1

Chondrocranium

Dermatocranium

Splanchnocranium

Remodeling

Triple evolutionary sources

Chondorcranium Oken/Owen

Richard Owen

Chondrocranium

CHONDROCRANIUM

trabeculae parachordals occipitals sensory capsules

sphenoids ethmoids occipitals otic, optic, nasal

CENTERS OF OSSIFICATION

2

CHONDROCRANIUM

General Functions1)Adult braincase

(chondrichthyes)

2) ScaffoldNeurocranium

SPLANCHNOCRANIUM(=Visceral Skeleton)

SPLANCHNOCRANIUM(=Visceral Skeleton)

1) support respiration

2) support feeding apparatus

3) later, jaws

SPLANCHNOCRANIUM

JAWS

General Functions1) Prey Traps

2) Crushing

3

Derived from Gill Arches

Romer Jarvik

Jaw Suspension

Figure 7.56

Quadrate Incus

Articular Malleus

(Hyomandibula) (stapes)

Cuvier

4

Quadrate Incus

Articular Malleus

(Hyomandibula) (stapes)

(Diarthrognathus) Probainognathus

Dermatocranium

DermatocraniumDerived from dermal Armor

Function

protect the brain

5

FUNCTION1) Secondary

FUNCTION1) Secondary

2) Primary

respiration

feeding

prey traps

swallowing

6

Water vs. Land FUNCTION(feeding)

Aquatic

SuspensionFeeders(cilia-mucus)

Agnathans

Suction Feeders(gape ‘n suck; inertial)

aquatic

7

Bass Hog sucker

FUNCTION(feeding)

Air

8

TongueSalamander

Salamander Salamander

LizardTongue

9

Projectile Tongue

Gary Larsen

PrehensionJaws

FUNCTIONSwallowing

suspension

whole (gizzard)

mastication

Swallowing

Mastication

10

SwallowingMastication

precise occlusionspecialized teethdiphyodont

(polyphyodont)

akinetic

CRANIAL KINESIS

Cranial kinesis

Kinetic

Akinetic

CRANIAL KINESISRapid change in size and configuration of buccalcavity.

Tooth position

Kinetic Kinetic

11

Strike Kinematics

braincasesupratemproalquadrate

pterygoid ectopterygoidmaxilla

fang

mandible

prefrontal

MODEL (minus mandible)

Strike Kinematics

12