Ben Creisler
Some recent fossil reptile papers (some with free pdfs):
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Allodoposuchus iberoarmoricanus sp. nov.
"Agaresuchus and Lohuecosuchus must be considered as members of Allodaposuchus."
Alejandro Blanco (2021)
Importance of the postcranial skeleton in eusuchian phylogeny: Reassessing the systematics of allodaposuchid crocodylians.
PLoS ONE 16(6): e0251900
doi:
https://doi.org/10.1371/journal.pone.0251900https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0251900Our current knowledge on the crocodyliform evolution is strongly biased towards the skull morphology, and the postcranial skeleton is usually neglected in many taxonomic descriptions. However, it is logical to expect that it can contribute with its own phylogenetic signal. In this paper, the changes in the tree topology caused by the addition of the postcranial information are analysed for the family Allodaposuchidae, the most representative eusuchians in the latest Cretaceous of Europe. At present, different phylogenetic hypotheses have been proposed for this group without reaching a consensus. The results of this paper evidence a shift in the phylogenetic position when the postcranium is included in the dataset, pointing to a relevant phylogenetic signal in the postcranial elements. Finally, the phylogenetic relationships of allodaposuchids within Eusuchia are reassessed; and the internal relationships within Allodaposuchidae are also reconsidered after an exhaustive revision of the morphological data. New and improved diagnoses for each species are here provided.
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Based on the known fossil record, the majority of crocodylians from the Cenozoic Era of Australia are referred to the extinct clade Mekosuchinae. The only extant crocodylians in Australia are two species of Crocodylus. Hence, the viewpoint that Crocodylus and mekosuchines have been the only crocodylians inhabiting Australia during the Cenozoic has remained largely undisputed. Herein we describe Australiaâs first tomistomine crocodylian, Gunggamarandu maunala gen. et sp. nov., thus challenging the notion of mekosuchine dominance during most of the Cenozoic. The holotype specimen of Gunggamarandu maunala derives from the Pliocene or Pleistocene of south-eastern Queensland, marking the southern-most global record for Tomistominae. Gunggamarandu maunala is known from a large, incomplete cranium that possesses a unique combination of features that distinguishes it from other crocodylians. Phylogenetic analyses place Gunggamarandu in a basal position within Tomistominae, specifically as a sister taxon to Dollosuchoides from the Eocene of Europe. These results hint at a potential ghost lineage between European and Australian tomistomines going back more than 50 million years. The cranial proportions of the Gunggamarandu maunala holotype specimen indicate it is the largest crocodyliform yet discovered from Australia.
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Paranecrosaurus gen. nov.
Paranecrosaurus feisti (Stritzke, 1983) comb. nov.
Krister T. SMITH & JÃrg HABERSETZER (2021)
The anatomy, phylogenetic relationships, and autecology of the carnivorous lizard "Saniwa"Âfeisti Stritzke, 1983 from the Eocene of Messel, Germany.
The evolution and interrelationships of carnivorous squamates (mosasaurs, snakes, monitor lizards, Gila Monsters) are a contentious part of reptile systematics and go to the heart of conflict between morphological and molecular data in inferring evolutionary history. One of the best-preserved fossils in this motley grouping is "Saniwa" feisti Stritzke, 1983, represented by complete skeletons from the early-middle Eocene of Messel, Germany. We re-describe it on the basis of superficial examination, stereoradiography, and high-resolution X-ray computed tomography of new and published specimens. The scalation of the lizard is unique, consisting of small, keeled scales on the head (including a row of enlarged medial supraorbitals) and large, rhomboidal, keeled scales (invested by osteoderms) that covered the rest of the body. Two paired longitudinal rows of enlarged scales ran down the neck. The head was laterally compressed and box-shaped due to the presence of a strong canthal-temporal ridge; the limbs and tail were very long. Notable osteological features include: a toothed, strap-like vomer; septomaxilla with a long posterior process; palpebral with a long posterolateral process; a lacrimal boss and a single lacrimal foramen; a well-developed cultriform process of the parabasisphenoid; two hypoglossal (XII) foramina in addition to the vagus; a lack of resorption pits for replacement teeth; and possibly the presence of more than one wave of developing replacement teeth per locus. There are no osteological modifications suggestive of an intramandibular hinge, but postmortem displacement of the angular-prearticular-surangular complex in multiple specimens suggests that there might have been some degree of mobility in the lower jaw based on soft-tissue modifications. Using phylogenetic analyses on a data-set comprising 473 morphological characters and 46 DNA loci, we infer that a monophyletic Palaeovaranidae Georgalis, 2017, including Eosaniwa Haubold, 1977, lies on the stem of Varanidae Merrem, 1820, basal to various Cretaceous Mongolian taxa. We transfer feisti to the new genus Paranecrosaurus n. gen. Analysis of gut contents reveals only the second known specimen of the cryptozoic lizard Cryptolacerta hassiaca MÃller, Hipsley, Head, Kardjilov, Hilger, Wuttke & Reisz, 2011, confirming a diet that was at least partly carnivorous; the preservation of the teeth of C. hassiaca suggests that the gastric physiology of Paranecrosaurus feisti (Stritzke, 1983) n. comb. had high acidity but low enzyme activity. Based on the foregoing and linear discriminant function analysis, we reconstruct P. feisti n. comb., as a powerful, widely roaming, faunivorous-carnivorous stem monitor lizard with a sensitive snout. If the molecular phylogeny of anguimorphs is correct, then many of the features shared by Helodermatidae Gray, 1837 and Varanidae must have arisen convergently, partly associated with diet. In that case, a reconciliation of morphological and molecular data would require the discovery of equally primitive fossils on the helodermatid stem.
