Fossil Snakes Research Articles

The first lacertid and partly articulated snake from the Middle Miocene of the Devínska Kobyla Hill in Slovakia, from the type locality of the earliest known seal

I here describe lacertid and snake remains from the classic Middle Miocene (MN 6) locality Bonanza of the Devínska Kobyla Hill near Bratislava (Slovakia). The locality is famous for being a type locality of an early seal Devinophoca Koretsky & Holec, 2002. During the Middle Miocene, the area of Devínska Nová Ves was part of an archipelago in the western part of the Central Paratethys in the northern part of the Vienna basin. The fossils described here comprise an incomplete left maxilla of a lacertid lizard and an articulated portion of a vertebral column of a small colubrid snake with several ribs still attached. The maxilla is tentativelly allocated here to Lacerta Linnaeus, 1758 and is a rare instance of the occurrence of the clade Lacertidae Oppel, 1811 in this environment during the Middle Miocene. Moreover, it represents the oldest known occurence of this clade in Slovakia. Articulated snake specimens from the Cenozoic are rare and although only party articulated, the specimen from Bonanza is therefore exceptional. On the basis of vertebrae alone, determination of fossil colubrids is very difficult. The morphology of the Bonanza specimen is most similar to the extant Dolichophis Gistel, 1868, as also to other small fossil snakes assigned to ‘Coluber’ Linnaeus, 1758 when that genus was a catch-all grade taxon recognised from both Europe and North America, notably ‘Coluber’ dolnicensis Szyndlar, 1987 and ‘Coluber’ pouchetii (Rochebrune, 1880). Because the potentially closest living relative of the European Miocene ‘Coluber’ is Dolichophis, I assigned tentatively the material from Bonanza to cf. Dolichophis, rather than to the wastebasket taxon ‘Coluber’.

Morphology and systematics of a new fossil snake from the early Rupelian (Oligocene) White River Formation, Wyoming

Abstract Extinct snake taxa are recognized primarily from isolated vertebrae. A new specimen from the early Oligocene of Wyoming provides a rare opportunity to examine four nearly complete and articulated fossil snakes. Informally assigned previously to the ‘erycine’ vertebral form taxa Ogmophis and Calamagras, a detailed comparison reveals that this fossil snake exhibits vertebral differences from both taxa and is, furthermore, a new taxon, Hibernophis breithaupti gen. et sp. nov., based on a combination of apomorphies such as absence of basal tubera, low subrectangular prootic, low parasphenoid wings obscuring the anterior opening of the Vidian canal, and foramen for the mandibular branch of the trigeminal nerve posteriorly displaced inside the adductor fossa of the compound. Parsimony and Bayesian phylogenetic analysis of combined morphological and molecular data from a broad selection of snakes places Hibernophis breithaupti as sister taxon to all other booids, distant from both Old and New World ‘erycines’. However, an alternative position close to New World ‘erycines’ and ungaliophiines cannot be rejected.

First fossil snake from McFaddin Beach, Texas, USA

First fossil snake from McFaddin Beach, Texas, USA

Fossil snakes of the Penny Creek Local Fauna from Webster County, Nebraska, USA, and the first record of snakes from the Early Clarendonian (12.5-12 Ma) of North America

Fossil snakes of the Penny Creek Local Fauna from Webster County, Nebraska, USA, and the first record of snakes from the Early Clarendonian (12.5-12 Ma) of North America

A new booid snake from the Eocene (Lutetian) Konservat-Lagerstätte of Geiseltal, Germany, and a new phylogenetic analysis of Booidea

Abstract We describe two exceptionally preserved fossil snakes from the Eocene Konservat-Lagerstätte of Geiseltal, located in the state of Saxony-Anhalt, Germany. The two snake specimens, GMH LIX-3-1992 and GMH XXXVIII-20-1964, can be confidently identified as booids based on general morphology and were thus compared to other geographically and/or temporally close fossil booids. We found that GMH LIX-3-1992 is morphologically very similar to Eoconstrictor spinifer, also from Geiseltal, and to Eoconstrictor fischeri, from the middle Eocene of Messel, but differs from both in a number of cranial and vertebral features. Based on these differences we erect the new species Eoconstrictor barnesi sp. nov.; GMH XXXVIII-20-1964 is very similar to GMH LIX-3-1992 and the two differ only in features that are likely ontogenetic. Phylogenetic analyses of snakes using maximum parsimony and Bayesian inference on datasets inclusive of both morphological and molecular data consistently support a close affinity of E. barnesi to E. fischeri and E. spinifer. Our preferred phylogenetic hypothesis places the three species of Eoconstrictor in a clade that is sister to Neotropical Boidae, a result consistent with previous studies. The genus Eoconstrictor could provide an important calibration point for molecular clock studies of booids and snakes in general.

