skulls

Question 1

fenestrae or fenestrations

Answer 1

openings that are a result of the presence of one or more arches

Question 2

purpose of fenestrations

Answer 2

allow muscles of lower jaw to attach to the surface of bones that surround the rim of the openings

Question 3

anapsid

Answer 3

“without arch” – do not possess temporal arches

in extant amniotes, only turtles have anapsid skulls

temporal muscles run from neurocranium to lower jaw

Question 4

emarginations

Answer 4

shallow notch similar to fenestrae present in turtles but are not homologous structures

Question 5

synapsid

Answer 5

“together arch” – skulls possess a single arch on each side of the skull

extensive attachment of jaw muscles to the surface of the dermatocranium

Question 6

infratemporal arch

Answer 6

composed of jugal, quadratojugal, squamosal bones… in extant mammals, the quadratojugal is often lost and the arch is frequently referred to as the zygomatic arch

Question 7

diapsid

Answer 7

“two arches” – skulls possess two arches on each side of the skull

basic skull condition for reptiles

extensive attachment of jaw muscles to the surface of the dermatocranium

Question 8

superior temporal fenestra

Answer 8

uppermost arch, the supratemporal arch and the opening defined by this arch

consists of the postorbital and squamosal bones

Question 9

infratemporal fenestra

Answer 9

lowermost arch, infratemporal arch and the opening defined by this arch

consists of the jugal, quadratojugal, and squamosal bones

Question 10

modifications of diapsid skulls

Answer 10

crocodylians and tuataras possess unmodified diapsid skull

birds have lost supratemporal arch

lizards have lost infratemporal arch (loss of quadratojugal)

snakes have lost both arches (loss of squamosal and quadratojugal)

Question 11

heterodont

Answer 11

animals which possess more than a single tooth morphology

mammals

Question 12

homodont

Answer 12

having teeth that are all the same type

most nonmammalian vertebrates

Question 13

diastema

Answer 13

space or gap between two teeth; area denuded of teeth

Question 14

carnassial teeth

Answer 14

laterally compressed, for shearing

Question 15

molariform teeth

Answer 15

molars and premolars

Question 16

dental formula

Answer 16

I C PM M / I C PM M = one side of mouth (upper/lower) as there can be variation in top and bottom but not sides

Question 17

mandible

Answer 17

two dentary bones fused at their anterior ends, mandibular symphysis

Question 18

styloid process

Answer 18

attachment site of a tongue muscle called the styloglossus muscle

Question 19

sella turcica

Answer 19

=Turkish saddle

bony concavity that houses the pituitary gland

Question 20

cribiform plate

Answer 20

region where olfactory neurons from the nasal region enter the brain

Question 21

crista galli

Answer 21

vertical plate projecting up from the cribiform plate; serves as the attachment site for the meninges that enclose the brain

Question 22

fontanel

Answer 22

“soft spot” in the head of a newborn that has not yet ossified

Question 23

modifications of synapsid skulls

Answer 23

most modern mammal synapsid skulls are slightly modified - the quadratojugal and postorbital bones are lost

Question 24

temporal bone

Answer 24

represents fusion of three bones: prootic, opisthotic, squamosal