Iaremys, new turtle from Cretaceous of Argentina + plesiosaur vertebrae from Lower Jurassic of Germany + non-semiaquatic adaptations of extinct crocodylomorphs
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Ben Creisler
Nov 26, 2024, 12:02:39 PM (7 days ago) Nov 26
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Ben Creisler
Sven Sachs, Jahn J. Hornung & Daniel Madzia (2024)
Early-diverging plesiosaurs from the Pliensbachian (Lower Jurassic) of northwestern Germany
PeerJ 12: e18408
doi: https://doi.org/10.7717/peerj.18408
https://peerj.com/articles/18408/
The knowledge of Pliensbachian (Early Jurassic, ∼192.9–184.2 Ma) plesiosaurs is notoriously insufficient. Although there have been specimens described from different parts of the world, only three of them have been established as diagnosable taxa. Here, we describe two previously unreported lower Pliensbachian plesiosaur occurrences that originate from two sites located in North Rhine-Westphalia, Germany. One of the new occurrences is represented by three cervical and three indeterminable vertebrae from Werther, the other includes two associated pectoral or anterior dorsal vertebrae from Bielefeld. Although highly incomplete, the Werther individual, which derived from the Uptonia jamesoni Zone, is found to represent the only reliably identified early Pliensbachian pliosaurid known to date. Its material is geographically and stratigraphically proximate to the late Pliensbachian pliosaurid Arminisaurus schuberti, found in a clay-pit located in the Bielefeld district of Jöllenbeck. However, even though the Werther plesiosaur and A. schuberti show a broadly similar morphology of the preserved cervical section, a precise identification of the Werther taxon is currently impossible.
New reptile papers:
Iaremys batrachomorpha gen. et sp. nov.
Federico L. Agnolín, Alexis M. Aranciaga-Rolando & Raúl Ortiz (2024)
New chelid turtle with a flattened skull from the Late Cretaceous of Northern Patagonia, Argentina
Alcheringa: An Australasian Journal of Palaeontology (advance online publication)
doi: https://doi.org/10.1080/03115518.2024.2427261
https://www.tandfonline.com/doi/full/10.1080/03115518.2024.2427261
The skull morphology of fossil chelids is poorly known because their fossil record is scarce. Here, we describe a new genus and species of flat-headed chelid turtle based on a partial skull. The remains derive from the Maastrichtian (Late Cretaceous) upper section of the Allen Formation at Morales Quarry, near General Roca city in the Río Negro province of Argentina. The new taxon belongs to the flat-headed long-necked chelid group Hydromedusinae and preserves the anterior part of the skull, which is unknown in other members of the clade. Despite being incomplete, the new fossil provides valuable information about cranial morphology in extinct chelid turtles.
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Federico L. Agnolín, Alexis M. Aranciaga-Rolando & Raúl Ortiz (2024)
New chelid turtle with a flattened skull from the Late Cretaceous of Northern Patagonia, Argentina
Alcheringa: An Australasian Journal of Palaeontology (advance online publication)
doi: https://doi.org/10.1080/03115518.2024.2427261
https://www.tandfonline.com/doi/full/10.1080/03115518.2024.2427261
The skull morphology of fossil chelids is poorly known because their fossil record is scarce. Here, we describe a new genus and species of flat-headed chelid turtle based on a partial skull. The remains derive from the Maastrichtian (Late Cretaceous) upper section of the Allen Formation at Morales Quarry, near General Roca city in the Río Negro province of Argentina. The new taxon belongs to the flat-headed long-necked chelid group Hydromedusinae and preserves the anterior part of the skull, which is unknown in other members of the clade. Despite being incomplete, the new fossil provides valuable information about cranial morphology in extinct chelid turtles.
