)
mantle cavity (Pallium)
Mantle layer: secretes the shell. Cavity contains: ctenidia and openings from digestive and reproductive systems.
Brown turban, or kelp snail Norrisia norrisii
Vital organs such as: heart gonads osphradia (some) kidneys digestive system
headfoot Sensory information Feeding Locomotion
The 5 Classes of Mollusks P h y lu m M OLLUSCA C la s s G ASTROPODA
Snails, slugs.
C la s s B IV A L V IA
Clams, oysters, scallops, mussels.
C la s s A M P H IN E U R A (P o ly p la c o p h o r a )
Chitons.
C la s s CEPHALOPODA
Octopus, squid.
C la s s SCAPHOPODA
Tusk or tooth shells.
Last 3 images from internet authors unknown
What’s a GASTROPOD?
Pink abalone Haliotis corrugata
mantle/cavity shell epipodium labial palps
mouth & radula foot
ABALONE GAS EXCHANGE
ABALONE REPRODUCTION
COMMON GASTROPODS AROUND HERE
California Cone Conus californicus
COMMON GASTROPODS AROUND HERE
California Cone Conus californicus
COMMON GASTROPODS AROUND HERE
Chestnut Cowry Cypraea spaedicea
COMMON GASTROPODS AROUND HERE
Kellet’s Whelk Kelletia kelletii
COMMON GASTROPODS AROUND HERE
Giant Keyhole Limpet Megathura crenulata
COMMON GASTROPODS AROUND HERE
Brown turban, or kelp snail Norrisia norrisii
COMMON GASTROPODS AROUND HERE
“Worm” Snail Serpulorbis squamigerus
COMMON GASTROPODS AROUND HERE
“Worm” Snail Serpulorbis squamigerus
COMMON GASTROPODS AROUND HERE
“Worm” Snail Serpulorbis squamigerus
COMMON GASTROPODS AROUND HERE
“Worm” Snail Serpulorbis squamigerus
COMMON GASTROPODS AROUND HERE
“Worm” Snail Serpulorbis squamigerus
COMMON GASTROPODS AROUND HERE
“Worm” Snail Serpulorbis squamigerus
GASTROPODS NOT SO COMMON AROUND HERE ANYMORE
Red Abalone Haliotis rufescens
GASTROPODS NOT SO COMMON AROUND HERE ANYMORE
Black Abalone Haliotis cracherodii Malibu Malibu, 1972
GASTROPODS NOT SO COMMON AROUND HERE ANYMORE
Black Abalone Haliotis cracherodii Channel Islands
San Nicolas Island early 1960’s
GASTROPODS NOT SO COMMON AROUND HERE ANYMORE
Pink Abalone Haliotis corrugata
Green Abalone pearl Haliotis fulgens
GASTROPOD MOLLUSKS:
MANTLE VISCERAL MASS
HEADFOOT
TORSION: HOW GASTROPODS “GOT THEIR TWIST” (OR SPIRAL SHAPE). (dorsal view)
ANCIENT
GASTROPOD
(lateral view)
TORSION: WHAT CHANGES OCCURRED AS GASTROPODS EVOLVED ? WHY?
MODERN
GASTROPOD
MANTLE CAVITY AND CTENIDIA:
SUBCL:OPISTHOBRANCHIA SUBCL:PROSOBRANCHIA
SUBCL:PULMONATA
THREE LAYERS OF A MOLLUSK SHELL: PERIOSTRACUM PRISMATIC LAYER
NACREOUS LAYER
MANTLE SIPHON ANTENNA + EYE
MOUTH
FOOT
MOUTH
EYE SHELL ANTENNA
SIPHON
MANTLE
OPISTHOBRACHS GASTROPODS WITHOUT EXTERNAL SHELLS
Janolus Nudibranch Janolus barbarensis
OPISTHOBRANCHS: THREE COMMON SUBORDERS APLYSIOMORPHA
Internal shell
“sea hares”
AEOLIDACEA
Gills exposed along back
Eolid Nudibranchs
DORIDACEA Dorid Nudibranchs
“nudibranch” means naked gills Gills in circle around anus
rhinophores cerata oral tentacles
headfoot
Spanish Shawl Nudibranch Flabellina iodinea
NUDIBRANCH ANATOMY tail
OPISTHOBRANCH FOOD & FEEDING:
http://www.asnailsodyssey.com/LEARNABOUT/NUDIBRANCH/nudiFood.php
Common Opisthobranchs around here. Hares and Nudibranchs
Sea Hare Aplysia californica
http://www.asnailsodyssey.com/LEARNABOUT/NUDIBRANCH/nudiFood.php
Common Opisthobranchs around here. Hares and Nudibranchs
Sea Hare Aplysia californica
Common Opisthobranchs around here. Hares and Nudibranchs
Sea Hare Aplysia californica
Common Opisthobranchs around here. Hares and Nudibranchs
Sea Hare Aplysia californica
Common Opisthobranchs around here. Hares and Nudibranchs
Sea Hare Aplysia californica
Common Opisthobranchs around here. Hares and Nudibranchs
Striped Hare Navanax inermis
Common Opisthobranchs around here. Hares and Nudibranchs
Striped Hare Navanax inermis
Striped Hare Navanax inermis
Common Opisthobranchs around here. Hares and Nudibranchs
MacFarland’s Dorid Chromadoris macfarlandi
Common Opisthobranchs around here. Hares and Nudibranchs
Black and white spotted Triopha Triopha maculata
Common Opisthobranchs around here. Hares and Nudibranchs
Shaggy Rug Nudibranch Aeolidia papillosa
Common Opisthobranchs around here. Hares and Nudibranchs
Shaggy Rug Nudibranch Aeolidia papillosa
Common Opisthobranchs around here. Hares and Nudibranchs
Spanish Shawl Nudibranch Flabellina iodinea
Common Opisthobranchs around here. Hares and Nudibranchs
Cerata with nematocysts
Opalescent Nudibranch Hermissenda crassicornis
Common Opisthobranchs around here. Hares and Nudibranchs
Catalina Triopha Triopha catalinae
What’s a BIVALVE ?
