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[dinosaur] Pliosaur teeth from Poland + Beelzebufo bite force + mesosaurid scoliosis (free pdfs)






Ben Creisler
bcreisler@gmail.com


Some recent non-dino papers in open access:


Daniel Madzia & Marcin Machalski (2017)

Isolated pliosaurid teeth from the Albian–Cenomanian (Cretaceous) of Annopol, Poland.

Acta Geologica Polonica Vol 67, No 3 (2017) 393–403

DOI: 10.1515/agp-2017-001

https://geojournals.pgi.gov.pl/agp/article/view/25837PDF




Brachauchenine pliosaurids were a cosmopolitan clade of macropredatory plesiosaurs that are considered to represent the only pliosaurid lineage that survived the faunal turnover of marine amniotes during the Jurassic–Cretaceous transition. However, the European record of the Early to early Late Cretaceous brachauchenines is largely limited to isolated tooth crowns, most of which have been attributed to the classic Cretaceous taxon Polyptychodon. Nevertheless, the original material of P. interruptus, the type species of Polyptychodon, was recently reappraised and found undiagnostic. Here, we describe a collection of twelve pliosaurid teeth from the upper Albian–middle Cenomanian interval of the condensed, phosphorite-bearing Cretaceous succession at Annopol, Poland. Eleven of the studied tooth crowns, from the Albian and Cenomanian strata, fall within the range of the morphological variability observed in the original material of P. interruptus from the Cretaceous of England. One tooth crown from the middle Cenomanian is characterized by a gently subtrihedral cross-section. Similar morphology has so far been described only for pliosaurid teeth from the Late Jurassic and Early Cretaceous. Even though it remains impossible to precisely settle the taxonomic distinctions, the studied material is considered to be taxonomically heterogeneous.


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A. Kristopher Lappin, Sean C. Wilcox, David J. Moriarty, Stephanie A. R. Stoeppler, Susan E. Evans & Marc E. H. Jones (2017)

Bite force in the horned frog (Ceratophrys cranwelli) with implications for extinct giant frogs

Scientific Reports 7, Article number: 11963 (2017)

doi:10.1038/s41598-017-11968-6

https://www.nature.com/articles/s41598-017-11968-6



Of the nearly 6,800 extant frog species, most have weak jaws that play only a minor role in prey capture. South American horned frogs (Ceratophrys) are a notable exception. Aggressive and able to consume vertebrates their own size, these “hopping heads” use a vice-like grip of their jaws to restrain and immobilize prey. Using a longitudinal experimental design, we quantified the ontogenetic profile of bite-force performance in post-metamorphic Ceratophrys cranwelli. Regression slopes indicate positive allometric scaling of bite force with reference to head and body size, results that concur with scaling patterns across a diversity of taxa, including fish and amniotes (lizards, tuatara, turtles, crocodylians, rodents). Our recovered scaling relationship suggests that exceptionally large individuals of a congener (C. aurita) and extinct giant frogs (Beelzebufo ampinga, Late Cretaceous of Madagascar) probably could bite with forces of 500 to 2200 N, comparable to medium to large-sized mammalian carnivores.



News:


https://phys.org/news/2017-09-reveals-dinosaur-eating-frog.html


https://www.livescience.com/60474-frog-with-powerful-bite.html



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Tomasz Szczygielski , Dawid Surmik, Agnieszka Kapuścińska & Bruce M. Rothschild (2017)

The oldest record of aquatic amniote congenital scoliosis.

PLoS ONE 12(9): e0185338. 

doi: https://doi.org/10.1371/journal.pone.0185338

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185338




We report the first occurrence of congenital scoliosis in an early Permian aquatic parareptile, Stereosternum tumidum from Paraná state, Brazil. The spine malformation is caused by a congenital hemivertebra. These observations give insight into the biomechanical aspects of underwater locomotion in an axial skeleton-compromised aquatic amniote. This is the oldest record of a hemivertebra in an aquatic animal.


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