Chart-1, BIO 3220, Skull and Lower Jaw Components in Tetrapods

(adapted from Walker, Vertebrate Dissection.)

 

X = present O = absent Unos. = unossified

 

NECTURUS ALLIGATOR MAMMAL
NEUROCRANIUM
Basioccipital Unos. X X – Occipital
Exoccipital X X X – Occipital
Supraoccipital Unos. X X – Occipital
Otics X X X – Petrous portion of temporal
Basisphenoid Unos. X X
Sphenethmoid Unos. X X – Presphenoid
Unos. Ethmoid region Unos. Unos. X – Ethmoid
Unos. nasal capsule Unos. Unos. X – Turbinates
DERMATOCRANIUM
Premaxilla – Upper jaw X X X
Maxilla- Upper jaw O X X
Nasal – Roofing O X X
Frontal – Roofing X X X
Parietal – Roofing X X X
Lacrimal – Roofing O X X
Jugal – Roofing O X X
Squamosal – Roofing X X X – Squamous portion of temporal
Vomer – Primary palate X X X
Palatine – Primary palate O X X
Pterygoid – Primary palate X X X – Pterygoid process of basisphenoid
LOWER JAW; DERMAL BONES
Dentary – Largest X X X
Splenial ( 2) X X O
Surangular O X O
Angular X X X – Tympanic portion of temporal
Coronoid O X O
Prearticular O X X – Anterior portion of Malleus
VISCERAL ARCHES
Palatoquadrate
Quadrate X X X – Incus
Epipterygoid O O X – Alisphenoid
Hyomandibular
Stapes X X X
LOWER JAW: VISCERAL ARCHES
Articular Unos. X X – Malleus