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| Eotephradactylus mcintireae Kligman, Whatley, Ramezani1, Marsh, Lyson, Fitch, Parker & Behrensmeyer, 2025 artwork: Brian Engh. |
Significance:
PFV 393 is the first radioisotopically dated (209.187 ± 0.083 Ma old) high-diversity continental vertebrate fossil assemblage to fill a 12-Ma fossil gap preceding the end-Triassic extinction. The taphonomy and depositional setting of this assemblage show that key members of post–Triassic Mesozoic vertebrate communities, including frogs, lepidosaur reptiles, pterosaurs, and turtles, coexisted with archaic lineages such as metoposaurid amphibians, trilophosaurid archosauromorphs, Vancleavea, doswelliids, phytosaurs, and aetosauriforms in the mesic fluvial environments of aridifying equatorial Pangaea approximately 7 Ma prior to the end-Triassic extinction. A member of this paleocommunity and one of the earliest few pterosaurs found outside of Europe, the newly described Eotephradactylus mcintireae gen. et sp. nov., reveals novel aspects of pterosaur mandibular evolution, ecology, and biogeography.
Abstract
Temporally constrained microvertebrate bone beds are powerful tools for understanding continent-scale biotic change. Such sites are rare globally in nonmarine settings during the 12 million years (Ma) preceding the end-Triassic extinction (ETE; ~201.5 Ma), obscuring patterns of faunal change across this interval. A vertebrate assemblage from Arizona, USA, provides unique insights into community composition and ecology prior to the ETE. PFV 393 is a macro- and microvertebrate bone bed preserved in a volcaniclastic fluvial channel-fill with a high-precision U-Pb zircon age of 209.187 ± 0.083 Ma. The fossil assemblage consists of three-dimensionally preserved, delicate, and small skeletal elements of known and new taxa that document a local paleocommunity including hybodontiformes, actinopterygians, actinistians, metoposaurids, salientians, synapsids, lepidosaurs, testudinatans, trilophosaurids, Vancleavea, doswelliids, Revueltosaurus, loricatans, phytosaurs, and pterosaurs. The new early-diverging pterosaur is one of the few Triassic pterosaurs found outside of Europe and the only one with a documented precise radioisotopic age. The testudinatan material shows the rapid dispersal of terrestrial stem-turtles across the Pangaean supercontinent in the Norian and refines temporal constraints on the origin of the turtle shell. The presence of vertebrate lineages endemic to the Triassic highlights their persistence in a mesic, fluvial paleocommunity through a prolonged phase of environmental change preceding the ETE. These lineages coexisted with frogs, lepidosaurs, turtles, and pterosaurs- all key elements of post–Triassic Mesozoic communities. The arrival of turtles and pterosaurs in west-central Pangaea therefore may have been driven by the northward drift of Laurentia from humid equatorial conditions into more arid subtropical latitudes.
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| life restoration of Eotephradactylus mcintireae catching a fish in the Chinle Formation environment. An artist's reconstruction of the fossilized landscape, plants and animals found preserved in a remote bonebed in Petrified Forest National Park in Arizona. Researchers led by paleontologist Ben Kligman,, present the fossilized jawbone of a new pterosaur species and describe the sea gull-sized flying reptile along with hundreds of other fossils they unearthed from the site. These fossils, which date back to the late Triassic period around 209 million years ago, preserve a snapshot of a dynamic ecosystem where older groups of animals lived with evolutionary upstarts. The newly described pterosaur Eotephradactylus mcintireae is seen eating an ancient ray-finned fish alongside an early species of turtle and an early frog species, with the skeleton of an armored crocodile relative lying on the ground and a palm-like plant growing in the background. artwork: Brian Engh. |
Eotephradactylus mcintireae gen. et sp. nov.
Ben T. Kligman, Robin L. Whatley, Jahandar Ramezani1, Adam D. Marsh, Tyler R. Lyson, Adam J. Fitch, William G. Parker and Anna K. Behrensmeyer. 2025. Unusual Bone Bed reveals A Vertebrate Community with Pterosaurs and Turtles in equatorial Pangaea before the end-Triassic Extinction. Proceedings of the National Academy of Sciences. 122 (29) e2505513122. DOI: doi.org/10.1073/pnas.2505513122 [July 7, 2025]
