The last European varanid

The Desert Monitor, Varanus griseus is the extant species
with the closest distribution to Europe today
In a recent paper, Georgalis et al. (2017) report the remains of a varanid lizard from the middle Pleistocene of the Tourkobounia 5 locality near Athens, Greece. The new fossil material comprises cranial elements only (one maxilla, one dentary, and one tooth) and is attributed to the monitor lizard genus Varanus, the genus to which all European Neogene varanid remains have been assigned. Previously, the most recent undisputed varanid from Europe had been recovered from upper Pliocene sediments. The new Greek fossils, therefore, constitute the most recent records of monitor lizards from the continent. Despite being incomplete, this new material enhances our understanding of the cranial anatomy of the last European monitor lizards and is clearly not referable to any of the extant species such as Varanus griseus or Varanus niloticus - the only species that could be taken into consideration on a present-day geographic basis. However, these fossils could represent a survivor of the monitor lizards of Asian origin that inhabited Europe during the Neogene. Varanids first appear in the European fossil record during the Eocene. They are entirely absent from the European Oligocene faunas but appear again in the fossil record after the early Miocene. It is possible the European Paleogene varanids were victims of the Grande Coupure. The Grande Coupure refers to a break or change in faunal continuity about 33.5 MYA and marks the the end of the Eocene assemblages of mammals, with the arrival of Asian species in Europe. The authors note that on the basis of the available data this cannot be demonstrated with certainty. All of the Neogene European varanids appear to be members of Varanus, and they seem to have dispersed into Europe in the early Miocene. In fact, the earliest evidence of the genus on the European continent is recorded in the early Miocene of Spain. Whether these early Miocene immigrants originated directly from Africa or have Asian affinities cannot be demonstrated with certainty. The occurrence of Varanus-like forms in the late Eocene and early Oligocene of Egypt favors an African origin, but the Asian record is too weak to offer any insights. The fact that the maxilla from Tourkobounia 5 does not show any relationship with extant African taxa (V. albigularis, V. exanthematicus, V. griseus, V. niloticus, V. ornatus) suggests Asian affinities, as already reported for the extinct Varanus amnhophilis from the late Miocene of Samos. Whatever their exact origin, monitor lizards rapidly achieved a wide distribution throughout Europe during the Miocene. Fossils attributed to this genus have been described from localities in Austria, Germany, Greece, Hungary, Italy, Moldova, Portugal, Romania, Spain, and the Ukraine.

Citation

Georgalis, G. L., A. Villa, and M. Delfino. 2017. The last European varanid: demise and extinction of monitor lizards (Squamata, Varanidae) from Europe. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1301946.

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