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Free pdf:
Pterosaurs in the Jehol Biota have been found in the Yixian and Jiufotang formations. The Jingangshan bedding is in the upper part of the Yixian Formation. The first two pterosaur embryos ever discovered in the world, two archaeopterodactyloid specimens, and the questionable Yixianopterus jingangshanensis have been reported in previous literature. Here, we describe a forelimb from this horizon and confirm its phylogenetic position in the Pteranodontoidea. The holotype of Y. jingangshanensis, now housed at Benxi Geological Museum, has been examined. The diagnosis of this taxon has been revised without the consideration of the artificial parts as following, a pteranodontoid pterosaur with a distinguished combination of characters: triangular and labiolingually compressed teeth with the first two more slender and longer than the others; teeth vertical to the occlusal surface; the second wing phalanx about 93% the length of the first wing phalanx. In the Jehol Biota, archaeopterodactyloid specimens have been mainly discovered from the Yixian Formation, while tapejaroids are almost found from the Jiufotang Formation. Including the new forelimb and Y. jingangshanensis, the pteranodontoids from the Jiufotang Formation are slightly greater in number than those from the Yixian Formation in species and specimens, differing from the previous thoughts on the distribution.
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[I don't have access, so I don't know if a new taxon is named...]
Josà Patricio O'Gorman, Paula Bona, MartÃn de los Reyes, Maria Eugenia Raffi & Marcelo Reguero (2020)
A non-aristonectine plesiosaur from Antarctica reveals new data on the mandibular symphysis of elasmosaurids.
Alcheringa (advance online publication)
doi:
https://doi.org/10.1080/03115518.2020.1824261https://www.tandfonline.com/doi/full/10.1080/03115518.2020.1824261Elasmosaurids are one of the most abundant fossil marine reptile groups identified from the Upper Cretaceous strata of Antarctica. However, the documented record of intact elasmosaurid skull remains is scarce. In this study, we describe the first non-aristonectine elasmosaurid skeleton from Antarctica that preserves an associated lower jaw. This specimen displays a unique character state combination including three symphyseal alveoli, the angle between the mandibular rami exceeding 90Â, and the absence of a ventral symphyseal sulcus or keel. This mandibular configuration has not been observed previously among elasmosaurids, prompting comparisons with other described examples and suggesting that mandibular morphology reached a variability peak during the Maastrichtian, which might be reflective of increased trophic diversity.
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Pachypes ollieri comb. nov.Â
Lorenzo Marchetti, Sebastian Voigt, Eudald Mujal, Spencer G. Lucas, Heitor Francischini, Josep Fortuny & Vincent L. Santucci (2020)
Extending the footprint record of Pareiasauromorpha to the Cisuralian: earlier appearance and wider palaeobiogeography of the group.
Papers in Palaeontology (advance online publication)
doi:
https://doi.org/10.1002/spp2.1342https://onlinelibrary.wiley.com/doi/full/10.1002/spp2.1342Data archiving statement:
Data (including DOIs for image data) for this study are available in the Dryad Digital Repository:
https://doi.org/10.5061/dryad.h9w0vt4g3Pareiasauromorpha is one of the most important tetrapod groups of the Permian. Skeletal evidence suggests a late Kungurian origin in North America, whereas the majority of occurrences come from the Guadalupian and Lopingian of South Africa and Russia. However, Pareiasauromorpha footprints include the ichnogenus Pachypes, which is unknown from strata older than late Guadalupian. A revision of several Pachypesâlike footprints from the Cisuralian-Guadalupian of Europe and North America confirm the occurrence of this ichnogenus and of the ichnospecies Pachypes ollieri comb. nov. beginning in the Artinskian. This is the earliest known occurrence of Pachypes and it coincides with the Artinskian reptile radiation. Based on a synapomorphyâbased trackâtrackmaker correlation, P. ollieri can be attributed to nycteroleter pareiasauromorphs such as Macroleter. Therefore, the earliest occurrences of pareiasauromorph footprints precede by at least 10 myr the earliest occurrence of this group in the skeletal record. Moreover, the palaeobiogeography of the group is extended to the Cisuralian and Guadalupian of western Europe.
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