Paarthurnax, new neosuchian from Lower Cretaceous of Arkansas + dinosaur extinction can explain continental facies shifts at K/Pg boundary
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Ben Creisler
Sep 15, 2025, 12:13:53 PMSep 15
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Ben Creisler
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New papers:
Paarthurnax holliensis gen. et sp. nov.
Nathan C. Platt, Thomas L. Adams & Christopher A. Brochu (2025)
A new neosuchian crocodyliform from the Lower Cretaceous (Aptian–Albian) Holly Creek Formation of southwest Arkansas and its implications on the relationships of Goniopholididae
Journal of Vertebrate Paleontology e2536843
doi: https://doi.org/10.1080/02724634.2025.2536843
https://www.tandfonline.com/doi/full/10.1080/02724634.2025.2536843
A new species of neosuchian crocodyliform, Paarthurnax holliensis gen. et sp. nov., is herein described based on a nearly complete skull from the Lower Cretaceous (Aptian–Albian) Holly Creek Formation of southwest Arkansas. This locality contains a wide array of semiaquatic, aquatic, and terrestrial vertebrate body and trace fossils. This new taxon is notable for having a ventrally offset premaxillary tooth row, maxillary groove, transverse interorbital crest, elongate anterolateral process of the postorbital, transversely flattened postorbital bar, large sub-rectangular transverse ellipsoid supratemporal fenestrae, and a laterally opened cranioquadrate passage. Its overall morphology is similar to that of the putative goniopholidid Denazinosuchus kirtlandicus from the Campanian Kirtland Formation of New Mexico, though unlike D. kirtlandicus the new form bears a palatal premaxilla-maxilla suture posteromedially directed on its lateral half and anteromedially directed along its medial region, a more tapered anterior projection of the frontal, and transverse sub-rectangular supratemporal fenestrae. It shares features typically associated with goniopholidids, such as a transverse interorbital crest and a perinarial crest. However, it also shares anterior and posterior rami of jugal comparable in depth, a rod-shaped jugal, and a frontal separated medially from the orbital margin with paluxysuchids. Phylogenetic analyses recover Paarthurnax holliensis as sister to D. kirtlandicus, both falling out as derived goniopholidids. Intriguingly, paluxysuchids are recovered in a derived position within Goniopholididae. This tree topology challenges long-held assumptions about the status and distribution of Goniopholididae, which may have a more expansive distribution in the Cretaceous of North America than previously believed.
Nathan C. Platt, Thomas L. Adams & Christopher A. Brochu (2025)
A new neosuchian crocodyliform from the Lower Cretaceous (Aptian–Albian) Holly Creek Formation of southwest Arkansas and its implications on the relationships of Goniopholididae
Journal of Vertebrate Paleontology e2536843
doi: https://doi.org/10.1080/02724634.2025.2536843
https://www.tandfonline.com/doi/full/10.1080/02724634.2025.2536843
A new species of neosuchian crocodyliform, Paarthurnax holliensis gen. et sp. nov., is herein described based on a nearly complete skull from the Lower Cretaceous (Aptian–Albian) Holly Creek Formation of southwest Arkansas. This locality contains a wide array of semiaquatic, aquatic, and terrestrial vertebrate body and trace fossils. This new taxon is notable for having a ventrally offset premaxillary tooth row, maxillary groove, transverse interorbital crest, elongate anterolateral process of the postorbital, transversely flattened postorbital bar, large sub-rectangular transverse ellipsoid supratemporal fenestrae, and a laterally opened cranioquadrate passage. Its overall morphology is similar to that of the putative goniopholidid Denazinosuchus kirtlandicus from the Campanian Kirtland Formation of New Mexico, though unlike D. kirtlandicus the new form bears a palatal premaxilla-maxilla suture posteromedially directed on its lateral half and anteromedially directed along its medial region, a more tapered anterior projection of the frontal, and transverse sub-rectangular supratemporal fenestrae. It shares features typically associated with goniopholidids, such as a transverse interorbital crest and a perinarial crest. However, it also shares anterior and posterior rami of jugal comparable in depth, a rod-shaped jugal, and a frontal separated medially from the orbital margin with paluxysuchids. Phylogenetic analyses recover Paarthurnax holliensis as sister to D. kirtlandicus, both falling out as derived goniopholidids. Intriguingly, paluxysuchids are recovered in a derived position within Goniopholididae. This tree topology challenges long-held assumptions about the status and distribution of Goniopholididae, which may have a more expansive distribution in the Cretaceous of North America than previously believed.
