E.N. ARNOLD 



Fig. 6 Lateral profiles of supratemporal process (left) and body of 

 parietal bone (right), arrow indicates border between the two regions, 

 a. Upper surface of body of parietal bone running more or less smoothly 

 into upper margin of supratemporal process (P. mystaceus). b. Upper 

 suface of body of parietal abruptly raised relative to upper margin of the 

 supratemporal process (P. persicus). c. Similar, but upper surface of 

 body of parietal tuberculated (P. scutellatus). 



and running more or less smoothly into upper margin of supra- 

 temporal processes which is relatively flat (0); upper surface of 

 body of parietal bone abruptly raised relative to upper margin of 

 supratemporal processes (1). 



Other skeletal features 



12. Number of scleral ossicles. Twelve (0); eleven (1); ten in some 

 individuals (2). 



Acrodonta including Agamidae usually have 12 scleral ossicles 

 in each eye instead of the usual lizard number of 14. While 

 Bufoniceps possesses 12 there is further reduction in 

 Phrynocephalus: most species and individuals have 1 1 ossicles 

 but some members of at least a proportion of species in the P. 

 interscapularis group have 10. This is true of P. interscapularis, 

 P. luteoguttatus, P. sogdianus and P. ornatus. Occurrence of 10 

 ossicles may in fact be wider, but the other two members of the 

 P. interscapularis group (P. eutilopus and P. clarkorum) are 

 known from relatively few specimens, so checks on ossicle 

 number have been very limited in these. 



13. Number of presacral vertebrae. Usually 22, occasionally 23 in 

 some species (0); usually 21, occasionally 20 (1). 

 Substantial data on presacral vertebral number are given by 

 Whiteman (1978) and my own observations confirm his. Excep- 

 tions to the usual numbers occur in some species but nearly 

 always constitute a small minority of not more than about 15% 

 of individuals. 



14. Number of caudal vertebrae. Usually 40-50 or more (0); usually 

 less than 40(1). 



Again, my own observations confirm data given by Whiteman 

 (1978). 



External features 



15. Largest individuals exceed 60mm from snout to vent. Yes (0); no 



(1). 



16. Outline of body viewed from above. Robust and rounded (0); 

 more slender (1). 



17. Position of nostrils relative to line joining anterior corners of 

 eyes when head viewed from in front (Figure 7). Nostrils clearly 

 below line (0); nostrils intersecting line or above it (2); interme- 

 diate (1). 



Differences in position of the nostril are associated with differ- 

 ences in the conformation of the distal limb of the tubular nasal 

 vestibule. The proximal limb of the vestibule is more or less 

 vertical in all cases, running downwards from its connection 

 with the primary nasal chamber. Where the nostril is low, the 

 distal limb of the vestibule is relatively short and runs obliquely 

 upwards and outwards from the base of the proximal limb to the 

 nostril. In animals where the nostril is high the distal limb runs 

 more or less vertically upwards parallel to the proximal limb and 

 is about as long as this. 



18. Number of internasal scales between the nasal scales (Figure 7). 

 Usually two or more - 0; usually one or nil - 1. 



Fig. 7 Anterior views of heads showing differences in nostril position and in number of scales between nasal scales, a. Nostrils lower and separated by 

 two or more internasal scales (P. theobaldi). b. Nostrils high and nasal scales in contact or separated by a single internasal scale (P. arabicus). 



