PHRYNOCEPHALUS PHYLOGENY 



a b 



coeliac 



caecal 

 m. cranialis 



caecal 

 coeliac 



m. cranialis 



coeliac 

 caecal 



m. cranialis 



Fig. 13 Variation in position of the origin of the caecal artery on the 

 dorsal aorta in Phrynocephalus. a. close to origin of mesenterica 

 cranialis artery, b, c. Close to origin of coeliac artery. 



Xenagama, Agama s. str., Pseudotrapelus and Trapelus, the 

 caecal artery originates well posterior to the coeliac artery and 

 close to and anterior to the mesenterica cranialis artery (Figure 

 1 3a). In a wide range of agamids, including Laudakia, the caecal 

 and coeliac arteries originate close together, with the former 

 usually, although not always, anterior (Figure 1 3b, c). (Informa- 

 tion from Henke, 1974 and personal observations). 

 Within Phrynocephalus some species exhibit an anterior origin 

 of the caecal artery, either a short distance in front of that of the 

 coeliac artery or, much less commonly, just posterior to it. In 

 contrast, the remaining members of the genus and Bufoniceps 



show a posterior origin close to the mesenterica cranialis artery. 

 Other characters 



45. Viviparous, giving birth to fully-formed young. No (0); yes (1). 



46. Tail used frequently in intraspecific signalling. No (0); yes (1). 



Hemipenial features 



It has been suggested that features of the hemipenis delineate species 

 groups within Phrynocephalus (Semenov & Danayev, 1989). These 

 authors illustrate apparent differences in lobe length and in whether 

 calyces are present on the lobes. However, personal observations of 

 a wide range of species, including P. mystaceus, P. maculatus, P. 

 arabicus, P. euptilopus, P. interscapularis, P. helioscopus, P. 

 theobaldi, P. vlangalii, P. guttatus, P. versicolor and P. przewalskii, 

 suggest that the hemipenis in these forms is consistently deeply 

 lobed with a honeycomb structure on the outer lobe surfaces. 

 Possibly the differences described by Semyonov and Danayev result 

 from examining hemipenes preserved in different stages of eversion. 



PHYLOGENETIC ANALYSIS 



The data set (Appendix 1) consists of 46 characters most of which 

 are binary but eight include three states. Trapelus andLaudakia were 

 used as alternative outgroups. Analysis was initially carried out 

 using the Hennig86 program (Farris, 1988) with the options ie- and 

 bb*, which apply branch swopping to a single tree certain to be of 

 minimum length. When characters were ordered and Trapelus used 

 as the outgroup, two trees of 110 steps were produced with a 

 consistency index of 0.49 and a retention index of 0.79. With 

 Laudakia as the outgroup two trees were again produced, with a 

 length of 1 1 2 steps, consistency index 0.48 and retention index 0.79. 



Fig. 14 Estimate of phytogeny of Phrynocephalus and Bufoniceps using Trapelus as an outgroup. Tree produced by parsimony analysis using branch and 

 bound on a tree guaranteed to be of shortest length. Figures indicate degree of bootstrap support, only that of 57% or above being shown. 



