Latest Articles from Fossil Record Latest 5 Articles from Fossil Record https://fr.pensoft.net/ Fri, 29 Mar 2024 08:16:47 +0200 Pensoft FeedCreator https://fr.pensoft.net/i/logo.jpg Latest Articles from Fossil Record https://fr.pensoft.net/ A digital redescription of the Middle Miocene (Langhian) carettochelyid turtle Allaeochelys libyca https://fr.pensoft.net/article/115046/ Fossil Record 27(1): 13-28

DOI: 10.3897/fr.27.115046

Authors: Yann Rollot, Serjoscha W. Evers, Walter G. Joyce

Abstract: Allaeochelys libyca is a carettochelyid turtle from the Middle Miocene of Libya. The species is the only valid carettochelyid taxon recovered from Africa and was named based on fragmentary material that includes a partial cranium and isolated shell remains. The description of the holotype cranium was limited to external aspects, and micro-computed tomography was only performed later on that material. Here, we use these micro-computed tomography scans to reinvestigate the external and internal anatomy of the holotype cranium to document several erroneous anatomical interpretations and provide new insights into the morphology of the trigeminal foramen area, the endosseous labyrinth, and circulatory system of Allaeochelys libyca. The anatomical insights provided herein have the potential to be translated into new phylogenetic characters that are expected to improve the resolution among the Anosteira and Allaeochelys lineages, which are still poorly resolved.

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Research Article Thu, 4 Jan 2024 11:36:14 +0200
A description of a Denazinemys nodosa specimen (Testudinata, Baenidae) from the Late Cretaceous Kaiparowits Formation of southern Utah https://fr.pensoft.net/article/102520/ Fossil Record 26(2): 151-170

DOI: 10.3897/fr.26.102520

Authors: Gaël E. Spicher, Joseph J. W. Sertich, Léa C. Girard, Walter G. Joyce, Tyler R. Lyson, Yann Rollot

Abstract: Denazinemys nodosa is a Late Cretaceous representative of the North American turtle clade Baenidae diagnosed, among others, by a shell surface texture consisting of raised welts. We provide a detailed description of a partial skeleton from the late Campanian Kaiparowits Formation of Utah, USA, including bone-by-bone analysis of its cranium based on images obtained using micro-computed tomography. A revised phylogenetic analysis confirms placement of Denazinemys nodosa close to Eubaena cephalica and Boremys spp. within the clade Eubaeninae. Comparison with a second skull from the Kaiparowits Formation previously assigned to Denazinemys nodosa questions its referral to this taxon. An assortment of specimens from the Early to Late Campanian of Mexico and the USA had previously been referred to Denazinemys nodosa based on shell surface texture alone, even though this characteristic is known to occur in other baenids. Our review of all available material concludes that Denazinemys nodosa is currently only known from the Late Campanian of New Mexico and Utah.

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Research Article Mon, 31 Jul 2023 14:53:32 +0300
The helochelydrid turtle Helochelydra nopcsai from the Early Cretaceous (late Barremian – early Aptian) fissure fills of Balve, North Rhine-Westphalia, Germany, including a large sample of granicones https://fr.pensoft.net/article/102128/ Fossil Record 26(1): 117-133

DOI: 10.3897/fr.26.102128

Authors: Walter G. Joyce, Serjoscha W. Evers, Sara Ren, Yann Rollot, Achim H. Schwermann

Abstract: Early Cretaceous (late Barremian – early Aptian) fissure fill deposits near Balve, North Rhine Westphalia, Germany, have yielded a rich continental vertebrate fauna over the course of the last two decades. More than 250 fragmentary specimens, including more than 150 osteoderms (i.e., granicones), represent the late Early Cretaceous helochelydrid Helochelydra nopcsai, which had previously been reported from the UK, France, and Spain. The new material mostly differs from that from the type section by exhibiting a reduced to absent entoplastral scute and by displaying distinct cranial scute sulci, both of which are interpreted as intraspecific variation. Although morphological insights are limited, the new material reveals that the visceral cavity extends anteriorly and posteriorly to the bridge, a relatively novel feature previously reported for an eclectic mix of compsemydids, pleurosternids, and other helochelydrids. The available sample of granicones reveals great shape diversity, but a morphometric analysis concludes that no distinct morphotypes exist.

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Research Article Fri, 2 Jun 2023 16:16:10 +0300
Stratigraphic range extension of the turtle Boremys pulchra (Testudinata, Baenidae) through at least the uppermost Cretaceous https://fr.pensoft.net/article/85563/ Fossil Record 25(2): 275-285

DOI: 10.3897/fr.25.85563

Authors: Brent Adrian

Abstract: New material of the derived baenid turtle Boremys pulchra from the Hell Creek Formation of Montana extends the stratigraphic range of the taxon through at minimum the latest Maastrichtian. Previously, the species was constrained to the Campanian of Montana and Alberta, so this extension constitutes at least 5 million years. Due to fossil reworking at the Bug Creek Anthills assemblage, where Maastrichtian and Paleocene deposits are mixed, a definitive extension for B. pulchra cannot currently include Paleocene strata. However, the presence of B. pulchra in latest Cretaceous strata, previous identification of Paleocene Boremys sp. and the general success of baenid taxa across the K–Pg boundary, make it quite plausible that B. pulchra survived the extinction event and that previously described Maastrichtian and Paleocene Boremys sp. material probably represents a new taxon. A stratigraphic extension beyond the Campanian indicates that B. pulchra survived the paleoenvironmental conditions of the latest Cretaceous, where adaptation to locally heterogeneous aquatic habitats and paleotemperature fluctuations may have facilitated latest Cretaceous and K–Pg survivorship. Additionally, ectoparasitic bore marks on the Boremys pulchra specimen described here can be attributed to the ichnotaxon Karethraichnus lakkos.

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Research Article Thu, 25 Aug 2022 07:53:18 +0300
An alternative interpretation of small-bodied turtles from the “Middle Purbeck” of England as a new species of compsemydid turtle https://fr.pensoft.net/article/85334/ Fossil Record 25(2): 263-274

DOI: 10.3897/fr.25.85334

Authors: Walter G. Joyce, Jason R. Bourque, Vincent Fernandez, Yann Rollot

Abstract: A series of small-sized fossil turtles were collected from Beckles’ Pit, Durlston Bay, Dorset, United Kingdom in 1856 from a sediment package referable to the Early Cretaceous (Berriasian) Purbeck Group. The two primary accounts that previously documented these turtles concluded that they represent the juveniles of the coeval early pleurosternid Pleurosternon bullockii. A brief, third account, however, suggested that these may represent a new species of compsemydid turtle. We here highlight a series of discrete morphological characters that consistently distinguish the small-bodied turtles from Beckles’ Pit from large-bodied Pleurosternon bullockii, in particular the arrangement of the bones and scutes along the anterior margin of the shell. As these characters are otherwise used to diagnose new species of turtles, in particular compsemydids, and to establish the phylogeny of fossil turtles, we side with the latter interpretation and name a new taxon of early compsemydid, Tongemys enigmatica gen. et sp. nov. The early record of compsemydid is restricted to the Early Cretaceous of Europe, but is extremely fragmentary. We suggest that this may be a bias towards the collection and identification of small turtle remains, but also that a re-study of Early Cretaceous continental turtle faunas is likely to yield further material.

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Research Article Wed, 17 Aug 2022 21:46:31 +0300