Ben Creisler
New non-dino papers:
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C. Henrik Woolley, Nathan D. Smith & Joseph J.W. Sertich (2020)
New fossil lizard specimens from a poorly-known squamate assemblage in the Upper Cretaceous (Campanian) San Juan Basin, New Mexico, USA.
PeerJ 8:e8846
doi: https://doi.org/10.7717/peerj.8846
https://peerj.com/articles/8846/
Recent collection efforts in the upper Campanian (â76-73.5 Ma) Fruitland and Kirtland formations of northwestern New Mexico have significantly increased the taxonomic diversity of lizards in this historically poorly understood squamate assemblage. New lizard specimens from the âHunter Wash Local Faunaâ of the upper Fruitland and lower Kirtland formations include: (1) new specimens referable to Chamopsiidae; (2) new material belonging to Scincomorpha, (3) new material belonging to Anguidae; and (4) the first reported predatory lizard (Platynota) material from the Campanian of New Mexico. The increase in lizard diversity in the âHunter Wash Local Faunaâ expands our understanding of Late Cretaceous squamate taxonomy, distribution, and diversity in the Western Interior of North America (Laramidia). Collectively, the described specimens represent family-level diversity similar to that seen in other Campanian foreland basin deposits of the Western Interior, such as the mid-paleolatitude Kaiparowits Formation of southern Utah, the higher paleolatitude Dinosaur Park Formation of southern Alberta, and the lower paleolatitude Aguja Formation of southwestern Texas. The lizards of the "Hunter Wash Local Fauna" represent crucial mid-paleolatitude data from a coastal plain depositional setting in Laramidiaâallowing for comparisons to more well-studied assemblages at different latitudes and in different depositional settings.
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Fabien Lafuma, ÂIan James Corfe, Julien Clavel & Nicolas Di-Poi (2020)
Multiple evolutionary origins and losses of tooth complexity in squamates.
bioRxiv (preprint)
doi: https://doi.org/10.1101/2020.04.15.042796
https://www.biorxiv.org/content/10.1101/2020.04.15.042796v1
Teeth act as tools for acquiring and processing food and so hold a prominent role in vertebrate evolution. In mammals, dental-dietary adaptations rely on tooth shape and complexity variations controlled by cusp number and pattern - the main features of the tooth surface. Complexity increase through cusp addition has dominated the diversification of many mammal groups. However, studies of Mammalia alone don't allow identification of patterns of tooth complexity conserved throughout vertebrate evolution. Here, we use morphometric and phylogenetic comparative methods across fossil and extant squamates ("lizards" and snakes) to show they also repeatedly evolved increasingly complex teeth, but with more flexibility than mammals. Since the Late Jurassic, six major squamate groups independently evolved multiple-cusped teeth from a single-cusped common ancestor. Unlike mammals, reversals to lower cusp numbers were frequent in squamates, with varied multiple-cusped morphologies in several groups resulting in heterogenous evolutionary rates. Squamate tooth complexity evolved in correlation with dietary change - increased plant consumption typically followed tooth complexity increases, and the major increases in speciation rate in squamate evolutionary history are associated with such changes. The evolution of complex teeth played a critical role in vertebrate evolution outside Mammalia, with squamates exemplifying a more labile system of dental-dietary evolution.
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Peter Pogoda, Marcus Zuber, Tilo Baumbach, Rainer R. Schoch & Alexander Kupfer (2020)
Cranial shape evolution of extant and fossil crocodile newts and its relation to reproduction and ecology.
Journal of Anatomy (advance online publication)
doi: https://doi.org/10.1111/joa.13201
https://onlinelibrary.wiley.com/doi/10.1111/joa.13201
Free pdf:
https://onlinelibrary.wiley.com/doi/pdf/10.1111/joa.13201
The diversity of the vertebrate cranial shape of phylogenetically related taxa allows conclusions on ecology and life history. As pleurodeline newts (the genera Echinotriton, Pleurodeles and Tylototriton) have polymorphic reproductive modes, they are highly suitable for following cranial shape evolution in relation to reproduction and environment. We investigated interspecific differences externally and differences in the cranial shape of pleurodeline newts via twoâdimensional geometric morphometrics. Our analyses also included the closely related but extinct genus Chelotriton to better follow the evolutionary history of cranial shape. Pleurodeles was morphologically distinct in relation to other phylogenetically basal salamanders. The subgenera within Tylototriton (Tylototriton and Yaotriton) were well separated in morphospace, whereas Echinotriton resembled the subgenus Yaotriton more than Tylototriton. Oviposition site choice correlated with phylogeny and morphology. Only the mating mode, with a random distribution along the phylogenetic tree, separated crocodile newts into two morphologically distinct groups. Extinct Chelotriton likely represented several species and were morphologically and ecologically more similar to Echinotriton and Yaotriton than to Tylototriton subgenera. Our data also provide the first comprehensive morphological support for the molecular phylogeny of pleurodeline newts.
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Denis GERAADS & Nikolaà SPASSOV (2020)
A skull of Machairodus Kaup, 1833 (Felidae, Mammalia) from the late Miocene of Hadjidimovo (Bulgaria), and its place in the evolution of the genus.
in StÃphane PeignÃ: Carnivores (Hyaenodonta and Carnivora) of the Cenozoic.
Geodiversitas 42(9): 123-137.
doi: https://doi.org/10.5252/geodiversitas2020v42a9
http://sciencepress.mnhn.fr/en/periodiques/geodiversitas/42/9
The late Miocene locality Hadjidimovo in Southwestern Bulgaria has yielded a huge collection of mammalian fossils, including a complete skull of Machairodus Kaup, 1833, first described (in Bulgarian) by Kovachev (2002). We re-describe it here, compare it with other Machairodus, and review the evolution of the genus. We conclude that the transition from M. aphanistus (Kaup, 1832) to M. giganteus (Wagner, 1848) is gradual and mosaic, that assigning these species to different genera fails to reflect this relationship, and that the Hadjidimovo skull represents a rather late evolutionary stage of this lineage.
A skull of Machairodus Kaup, 1833 (Felidae, Mammalia) from the late Miocene of Hadjidimovo (Bulgaria), and its place in the evolution of the genus.
in StÃphane PeignÃ: Carnivores (Hyaenodonta and Carnivora) of the Cenozoic.
Geodiversitas 42(9): 123-137.
doi: https://doi.org/10.5252/geodiversitas2020v42a9
http://sciencepress.mnhn.fr/en/periodiques/geodiversitas/42/9
The late Miocene locality Hadjidimovo in Southwestern Bulgaria has yielded a huge collection of mammalian fossils, including a complete skull of Machairodus Kaup, 1833, first described (in Bulgarian) by Kovachev (2002). We re-describe it here, compare it with other Machairodus, and review the evolution of the genus. We conclude that the transition from M. aphanistus (Kaup, 1832) to M. giganteus (Wagner, 1848) is gradual and mosaic, that assigning these species to different genera fails to reflect this relationship, and that the Hadjidimovo skull represents a rather late evolutionary stage of this lineage.
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