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

Large constrictor snakes, referred to the genera Palaeopython and Paleryx , are an ecologically prominent part of the fauna of Europe during the Paleogene. Most species were named over a century ago and their taxonomy is largely based on isolated vertebrae. Furthermore, the majority of named taxa originate from imprecisely known localities within the Phosphorites du Quercy, in southern France, and thus their exact age is not known. We critically review and re-diagnose these genera based on personal examination of all existing type material, an array of new specimens, and a detailed literature review. We consider Palaeopython and Paleryx to be valid and propose vertebral characters to distinguish them. We recognize three valid species of Palaeopython , i.e. Palaeopython cadurcensis (type species) from the Phosphorites du Quercy, Palaeopython ceciliensis from Geiseltal, and Palaeopython helveticus from Dielsdorf (Switzerland), and one valid species of Paleryx , i.e. Paleryx rhombifer (type species) from Hordle Cliff (England). Four other species, which were previously treated as members of Palaeopython and Paleryx , i.e. “ Palaeopython ” filholii and “ Palaeopython ” neglectus from the Phosphorites du Quercy, “ Palaeopython ” fischeri from Messel, and “ Paleryx ” spinifer from Geiseltal, are also considered as valid but pertain to other genera. Among these four taxa, “ Palaeopython ” fischeri has been recently assigned to its own genus, Eoconstrictor . A new genus, Phosphoroboa gen. nov. is established to accommodate “ Palaeopython ” filholii . We designate a lectotype for Palaeopython cadurcensis and establish that the paralectotype maxilla and dentary are reasonably referred to this species. New material attributed to Palaeopython cadurcensis is described from the old collections of the Phosphorites du Quercy. Paleryx cayluxi , another species established from the old collections of the Phosphorites du Quercy, is synonymized here with Palaeopython cadurcensis . We further clarify important errors in the original description and figures of Paleryx cayluxi , identify the exact specimens that comprise the type series, and designate a lectotype. Much new material is described for Palaeopython ceciliensis from its type area in Geiseltal and intracolumnar variation is considered. We describe additional vertebral and cranial material of Paleryx rhombifer from its type area in Hordle Cliff. Based on this cranial material, we suggest non-booid affinities for Paleryx rhombifer. We designate a lectotype for Paleryx depressus and agree with its previous suggested synonymy with Paleryx rhombifer . We re-describe the lectotype and paralectotypes of “ Palaeopython ” neglectus and refer and describe new material of this species from the Phosphorites du Quercy, paying special attention to intracolumnar variation; we also defer a decision on its generic relations until more abundant and complete material can be studied. We describe new vertebral material of the booid Eoconstrictor cf. fischeri from Geiseltal; similar material was previously known only from Messel and Dielsdorf. We determine that Eoconstrictor fischeri contains two distinct and unrelated species and describe intracolumnar variation in the nominotype. We clarify certain issues regarding the type series of Paleryx spinifer , designate a lectotype, and report previously unrecognized cranial material associated with the latter specimen; we transfer this species to Eoconstrictor based on cranial features and recombine it as Eoconstrictor spinifer comb. nov. We finally describe much new vertebral and cranial material of Phosphoroboa filholii comb. nov. from the Phosphorites du Quercy (both from the old collections but also from the late Eocene localities of Escamps A and C), paying special attention to intracolumnar variation. Based on this cranial material from Escamps, we identify Phosphoroboa gen. nov. as a booid. An analytical approach is undertaken in many isolated remains in order to quantify vertebral structures and assess intracolumnar variation, as well as associating isolated cranial elements to vertebral-based taxa. 3D models of the type material of the Geiseltal and Messel taxa are presented. The importance of vertebrae in the taxonomy of fossil Constrictores is addressed, although it is acknowledged that it is cranial material that can afford the most reliable phylogenetic conclusions. The diversity, distribution, biogeographic origins, and final demise and extinction of large Constrictores in the Paleogene of Europe are discussed.

