Cranial Osteology of the Bridled Skink, Trachylepis vittata (Olivier, 1804), and Its Comparison with Trachylepis aurata transcaucasica (Chernov, 1926) (Sauria: Scincidae)

Abstract

In spite of high diversity of the Iranian Plateau herpetofauna, especially the lizards, and numerous studies done on the morphometric characters of lizards, information on the detailed characters of their skeleton remains insufficient. Herein, the adult cranial osteology of the bridled skink, Trachylepis vittata (Olivier, 1804), is described in detail for the first time based on cleared and double-stained skeletal elements and compared with Trachylepis aurata transcaucasica (Chernov, 1926). In this study, characters of the skull and mandibular elements were examined. The existence of slight differences between the two studied species according to bone and skull characters, are explained. The skull of both species, as typical representatives of the Scincidae, bear teeth on the premaxilla, maxilla, and pterygoids. The mandibular teeth are present on the dentaries. Some obvious differences that show off are: different number of pleurodont maxillary teeth as T. vittata and T. a. transcaucasica have 20 and 21–26 maxillary pleurodont teeth, respectively, narrower tip of the nasal processes of the premaxilla in T. vittata than that of T. a. transcaucasica , different ornamentation of the nasal processes of the frontals as are more projected to the nasals in T. vittata than those of T. a. transcaucasica , slightly higher degree of serration on the posterior margin of the frontals in T. vittata than that of T. a. transcaucasica , and fine differences in form, size and special manner of articulation in bones such as: the lacrimals, prefrontals, postfrontals, palatines, pterygoids, dentary and prearticular.