EVOLUTION OF HOLASP1S 



Appendix 1 



Derived features of Holaspis not found in immediate relatives in the 

 paraphyletic genus Adolf us. Most features are unique in the Lacertidae 

 as a whole and these are denoted by *. Separate postorbital and 

 postfrontal bones are primitive in the Lacertidae but fusion is the 

 usual condition in the African Equatorial group and separation in 

 Holaspis is a reversal (Arnold, 1989a). Most features appear to 

 confer a performance advantage in one or more of the characteristic 

 behaviours of Holaspis or ameliorate a problem associated with 

 them. The behaviours concerned are designated as follows: L - 

 locomotion on steep surfaces, C - use of crevices, G - gliding. 

 Brackets indicate a relatively minor role. 



163 



Proportions 



1 . Head, body, limbs and tail extremely depressed* 



2. Snout sharply wedge-shaped in lateral view* 



3. Fore and hind limbs approach equality in length* 



Skeleton and musculature 



4. Skull light and very thin-boned with some 

 deformability* 



5. Premaxilla forming a large semicircular boss* 



6. Nasal openings of skull very large and widely 

 expose primary nasal chambers 



7. Fronto-parietal suture a simple abuttment, not strongly 

 interdigitated*. 



8. Postorbital and postfrontal bones separate 



9. Supraocular osteoderms very reduced* 



10. Inferior orbital foramen extremely large 



1 1 . Pterygoid teeth absent 



12. Increased cranial kinesis 



13. Ring of scleral ossicles reduced to twelve and 

 emarginated above and below* 



14. Retroarticular process of mandible directed 

 somewhat ventrally* 



15. Dorsal vertebrae depressed with very reduced neural 

 spines* 



16. Anterior free ribs elongated with long cartilagenous 

 extensions at their tips* 



17. Coracoid plate with an extra fontanelle* 



18. Sternal fontanelle very large* 



19. M. intercostalis scalaris well developed, consisting of 

 slips originating on tips of anterior free dorsal ribs 



CG 

 C 

 L 



CG 



20. 



21. 



22. 

 23. 



and running forwards and medially to insert on upper 



surface of m. rectus abdominis, above outer margins 



of second row of ventral scales* 



Manus and pes have syndrome of features associated 



with climbing on continuous open surfaces very 



pronounced*. 



Length and downward curvature of penultimate 



phalanges of digits better developed than in other 



lacertids* 



Digits 2-5 of manus subequal in length* 



In manus, shortening and downward flexure of phalanx 



2 of toe, 3 and phalanges 2 and 3 of toe 4, very 



pronounced* 



c 





•(G) 



29. 



C 



30. 





31. 



c 





'(G) 



32. 



C 







33. 



c 





c 



34. 





35. 



c 





c 



36 





37. 



G 



38. 



G 



39. 



CG 



40. 



CG 



41. 



G 





External features 



24. Rostral scale very large, extending on to top of snout C 

 with broad frontonasal contact* 



25. Nostrils set back, on sides of snout* C 



26. Interparietal and paired frontoparietal scales all C 

 replaced by a single triangular scale* 



27. A window in the lower eyelid made up of 1-5 enlarged 

 semitransparent scales 



28. Temporal scales differentiated with anterior ones C 

 arranged in diagonal lines* 



Neck with sharp-edged flap on each side when G 



pharynx not expanded* 



Cross section of body convex above and flat below G 



A double series of very large flat scales along (C)G 



vertebral region of body* 



Dorsal scales on sides of posterior trunk laterally G 



expandable* 



Lateral dorsal scales on posterior trunk sometimes G 



joined by a system of bridges* 



Collar and belly scales with very reduced imbrication C 



Tail with two longitudinal rows of broad enlarged G 



scales above and below, the former with multiple 

 sensory pores* 



Tail with lateral fringes of interconnected pointed scales* G 

 Two rows of large scales on front of forelimbs* CG 



A patagium behind the knee* G 



A row of flat triangular scales on trailing edge of cms* G 

 Second and third fingers of manus conjoined at base* L 



Digits 3-5 of pes with a fringe of interlocking G 



pointed scales* 



42. Distinctive colouring* 



