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[dinosaur] Pterosaur tracks from Jurassic of Poland + Plesiochelys morphology + Triassic Sonsela Sandstone




Ben Creisler


New non-dino papers:

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Erik Elgh, Grzegorz PieÅkowski & Grzegorz NiedÅwiedzki (2019)
Pterosaur track assemblages from the Upper Jurassic (lower Kimmeridgian) intertidal deposits of Poland: Linking ichnites to potential trackmakers.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)

Highlights

Numerous pterosaur tracks have been preserved in the Kimmeridgian strata.
Specimens are larger than other pterosaurian ichnites of Late Jurassic age.
The tracks are assigned to Pteraichnus isp.
The analyses show that different pterosaur species were the trackmakers.
Tidal flat was environment frequented by pterosaurs.


Abstract

Two distinct tetrapod track assemblages, dominated by pterosaur traces, are reported from Upper Jurassic (lower Kimmeridgian, Hypselocyclum Zone) tidal flat carbonate deposits exposed in Wierzbica Quarry, 20âkm south of Radom, Poland. The pterosaur tracks, tentatively assigned to Pteraichnus isp. are well preserved as a positive hyporelief in intertidal facies especially in mixed flat deposits with microbial mats. Some are preserved with anatomical details (e.g., skin, claw or digital pad impressions) and quality sufficient to make ichnotaxonomic assignment. Nearly all collected specimens are larger than most other pterosaurian ichnites of the Late Jurassic age, thus adding to the growing diversity of pterosaur traces known from this time period. Morphometrical and anatomical analyses show that ctenochasmatoids or possibly non-pterydactyloid monofenestratans or rhamphorhynchids were most likely the trackmakers. Anatomical comparisons give new insights into the morphology of the pes of pterydactyloids and the most closely related non-pterodactyloids which may be correlated with a niche expansion into marginal marine and lacustrine environments by Middle and Late Jurassic pterosaurs. The palaeoenvironmental interpretation as tidal flat is confirmed by presence of vertically accreted tidal bundles, each representing deposition in one tidal cycle. Most likely then, this was one of the environments frequented by these pterosaurs and other small tetrapods. The wider palaeoecological significance of the tracks is evaluated in the context of other similar reports from the Late Jurassic of Europe, Africa and North America.

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Free pdf:


Irena Raselli & JÃrÃmy Anquetin (2019)
Novel insights into the morphology of Plesiochelys bigleri from the early Kimmeridgian of Northwestern Switzerland.Â
PLoS ONE 14(5): e0214629.


Plesiochelyidae were relatively large coastal marine turtles, which inhabited the epicontinental seas of Western Europe during the Late Jurassic. Their fossil record can be tracked in Germany, Switzerland, the United Kingdom, France, Spain and Portugal. The Jura Mountains, in northwestern Switzerland, have been the main source for the study of this group, mostly thanks to the rich and famous historical locality of Solothurn. In the last two decades, numerous plesiochelyid remains have been collected from Kimmeridgian deposits (Lower Virgula Marls and Bannà Marls) in the area of Porrentruy (Canton of Jura, Switzerland). This material was revealed by construction works of the A16 Transjurane highway between 2000 and 2011, and led to the recent description of the new species Plesiochelys bigleri. In the years 2014 and 2016, new fragmentary turtle material was collected from the Bannà Marls (Reuchenette Formation, lower Kimmeridgian) near the village of Glovelier, Canton of Jura, Switzerland. The new material consists of a complete shell, additional shell elements, a few bones from the appendicular and vertebral skeleton, and a fragmentary basicranium. This material can be confidently assigned to the species P. bigleri. It supports the presence of this species in the Bannà Marls, slightly extends its spatial distribution and confirms the differences with the closely related species P. etalloni. The new material reveals that the split between the cerebral and palatine branches of the internal carotid artery occurs in a vertical plane in P. bigleri. This condition could not be observed in the type material due to poor preservation. This new character clearly distinguishes P. bigleri from P. etalloni and seems to be unique among thalassochelydians.


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Free pdf:

Adam D. Marsh, William G. Parker, Daniel F. Stockli & Jeffrey W. Martz (2019)
Regional correlation of the Sonsela Member (Upper Triassic Chinle Formation) and detrital U-Pb zircon data from the Sonsela Sandstone bed near the Sonsela Buttes, northeastern Arizona, USA, support the presence of a distributive fluvial systemÂ
Geosphere (advance online publication)



The Sonsela Sandstone bed was first named as an informal unit in the lower part of the Chinle Formation in northern Arizona, USA, and it was later assigned a type section near the Sonsela Buttes, where it is composed of two prominent sandstone units separated by a predominately siltstone unit. The Sonsela Sandstone bed has been correlated to a number of specific sandstones within the thicker, formal Sonsela Member at Petrified Forest National Park in northern Arizona. Here, we present the first detrital U-Pb zircon data for the Sonsela Sandstone bed at the Sonsela Buttes to hypothesize the maximum deposition age of that unit (216.6 Â 0.3 Ma) that are consistent with the proposed lithostratigraphic correlation with the fossiliferous Jasper Forest bed of the lower part of the Sonsela Member at the Park. These results are corroborated by previous high-resolution U-Pb dates and detrital zircon provenance studies from Petrified Forest National Park and similar sections in northern Arizona and western New Mexico, USA. The hypothesized chronostratigraphic correlation of these sandstones throughout northern Arizona permits the recognition of diachronous facies distributions in the lower part of the Chinle Formation as these coarse sediments prograded from the southwest into a continental basin already receiving finer-grained fluvial sediments from the southeast. The new age data corroborate the Norian age designation for the Sonsela Member (and the Sonsela Sandstone bed) and suggest that the Sonsela Sandstone bed at the Sonsela Buttes is within the Adamanian land vertebrate estimated holochronozone.


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