Therapsid phylogeny + Priosphenodon "beak" structure + nanhsiungchelyid turtles + Mesozoic frogs from Niger
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Ben Creisler
Mar 12, 2026, 2:04:48 PM (18 hours ago) Mar 12
to DinosaurMa...@googlegroups.com
Ben Creisler
Some recent papers:
Free pdf:
Alienor Duhamel, Brenen Wynd, April Marie Wright, Atashni Moopen, Julien Benoit & Bruce Rubidge (2026)
Rethinking therapsid phylogeny through Bayesian and cladistic approaches
Scientific Reports (advance online publication)
doi: https://doi.org/10.1038/s41598-026-38195-2
https://www.nature.com/articles/s41598-026-38195-2
We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.
Alienor Duhamel, Brenen Wynd, April Marie Wright, Atashni Moopen, Julien Benoit & Bruce Rubidge (2026)
Rethinking therapsid phylogeny through Bayesian and cladistic approaches
Scientific Reports (advance online publication)
doi: https://doi.org/10.1038/s41598-026-38195-2
https://www.nature.com/articles/s41598-026-38195-2
We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.
Therapsids are early-diverging synapsids that thrived during the Permian and Triassic periods, and ultimately gave rise to mammals. They include six major groups, which already exhibited considerable diversity at their first appearance in the fossil record. Their early to middle Permian origins remain poorly understood due to a scarcity of fossils with clear therapsid morphology in the early Permian and the presence of an interval of poor fossil preservation near the early to middle Permian boundary (Olson’s Gap). This limits our insight into the phylogenetic relationships among the main middle Permian groups. This study presents a novel approach to therapsid phylogeny, using probabilistic frameworks. In performing a phylogenetic analysis based exclusively on cranial characters, using both RevBayes and MrBayes, this study challenges understanding of the early diversification of Therapsida. We recover Neotherapsida, with Anomodontia branching as the sister taxon to Theriodontia. Biarmosuchia and Dinocephalia form a clade. The positions of taxa such as Sinophoneus and Biseridens are reconsidered. The application of Fossilized Birth-Death models suggests that while Therapsida originated in the early Permian, currently known therapsid groups diversified around 281 to 272 million years ago and subsequently underwent rapid radiation into five clades: Biarmosuchia, Dinocephalia, Anomodontia, Gorgonopsia, and Eutheriodontia.
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Sol A. Cavasin, Ignacio A. Cerda & Sebastián Apesteguía (2026)
Bone microstructure of the beak-like structure in the herbivorous sphenodontian Priosphenodon avelasi (Lepidosauria)
Cretaceous Research 106363
doi: https://doi.org/10.1016/j.cretres.2026.106363
https://www.sciencedirect.com/science/article/abs/pii/S0195667126000522
The skull of Priosphenodon avelasi, a giant eilenodontine sphenodontian from the Upper Cretaceous of Argentina, is characterized by a prominent beak-like structure (BLS) in the upper jaw. Based on data from the living Sphenodon, the BLS of Priosphenodon avelasi has been interpreted presumably conformed by fused premaxillary teeth. To test this hypothesis, we analyzed the histology of the premaxillary BLS in five specimens of Priosphenodon avelasi from different ontogenetic stages. The histological analysis revealed that the BLS of Priosphenodon avelasi is entirely formed by bone tissue, not by teeth fused to the premaxillae. The growth of this particular structure only occurs on its anterior and lateral surfaces. In this regard, osteoblastic and osteoclastic activity related with both growth and modeling is restricted to these surfaces of the bony structure. Also, the evidence of osteoblastic and osteoclastic activity indicates that the cranial integument of Priosphenodon avelasi extended over the anterior and lateral surface of the beak, reaching the distal end of the same. The bone-on-bone contact between the BLS and the anterior end of the dentary creates distinct wear facets in these elements. A particular histologic feature, here referred as “filiform structures” is recorded in the bone tissue of all the sampled elements. The same structure has been described for rhynchosaurs and interpreted as extrinsic fibers related with the presence of a cornified sheath/ramphoteca. The smooth texture of the external surface of the Priosphenodon avelasi beak, however, is not consistent with the presence of this kind of keratinized tissue.
