Earliest example of a giant monitor lizard (varanus, varanidae, squamata)

Background

Varanidae is a clade of tiny (<20 mm pre-caudal length [PCL]) to giant (>600 mm PCL) lizards first appearing in the Cretaceous. True monitor lizards (Varanus) are known from diagnostic remains beginning in the early Miocene (Varanus rusingensis), although extremely fragmentary remains have been suggested as indicating earlier Varanus. The paleobiogeographic history of Varanus and timing for origin of its gigantism remain uncertain.

Methodology/Principal Findings

A new Varanus from the Mytilini Formation (Turolian, Miocene) of Samos, Greece is described. The holotype consists of a partial skull roof, right side of a braincase, partial posterior mandible, fragment of clavicle, and parts of six vertebrae. A cladistic analysis including 83 taxa coded for 5733 molecular and 489 morphological characters (71 previously unincluded) demonstrates that the new fossil is a nested member of an otherwise exclusively East Asian Varanus clade. The new species is the earliest-known giant (>600 mm PCL) terrestrial lizard. Importantly, this species co-existed with a diverse continental mammalian fauna.

Conclusions/Significance

The new monitor is larger (longer) than 99% of known fossil and living lizards. Varanus includes, by far, the largest limbed squamates today. The only extant non-snake squamates that approach monitors in maximum size are the glass-snake Pseudopus and the worm-lizard Amphisbaena. Mosasauroids were larger, but exclusively marine, and occurred only during the Late Cretaceous. Large, extant, non-Varanus, lizards are limbless and/or largely isolated from mammalian competitors. By contrast, our new Varanus achieved gigantism in a continental environment populated by diverse eutherian mammal competitors.     

Evolution,diversity and interactions with past human populations of recently extinct Pholidoscelis lizards (Squamata: Teiidae) from the Guadeloupe Islands (French West-Indies)

This paper aims to demonstrate how subfossil bone remains from Pleistocene and Holocene deposits can help to reconstruct the history of recently extinct taxa through the example of Pholidoscelis lizards from the Guadeloupe Islands in the French West Indies. To achieve this, we conducted a new anatomical and zooarchaeological study of fossil Pholidoscelis remains collected from 23 archaeological and paleontological deposits on the Guadeloupe Islands from which this genus is nowadays absent. Our results shed light on the past existence of large Pholidoscelis lizards on all the Guadeloupe islands but also on the difficulties of confident specific identification for these remains. Nevertheless, we suggest a possible past occurrence of the now extinct Pholidoscelis major on nearly all of the Guadeloupe islands. In addition, we identified a new Pholidoscelis species, Pholidoscelis turukaeraensis sp. nov., on Marie-Galante Island, where no Pholidoscelis lizards were previously reported. This new species underwent an increase in size after the end of the Pleistocene period, possibly due to reduced predation pressure. We also highlight the consumption of Pholidoscelis lizards by pre-Columbian Amerindians and the huge impact of European colonization, which led to the extinction of all these lizards in less than 300 years.http://zoobank.org/urn:lsid:zoobank.org:pub:15C39436-A083-483F-B35E-78807B606904     

Middle to Late Pleistocene herpetofauna from Scladina and Sous-Saint-Paul caves (Namur,Belgium)

For the first time, the fossil herpetofauna from the Middle and Late Pleistocene of Scladina and Sous-Saint-Paul caves (Sclayn, Belgium) is described. The amphibians and squamate reptiles are represented by one salamander (Salamandra salamandra), three anurans (Pelodytes punctatus, Bufo bufo and Rana temporaria), two lizards (Lacerta cf. agilis and Anguis fragilis) and two snakes (Zamenis longissimus and Vipera cf. berus). The occurrence of the Parsley Frog (Pelodytes punctatus) and the Aesculapian Snake (Zamenis longissimus), which are not currently represented in Belgium, is of particular interest. Scladina also represents one of the northernmost fossil mentions for the Fire Salamander (Salamandra salamandra) although it is within its current distribution in Europe. Finally, the presence of the Adder (Vipera cf. berus) is very probably attested in Scladina whereas today this snake is infrequent and classified as endangered in Belgium.     

