postfrontal . i .. i 



.nnlH 1 P°s'°rbital parietal 



nasal 



septomaxilio 

 premaxilla 



A 



orbitosphenoid !►------■ par 



frontal ^__,,.-— V-— H^T/ ^'^---. epipterygoid 



prefrontal, _^r::rIlS--'--''~VS \\ /X^squamosol 



^supratemporal 

 epiphysis 

 paroccipital process 



occipital condyle 

 quadrate 

 prootic 

 bosisphenoid 



squamosal 



quadrate 

 epiphysis 

 suprotemporol 



paroccipital process 

 of opisthotic 



supraoccipital 



'basioccipital 



■exoccipital 



prootic 



palatine 

 ectopterygoid , 



parosphenoid P^^'YQO'd 



maxilla 

 lacrima 

 prefronto 



B 



fronta 



foramen for Jacobson's organ 

 vomei 



premoxillo 



|ugal 

 postfrontal 



basipterygoid process 

 ectopterygoid epipterygoid / bosisphenoid covered by 



palatine 



septomaxilio 



new tooth in socket 

 ^ maxilla 



orbitosphenoid 



Figure 4-1. Skull of the Tegu lizard, Tupinombis nigropunctatus. A, laterol view; B, dorsal view; 

 C, ventral view. 



Sphenodon, the Tuafara The Tuatara head skeleton 

 looks like that of the lizard (Figures 4-7, 4-8). The arches 

 of this diapsid reptile are even better developed than the 

 lizard's, and the inferior temporal fenestra is margined be- 

 low by a labial arch, formed in part by a quadratojugal. 

 The roof is similar, and a parietal foramen is present. A 

 supratemporal and lacrimal are lacking. The palate diffei-s 



in having the pterygoid contacting the vomer medial to the 

 palatine. The joint between the roof and the oticoccipital 

 segment is not capable of movement. Since the palatoquad- 

 rate complex is strongly attached at all points, this skull 

 is nonkinetic. There is no orbitosphenoid. The teeth are 

 fused to the jaw margin in the acrodont style of attachment. 

 The lower jaw lacks a splenial. The hyoid apparatus is like 



OTHER TETRAPODS • 65 