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Pavel P. Skutschas, Andrey G. Sennikov, Elena V. Syromyatnikova, Dmitriy D. Vitenko, Igor A. Parakhin, Roman A. Bapinaev & Susan E. Evans (2021)
A lepidosauromorph specimen from the Middle Jurassic (Bathonian) Moskvoretskaya Formation of the Moscow Region, Russia.
Historical Biology (advance online publication)
doi:
https://doi.org/10.1080/08912963.2021.1935921 https://www.tandfonline.com/doi/full/10.1080/08912963.2021.1935921A fragmentary diapsid left maxilla from the Bathonian Peski locality in Moscow Region, previously referred to Choristodera, is identified as Lepidosauromorpha indet. This specimen represents the first fossil record of basal lepidosauromorphs in the Middle Jurassic of European Russia. Among basal lepidosauromorphs, the maxilla from the Peski locality resembles those of the Middle Triassic Fraxinisaura and the contemporary Middle Jurassic (Bathonian) Marmoretta in subpleurodont tooth implantation, a relatively low dorsal process, and high keeled teeth with gently recurved apices and striae on the lingual side. This similarity suggests possible close relationships of Fraxinisaura, Marmoretta and the Peski form. The recognition of a basal lepidosauromorph in the fauna of the Peski locality extends the known geographical range of the Bathonian non-lepidosaurian lepidosauromorphs and demonstrates their wide Laurasian distribution at this time. It is additional evidence that Bathonian vertebrate faunas of Europe and Western Siberia were similar in composition.
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The Maastrichtian deposits in Egypt and generally in Africa contain very few records of chelonioids. This scarcity hinders understanding the evolution and extinction of African chelonioids during this age. The Dakhla Basin in Egypt presents excellent Maastrichtian outcrops that consist of highly fossiliferous, calcareous siltstone and sandstone layers rich in ammonites, bivalves (Exogyra overwagi, Pycnodonta vesicularis, pectinids), gastropods, echinoids, corals, fossilized fruits of mangrove plants (Nypa) and vertebrate remains. The well-preserved humerus of giant turtle and other vertebrate remains have been discovered in the early late Maastrichtian Ammonite Hill Member of the Dakhla Formation in the Abu Minqar area, Southern Western Desert, Egypt. The Ammonite Hill Member was deposited in very shallow coastal, inner neritic to littoral environments. The well-preserved giant humerus represents the first record of gigantic Mesozoic chelonioids in Africa and the second record of chelonioids in the Maastrichtian deposits in Egypt. The present specimen contributes to fill the missing gaps in the history of Egyptian turtles from the Cretaceous through the Cenozoic.
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The herpetofaunal biodiversity of West Indies suffered a significant change during the last few million years that is well documented for some squamate reptiles (lizards). However, almost nothing is known about past biodiversity of snakes, which are active predators and important component of terrestrial ecosystems. Here we describe the fossil remains of snakes (Reptilia: Serpentes) from the late Pleistocene of El AbrÃn Cave, Cuba. This is the first representative assemblage of fossil snakes from Cuba. It allows us to evaluate the taxonomic diversity of snakes in the Pleistocene of the island for the first time. The material includes eight taxa from the four snake families: cf. Cubatyphlops (Typhlopidae), Tropidophis melanurus, Tropidophis sp., Cubophis cf. cantherigerus, Arrhyton sp., cf. Caraiba andreae, Dipsadidae indet., and Natricidae indet. (Natricidae). Two (Dipsadidae indet. and Natricidae indet.) are not known in the modern fauna of Cuba. The assemblage from El AbrÃn Cave shows that ophidian Pleistocene assemblage was different from modern snake fauna of Cuba and was probably more diverse at genus level than it is now. Most of taxa revealed in El AbrÃn Cave were not previously known in the fossil record.
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Hans Recknagel, Nicholas A. Kamenos & Kathryn. R. Elmer (2021)
Evolutionary origins of viviparity consistent with palaeoclimate and lineage diversification.
Journal of Evolutionary Biology (advance online publication)
doi:
https://doi.org/10.1111/jeb.13886https://onlinelibrary.wiley.com/doi/10.1111/jeb.13886It is of fundamental importance for the field of evolutionary biology to understand when and why major evolutionary transitions occur. Live-bearing young (viviparity) is a major evolutionary change and has evolved from egg-laying (oviparity) independently in many vertebrate lineages and most abundantly in lizards and snakes. While contemporary viviparous squamate species generally occupy cold climatic regions across the globe, it is not known whether viviparity evolved as a response to cold-climate in the first place. Here, we used available published time-calibrated squamate phylogenies and parity data on 3498 taxa. We compared the accumulation of transitions from oviparity to viviparity relative to background diversification and a simulated binary trait. Extracting the date of each transition in the phylogenies and informed by 65 my of global palaeoclimatic data, we tested the nonexclusive hypotheses that viviparity evolved under: i) cold, and ii) long-term stable climatic conditions, and iii) with background diversification rate. We show that stable and long-lasting cold climatic conditions are correlated with the transitions to viviparity across squamates. This correlation of parity mode and palaeoclimate is mirrored by background diversification in squamates, and simulations of a binary trait also showed a similar association with palaeoclimate, meaning that trait evolution cannot be separated from squamate lineage diversification. We suggest that these trait transitions depend on environmental and intrinsic effects, and that background diversification rate may be a factor in trait diversification more generally.