Late Quaternary woolly mammoth (Mammuthus primigenius Blum) remains from southern Transdanubia,Hungary

Six samples of subfossil tusk, bone and tooth remains from the woolly mammoth (Mammuthus primigenius Blum) were discovered in south-western Hungary. The remains are relatively well preserved in a Late Pleistocene loess deposit. The samples have been radiocarbon dated (AMS) and are of Late Weichselian (MIS 2) age (21.8–24.1 ka cal BP). The skull fragments, the tusks and maxillary teeth are in close proximity to associated postcranial remains, indicating that the mammoth died where it was found. The size and characteristics of skeletal elements have allowed us to determine that this was a mature male of about 38 years of age.     

Late Pleistocene skeleton of Canis lupus l., 1758 from Grotta Mora Cavorso (Jenne,Latium, central Italy)

This paper describes the skeleton of Canis lupus found in Layer 7 of Grotta Mora Cavorso (Latium, central Italy), correlated with the MIS 3. Research on the deposition dynamics of this find is still in progress, but the action of human or other predators can be excluded. This specimen consists of a near complete articulated skeleton, lacking only the calvarium. The age at death was estimated at around six years old. Preliminary morphometric analyses and comparisons with samples of Italian Late Pleistocene wolf and extant Apennine wolf (C. lupus italicus) remains, show that the dimensions of the teeth and long bones are among the biggest known from the Italian Late Pleistocene and larger than the extant Apennine wolf.     

Reconstruction of Late Pleistocene palaeoecology of the Upper Narmada valley (Central India) using fossil communities

Pleistocene deposits of Narmada valley are exposed in the Jabalpur and Narshingpur districts of Central India and have yielded microvertebrates (rodents, lizards and fish) as well as invertebrates (gastropods and pelecypods). The Late Pleistocene fossil-bearing horizons are from two fossil localities, Bhedaghat and Devakachar. Earlier report of Homo erectus from the valley strengthens palaeoecological interpretations. Here, we combine our study of microfossils with the earlier work on large mammals in our tentative reconstruction of palaeoecology of the area. The most common microfossil communities belong to stream, pond–pond bank, wooded grassland and arid to semi-arid habitats.     

The fossil American lion (Panthera atrox) in South America: Palaeobiogeographical implications

By the late 19th and early 20th centuries, authors described several specimens belonging to a very large felid, the size of a lion, from some Late Pleistocene localities at southern Chile and Argentina. These remains were considered as belonging to large and now extinct subspecies of jaguar. In the present contribution based on qualitative and quantitative postcranial and cranial characters, we conclude that that the “Patagonian Panthera” should be considered as representing remains of the American Cave Lion Panthera atrox. Evidence at hand indicates that Panthera atrox was a very large lion-like felid, with reddish skin, that inhabited dry open habitats. Furthermore, in contrast to living jaguars, transported and accumulated its preys in rocky dens. The presence of at least two pantherine lineages (i.e. P. onca and P. atrox) in the Pleistocene of South America indicates that the lineage has a long and complex history in the New World, and that the history of the clade in this landmass is still far from being well understood.     

Cold-climate rodent indicators for the Late Pleistocene of Central Iberia: New data from the Buena Pinta Cave (Pinilla del Valle,Madrid Region,Spain)

In the Iberian Peninsula, the Late Pleistocene record of small mammal indicators of cold climates is largely restricted to two sets of sites at the eastern and western ends of the Pyrenees. Some assemblages from other sites at the Peninsular centre have, however, recently yielded such taxa. This work describes the remains of three such rodent species from the Buena Pinta Cave, a site in the Sierra de Guadarrama mountains in the Spanish Central System. Excavation campaigns in the cave have taken place every summer since 2003. Thermoluminescence analyses of sediments from levels 2–5 of the site suggest an age corresponding to the middle of the Late Pleistocene, within Marine Isotope Stage 4 or the beginning of Marine Isotope Stage 3. Sieve-washing and picking out of the small fossils contained in the sediments of levels 2–5 yielded several thousand small mammal teeth and other remains, dominated by Microtus arvalis. Smaller numbers of remains belonging to other rodents typical of cold climates were also identified, such as Microtus oeconomus, Microtus gregalis and Chionomys nivalis. Thus, the small mammal record of the Buena Pinta Cave shows that rodent indicators of cold climates reached the centre of the Iberian Peninsula during the mid-Late Pleistocene, i.e., well before the Last Glacial Maximum. These findings represent one of the southernmost Pleistocene records for M. oeconomus in Europe, and the most southerly for M. gregalis.     