Bone microstructure of the beak-like structure in the herbivorous sphenodontian Priosphenodon avelasi (Lepidosauria)
Cretaceous Research 106363
doi: https://doi.org/10.1016/j.cretres.2026.106363
https://www.sciencedirect.com/science/article/abs/pii/S0195667126000522
The skull of Priosphenodon avelasi, a giant eilenodontine sphenodontian from the Upper Cretaceous of Argentina, is characterized by a prominent beak-like structure (BLS) in the upper jaw. Based on data from the living Sphenodon, the BLS of Priosphenodon avelasi has been interpreted presumably conformed by fused premaxillary teeth. To test this hypothesis, we analyzed the histology of the premaxillary BLS in five specimens of Priosphenodon avelasi from different ontogenetic stages. The histological analysis revealed that the BLS of Priosphenodon avelasi is entirely formed by bone tissue, not by teeth fused to the premaxillae. The growth of this particular structure only occurs on its anterior and lateral surfaces. In this regard, osteoblastic and osteoclastic activity related with both growth and modeling is restricted to these surfaces of the bony structure. Also, the evidence of osteoblastic and osteoclastic activity indicates that the cranial integument of Priosphenodon avelasi extended over the anterior and lateral surface of the beak, reaching the distal end of the same. The bone-on-bone contact between the BLS and the anterior end of the dentary creates distinct wear facets in these elements. A particular histologic feature, here referred as “filiform structures” is recorded in the bone tissue of all the sampled elements. The same structure has been described for rhynchosaurs and interpreted as extrinsic fibers related with the presence of a cornified sheath/ramphoteca. The smooth texture of the external surface of the Priosphenodon avelasi beak, however, is not consistent with the presence of this kind of keratinized tissue.
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Free pdf:
Haiyan Tong, Lu Li, Yuzheng Ke and Yanyin Wang (2026)
Nanhsiungchelyid Turtles from the Nanxiong Basin, Southern China, and the Cretaceous–Paleogene Mass Extinction
Fossil Studies 4(1): 6
doi: https://doi.org/10.3390/fossils4010006
https://www.mdpi.com/2813-6284/4/1/6
Nanxiong Basin (Guangdong Province, southern China) preserves one of the most complete nanhsiungchelyid turtle records from the latest Cretaceous in Asia. In this study, we review nanhsiungchelyid remains recorded from Nanxiong Basin within a refined stratigraphical framework. Nanhsiungchelyids show constant occurrence in the Nanxiong Basin, recorded from most formations of the Nanxiong Group, with their probable last occurrence close to the Cretaceous–Paleogene boundary.
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Free pdf:
Alfred LEMIERRE, Annelise FOLIE, Salvador BAILON & Michel LAURIN (2026)
Anurans of In Becetèn (Republic of Niger): the most diverse site for amphibians in Mesozoic Africa.
Geodiversitas 48 (4): 51-67.
doi: https://doi.org/10.5252/geodiversitas2026v48a4.
https://sciencepress.mnhn.fr/en/periodiques/geodiversitas/48/4
Free pdf:
https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/geodiversitas2026v48a4.pdf
In Becetèn (Niger) represents one of the most diverse continental vertebrate faunas from the Late Cretaceous of Africa. Recently, anurans, in particular aquatic pipimorphs, have generated renewed interest, with the identification of four distinct pipimorph taxa. Here we describe the remaining anuran specimens from In Becetèn, which represent at least three new anuran taxa that cannot be assigned to pipimorphs (Anura indet, Neobatrachia and a ranoid). Among them, one taxon, documented by ornamented cranial material, is a large Neobatrachia incertae sedis, as suggested by our phylogenetic analyses. This marks only the third Mesozoic occurrence of neobatrachians in Africa. In addition, an isolated humerus is referred as a new unnamed ranoid and is not only the oldest known occurrence of the clade, but also the first known Mesozoic specimen of this cosmopolitan family from Africa. With at least seven anuran taxa identified, In Becetèn is the most diverse locality of Africa, and one of the most diverse localities across the Late Cretaceous (Coniacian or Santonian).
Alfred LEMIERRE, Annelise FOLIE, Salvador BAILON & Michel LAURIN (2026)
Anurans of In Becetèn (Republic of Niger): the most diverse site for amphibians in Mesozoic Africa.
Geodiversitas 48 (4): 51-67.
doi: https://doi.org/10.5252/geodiversitas2026v48a4.
https://sciencepress.mnhn.fr/en/periodiques/geodiversitas/48/4
Free pdf:
https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/geodiversitas2026v48a4.pdf
In Becetèn (Niger) represents one of the most diverse continental vertebrate faunas from the Late Cretaceous of Africa. Recently, anurans, in particular aquatic pipimorphs, have generated renewed interest, with the identification of four distinct pipimorph taxa. Here we describe the remaining anuran specimens from In Becetèn, which represent at least three new anuran taxa that cannot be assigned to pipimorphs (Anura indet, Neobatrachia and a ranoid). Among them, one taxon, documented by ornamented cranial material, is a large Neobatrachia incertae sedis, as suggested by our phylogenetic analyses. This marks only the third Mesozoic occurrence of neobatrachians in Africa. In addition, an isolated humerus is referred as a new unnamed ranoid and is not only the oldest known occurrence of the clade, but also the first known Mesozoic specimen of this cosmopolitan family from Africa. With at least seven anuran taxa identified, In Becetèn is the most diverse locality of Africa, and one of the most diverse localities across the Late Cretaceous (Coniacian or Santonian).
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beak sphenodonts
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