Exhibit slides from Lab 4 Flashcards
how does a snake skull and a mammalian skull differ?
snakes have kinetic skulls and mammalian skulls is akinetic in that the upper jaw bones are fused directly with bones of the braincase.
unlike the tongues of mammals, which are primarily muscular, the tongues of birds are rigidly supported by a cartilage and bone skeleton called what?
the hyoid apparatus
all tetrapo vertebrates have a hyoid apparatus in one form or another that serves as an attachment site for certain muscles of the throat and tongue. How is the bird different?
the Y shaped hyoid apparatus of birds however extends all the way to the top of their tongues.
temporal fenestrae basically means…..
holes in the head
the first two arches (hyoid and mandibular) transformed into what?
the jaw and jaw support
In chondricthyians, remnants of the slit between the mandibular and hyoid arches is retained as the ——–
spiracle
chondrycthyian fish have experienced a secondary loss of what?
bone
turtles are ——-
diapsids
diapsid:
2 pairs of temporal fenestrae
synapsids and examples:
taxa with a pair of lower temproal fenestrae like mammals
parapsida:
taxa with a pair of upper temporal fenestrae (eurypsida, ichtyosaurs and squamates)
a big problem with mastication is the need to somehow keep air flowing into the lungs while the mouth and pharynx are being used in matication, how is this solved?
solved in mammals by the development of a secondary palate.
what can be seen in both chicken and owl and where does it derive from?
scleral ossicles and is dermal bone derived from neural crest cells
the lower jaw of gnathostomes originates from what?
upper jaw?
maekels cartilage, a ventral skeletal elment in the mandibular arch
whereas the upper jaw is derived from a more dorsal element, the palatoquadrate