Pleistocene and Holocene rhinocerotids (Mammalia,Perissodactyla) from the Indochinese Peninsula

Rhinocerotids were abundant and diverse in southern Asia during the Pleistocene and the Holocene epochs, as shown by palaeontological and archaeological discoveries published throughout the last century, whereas the only living rhinoceros in the Indochinese Peninsula is Rhinoceros sondaicus (Cat Loc Reserve, Vietnam). The Pleistocene-Holocene Indochinese rhinocerotid record consists of the extinct species Dicerorhinus gwebinensis (Early Pleistocene, Myanmar) and representatives of the Recent Asian Species Rhinoceros unicornis (Middle-Late Pleistocene), R. sondaicus (Middle Pleistocene-Recent), and Dicerorhinus sumatrensis (Middle Pleistocene-Holocene). This fossil record is synthesized, mapped for Early/Middle/Late Pleistocene and Holocene/Recent times, and then compared with coeval rhinocerotid assemblages from the adjacent areas (South China), subregions (Indian, Sundaic, Philippine, and Wallacean), and region (Palearctic), from a biochronological and biogeographical perspective.     

Human talus bones from the Middle Pleistocene site of Sima de los Huesos (Sierra de Atapuerca,Burgos, Spain)

Here we present and describe comparatively 25 talus bones from the Middle Pleistocene site of the Sima de los Huesos (SH) (Sierra de Atapuerca, Burgos, Spain). These tali belong to 14 individuals (11 adult and three immature). Although variation among Middle and Late Pleistocene tali tends to be subtle, this study has identified unique morphological characteristics of the SH tali. They are vertically shorter than those of Late Pleistocene Homo sapiens, and show a shorter head and a broader lateral malleolar facet than all of the samples. Moreover, a few shared characters with Neanderthals are consistent with the hypothesis that the SH population and Neanderthals are sister groups. These shared characters are a broad lateral malleolar facet, a trochlear height intermediate between modern humans and Late Pleistocene H. sapiens, and a short middle calcaneal facet. It has been possible to propose sex assignment for the SH tali based on their size. Stature estimates based on these fossils give a mean stature of 174.4 cm for males and 161.9 cm for females, similar to that obtained based on the long bones from this same site.     

Amphibians and squamate reptiles from the late Pleistocene of the “Caverne Marie-Jeanne” (Hastière-Lavaux,Namur, Belgium): Systematics,paleobiogeography, and paleoclimatic and paleoenvironmental reconstructions

Archeological sites usually provide important information about the past distribution of small vertebrate fauna, and by extension about past terrestrial environments and climate in which human activities took place. In this context, Belgium has an interesting location in northwestern Europe between the fully studied zooarcheological records of Germany and England. We present here the revision of the late Pleistocene (Marine Isotope Stages 3 and 2) collection of the “Caverne Marie-Jeanne” (Hastière-Lavaux, Namur), studied by Jean-Claude Rage in the 1970s and the revision of the whole “indeterminate” small vertebrate materials from the “Caverne Marie-Jeanne” stored in the Royal Belgian Institute of Natural Sciences (RBINS) Quaternary collections in search of more herpetofaunal remains. It is now by far the largest late Pleistocene collection at RBINS with more than 20,500 recognized bones of amphibians and reptiles and covering the last 60,000 years. The faunal list comprises two urodeles (Lissotriton gr. L. vulgaris and Salamandra salamandra), four anurans (Bufo gr. B. bufo-spinosus, Epidalea calamita, Rana temporaria and Rana cf. R. arvalis), three lizards (Lacerta cf. L. agilis, Zootoca vivipara and Anguis gr. A. fragilis), and three snakes (Natrix gr. N. natrix, Coronella austriaca, and Vipera berus). This study represents the first fossil record in Belgium for L. gr. L. vulgaris, R. arvalis, Z. vivipara, N. gr. N. natrix and C. austriaca. As a whole, this assemblage suggests a patchy humid landscape under colder and dryer climatic conditions in comparison with present ones. This study also underlines the necessity of a primary separation in larger taxonomical categories by the specialist itself.     

