Metriorhynchid tail bend + turtles from Upper Cretaceous of Izhberda Locality in Russia
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Ben Creisler
Dec 3, 2025, 11:01:44 AM (4 days ago) Dec 3
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Ben Creisler
New Mesozoic reptile papers:
Jonas Le Mort, Jeremy E. Martin, Laurent Picot & Stéphane Hua (2025)
The tailbend of Metriorhynchidae (Crocodylia: Thalattosuchia) measurements, limits and paleoecological implications
PalZ (advance online publication)
doi: https://doi.org/10.1007/s12542-025-00753-w
https://link.springer.com/article/10.1007/s12542-025-00753-w
Although the remains of Metriorhynchidae have been known in Normandy since the nineteenth century, few complete postcranial elements have been studied in detail. Analysis of the angle of flexure of the tail of one of the most complete specimens of Metriorhynchus aff. superciliosus (MPV 2010.3.610) discovered in the Callovian of the Vaches-Noires cliffs provides an opportunity to conduct the first quantitative study of the angle of heterocercy in Metriorhynchidae. Until now, this angle was only estimated qualitatively for complete specimens of Metriorhynchidae from the Late Jurassic of Germany. In this paper, we investigate new metrics and present the first 3D reconstruction of the flexure in a Callovian specimen. To compare and highlight variations, we estimate the angle of tail flexure for other Metriorhynchidae from the German Late Jurassic and from the English Callovian. The measurements highlight the variation in the angle of flexure between the different Metriorhynchidae. The palaeoecological implications of these variations are discussed and imply different swimming capabilities within the studied group.
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PalZ (advance online publication)
doi: https://doi.org/10.1007/s12542-025-00753-w
https://link.springer.com/article/10.1007/s12542-025-00753-w
Although the remains of Metriorhynchidae have been known in Normandy since the nineteenth century, few complete postcranial elements have been studied in detail. Analysis of the angle of flexure of the tail of one of the most complete specimens of Metriorhynchus aff. superciliosus (MPV 2010.3.610) discovered in the Callovian of the Vaches-Noires cliffs provides an opportunity to conduct the first quantitative study of the angle of heterocercy in Metriorhynchidae. Until now, this angle was only estimated qualitatively for complete specimens of Metriorhynchidae from the Late Jurassic of Germany. In this paper, we investigate new metrics and present the first 3D reconstruction of the flexure in a Callovian specimen. To compare and highlight variations, we estimate the angle of tail flexure for other Metriorhynchidae from the German Late Jurassic and from the English Callovian. The measurements highlight the variation in the angle of flexure between the different Metriorhynchidae. The palaeoecological implications of these variations are discussed and imply different swimming capabilities within the studied group.
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E. A. Zvonok, A. V. Mizetskaya & I. G. Danilov (2025)
Turtles from the Upper Cretaceous of the Izhberda Locality (Orenburg Region, Russia)
Paleontological Journal 59: 550–561
doi: https://doi.org/10.1134/S0031030125600696
https://link.springer.com/article/10.1134/S0031030125600696
A turtle assemblage is described from the Upper Santonian or Lower Campanian of the Izhberda locality in Orenburg Region, Russia. The assemblage includes at least four taxa of sea turtles: Protostegidae indet., Toxochelyinae indet. (the first reliable find in Eurasia), Ctenochelyidae indet., and Pan-Chelonioidea indet. similar to Corsochelys haliniches Zangerl, 1960. Moreover, remains of Pan-Chelonioidea indet., which may belong to a wide range of taxa, as well as a fragment of a sculptured peripheral plate of Testudines indet., which may belong to a representative of the genus Peritresius (Ctenochelyidae) or a large representative of Nanhsiungchelyidae (not previously reported from Europe), are described.
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Turtles from the Upper Cretaceous of the Izhberda Locality (Orenburg Region, Russia)
Paleontological Journal 59: 550–561
doi: https://doi.org/10.1134/S0031030125600696
https://link.springer.com/article/10.1134/S0031030125600696
A turtle assemblage is described from the Upper Santonian or Lower Campanian of the Izhberda locality in Orenburg Region, Russia. The assemblage includes at least four taxa of sea turtles: Protostegidae indet., Toxochelyinae indet. (the first reliable find in Eurasia), Ctenochelyidae indet., and Pan-Chelonioidea indet. similar to Corsochelys haliniches Zangerl, 1960. Moreover, remains of Pan-Chelonioidea indet., which may belong to a wide range of taxa, as well as a fragment of a sculptured peripheral plate of Testudines indet., which may belong to a representative of the genus Peritresius (Ctenochelyidae) or a large representative of Nanhsiungchelyidae (not previously reported from Europe), are described.
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