Taxonomic revision of the giant marine snake genus Pterosphenus Lucas, 1898, based on new fossil material from the middle Eocene (Bartonian) Harudi Formation of Kachchh (Kutch) Basin, India

ABSTRACT Fossil snakes of the family Palaeophiidae are primarily known from rare, isolated vertebrae, leading to a poor understanding of the intra- and inter-columnar variation within a palaeophiid species. This leads to ambiguity in the taxonomic identity of these snakes, as in the case of the Eocene-age marine snakes of the genus Pterosphenus, in which the majority of species have been described by characters of problematic taxonomic value. Here, we propose a taxonomic revision of the genus based on an articulated to semi-articulated section of the vertebral column at the anterior to mid trunk-transition of Pterosphenus schucherti discovered from the middle Eocene (Bartonian) Harudi Formation, Kachchh (Kutch) Basin. The characters that separate Pterosphenus schucherti from ‘Pterosphenus schweinfurthi’ and ‘Pterosphenus biswasi,’ viz., the height of the pterapophysis and the anterior concavity of the zygosphene, have been found to be non-diagnostic, and the latter two species have been synonymized with the type species. Additionally, we utilized 2D and 3D landmark-based geometric morphometry to determine the morphometric affinity of palaeophiids amongst the alethinophidian snakes. The body size of the snake was estimated based on extant snakes with a morphometric affinity to Palaeophiidae. The cosmopolitan distribution of Pterosphenus schucherti is modelled based on the sea surface temperature (SST) constraints of the modern cosmopolitan snake Hydrophis platurus, and the known fossil localities of the species. The present findings provide crucial insights into the global paleoecological landscape of the Eocene, and the interactions of Pterosphenus schucherti with other palaeophiid snakes as well as the other Eocene fauna.

Pleistocene fossil snake traces on South Africa’s Cape south coast

Snakes form a large, familiar, and distinctive component of the world’s reptile fauna, with a rich body fossil record stretching back to the Jurassic. The sparse, minimal, and questionable evidence of snake traces in the ichnological record is therefore surprising. Extant snakes in southern Africa employ three types of locomotion—rectilinear, sidewinding, and undulatory, all of which result in distinctive, recognizable traces. A site exhibiting convincing evidence of rectilinear motion, probably made by a puff adder, has been identified in Pleistocene aeolianites on South Africa’s Cape south coast. A new ichnogenus and ichnospecies, Anguinichnus linearis, have been erected to describe this trace. A new suite of optically stimulated luminescence (OSL) ages from aeolianites from the De Kelders Cave locality, 1.4 km to the south, suggests that the site dates to ∼93–83 ka. Trace fossil evidence of sidewinding and undulatory motion is more equivocal and open to alternative interpretations.

Corrigendum

Corrigendum

A conserved tooth resorption mechanism in modern and fossil snakes

Whether snakes evolved their elongated, limbless bodies or their specialized skulls and teeth first is a central question in squamate evolution. Identifying features shared between extant and fossil snakes is therefore key to unraveling the early evolution of this iconic reptile group. One promising candidate is their unusual mode of tooth replacement, whereby teeth are replaced without signs of external tooth resorption. We reveal through histological analysis that the lack of resorption pits in snakes is due to the unusual action of odontoclasts, which resorb dentine from within the pulp of the tooth. Internal tooth resorption is widespread in extant snakes, differs from replacement in other reptiles, and is even detectable via non-destructive μCT scanning, providing a method for identifying fossil snakes. We then detected internal tooth resorption in the fossil snake Yurlunggur, and one of the oldest snake fossils, Portugalophis, suggesting that it is one of the earliest innovations in Pan-Serpentes, likely preceding limb loss.

