Bivalvia 101Bivalvia 101

An Introduction to An Introduction to Marine BivalvesMarine Bivalves

Paul ValentichPaul Valentich--ScottScott

Curator of MalacologyCurator of Malacology

Santa Barbara Museum of Natural HistorySanta Barbara Museum of Natural HistorySanta Barbara Museum of Natural HistorySanta Barbara Museum of Natural History

Beautiful Bivalves Beautiful Bivalves of Southern Californiaof Southern California

Class BivalviaClass BivalviaClass BivalviaClass Bivalvia= two valves (shells)= two valves (shells)

Clams, mussels, scallops, oysters and their kinClams, mussels, scallops, oysters and their kin, , p , y, , p , y

•• Two part shellTwo part shell

BivalviaBivalviaBivalviaBivalviaClams, mussels, scallops, oysters and their kinClams, mussels, scallops, oysters and their kin

•• Two part shellTwo part shell•• No head No head

BivalviaBivalviaBivalviaBivalviaClams, mussels, scallops, oysters and their kinClams, mussels, scallops, oysters and their kin

•• Two part shellTwo part shell•• No headNo head•• Most are filter feedersMost are filter feedersMost are filter feedersMost are filter feeders

BivalviaBivalviaBivalviaBivalviaClams, mussels, scallops, oysters and their kinClams, mussels, scallops, oysters and their kin

•• Two part shellTwo part shell•• No head No head •• Most are filter feedersMost are filter feedersMost are filter feedersMost are filter feeders•• Broadcast spawnersBroadcast spawners

BivalviaBivalviaBivalviaBivalviaClams, mussels, scallops, oysters and their kinClams, mussels, scallops, oysters and their kin

•• Bivalves are great to EAT!!!Bivalves are great to EAT!!!

Bivalve OrienteeringBivalve OrienteeringBivalve OrienteeringBivalve Orienteering

Looking from the top – Dorsal viewg p

Bi l O i t iBi l O i t iBivalve OrienteeringBivalve Orienteering

Posterior Anterior

How do we know which end is which??

Bi l O i t iBi l O i t iBivalve OrienteeringBivalve Orienteering

Ligament

Posterior Anterior

Ligament is usually posteriorg y p

Bi l O i t iBi l O i t iBivalve OrienteeringBivalve Orienteering

B kBeaks

Posterior Anterior

Beaks often point anteriorp

Bi l O i t iBi l O i t iBivalve OrienteeringBivalve Orienteering

Left valve

Posterior Anterior

Right valve

Determining left from right

Bi l O i t iBi l O i t iBivalve OrienteeringBivalve Orienteering

Left valveLeft hand

Anterior pointed away ffrom you

Right valveRight hand

Quick hintQuick hintAnterior pointed away from you

Bivalve OrienteeringBivalve OrienteeringBivalve OrienteeringBivalve OrienteeringDorsal

PosteriorAnterior

Ventral

Looking from the side – Lateral view

Bivalve OrienteeringBivalve OrienteeringBivalve OrienteeringBivalve OrienteeringDorsal

PosteriorAnterior

Ventral

Looking on the inside

Bivalve CharactersBivalve CharactersUmbo

Beak

Beak vs. Umbo

Bivalve Characters Bivalve Characters –– SculptureSculpture

Radial Sculpture

Bivalve Characters Bivalve Characters –– SculptureSculpture

Commarginal Sculpture

Bivalve Characters Bivalve Characters –– SculptureSculpture

Cancellate Sculpture

Bivalve Characters Bivalve Characters –– SculptureSculpture

Divaricate Sculpture

Bivalve Characters Bivalve Characters –– SculptureSculpture

Commarginal Commarginal LamallaeLamallae

Bivalve Characters Bivalve Characters –– SculptureSculpture

SmoothCrenulate

Inner Ventral MarginCrenulate

Bivalve CharactersBivalve CharactersBivalve CharactersBivalve Characters

Escutcheon L lEscutcheon Lunule

Lunule and Escutcheon

Bivalve Characters Bivalve Characters -- LigamentLigament

External Ligament

Bivalve Characters Bivalve Characters -- LigamentLigament

Internal Ligament

Internal Ligament

Bivalve Characters Bivalve Characters -- DentitionDentition

Taxodont Teeth

Taxodont Teeth

Bivalve Characters Bivalve Characters -- DentitionDentition

Heterodont Teeth

Bivalve Characters Bivalve Characters -- DentitionDentition

Without Teeth - Edentulous

Bivalve Characters Bivalve Characters -- DentitionDentition

Cardinal teeth

L t l t th

Cardinal teeth

Lateral teeth

Cardinal Teeth & Lateral Teeth

Bivalve Characters Bivalve Characters -- ScarsScars

Pallial sinusPallial linePallial line

Pallial Line & Pallial Sinus

Bivalve Characters Bivalve Characters -- ScarsScars

Posterior Adductor

Anterior Adductor

Muscle Scar Muscle Scar

Adductor Muscle Scars

Bivalve CharactersBivalve Characters ColorColorBivalve Characters Bivalve Characters -- ColorColor