Lizards and snakes from the late Miocene hominoid locality of Ravin de la Pluie (Axios Valley, Greece)

Abstract

We here describe lizards and snakes from the late Miocene (MN 10) of Ravin de la Pluie, near Thessaloniki, Greece, a locality widely known for its hominoid primate Ouranopithecus macedoniensis. The new finds comprise two large-sized lizards (a probable anguine and a varanid) and two snakes (an elapid and a small-sized ''colubrine''). Even if the material is represented by few specimens, this is the first record of squamates from the late Miocene MN 10 biozone of southeastern Europe and the third only for the whole continent. The importance of the varanid vertebrae for systematic attributions is discussed. The new varanid limb elements described herein rank among the few such specimens in the fossil record of monitor lizards. Judging from the new and previously published varanid appendicular material, we suggest that Neogene monitor lizards from Europe possessed comparatively short and robustly built limbs. Distinctive scars on one of the limb elements are interpreted as bite marks of a predator or scavenger, offering insights on the palaeoecology of the herpetofauna of the locality.

Fossil amphibians and reptiles from the Neogene locality of Maramena (Greece), the most diverse European herpetofauna at the Miocene/Pliocene transition boundary

“…The pseudozygosphene, however, is not present in the caudal vertebrae (Estes, 1983) characterized by a lesser degree of precondylar constriction in comparison to those of Varanus (Smith et al, 2008). Besides, European material assigned to Saniwa is strictly restricted to the Paleogene, and Varanus is the only valid varanoid genus currently known from the European Neogene Georgalis et al, 2017bGeorgalis et al, , 2018bIvanov et al, 2018;Villa et al, 2018a). Taking all these into consideration, we herein follow this view in assigning the fossils from Maramena to Varanus.…”

“…hofmanni by Tempfer [2005]). The second hypothesis, about higher species diversity, appears strange for European standards, considering that there has almost never been more than one species / morphotype of varanids coexisting in a single Neogene or Quaternary European locality (e.g., Böhme and Vasilyan, 2014;Colombero et al, 2014;Georgalis et al, 2017bGeorgalis et al, , 2018bIvanov et al, 2018;Villa et al, 2018a). The only exception is the Greek late Miocene locality of Pikermi, from which two species have been named: Varanus marathonensis and Varanus atticus Nopcsa, 1908.…”

“…Remarks. Both vertebrae can be assigned to Elapidae on the basis of their non-lightly built general shape and the probable presence of a hypapophysis, the relatively low neural spine, the depressed neural arch, the well-developed subcentral ridges, and the short condylar neck (Szyndlar, 1991b;Scanlon et al, 2003;Ikeda, 2007;Ivanov and Böhme, 2011;Georgalis et al, 2018b). Among elapids, UU MAA 7257 and UU MAA 7531 can be attributed to the genus Naja on the basis of their absolute size and the relatively low ratio of centrum length / neural arch width (Ivanov and Böhme, 2011).…”

“…Anguids are currently abundant and diverse in extant Greek herpetofaunas, pertaining to species belonging to two genera: the small-sized Anguis and the much larger Pseudopus (Valakos et al, 2008;Georgalis et al, 2017a). So far, anguid fossils from Greece had only been described from few early and late Miocene localities (Richter, 1995;Georgalis et al, 2018bGeorgalis et al, , 2019, including also Ano Metochi (Georgalis et al, 2017a), whereas they have also been recovered from multiple localities in the Oligocene and Miocene of nearby Turkey (Čerňanský et al, 2017;Syromyatnikova et al, 2019). The new anguid material from Maramena is by far the most abundant and demonstrates that the anguid fauna of Greece during the latest Miocene/earliest Pliocene was rather diverse with multiple taxa belonging to Anguis, Ophisaurus, and Pseudopus.The large number of morphotypes (five) within Ophisaurus material from Maramena is truly remarkable, although it cannot be fully evaluated whether and how this diversity of morphs also reflects species level taxonomy or if it could simply be attributed to some kind of intraspecific (e.g., ontogenetic) variation, or tooth wear.…”

“…Cobras of the genus Naja had already been described from Maramena (Szyndlar, 1995). In fact, cobras have been so far only rarely recorded from Greece and, besides Maramena, they were known only from the late Miocene (MN 10) of Ravin de la Pluie (Georgalis et al, 2018b) and the late Pliocene (MN 16) of Tourkobounia 1 (Szyndlar and Zerova, 1990;Szyndlar, 1991b). In any case, the presence of the cobra Naja in the late Miocene and Pliocene of Greece is fully concordant with the presence of that genus in approximately coeval deposits in Spain (Szyndlar, 1985;Szyndlar and Rage, 1990), France (Hoffstetter, 1939;Rage, 2013), and Turkey (Rage and Sen, 1976).…”