The earliest evidence for Upper Paleolithic occupation in the Armenian Highlands at Aghitu-3 Cave.

With its well-preserved archaeological and environmental records, Aghitu-3 Cave permits us to examine the settlement patterns of the Upper Paleolithic (UP) people who inhabited the Armenian Highlands. We also test whether settlement of the region between ∼39-24,000 cal BP relates to environmental variability. The earliest evidence occurs in archaeological horizon (AH) VII from ∼39-36,000 cal BP during a mild, moist climatic phase. AH VI shows periodic occupation as warm, humid conditions prevailed from ∼36-32,000 cal BP. As the climate becomes cooler and drier at ∼32-29,000 cal BP (AH V-IV), evidence for occupation is minimal. However, as cooling continues, the deposits of AH III demonstrate that people used the site more intensively from ∼29-24,000 cal BP, leaving behind numerous stone artifacts, faunal remains, and complex combustion features. Despite the climatic fluctuations seen across this 15,000-year sequence, lithic technology remains attuned to one pattern: unidirectional reduction of small cores geared towards the production of bladelets for tool manufacture. Subsistence patterns also remain stable, focused on medium-sized prey such as ovids and caprids, as well as equids. AH III demonstrates an expansion of social networks to the northwest and southwest, as the transport distance of obsidian used to make stone artifacts increases. We also observe the addition of bone tools, including an eyed needle, and shell beads brought from the east, suggesting that these people manufactured complex clothing and wore ornaments. Remains of micromammals, birds, charcoal, pollen, and tephra relate the story of environmental variability. We hypothesize that UP behavior was linked to shifts in demographic pressures and climatic changes. Thus, by combining archaeological and environmental data, we gain a clearer picture about the first UP inhabitants of the Armenian Highlands.

A new stem-varanid lizard (Reptilia, Squamata) from the early Eocene of China.

Monitor lizards (genus Varanus) are today distributed across Asia, Africa and Australasia and represent one of the most recognizable and successful lizard lineages. They include charismatic living species like the Komodo dragon of Indonesia and the even larger extinct Varanus prisca (Megalania) of Australia. The fossil record suggests that living varanids had their origins in a diverse assemblage of stem (varaniform) species known from the Late Cretaceous of China and Mongolia. However, determining the biogeographic origins of crown-varanids has proved problematic, with Asia, Africa and Australia each being proposed. The problem is complicated by the fragmentary nature of many attributed specimens, and the fact that the most widely accepted, and most complete, fossil of a stem-varanid, that of Saniwa ensidens, is from North America. In this paper, we describe a well-preserved skull and skeleton of a new genus of stem-varanid from the Eocene of China. Phylogenetic analysis places the new genus as the sister taxon of Varanus, suggesting that the transition from Cretaceous varaniform lizards to Varanus occurred in East Asia before the origin and dispersal of Varanus to other regions. The discovery of the new specimen thus fills an important gap in the fossil record of monitor lizards. The similar lengths of the fore- and hindlimbs in this new taxon are unusual among the total group Varanidae and suggest it may have had a different lifestyle, at least from the contemporaneous North American S. ensidens. This article is part of the theme issue 'The impact of Chinese palaeontology on evolutionary research'.

The fossil record of the genus Varanus from the Southern Caucasus (Armenia, Georgia).

The Southern Caucasus, with its special geographic position and complex topography, is a well-known biodiversity hotspot. However, the formation of this hotspot remains largely unstudied. To reveal this, a thorough study of the fossil record of the region is necessary. In the present paper, we describe for the first time fossil monitor lizards (Varanus sp.) from two late Miocene localities from the Southern Caucasus (Jradzor, Armenia and Tetri Udabno, Georgia). We suggest that both fossils belong to a small-sized monitor lizard, comparable to the present-day species found in Iran and the Middle East (e.g., Iraq, Saudi Arabian)-the most western part of the extant monitor lizards' Eurasian distribution range. Our finds show that the genus had a broad distribution in the Eastern Paratethyan region during the late Miocene. In addition, we provide the probable temperature ranges for fossil localities.

The last Palaeoproteus (Urodela: Batrachosauroididae) of Europe.

The Batrachosauroididae are an enigmatic group of salamanders known from the Cretaceous and Tertiary of North America and Europe. In Europe, the family is known only by two species of the genus Palaeoproteus. The genus has limited distribution in Western and Central Europe. In the present paper, we describe a new species, Palaeoproteus miocenicus, from the early late Miocene (11-9 Ma) of Austria and Ukraine, representing the youngest record of the family Batrachosauroididae from the Neogene of Europe. The new species differs from the Paleogene representatives of the genus by 12 characters, including large body size, the long anterior extension of the Meckelian groove and the size and shape of the odontoid process on the dentary. The µCT scanning of bones of the new species revealed novel features (e.g. anterior extension of Meckelian groove, interconnected network of canals and small cavities in atlas) observable only in this species. P. miocenicus inhabited aquatic environments, which existed under wet climatic conditions with mean annual precipitation higher than 900 mm. The new species expands the temporal range of the genus by at least 30 million years and enlarges the palaeogeographic distribution of the genus into Eastern Europe.