Phylogeographic and Demographic Analysis of the Asian Black Bear (Ursus thibetanus) Based on Mitochondrial DNA

The Asian black bear Ursus thibetanus is widely distributed in Asia and is adapted to broad-leaved deciduous forests, playing an important ecological role in the natural environment. Several subspecies of U. thibetanus have been recognized, one of which, the Japanese black bear, is distributed in the Japanese archipelago. Recent molecular phylogeographic studies clarified that this subspecies is genetically distantly related to continental subspecies, suggesting an earlier origin. However, the evolutionary relationship between the Japanese and continental subspecies remained unclear. To understand the evolution of the Asian black bear in relation to geological events such as climatic and transgression-regression cycles, a reliable time estimation is also essential. To address these issues, we determined and analyzed the mt-genome of the Japanese subspecies. This indicates that the Japanese subspecies initially diverged from other Asian black bears in around 1.46Ma. The Northern continental population (northeast China, Russia, Korean peninsula) subsequently evolved, relatively recently, from the Southern continental population (southern China and Southeast Asia). While the Japanese black bear has an early origin, the tMRCAs and the dynamics of population sizes suggest that it dispersed relatively recently in the main Japanese islands: during the late Middle and Late Pleistocene, probably during or soon after the extinction of the brown bear in Honshu in the same period. Our estimation that the population size of the Japanese subspecies increased rapidly during the Late Pleistocene is the first evidential signal of a niche exchange between brown bears and black bears in the Japanese main islands.This interpretation seems plausible but was not corroborated by paleontological evidence that fossil record of the Japanese subspecies limited after the Late Pleistocene. We also report here a new fossil record of the oldest Japanese black bear from the Middle Pleistocene, and it supports our new evolutionary hypothesis of the Japanese black bear.     

The Xujiayao 14 Mandibular Ramus and Pleistocene Homo Mandibular Variation

The earlier Late Pleistocene mandibular ramus from Xujiayao (northern China) preserves traits that vary distributionally among western Old World Pleistocene Homo samples and between Early/Middle Pleistocene archaic humans and Late Pleistocene modern humans in eastern Eurasia. Xujiayao 14 presents a lateral mandibular notch crest, an open mandibular foramen, a wide ramus, an asymmetrical mandibular notch, an enlarged superior medial pterygoid tubercle, (probably) a retromolar space, and gonial eversion, as well as an unusual depression in the planum triangulare. The first two traits appear ancestral for Later Pleistocene and recent Homo and are dominant among modern humans. The second two traits largely separate Xujiayao 14 and archaic Homo from modern humans. The next two traits are found in the highest frequency among the Neandertals, although gonial eversion contrasts with Late Pleistocene Neandertals. Xujiayao 14, in the context of Pleistocene and recent Homo samples and the other Xujiayao human remains, therefore provides a morphological mosaic, highlighting regional variation through the Pleistocene.     

Head shape evolution in monitor lizards (Varanus): interactions between extreme size disparity,phylogeny and ecology

Characterizing patterns of observed current variation, and testing hypotheses concerning the potential drivers of this variation, is fundamental to understanding how morphology evolves. Phylogenetic history, size and ecology are all central components driving the evolution of morphological variation, but only recently have methods become available to tease these aspects apart for particular body structures. Extant monitor lizards (Varanus) have radiated into an incredible range of habitats and display the largest body size range of any terrestrial vertebrate genus. Although their body morphology remains remarkably conservative, they have obvious head shape variation. We use two‐dimensional geometric morphometric techniques to characterize the patterns of dorsal head shape variation in 36 species (375 specimens) of varanid, and test how this variation relates to size, phylogenetic history and ecology as represented by habitat. Interspecific head shape disparity is strongly allometric. Once size effects are removed, principal component analysis shows that most shape variation relates to changes in the snout and head width. Size‐corrected head shape variation has strong phylogenetic signal at a broad level, but habitat use is predictive of shape disparity within phylogenetic lineages. Size often explains shape disparity among organisms; however, the ability to separate size and shape variation using geometric morphometrics has enabled the identification of phylogenetic history and habitat as additional key factors contributing to the evolution of head shape disparity among varanid lizards.     

