Ben Creisler
Some new papers:
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Free pdf:
Valentin Fischer, Robert Weis & Ben Thuy (2021)
Refining the marine reptile turnover at the Early-Middle Jurassic transition.
PeerJ 9:e10647
doi:
https://doi.org/10.7717/peerj.10647https://peerj.com/articles/10647/Â
Even though a handful of long-lived reptilian clades dominated Mesozoic marine ecosystems, several biotic turnovers drastically changed the taxonomic composition of these communities. A seemingly slow paced, within-geological period turnover took place across the EarlyâMiddle Jurassic transition. This turnover saw the demise of early neoichthyosaurians, rhomaleosaurid plesiosaurians and early plesiosauroids in favour of ophthalmosaurid ichthyosaurians and cryptoclidid and pliosaurid plesiosaurians, clades that will dominate the Late Jurassic and, for two of them, the entire Early Cretaceous as well. The fossil record of this turnover is however extremely poor and this change of dominance appears to be spread across the entire middle ToarcianâBathonian interval. We describe a series of ichthyosaurian and plesiosaurian specimens from successive geological formations in Luxembourg and Belgium that detail the evolution of marine reptile assemblages across the Early-Middle Jurassic transition within a single area, the Belgo-Luxembourgian sub-basin. These fossils reveal the continuing dominance of large rhomaleosaurid plesiosaurians, microcleidid plesiosaurians and Temnodontosaurus-like ichthyosaurians up to the latest Toarcian, indicating that the structuration of the upper tier of Western Europe marine ecosystems remained essentially constant up to the very end of the Early Jurassic. These fossils also suddenly record ophthalmosaurid ichthyosaurians and cryptoclidid plesiosaurians by the early Bajocian. These results from a geographically-restricted area provide a clearer picture of the shape of the marine reptile turnover occurring at the early-Middle Jurassic transition. This event appears restricted to the sole Aalenian stage, reducing the uncertainty of its duration, at least for ichthyosaurians and plesiosaurians, to 4 instead of 14 million years.
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Kinga Gere, Emese RÃka Bodor, LÃszlà MakÃdi & Attila Åsi (2021)
Complex food preference analysis of the Late Cretaceous (Santonian) lizards from IharkÃt (Bakony Mountains, Hungary).
Historical Biology (advance online publication)
doi:
https://doi.org/10.1080/08912963.2021.1887862 https://www.tandfonline.com/doi/full/10.1080/08912963.2021.1887862The Upper Cretaceous IharkÃt vertebrate locality (Bakony Mountains, Hungary) provided a diverse lizard fauna. In order to infer their food preference, jaw and tooth morphology, as well as dental macro- and microwear, were analysed. Due to preservation, only specimens of three taxa (Chromatogenys, Bicuspidon, 'Scincomorpha indet. A') were studied. Extant lizards, including omnivores, durophages, insectivores, molluscivores and a herbivore, were used as analogies for interpretation. Based on morphological and dental wear studies, Chromatogenys seems to have consumed and processed hard objects regularly with its enlarged posterior teeth. In contrast, Bicuspidon with its complex bicuspid teeth might have fed on both softer and harder food items, and according to dental wear analysis, its diet can be placed between herbivory and insectivory. The sharply pointed teeth and jaw morphology of 'Scincomorpha indet. A' are comparable to recent insectivorous taxa though tooth crown morphology is most similar to burrowing species. This investigation is considered as a pilot study providing insight into the complexity of food chains of the Late Cretaceous IharkÃt terrestrial communities. Furthermore, our results clearly demonstrate that the two-dimensional dental microwear analysis works well on the small (tooth crown diameter less than 1 mm) teeth of both extinct and extant lizards.
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Also:
AdiÃl A Klompmaker & Neil H Landman (2021)
Octopodoidea as predators near the end of the Mesozoic Marine Revolution.
Biological Journal of the Linnean Society, blab001
doi:
https://doi.org/10.1093/biolinnean/blab001https://academic.oup.com/biolinnean/advance-article-abstract/doi/10.1093/biolinnean/blab001/6131869Octopodoidea are a highly versatile and diverse group of marine predators comprising > 200 species today; however, their diversity and ecology in deep time are virtually unknown. Because these soft-bodied cephalopods have a low preservation potential, only a single body fossil species has been documented. Unlike other modern cephalopods, octopodoids leave behind a characteristic drill hole on their molluscan and crustacean prey. These traces provide a means to track their presence and behaviour in deep time. Although severely understudied, some of such holes have been documented from the Eocene-Pleistocene fossil record. We document the oldest recognized drill holes attributed to octopodoids, found in lucinid bivalves from the Late Cretaceous (Campanian) of South Dakota, USA. These observations demonstrate that the drilling habit of these animals evolved early in the evolutionary history of Octopodoidea, ~25 Myr earlier than was previously known. The drilled lucinids lived in cold methane seeps in the Western Interior Seaway. These predation traces have never been found in fossil seeps previously, thus adding a new predator to the food web of cold seeps. Finally, our results provide direct evidence that Octopodoidea were an integral component of the rise of shell-destroying predators during the Mesozoic Marine Revolution.