Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 23. 2005. (Budapest, 2005)

FRAGMENTA PALAEONTOLOGICA HUNGARICA 23, BUDAPEST, 2005 Fossil snakes from the Late Pleistocene of Tokod (Gerecse Mountains, Hungary) by Charles M. MESZOELY, Márton VENCZEL & Mihály G ASP ARIK Abstract — An impressive array of Late Pleistocene Vertebrate fossil bones has been excavated and described from Tokod, Hungary (GASPARD^ 1993). Most of the bones of the repülés are very small, fragmentary skull elements, ribs and vertebrae. So far more than sixty species of vertebrates, among them at least eight genera of reptiles and amphibians have been recognized. Among the reptiles, four genera of snakes have been identified on basis of the morphology of the basiparasphenoid bone or vertebrae. All four of these snake genera: Coluber, Coronella, Matrix, and Vipera süli occur in Hungary today. Due to the fragmentary nature of the fossil material, positive identification as to the species is not possible at this time and the four snake species are tentatively referred to the modern species found in Hungary: Coluber caspius, Coronella austriaca, Matrix natrix, and Vipera berus. The positive identification of these four snake genera in the Tokod Late Pleistocene fossil assemblage not only expands its faunal list, but because of the specific habitat requirement of these snakes, it provides some palaeoecological information about the environment of the Tokod fossil locality. Keywords — Late Pleistocene, mosaic vegetation, Vipera, Matrix, Coluber, Coronella MESZOELY, C. M., VENCZEL, M. & GASPARIK, M.: Fossil snakes from the Late Pleistocene of Tokod (Gerecse Mountains, Hungary). — Fragmenta Palaeontologica Hungarica, 23: 1-4. Material From the record, the following remains of the four snake taxa were identified. In parentheses, the acquisition numbers (Gyn/...) or the inventory numbers (V...) of the specimens are. All specimens are stored in the Department of Geology and Palaeontology of the Hungarian Natural History Museum (FINHM). Coronella sp.: altogether 63 vertebrae (Gyn/408., Gyn/411., Gyn/417., Gyn/425.) and one basiparasphenoid (V.98.8.; Figure 1). Coluber sp.: altogether 107 vertebrae (Gyn/486., Gyn/413., Gyn/414., Gyn/421., Gyn/424.). Natrix. sp.: altogether 39 vertebrae (Gyn/487., Gyn/412., Gyn/419., Gyn/422.) and one basiparasphenoid (V.98.7.; Figure 3). Vipera sp.: altogether 302 vertebrae (Gyn/409., Gyn/410., Gyn/420., Gyn/427.) and one basiparasphenoid (V.98.9.; Figure 2). Table 1 shows the distribution of the specimens in the different layers from the locality. Description and comparison The Coronella basiparasphenoid (HNHM V.98.8.) foramina are widely separated from the constricto internus measures 7.8 mm and is nearly complete. In comparison dorsalis (cid nerve) foramina (Figure lb), to the other two snakes, the ventral surface is quite flat The trunk vertebrae assigned to Coronella (HNHM due to a poorly developed basisphenoid crest and associated Gyn/408., Gyn/411., Gyn/417., Gyn/425.) are of very lateral developments. However, the anterior parasphenoid small size (measuring less than 3.5 mm) and are x-shaped. portion exhibits a relatively deep ventral mid-sagittal Their neural arches are dorsoventrally compressed and depression along its entire length. The well-developed have a low but relatively long neural spine. The haemal pterygoid crests extend from the center to the lateral keels are flattened and the prezygapophyseal processes are margins of the bone. The Vidian canal is relatively long, a very short. character regarded as primitive by UNDERWOOD (1967). The Vipera basiparasphenoid (HNHM V.98.9.) measures The posterior opening of this canal is at some distance 5 mm and most of the parasphenoid portion is missing, from the posterolateral margin of the basisphenoid, while On its ventral surface it has a well-developed basisphenthe anterior opening is covered by the pterygoid crest oid crest which bifurcates anteriorly giving it a Y-shaped (Figure la). configuration (Figure 2a). On the dorsal surface the pituitary fossa (i.e. sella On the dorsal surface, the well-developed pituitary fossa turcica) is well-developed and is somewhat heart-shaped. has an ovaloid configuration. The cultiform process is not The cultiform process is nearly complete and flanked on preserved, but a small portion of the crista trabecularis on both sides by narrow crista trabecularis. The frontal step the left-hand side of the bone suggests that this process is of the bone is relatively low. The abducens nerve (VI) better developed in Vipera than in Coronella (Figure 2b).