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Free pdf:
Lucas N. Weaver, Thomas S. Tobin, Courtney J. Sprain, Paige K. Wilson Deibel, Vera A. Korasidis, Mónica R. Carvalho, Pim Kaskes & Isabel M. Fendley (2025)
Dinosaur extinction can explain continental facies shifts at the Cretaceous-Paleogene boundary
Communications Earth & Environment 6: 712
doi: https://doi.org/10.1038/s43247-025-02673-8
https://www.nature.com/articles/s43247-025-02673-8
Continental Cretaceous-Paleogene boundary sections are best known from North America, where they invariably exhibit a marked shift in sedimentary facies at or very near the boundary level. Uppermost Cretaceous strata typically reflect water-logged soils and unstable meandering-river deposits, whereas lowermost Paleogene strata typically reflect coal swamps and broad, stable meander-belt deposits. Causal links between facies shifts at the Cretaceous-Paleogene boundary and the end-Cretaceous mass extinction have been largely dismissed. Here, we present five new Cretaceous-Paleogene boundary sections identified via iridium anomalies in the Bighorn and Williston basins and assess the sedimentological changes that occur at North American Cretaceous-Paleogene boundaries. We hypothesize that the geographically widespread Cretaceous–Paleogene facies shifts were driven by the extinction of dinosaur megafauna. Large-bodied dinosaurs likely promoted open vegetation structure, prompting fluvial avulsion and clastic sediment input to distal floodplains. After the end-Cretaceous mass extinction, dense forests could establish, stabilizing meander belts and starving the floodplain of clastic sediment, favoring the accumulation of organic-rich strata. More empirical data are needed, but facies change in continental Cretaceous-Paleogene boundary sections suggests dinosaurs were ecosystem engineers that promoted habitat openness in the Late Cretaceous, and their extinction likely led to a dramatic reorganization of ecosystem structure in the earliest Paleogene.
Lucas N. Weaver, Thomas S. Tobin, Courtney J. Sprain, Paige K. Wilson Deibel, Vera A. Korasidis, Mónica R. Carvalho, Pim Kaskes & Isabel M. Fendley (2025)
Dinosaur extinction can explain continental facies shifts at the Cretaceous-Paleogene boundary
Communications Earth & Environment 6: 712
doi: https://doi.org/10.1038/s43247-025-02673-8
https://www.nature.com/articles/s43247-025-02673-8
Continental Cretaceous-Paleogene boundary sections are best known from North America, where they invariably exhibit a marked shift in sedimentary facies at or very near the boundary level. Uppermost Cretaceous strata typically reflect water-logged soils and unstable meandering-river deposits, whereas lowermost Paleogene strata typically reflect coal swamps and broad, stable meander-belt deposits. Causal links between facies shifts at the Cretaceous-Paleogene boundary and the end-Cretaceous mass extinction have been largely dismissed. Here, we present five new Cretaceous-Paleogene boundary sections identified via iridium anomalies in the Bighorn and Williston basins and assess the sedimentological changes that occur at North American Cretaceous-Paleogene boundaries. We hypothesize that the geographically widespread Cretaceous–Paleogene facies shifts were driven by the extinction of dinosaur megafauna. Large-bodied dinosaurs likely promoted open vegetation structure, prompting fluvial avulsion and clastic sediment input to distal floodplains. After the end-Cretaceous mass extinction, dense forests could establish, stabilizing meander belts and starving the floodplain of clastic sediment, favoring the accumulation of organic-rich strata. More empirical data are needed, but facies change in continental Cretaceous-Paleogene boundary sections suggests dinosaurs were ecosystem engineers that promoted habitat openness in the Late Cretaceous, and their extinction likely led to a dramatic reorganization of ecosystem structure in the earliest Paleogene.
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Adrian Boeye
Sep 15, 2025, 12:31:45 PMSep 15
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Have to appreciate the Skyrim reference with Paarthurnax holliensis, fun paper with an awesome genus name.
Adrian
Dawid Mazurek
Sep 15, 2025, 4:19:28 PMSep 15
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Lucas N. Weaver, Thomas S. Tobin, Courtney J. Sprain, Paige K. Wilson Deibel, Vera A. Korasidis, Mónica R. Carvalho, Pim Kaskes & Isabel M. Fendley (2025)
Dinosaur extinction can explain continental facies shifts at the Cretaceous-Paleogene boundary
Communications Earth & Environment 6: 712
doi: https://doi.org/10.1038/s43247-025-02673-8
https://www.nature.com/articles/s43247-025-02673-8
The title is misleading as the study concerns dinosaur megafauna extinction (as stated in the abstract) and not dinosaurs as a whole - they are doing quite well, with +10 000 species alive today.
DM
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