COMMON BIVALVES AROUND HERE...
Giant Rock Scallop Crassidoma gigantea
COMMON BIVALVES AROUND HERE...
Giant Rock Scallop Crassidoma gigantea
COMMON BIVALVES AROUND HERE...
Giant Rock Scallop Crassidoma gigantea
COMMON BIVALVES AROUND HERE...
California Mussel Mytilus californianus
ANTERIOR REGION
POSTERIOR REGION
DORSAL REGION
VENTRAL REGION SHELL ORIENTATION QUESTION: WHICH OF THE 2 SHELLS IS THIS? HOW TO YOU KNOW?
BIVALVE SHELL FEATURES AND ORIENTATION
DORSAL HINGE LIGAMENT
ANTERIOR ADDUCTOR MUSCLE
POSTERIOR ADDUCTOR MUSCLE
HOW DO THE SHELLS OPEN? HOW DO THEY CLOSE?
SHELL ANATOMY OF Mytilus californianus
INTERNAL ANATOMY OF Mytilus californianus
DORSAL
POSTERIOR
ANTERIOR VENTRAL (gonads removed)
Mytilus FEEDING AND GAS EXCHANGE
n
n
SIPHONS
FOOT
HOW DO CLAMS MOVE? HOW DO THEY CARRY OUT LIFE FUNCTIONS?
CTENIDIA WHAT 2 MAIN LIFE FUNCTIONS ARE PERFORMED BY THE BIVALVE CTENIDIA?
Rock-Boring Clam (Piddock) Penitella penita
What does the word “veliger” mean?
CEPHALOPODA
Cephalopoda (Greek plural Κεφαλόποδα (kephalópoda); "head-foot"): These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot.
COMMON CEPHALOPODS AROUND HERE
Two spot Octopus Octopus bimaculatus
Octopus feeding:
COMMON CEPHALOPODS AROUND HERE
Two spot Octopus Octopus bimaculatus
Copy this link into browser:
http://www.wimp.com/octopusmimic/ Thanks, Mark
Octopus mating:
COMMON CEPHALOPODS AROUND HERE
Two spot Octopus Octopus bimaculatus
COMMON CEPHALOPODS AROUND HERE
© Robert Perry
Common Market Squid Loligo opalescens
EXTINCT
WHAT ARE THE 5 LIVING FORMS OF CEPHALOPODS?
External anatomy
Identification of foods eaten by squids is made difficult by the often fragmented and well-digested state of the stomach contents. Researchers in the Moss Landing Marine Laboratories, California therefore rely mostly on the presence of paired eye-lenses, mandibles, statoliths, otoliths, polychaete jaws, and so on, to identify prey items in the stomach contests of Dorytheuthis opalescens captured by trawling in Monterey Bay, California. To estimate prey preferences, the researchers compare frequencies of occurrence of prey in the diet with those in the habitat. Results show that crustaceans predominate in the diets of both small and large squids, with euphausiids being the most preferred. A few fishes and gastropods are also eaten.
Internal anatomy
Loligo opalescens Common or Market Squid Common Market Squid Loligo opalescens
Loligo opalescens egg capsules
Common Market Squid Loligo opalescens
Loligo opalescens paralarvae
What methods are used to catch Loligo ?
Common Market Squid Loligo opalescens
Common Market Squid Loligo opalescens
Common Market Squid Loligo opalescens
Common Market Squid Loligo opalescens
The End