Early Pliocene fossil snakes (Squamata, Colubroidea) with various teeth from the fissure deposit from Queshan, Henan, China

ABSTRACT Despite the world-widely reported snake fossils throughout the Cenozoic, snake fossils from China have not yet been frequently reported. Here we report a series of early Pliocene snake fossils entombed with the mammalian fauna from Houxushan, Queshan, Henan, China. By the comprehensive osteological comparison between the fossils and many extant snakes, we report three families (Colubridae, Natricidae, and Viperidae) and six genera (Cyclophiops, Elaphe, Gloydius, Lycodon, Protobothrops, and Rhabdophis) and summarised brief diagnoses of these genera. Those fossil snakes present at least three different dental types: solid teeth (regular teeth), tubular teeth, and blade-like teeth. Based on the mammalian faunas, the age of the fossil snakes can be inferred as the end of the early Pliocene near MN15 (~4.2 − 3.6 Ma). The discovery of the snake fossils emphasises the necessity of further investigating the Cenozoic snake faunas in China and provides new insights into the Cenozoic biodiversity and climate. In contrast to the cold and dry climate inferred by earlier studies, a diverse number of Oriental species and anuran-preying snakes in the Queshan herpetofauna might reveal a warmer and more humid climate in this region during the early Pliocene.

Live birth in a 47-million-year-old snake.

Viviparity is a widespread reproductive trait in snakes, although fossil evidence bearing on its evolution is extremely sparse. Here, we report an exceptional specimen of the minute booid snake Messelophis variatus recovered in the paleolake of the Messel Formation (early-middle Eocene, Germany). This gravid female contains at least two embryos located in the posterior third of the trunk region. The morphology, size, and degree of ossification of the cranial and postcranial remains indicate they correspond with late embryos. This specimen documents the first occurrence of viviparity in a fossil snake and extends the temporal distribution of this reproductive strategy in booid snakes by over 47Ma. The evolution of viviparity in squamates has traditionally been associated with cold climates, but its presence at the dawn of the evolution of booids during early Palaeogene thermal peaks indicates that viviparity may have evolved under different selective pressures in this clade.

Amphibian and reptilian fauna from the early Miocene of Echzell, Germany

The present study describes a rich amphibian and reptilian assemblage from the early Miocene locality Echzell, Germany. It consists of one allocaudate, five salamander, five frog, one gecko, chamaeleonids, anguine lizards, one lacertid, one skink and five snake taxa. The entire herpetofauna of Echzell is represented by genera and/or families very broadly known from the early Miocene of Europe. Contrary to other early Miocene herpetofaunas, the Echzell assemblage includes surprisingly only one form of crocodile-newts (Chelotriton). The EchzellPalaeobatrachus robustusrepresents the youngest record of the species and extends its stratigraphic range to the late early Miocene. Regarding chameleons, the frontal is partly preserved, but represents the first described frontal of the extinct speciesChamaeleo andrusovi. The only anguine lizard that can be identified in the assemblage is represented by a new genus and speciesSmithosaurus echzellensis.Our phylogenetic analyses consistently recovered it as the sister taxon to either [Ophisauriscus quadrupes+Ophisaurus holeci] + [Anguis+Ophisaurus] (in the first analysis) or [Anguis+Ophisaurus] (in the second analysis). However, the results are based on limited fossil material – the parietal – and the support for the clade is very low. Thus, the interpretation of theSmithosaurusrelationship among anguines needs to be taken with caution and has to be tested in further studies. Among snakes,Natrix longivertebratarepresents the oldest record of the species and extends the stratigraphic range of this fossil snake back to the early Miocene. In addition, we provide here a broader comparison of the Echzell amphibian and reptilian assemblage with their European records for the MN3 and MN4 biostratigraphical units. Besides that, the entire herpetofauna of Echzell includes very broadly known early Miocene European forms. Remains of other groups of the same period such as Bufonidae, Hylidae, Pelodytidae, Amphisbaenia, Varanidae, Cordylidae,Pseudopus, are not found in the material available to us. We also conclude that the amphibian and reptilian fossil record across MN3–MN4 is significantly biased by taphonomic and/or environmental conditions. The amphibian and reptilian assemblage of Echzell is rich in forms living in humid and warm environments with forested areas, permanent water bodies and also some open habitats. The following climatic parameters can be reconstructed based on the herpetofauna: a mean annual temperature of 17.4–28.8 °C, minimal warm month temperature 18–28.3 °C, minimal cold month temperature 8–22.2 °C, and mean annual precipitation with a value of 791±254 mm.