Late Pleistocene and Holocene chitons (Mollusca, Polyplacophora) from Uruguay: Palaeobiogeography and palaeoenvironmental reconstruction in mid latitudes of the southwestern Atlantic

Here we present a revision of the fossil record of chitons (Mollusca, Polyplacophora) of Late Pleistocene and Holocene marine deposits of Uruguay and discuss their potential for palaeoenvironmental reconstruction. Chitons were recorded as isolated valves in bivalve- and gastropod-rich assemblages. They are represented by the species Chaetopleura angulata (Spengler), C. isabellei (d’Orbigny), C. asperrima (Gould) and Ischnochiton striolatus (Gray). The last two species are recorded for the first time as fossils not only in Uruguay but also in South America. Exclusively recorded for the Late Pleistocene is the warm water species I. striolatus, whose current southern range limit is located in Santa Catarina, Brazil. Higher temperatures than at present are inferred for the Uruguayan coast during the Late Pleistocene, probably driven by the southward influence of the warm Brazilian Current along the eastern margin of South America. Chitons from Holocene deposits show a wider geographic distribution along the Uruguayan coast in comparison to current distributions. They are recorded where an estuarine and eurihaline fauna lives today, which suggests the former existence of marine conditions. This is explained by the westward displacement of the marine front in the Uruguayan coast during the Holocene transgressive events. Chitons have proven to be useful palaeoenvironmental proxies for the reconstruction of salinity and temperature trends in the Uruguayan coast during the climatic oscillations of the Late Pleistocene and Holocene epochs. As such, their patterns of distribution are related to the recent physical evolution of the Southwestern Atlantic Ocean.     

Testing the phylogenetic affinities of Southeast Asia's rarest geckos: Flap-legged geckos (Luperosaurus), Flying geckos (Ptychozoon) and their relationship to the pan-Asian genus Gekko

Some of Southeast Asia's most poorly known vertebrates include forest lizards that are rarely seen by field biologists. Arguably the most enigmatic of forest lizards from the Indo Australian archipelago are the Flap-legged geckos and the Flying geckos of the genera Luperosaurus and Ptychozoon. As new species have accumulated, several have been noted for their bizarre combination of morphological characteristics, seemingly intermediate between these genera and the pan-Asian gecko genus Gekko. We used the first multilocus phylogeny for these taxa to estimate their relationships, with particular attention to the phylogenetic placement of the morphologically intermediate taxa Ptychozoon rhacophorus, Luperosaurus iskandari, and L. gulat. Surprisingly, our results demonstrate that Luperosaurus is more closely related to Lepidodactylus and Pseudogekko than it is to Gekko but that some species currently classified as Luperosaurus are nested within Gekko. The Flying Gecko genus Ptychozoon is also nested within Gekko, suggesting that higher-level taxonomic revision of the generic boundaries within Southeast Asian gekkonines will be a priority for the immediate future.     

Monitor lizards: a pan-African check-list of their zoogeography (Sauria: Varanidae: Polydaedalus)

Aim This goal of this paper is to present an up‐to‐date, accurate check‐list and distribution of the monitor lizards on the African continent. No such list of their distribution has been attempted since Robert F. Mertens' (1942) treatise (Abhandlungen Senckenbergischen Naturforschenden Gesellschaft, 462 , 465 , 466 ). Location The localities included herein are all countries on the African continent, and adjacent islands, with a list of Varanus known to Yemen and Saudi Arabian Republics included for clarity. One fossil Varanus rusingensis is included, as it is the first, and only described, fossil African Varanus known. Methods Locality records were reviewed from literature sources, museum voucher specimens, personal comments, field observations and photographic records. Results A summation of 3,268 locality records are included herein from the methods listed, with maps depicting these records. Main conclusions From the locality records listed herein, it is evident that the Nile monitor (V. niloticus) has the widest distribution, and that the Yemen monitor (V. yemenensis) has the most restricted distribution; paradoxically, both features may be indicative of their relic habitation on the African continent.