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[dinosaur] Omphalosaurus from Triassic of Poland + Jurassic thalattosuchians from Slovakia + Cretaceous turtle Helopanoplia

Ben Creisler

Some recent non-dino papers:

Tanja Wintrich, Hans Hagdorn & P. Martin Sander (2017)
An enigmatic marine reptileâthe actual first record of Omphalosaurus in the Muschelkalk of the Germanic Basin.Â
Journal of Vertebrate Paleontology Article: e1384739 (advance online publication)
DOI: 10.1080/02724634.2017.1384739

Omphalosaurus is an enigmatic marine reptile of probable ichthyosaurian affinities known from Early and Middle Triassic marine deposits of the Northern Hemisphere. Based on its unique crushing dentition combined with elongate jaws, Omphalosaurus appears to have been a specialized ammonoid feeder. Here we describe a jaw fragment from the Lower Muschelkalk of Silesia, Poland (Karchowice Formation, Anisian, Pelsonian/early Illyrian), and assign it to Omphalosaurus sp. based on tooth morphology, tooth replacement pattern, enamel surface morphology, and enamel microstructure. This is the first record of Omphalosaurus from shallow marine carbonates and from the Muschelkalk facies, a classical source of Middle Triassic marine reptiles. The discovery is unexpected because all other records of Omphalosaurus are from open-water deposits rich in ichthyosaurs and ammonoids. We reidentify an earlier putative record of Omphalosaurus from the Lower Muschelkalk of RÃdersdorf near Berlin, Germany, as the left maxilla of the common Muschelkalk placodont Placodus. This reidentification is based on shared characters of osteology, dentition, mode of tooth replacement, and tooth enamel microstructure. Data on both specimens were collected using visual inspection, micro-computed tomography (ÂCT), and scanning electron microscopy.


Andrej ÄerÅanskÃ, JÃn SchlÃgl, TomÃÅ Mlynskà & Åtefan JÃzsa (2017)
First evidence of the Jurassic thalattosuchian (both teleosaurid and metriorhynchid) crocodylomorphs from Slovakia (Western Carpathians).
Historical Biology (advance online publication)
doi:Â https://doi.org/10.1080/08912963.2017.1414212Â Â

We report here finds of thalattosuchians from Western Carpathians. The material consists of two isolated teeth from two different localities of the Pieniny Klippen Belt. The material represents the first evidence of the occurrence of both clades Teleosauridae and Metriorhynchidae in Slovakia. The first, a small tooth comes from the locality BeÅatina and is dated early Middle Jurassic (Aalenian). Identification of the specimen shows it belongs to a longirostrine teleosaurid, possibly to Steneosaurus. Teleosaurids were largely restricted to lagoonal/near-shore environments. Their limbs allow them to support and walk on land. Regarding that fact, the presence of this taxon in BeÅatina might be an indication of terrestrial land in the nearby area and shows a location of epicontinental seaways. A second larger tooth was found in the Upper Jurassic (Tithonian) sediments of the locality Kyjov, and is tentatively allocated in the genus Plesiosuchus. The members of Plesiosuchina are known in England, France, Portugal and Sicily. Our findings indicate a much wider spatial distribution of this clade in Europe and it fits well with the previous interpretation of sediments of the locality Kyjov as deep-water pelagic deposits.


Free pdf:

Walter G. Joyceâ & Tyler R. Lyson (2017)
The shell morphology of the latest Cretaceous (Maastrichtian) trionychid turtle Helopanoplia distincta.
PeerJ 5:e4169
doi:Â https://doi.org/10.7717/peerj.4169

Helopanoplia distincta is an extinct soft-shelled turtle (Pan-Trionychidae) for which the type specimen is a fragmentary costal and the inguinal notch portion of the left hypoplastron from the Late Cretaceous (Maastrichtian) Lance Formation of Wyoming, USA that bear a distinct surface sculpture pattern consisting of raised tubercles. Over the course of the past few decades, a number of additional, fragmentary specimens from the Late Cretaceous (Maastrichtian) Hell Creek Formation of Montana and North Dakota have been referred to this taxon based on the presence of these tubercles, but a more complete understanding of the anatomy and phylogenetic relationships of this distinctive soft-shelled turtle is still outstanding.


We here figure and describe shell remains of eight fossils referable to Helopanoplia distincta from the Hell Creek Formation of Montana and North Dakota that, in combination, document nearly all aspects of the shell morphology of this taxon. We furthermore explore the relationships of this fossil turtle by inserting it into a modified phylogenetic analysis of pan-trionychid relationships.


The new fossil material thoroughly supports the validity of Helopanoplia distincta. In addition to its unique surface sculpture pattern, this turtle can be diagnosed relative to all other named pan-trionychids by the presence of a distinct corner along the margin of costals II, the complete covering of costal ribs IâVI by metaplastic bone, midline contact of the main plastral elements, hyoplastral shoulder, presence of a lateral, upturned margin on the hyo/hypoplastron that is covered dorsally and laterally by sculptured metaplastic bone, a single, lateral hyoplastral process, and the apomorphic presence of fine scallops along the margin of costals VIII, formation of a laterally embraced, rounded nuchal, anteriorly rounded costals I, distally expanded costals II, and narrow costals VII. A phylogenetic analysis places Helopanoplia distincta as sister to the clade formed by Plastomenus thomasii and Hutchemys spp., thereby confirming its identity as a plastomenid. The vast majority of Helopanoplia distincta material has been recovered from fine-grained overbank deposits, thereby supporting the hypothesis that this turtle favored ponded waters.