Novel findings of late Cenomanian-Turonian Pachyophiid snakes, fishes and plants in the SE Bosnia-Herzegovina

New fossils from the Late Cenomanian-Turonian locality in the Bileca area are reported. The fossils include a diverse assemblage of snakelike reptile remains, fishes and plants. While fossil snakes have already been found in this area, the remains of fish and plants are reported for the first time. Based on the state of fossil preservation, the following were identified: the snake Pachyophis (Simoliophiidae), the pychnodont fish Coelodus sp., and plant remains of the flowering plants groups Magnoliidae exc. Lilianae, Arecaceae (palm trees), and Cycadopsida.

Redescription, taxonomy and phylogenetic relationships of Boavus Marsh, 1871 (Serpentes: Booidea) from the early–middle Eocene of the USA

The extinct fossil snake Boavus occurs in early–middle Eocene localities in the United States. Four species are currently recognized, but until now, no formal phylogenetic analyses have been conducted to test its relationships within snakes. Here, we provide an osteological redescription and systematic revision of the genus, accompanied by phylogenetic analyses using multiple methods. Based on new morphological information obtained through first-hand observation and published descriptions, differences between Boavus occidentalis, B. agilis and B. affinis can be ascribed to normal intracolumnar vertebral variation, making the latter two junior synonyms of the first species. Our phylogenetic analyses retrieved Boavus within crown-Booidea as an early booid but outside of Boidae. A morphological and molecular analysis of booids, with dense taxon sampling including fossil and living forms, results in a new booid phylogeny. Boavus, along with other fossil booids from Europe (Eoconstrictor, Messelophis, Rieppelophis, Rageryx), suggests that crown-Booidea likely diverged earlier than estimated by some molecular studies (∼45.4 Ma).

The oldest lamprophiid (Serpentes, Caenophidia) fossil from the late Oligocene Rukwa Rift Basin, Tanzania and the origins of African snake diversity

Extant snake faunas have their origins in the mid-Cenozoic, when colubroids replaced booid-grade snakes as the dominant species. The timing of this faunal changeover in North America and Europe based on fossils is thought to have occurred in the early Neogene, after a period of global cooling opened environments and made them suitable for more active predators. However, new fossils from the late Oligocene of Tanzania have revealed an early colubroid-dominated fauna in Africa suggesting a different pattern of faunal turnover there. Additionally, molecular divergence times suggest colubroid diversification began sometime in the Paleogene, although the exact timing and driving forces behind the diversification are not clear. Here we present the first fossil snake referred to the African clade Lamprophiinae, and the oldest fossil known of Lamprophiidae. As such, this specimen provides the only potential fossil calibration point for the African snake radiation represented by Lamprophiidae, and is the oldest snake referred to Elapoidea. A molecular clock analysis using this and other previously reported fossils as calibration points reveals colubroid diversification minimally occurred in the earliest Paleogene, although a Cretaceous origin cannot be excluded. The elapoid and colubrid lineages diverged during the period of global warming near the Paleocene-Eocene boundary, with both clades diversifying beginning in the early Eocene (proximate to the Early Eocene Climate Optimum) and continuing into the cooler Miocene. The majority of subclades diverge well before the appearance of colubroid dominance in the fossil record. These results suggest an earlier diversification of colubroids than generally previously thought, with hypothesized origins of these clades in Asia and Africa where the fossil record is relatively poorly known. Further work in these regions may provide new insights into the timing of, and environmental influences contributing to, the rise of colubroid snakes.

Cretaceous Blind Snake from Brazil Fills Major Gap in Snake Evolution

SummaryBlind snakes (Scolecophidia) are minute cryptic snakes that diverged at the base of the evolutionary radiation of modern snakes. They have a scant fossil record, which dates back to the Upper Paleocene-Lower Eocene (∼56 Ma); this late appearance conflicts with molecular evidence, which suggests a much older origin for the group (during the Mesozoic: 160–125 Ma). Here we report a typhlopoid blind snake from the Late Cretaceous of Brazil, Boipeba tayasuensis gen. et sp. nov, which extends the scolecophidian fossil record into the Mesozoic and reduces the fossil gap predicted by molecular data. The new species is estimated to have been over 1 m long, much larger than typical modern scolecophidians (<30 cm). This finding sheds light on the early evolution of blind snakes, supports the hypothesis of a Gondwanan origin for the Typhlopoidea, and indicates that early scolecophidians had large body size, and only later underwent miniaturization.