First fossil frog from Antarctica: implications for Eocene high latitude climate conditions and Gondwanan cosmopolitanism of Australobatrachia.

Cenozoic ectothermic continental tetrapods (amphibians and reptiles) have not been documented previously from Antarctica, in contrast to all other continents. Here we report a fossil ilium and an ornamented skull bone that can be attributed to the Recent, South American, anuran family Calyptocephalellidae or helmeted frogs, representing the first modern amphibian found in Antarctica. The two bone fragments were recovered in Eocene, approximately 40 million years old, sediments on Seymour Island, Antarctic Peninsula. The record of hyperossified calyptocephalellid frogs outside South America supports Gondwanan cosmopolitanism of the anuran clade Australobatrachia. Our results demonstrate that Eocene freshwater ecosystems in Antarctica provided habitats favourable for ectothermic vertebrates (with mean annual precipitation ≥900 mm, coldest month mean temperature ≥3.75 °C, and warmest month mean temperature ≥13.79 °C), at a time when there were at least ephemeral ice sheets existing on the highlands within the interior of the continent.

Possible species-flock scenario for the evolution of the cyprinid genus Capoeta (Cypriniformes: Cyprinidae) within late Neogene lake systems of the Armenian Highland.

We studied 4 Ma old isolated pharyngeal teeth from lake sediments of Çevirme (Tekman Palaeolake, Erzurum Province). Based on shape characters defined for 3D models of modern species, we found that the Pliocene lake constitutes sympatric occurrence of four Capoeta species (C. cf. umbla, C. cf. baliki, C. cf. sieboldi and C. sp. sevangi/capoeta), whose modern relatives belong to a monophyletic clade inhabiting today three different drainage systems of this region (Euphrates River, Kura River and Black Sea). We interpreted this high local diversity of closely related species in terms of the species-flock model. The Tekman palaeolake was a part of an unrecognized extended late Miocene to Pliocene palaeolake system in the present-day Armenian Highland, which has been disrupted by Pliocene tectonic activities. Surface uplift of the Armenian Highland contributed to the very characteristic biogeographic distribution and endemism of Capoeta in West Asian drainage systems. Thus, we proposed a species-flock scenario for the evolution and dispersal of the cyprinid genus Capoeta in a huge unrecognized palaeolake system in the present-day Armenian Highland.

A new alligatoroid from the Eocene of Vietnam highlights an extinct Asian clade independent from extant Alligator sinensis.

During systematic paleontological surveys in the Na Duong Basin in North Vietnam between 2009 and 2012, well-preserved fossilized cranial and postcranial remains belonging to at least 29 individuals of a middle to late Eocene (late Bartonian to Priabonian age (39-35 Ma)) alligatoroid were collected. Comparative anatomical study of the material warrants the diagnosis of a new taxon, Orientalosuchus naduongensis gen. et sp. nov. The combined presence of an enlarged fifth maxillary tooth, prominent preorbital ridges, a large supraoccipital exposure on the skull table, a palatine-pterygoid suture anterior to the posterior end of the suborbital fenestra, and a pterygoid forming a neck surrounding the choana is unique to this species. Unlike previous phylogenies, our parsimony analysis recovers a monophyletic Late Cretaceous to Paleogene East to Southeastern Asian alligatoroid group, here named Orientalosuchina. The group includes Orientalosuchus naduongensis, Krabisuchus siamogallicus, Eoalligator chunyii, Jiangxisuchus nankangensis and Protoalligator huiningensis, all of them sharing a medial shifted quadrate foramen aerum. The recognition of this clade indicates at least two separate dispersal events from North America to Asia: one during the Late Cretaceous by Orientalosuchina and one by the ancestor of Alligator sinensis during the Paleogene or Neogene, the timing of which is poorly constrained.

Eocene Western European endemic genus Thaumastosaurus: new insights into the question "Are the Ranidae known prior to the Oligocene?"

