internal auditory meatus parietal 

 orbitosphenoid Vll^ _\J__ processus ascendens 



supraoccipital 



fronto 



prefrontal 



nasal 

 septomaxilla 

 premaxilla 



vomer 



maxilla palatine 



porasphenoid 

 parietal 

 supraoccipital \ exoccipital parietal 

 prootic, ,,.,\J_ L epipterygoid ep,pterygor^^^ P ^ 



prootic 

 endolymphatic foramen 



opisthotic 

 jugular foramen 

 <J^;-Cl^ exoccipital 

 basioccipital 

 perilymphatic fenestra, IX 

 quadrate 

 sella turcica 

 carotid foramen 



postorbita 



squamosa 

 juga 



supratempi 

 epiphysis 



-quadrate 

 para 



columella 

 pterygoid 



B 



jugular foramen 

 hypoglossal foramen 

 foramen magnum 



occipital 

 estra vestibuli 



perilymphatic 

 fenestra, IX 



.ipterygc 

 \, pterygoid 



jiar foramen 

 pitol process 

 parabasal canal 



coronoid 



supraongulare 



orticulare 



angulare 



coronoid 



angulare 



Figure 4-2. Skull and mandible of the Tegu lizard, Tupinambis nigropunctatus. A, medial view of right 

 half of skull; B, rear view of skull; C, lateral view of cranium with temporal arch removed; D, lateral 

 view of mandible; E, medial view of mandible. 



the lizard's but attaches dorsally through the epihyal to the 

 extracolumella. The development of the head skeleton fol- 

 lows the pattern of the lizard. 



The similarity between the Tuatara and the agamid lizard 

 Uromaslix in terms of vomer-pterygoid relationship, acrodont 

 dentition, and over-all appearance indicates either close 

 common ancestry with parallel evolution of structure or a 

 case of convergent evolution from quite dissimilar ancestors. 

 The former view is now generally accepted. In terms of 



retaining the supratemporal and in its usual plcurodont style 

 of tooth anchorage, the lizard is just as primitive as the 

 Tuatara. 



Turfle In strong contrast to the diapsid is the anapsid, in 

 which there are no temporal fenestrae and the skull is non- 

 kinetic. The only living anapsids are the turtles. The follow- 

 ing description (the "type" turtle) is based on the variations 

 observed in Carrlla carrlla. the Loggerhead Turtle; Macni- 



66 • HEAD SKELETON OF OTHER TETRAPODS AND CHOANATES 



