MOLLUSCA Part 1 - City College of San Francisco · 2009-10-08 · MOLLUSCA Part 1 Polyphacophora...
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1 MOLLUSCA Part 1 Polyphacophora Scaphopoda Gastropoda Phylum Mollusca Large group of aquatic & terrestrial invertebrates with bilateral symmetry and a body covering called the mantle, commonly with a calcareous shell Most well preserved (except slugs) Most Important group of Fossils (numbers) Organs include heart, stomach, nerve cord, muscles Inferred evolution from the Hypothetical Ancestral Mollusc
Transcript of MOLLUSCA Part 1 - City College of San Francisco · 2009-10-08 · MOLLUSCA Part 1 Polyphacophora...
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MOLLUSCA Part 1
PolyphacophoraScaphopodaGastropoda
Phylum Mollusca
Large group of aquatic & terrestrial invertebrates with bilateral symmetry and a body covering called the mantle, commonly with a calcareous shellMost well preserved (except slugs)Most Important group of Fossils (numbers)Organs include heart, stomach, nerve cord, musclesInferred evolution from the Hypothetical Ancestral Mollusc
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Taxonomy to know
Kingdom AnimaliaPhylum Mollusca
Class Polyplacophora- chitonsClass Scaphopoda-tusk shellsClass Gastropoda-snailsClass Bivalvia-clamsClass Cephalopoda-nautiloids
Class Polyplacophora
Shell with 8 dorsal platesHerbivores, rocky environmentsCambrian to recent
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Fossil Polyplacophora
Cambrian – disarticulated plates
Ordovician
Class Scaphopoda
Tusk shaped, hollow shell (boat foot)Sandy or silty bottom, shallow water marineOrdovician to RecentSometimes very abundant e.g. Pennsylvanian of Texas
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Class Scaphopoda
Fossil Scaphopods
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Class Gastropoda
Stomach footSnails, slugs, whelks, limpets, abaloneHead with eyes, tentacles, broad flat foot, gills or lungsTypically coiled, unchambered shell (some cap-shaped)
coiled around a columella (axial pillar)Apex, whorl, spire, lip (see p. 291)Operculum
Typically aragonite shells that disolve in acid – casts, molds, steinkernsCambrian to Recent
Class Gastropoda
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Class Gastropoda
Fossil Gastropods
Pliocene Turritella
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Fossil Gastropoda
Amphiscapha catilloides Penn. Texas
Fossil Gastropoda
Worthenia tabulataPenn. TexasGyrodes genti Cretaceous, England
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MOLLUSCA Part 2
BivalviaCephalopoda
Taxonomy to know
Kingdom AnimaliaPhylum Mollusca
Class Polyplacophora- chitonsClass Scaphopoda-tusk shellsClass Gastropoda-snailsClass Bivalvia-clamsClass Cephalopoda-nautiloids
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Class Bivalvia
Class Bivalvia aka Pelecypoda
Shell with two mirror image partsHinge with various designsNo headCambrian to recent
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Class Bivalvia
Class Bivalvia
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Class Bivalvia
Fossil Bivalves
Anadara, a bivalve with taxodontdentition from the Pliocene of
Cyprus.
an extinct bivalve from the of Wooster, Ohio (external mold).
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Class Cephalopoda
Class Cephalopoda
“Head Foot” eyes, tentacles, head well developedIntellegentStraight or coiled shell, usually planispiralOrdovician – Recent1st large group of predators
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Class Cephalopoda
Ammonites
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Fossil Cephalopod
Fossil Cephalopod