A long-forgotten, old collection of lizards from the Phosphorites du Quercy in southern France, housed in the Naturhistorisches Museum in Vienna (NHMW), is described in detail in this paper. The material, consisting of several almost complete cranial and postcranial disarticulated elements, originates from different, imprecisely known localities. Nevertheless, the completeness and exceptional preservation of many of these specimens permitted the identification of new taxa, as well as the recognition and better understanding of novel anatomical features of previously described forms. Among the specimens, the material described herein and referred to Cadurcogekko cf. piveteaui ranks among the most complete cranial remains of Paleogene gekkotans. A clarification about the type material of the previously described species Cadurcogekko verusBolet, Daza, Augé & Bauer, 2015, is provided. A new species of lacertids is established, Pseudeumeces kyrillomethodicus n. sp. Additional, large lacertid material is referred to Mediolacerta Augé, 2005, representing also the largest one attributable to this genus. At least two glyptosaurine taxa are present in this collection, among which, the genus ParaplacosauriopsAugé & Sullivan, 2006, is represented by exceptional cranial material, referred to Paraplacosauriops quercyi (Filhol, 1882). The completeness of the cranial material of Paraplacosauriops permits a more comprehensive understanding of its maxillary and mandibular anatomy. A detailed documentation of cranial and postcranial material for the genus PalaeovaranusZittel, 1887-1890, is conducted. The new maxilla described herein allows a better understanding of the peculiar maxillary features of the genus Palaeovaranus. Emended diagnoses are provided for the genus Palaeovaranus and its type species Palaeovaranus cayluxiZittel, 1887-1890. The parietal morphology of Palaeovaranus is analyzed in detail and intraspecific variation in this element is assessed. A new species of Palaeovaranus is established, Palaeovaranus lismonimenos n. sp., on the basis of an almost complete parietal that can be differentiated from that of Palaeovaranus cayluxi on the basis of a number of distinctive features. Additional, previously published specimens from Quercy are here referred to Palaeovaranus lismonimenos n. sp., representing younger individuals of this species, and photographs of this material is provided for the first time. The diversity of platynotans in the Paleogene of Europe is discussed and their distinction on the basis of parietal morphology is provided. According to the new emended diagnosis for Palaeovaranus, the genus Melanosauroides Kuhn, 1940, is revalidated herein to accommodate Melanosauroides giganteus Kuhn, 1940, from the late early or middle Eocene of Geiseltal, Germany. So far, Melanosauroides giganteus is solely known from its type area in Geiseltal, and all previously supposed occurrences of this taxon in Quercy are discarded. Abundant anguimorph vertebral material is referred to Placosaurus sp., Melanosaurini indet., Anguinae indet., Palaeovaranus sp., Saniwa sp., and Anguimorpha indet., although it is highlighted that certain of these referrals should be taken into consideration with caution. Especially, the problem of certain large isolated lizard vertebrae from Quercy is addressed; a tentative, potential distinction between vertebrae of the genera Palaeovaranus and PlacosaurusGervais, 1848-1852, is suggested, although admittedly only articulated skeletons of these genera may confirm or refute such taxonomic referrals. The importance of fossil squamates from the area of the Phosphorites du Quercy is highlighted. Detailed figuring of the specimens is provided through the means of both photography and micro-CT scanning, with 3D models of the most significant material also presented. This is the first time that micro-CT scanning is conducted on fossil squamates from Quercy. The many figures provided in this paper may serve as a pictorial key guide for fossil lizards from the Paleogene of Europe.

Lizard and snake remains from the early Miocene (Burdigalian) of the Moghra Formation, Egypt, are described herein. This material comprises the first fossil remains of squamates recovered from the otherwise rich and well known vertebrate assemblage of Moghra. The material pertains to two different genera, the varanid lizardVaranusand the pythonid snakePythonand adds to the so far rather poorly known squamate fossil record from Africa. On the basis of the new remains, Moghra marks the oldest so far described co-occurrence ofVaranusandPythonin the African continent. The close sympatry of these two genera in the African fossil record is thoroughly analyzed and discussed, a co-existence, which is still widespread in the extant herpetofauna of the continent. Situated rather close to the so called “Levantine Corridor” and dated at the Burdigalian, practically when Afro-Arabia collided with Eurasia, the Moghra squamate assemblage offers the potential of important insights in the biogeography and dispersal events of vertebrate groups during the early Miocene.

We here describe a new squamate fauna from the late Miocene (Messinian, MN 13) of Ano Metochi, northern Greece. The lizard fauna of Ano Metochi is here shown to be rather diverse, consisting of lacertids, anguids, and potential cordylids, while snakes are also abundant, consisting of scolecophidians, natricines and at least two different colubrines. If our identification is correct, the Ano Metochi cordylids are the first ones identified from Greece and they are also the youngest representatives of this group in Europe. A previously described scincoid from the adjacent locality of Maramena is here tentatively also referred to cordylids, strengthening a long term survival of this group until at least the latest Miocene. The scolecophidian from Ano Metochi cannot be attributed with certainty to either typhlopids or leptotyphlopids, which still inhabit the Mediterranean region. The find nevertheless adds further to the poor fossil record of these snakes. Comparison of the Ano Metochi herpetofauna with that of the adjacent locality of Maramena reveals similarities, but also striking differences among their squamate compositions.

The lizard and snake fauna from the late middle–late Eocene (MP 16–MP 20) of Dielsdorf, near Zurich, Switzerland, is described comprehensively in this paper. Detailed comparisons of the Dielsdorf material with other extinct taxa allow us to establish a new species of the large “booid” genus Palaeopython, i.e., Palaeopython helveticus sp. nov., characterized by a unique combination of vertebral features, most prominently a highly vaulted neural arch. Other squamates of the Dielsdorf assemblage comprise the large lizard Palaeovaranus sp. and as many as three other taxa of snakes, i.e., Palaeopython cf. fischeri, Palaeopython sp. (morphotype 3), and “Booidea” indet. We conducted micro-CT scanning in the Palaeovaranus dentary, which confirmed the presence of plicidentine in this lizard genus. Micro-CT scanning was also conducted in differently sized snake vertebrae from our sample, revealing that the respective anatomical differences were probably due to ontogenetic variation. This is the first time that micro-CT scanning is applied in Palaeovaranus and Palaeopython. The importance of this method for potentially clarifying the taxonomy and precise affinities of extinct snakes is addressed. We also provide digital 3D model reconstructions of the Palaeovaranus dentary and Palaeopython vertebrae (including that of the holotype of Palaeopython helveticus sp. nov.) for the first time. The palaeobiogeographic significance of the Dielsdorf lizards and snakes is discussed and the sympatric occurrences of the genera Palaeovaranus and Palaeopython throughout the Eocene of Europe are presented in detail.