BACKGROUND: Amphibians, due to their ecophysiological peculiarities, have a physiology dependent on environmental conditions and sensitively respond to their changes. Here, the oldest record of the genus Thaumastosaurus is described, whose fossil record known exclusively from Western Europe is discussed in the scope of the climatic changes of 33.5-40.5 Ma. RESULTS: In the present paper, the fossil remains of the genus from three localities in Switzerland (11 samples overall) have been studied and referred to the species Thaumastosaurus bottii. Its stratigraphic distribution has been revised and summarised. The studied localities present the stratigraphically oldest and the most eastern occurrences of the genus Thaumastosaurus. Eocene probable ranids (Ranidae indet./Rana sp./? Rana sp.) from Europe could be referred to Thaumastosaurus. DISCUSSION: Their first occurrence of ranids most likely coincides with a warm phase of the global climate at 40 Ma, as tropical conditions were prevailing in Europe. As a result of the gradual cooling of the global climate, the tropical conditions in Europe were replaced by drier open habitats towards the latest Eocene at 34 Ma, when the latest occurrence of the European endemic genus Thaumastosaurus is known. Taking the fossil record and the climate evolution of that time into account, it can be concluded that Thaumastosaurus represents one of the groups among the vertebrates that disappeared during the large extinction event at the Eo-Oligocene transition, known as the Grande Coupure. The fossil finds of the genus from the studied localities allow to refer the previously suggested Eocene true frogs to the genus Thaumastosaurus, hereby stating the arrival of the true frog family Ranidae by the genus Pelophylax in Europe from the east at the earliest Oligocene.

Neogene amphibians and reptiles (Caudata, Anura, Gekkota, Lacertilia, and Testudines) from the south of Western Siberia, Russia, and Northeastern Kazakhstan.

BACKGROUND: The present-day amphibian and reptile fauna of Western Siberia are the least diverse of the Palaearctic Realm, as a consequence of the unfavourable climatic conditions that predominate in this region. The origin and emergence of these herpetofaunal groups are poorly understood. Aside from the better-explored European Neogene localities yielding amphibian and reptile fossil remains, the Neogene herpetofauna of Western Asia is understudied. The few available data need critical reviews and new interpretations, taking into account the more recent records of the European herpetofauna. The comparison of this previous data with that of European fossil records would provide data on palaeobiogeographic affiliations of the region as well as on the origin and emergence of the present-day fauna of Western Siberia. An overview of the earliest occurrences of certain amphibian lineages is still needed. In addition, studies that address such knowledge gaps can be useful for molecular biologists in their calibration of molecular clocks. METHODS AND RESULTS: In this study, we considered critically reviewed available data from amphibian and reptile fauna from over 40 Western Siberian, Russian and Northeastern Kazakhstan localities, ranging from the Middle Miocene to Early Pleistocene. Herein, we provided new interpretations that arose from our assessment of the previously published and new data. More than 50 amphibians and reptile taxa were identified belonging to families Hynobiidae, Cryptobranchidae, Salamandridae, Palaeobatrachidae, Bombinatoridae, Pelobatidae, Hylidae, Bufonidae, Ranidae, Gekkonidae, Lacertidae, and Emydidae. Palaeobiogeographic analyses were performed for these groups and palaeoprecipitation values were estimated for 12 localities, using the bioclimatic analysis of herpetofaunal assemblages. CONCLUSION: The Neogene assemblage of Western Siberia was found to be dominated by groups of European affinities, such as Palaeobatrachidae, Bombina, Hyla, Bufo bufo, and a small part of this assemblage included Eastern Palaearctic taxa (e.g. Salamandrella, Tylototriton, Bufotes viridis). For several taxa (e.g. Mioproteus, Hyla, Bombina, Rana temporaria), the Western Siberian occurrences represented their most eastern Eurasian records. The most diverse collection of fossil remains was found in the Middle Miocene. Less diversity has been registered towards the Early Pleistocene, potentially due to the progressive cooling of the climate in the Northern Hemisphere. The results of our study showed higher-amplitude changes of precipitation development in Western Siberia from the Early Miocene to the Pliocene, than previously assumed.

Pronounced peramorphosis in lissamphibians--Aviturus exsecratus (Urodela, Cryptobranchidae) from the Paleocene-Eocene Thermal Maximum of Mongolia.

BACKGROUND: The oldest and largest member of giant salamanders (Cryptobranchidae) Aviturus exsecratus appears in the latest Paleocene (near the Paleocene-Eocene Thermal Maximum) of Mongolia. Based on femoral and vertebral morphology and metrics, a terrestrial adaptation has been supposed for this species. METHODOLOGY/PRINCIPAL FINDINGS: A detailed morphological reinvestigation of published as well as unpublished material reveals that this salamander shows a vomerine dentition that is posteriorly shifted and arranged in a zigzag pattern, a strongly developed olfactory region within the cranial cavity, and the highest bone ossification and relatively longest femur among all fossil and recent cryptobranchids. CONCLUSIONS/SIGNIFICANCE: The presence of these characteristics indicates a peramorphic developmental pattern for Aviturus exsecratus. Our results from Av. exsecratus indicate for the first time pronounced peramorphosis within a crown-group lissamphibian. Av. exsecratus represents a new developmental trajectory within both fossil and recent lissamphibian clades characterized by extended ontogeny and large body size, resembling the pattern known from late Paleozoic eryopines. Moreover, Av. exsecratus is not only a cryptobranchid with distinctive peramorphic characters, but also the first giant salamander with partially terrestrial (amphibious) lifestyle. The morphology of the vomers and dentaries suggests the ability of both underwater and terrestrial feeding.