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Free pdf:
Sven Sachs, Jahn J. Hornung & Daniel Madzia (2024)
Early-diverging plesiosaurs from the Pliensbachian (Lower Jurassic) of northwestern Germany
PeerJ 12: e18408
doi: https://doi.org/10.7717/peerj.18408
https://peerj.com/articles/18408/
The knowledge of Pliensbachian (Early Jurassic, ∼192.9–184.2 Ma) plesiosaurs is notoriously insufficient. Although there have been specimens described from different parts of the world, only three of them have been established as diagnosable taxa. Here, we describe two previously unreported lower Pliensbachian plesiosaur occurrences that originate from two sites located in North Rhine-Westphalia, Germany. One of the new occurrences is represented by three cervical and three indeterminable vertebrae from Werther, the other includes two associated pectoral or anterior dorsal vertebrae from Bielefeld. Although highly incomplete, the Werther individual, which derived from the Uptonia jamesoni Zone, is found to represent the only reliably identified early Pliensbachian pliosaurid known to date. Its material is geographically and stratigraphically proximate to the late Pliensbachian pliosaurid Arminisaurus schuberti, found in a clay-pit located in the Bielefeld district of Jöllenbeck. However, even though the Werther plesiosaur and A. schuberti show a broadly similar morphology of the preserved cervical section, a precise identification of the Werther taxon is currently impossible.
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Yohan Pochat-Cottilloux (2024)
A review of the non-semiaquatic adaptations of extinct crocodylomorphs throughout their fossil
The Anatomical Record (advance online publication)
doi: https://doi.org/10.1002/ar.25586
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.25586
Crocodylomorphs constitute a clade of archosaurs that have thrived since the Mesozoic until today and have survived numerous major biological crises. Contrary to historic belief, their semiaquatic extant representatives (crocodylians) are not living fossils, and, during their evolutionary history, crocodylomorphs have evolved to live in a variety of environments. This review aims to summarize the non-semiaquatic adaptations (i.e., either terrestrial or fully aquatic) of different groups from different periods, highlighting how exactly those different lifestyles are inferred for those animals, with regard to their geographic and temporal distribution and phylogenetic relationships. The ancestral condition for Crocodylomorpha seems to have been a terrestrial lifestyle, linked with several morphological adaptations such as an altirostral skull, long limbs allowing a fully erect posture and a specialized dentition for diets based on land. However, some members of this clade, such as thalattosuchians and dyrosaurids display adaptations for an opposite, aquatic lifestyle, interestingly inferred from the same type of morphological observations. Finally, new techniques for inferring the paleobiology of those extinct animals have been put forward in the last decade, appearing as a complementary approach to traditional morphological descriptions and comparisons. Such is the case of paleoneuroanatomical (CT scan data), histological, and geochemical studies.
The Anatomical Record (advance online publication)
doi: https://doi.org/10.1002/ar.25586
https://anatomypubs.onlinelibrary.wiley.com/doi/10.1002/ar.25586
Crocodylomorphs constitute a clade of archosaurs that have thrived since the Mesozoic until today and have survived numerous major biological crises. Contrary to historic belief, their semiaquatic extant representatives (crocodylians) are not living fossils, and, during their evolutionary history, crocodylomorphs have evolved to live in a variety of environments. This review aims to summarize the non-semiaquatic adaptations (i.e., either terrestrial or fully aquatic) of different groups from different periods, highlighting how exactly those different lifestyles are inferred for those animals, with regard to their geographic and temporal distribution and phylogenetic relationships. The ancestral condition for Crocodylomorpha seems to have been a terrestrial lifestyle, linked with several morphological adaptations such as an altirostral skull, long limbs allowing a fully erect posture and a specialized dentition for diets based on land. However, some members of this clade, such as thalattosuchians and dyrosaurids display adaptations for an opposite, aquatic lifestyle, interestingly inferred from the same type of morphological observations. Finally, new techniques for inferring the paleobiology of those extinct animals have been put forward in the last decade, appearing as a complementary approach to traditional morphological descriptions and comparisons. Such is the case of paleoneuroanatomical (CT scan data), histological, and geochemical studies.
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