Lacertidae

Lacertidae View in CoL View at ENA ( Figs 30 View Figure 30 , 31A–E View Figure 31 , 37I–M View Figure 37 )

In lacertids, the basipterygoid processes of the sphenoid are moderately short. They can be moderately narrow proximally and strongly enlarged by the distal end ( Ac. erythrurus , Ophisops elegans and juveniles of other species; Fig. 30D, E View Figure 30 ) or enlarged for their entire length (adults of other species; Figs 30I, J View Figure 30 , 31D, E View Figure 31 , 37I, J, L View Figure 37 ). In proportion, larger species have larger processes than smaller ones. The distal end of the processes is strongly dorsolaterally concave and not distinctly tilted mediolaterally. Its medial portion is expanded in anterior view. Well-developed (shorter in Al. marchi , Al. moreoticus and Al. nigropunctatus ; Fig. 37J View Figure 37 ) cristae ventrolaterales and a long, narrow and laminar parasphenoid rostrum are present. The cristae reach the sphenooccipital tubercles. The trabeculae cranii are dorsoventrally flattened. They are small and well separated from one another in small-sized animals (e.g. Ac. erythrurus ; Fig. 30D View Figure 30 ), but they grow bigger and tend to come into contact in adults of larger ones (e.g. Lacerta bilineata and Ti. lepidus ; Fig. 30I View Figure 30 ). Cristae trabeculares merge posteriorly with the well-developed crista sellaris, which does not develop a dorsum sellae. The alar processes of the crista sellaris expand anteriorly, forming vertical and subquadrangular supravenous processes. It is not clear if they are homologous to those of gekkotans ( Villa et al., 2018a). Supravenous processes of lacertids are moderately long and moderately wide and they may be connected to the distal end of the basipterygoid processes by a ventral osseous expansion. The anterior openings of the abducens foramina are visible on the medial surfaces of these processes, and a deep and a wide groove for the lateral head vein separates each process from the related basipterygoid process. A low transverse ridge is present on the dorsolateral surface of the latter process and marks the ventral margin of this groove. In some individuals, posterolateral openings of the Vidian canals can be located posteriorly, by the contact with the prootics. In adults of Ac. erythrurus , Ar. bedriagae , E. arguta , Ophisops elegans , Po. tiliguerta , Psammodromus algirus and Ti. lepidus , as well as in both adults and juveniles of Da. oxycephala , H. graeca and Po. siculus , the ventral surface of the sphenoid has a moderately to strongly sunken area in the middle ( Fig. 30E View Figure 30 ). A distinctly less-developed concavity can also be visible on the ventral surface of other species, such as I. cyreni , Po. melisellensis and Po. muralis . In adults of Lacerta and in Po. tauricus , the ventral surface can be either deeply sunken or not. In the observed specimens of Da. oxycephala , the concavity is deep in NHMW 629 and shallow in the other specimens: this suggests that this feature is variable in the species, but because NHMW 629 is probably a subadult and the shallow morphology is present in both juveniles (NHMW 659- 2) and adults (NHMW 651 and 659-2), this variation is most probably not strictly linked to ontogeny. This variation is present also in Po. siculus , because MDHC 91, an adult, has an unsunken surface.