Exquisitely Preserved Fossil Snakes of Messel: Insight into the Evolution, Biogeography, Habitat Preferences and Sensory Ecology of Early Boas

Our knowledge of early evolution of snakes is improving, but all that we can infer about the evolution of modern clades of snakes such as boas (Booidea) is still based on isolated bones. Here, we resolve the phylogenetic relationships of Eoconstrictor fischeri comb. nov. and other booids from the early-middle Eocene of Messel (Germany), the best-known fossil snake assemblage yet discovered. Our combined analyses demonstrate an affinity of Eoconstrictor with Neotropical boas, thus entailing a South America-to-Europe dispersal event. Other booid species from Messel are related to different New World clades, reinforcing the cosmopolitan nature of the Messel booid fauna. Our analyses indicate that Eoconstrictor was a terrestrial, medium- to large-bodied snake that bore labial pit organs in the upper jaw, the earliest evidence that the visual system in snakes incorporated the infrared spectrum. Evaluation of the known palaeobiology of Eoconstrictor provides no evidence that pit organs played a role in the predator–prey relations of this stem boid. At the same time, the morphological diversity of Messel booids reflects the occupation of several terrestrial macrohabitats, and even in the earliest booid community the relation between pit organs and body size is similar to that seen in booids today.

Exquisitely Preserved Fossil Snakes of Messel: In-sight into the Evolution, Biogeography, Habitat Pref-erences and Sensory Ecology of Early Boas

Exquisitely Preserved Fossil Snakes of Messel: In-sight into the Evolution, Biogeography, Habitat Pref-erences and Sensory Ecology of Early Boas

Flap-Footed Lizards (Gekkota: Pygopodidae) Have Forelimbs, Albeit During Embryonic Development

Limb reduction among squamate clades is common; limbless (forelimbs, hindlimbs, or both) forms have had at least 25 independent origins among snakes and lizards. The general evolutionary pattern is the gradual loss of limb elements proceeding from the toes to the shoulder or hip. In contrast, forelimbs are not known to have ever existed in snakes. Forelimbs are not known for either stem or crown snakes; snake fossils lack forelimbs and the embryos of modern snakes lack the signaling pathways that initiate forelimb development. Both fossil and developmental data thus imply an abrupt loss of forelimbs. In contrast, the well-developed hindlimbs of the oldest fossil snakes and vestigial hindlimbs of some basal clades of modern snakes imply the historical presence of hindlimbs, and their gradual reduction during snake evolution. In contrast, observations on limb-reduced lizards are in accord with gradual reduction of both fore- and hindlimbs; embryos of even limbless species initiate limb development. The question then arises, have any clades of limbless lizards become limbless abruptly, as have snakes? To address this question, I examined limb development in the family Pygopodidae. Like basal snakes, pygopodids are characterized by the absence of forelimbs and by vestigial hindlimbs. My observations on the development of forelimb buds in Delma molleri support gradual limb reduction, as do observations on other limbless lizards. Nonetheless, many clades of limbless lizards are yet to be studied and hence provide a wealth of opportunities to address modes of limb reduction and loss in squamate reptiles.

The evolution of the axial skeleton intercentrum system in snakes revealed by new data from the Cretaceous snakes Dinilysia and Najash

Snakes are an extremely modified and long-lived clade of lizards that have either lost or highly altered many of the synapomorphies that would clearly link them to their closest sister-group among squamates. We focus here on one postcranial morphological complex, the intercentrum system which in most non-ophidian squamates is limited to the cervical and caudal regions. The Cervical Intercentrum System (CeIS) is composed of a single intercentral element that sometimes articulates with a ventral projection (hypapophyses) of the centrum; the Caudal Intercentrum System (CaIS) is formed by an intercentral element, the haemal arch/chevron bone, and paired ventral projections of the centrum, the haemapophyses. In modern snakes, the intercentrum element of the CeIS is considered lost or fused to the hypaphophysis, and the chevron bone in CaIS is considered lost. Here, we describe new specimens of the early snake Dinilysia patagonica, and reinterpret previously known specimens of Dinilysia and Najash rionegrina, that do not show the expected snake morphology. The anatomy of these fossil taxa unambiguously shows that free cervical and caudal intercentra attached to distinct downgrowths (hypapophyses and haemapophyses) of the centra, are present in basal fossil snakes, and agrees with the proposed loss of post atlas-axis intercentra in later evolving snakes.