Skulls & Jaws Lab Flashcards
Three main components of vertebrate head
- dermatocranium
- splanchnocranium
- chondrocranium
dermatocranium
dermal elements making up the external, outermost framework of the skull, surrounding the other components and contributing to the jaws, braincase, and teeth
splanchnocranium
visceral skeleton
provides support for gill arches and gill arch derivatives
chondrocranium
support for sense organs and brain
Which component of the vertebrate head is not always present?
Dermatocranium
Components have been lost or fused in more derived animals
Williston’s law
trend toward fewer bones
Skull
Region enclosing the braincase and extending to the upper jaw
Mandible
Lower jaw
As the number of bones decreases, the number of ____ decrease and the structure becomes _____.
suture lines
stronger
The ___ is anterior to the maxilla
Premaxilla
Frontal is ____ to the nasal
posterior
Why temporal fossae?
They give a more secure area for muscle attachment and allow more space for the jaw muscles to expand during contraction
Anapsid
No temporal fossae
Examples of anapsid skulls
Fish, turtle, tortoise skulls
How does the snapping turtle have a powerful bite without temporal fossae?
otic/temporal notch on the dorsal posterior area of the midline is where muscles attach, increasing bite power
Supratemporal fossa
upper
Infratemporal fossa
lower
Diapsid
both the supratemporal and infratemporal fossae