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[dinosaur] Montealtosuchus cursorial limbs + Iberian fossil turtles + Rhynchosauroides + more





Ben Creisler
bcreisler@gmail.com


Some recent non-dino papers:


Sandra Aparecida Simionato Tavares, Fresia Ricardi Branco, Ismar de Souza Carvalho & Lara Maldanis (20170
The morphofunctional design of Montealtosuchus arrudacamposi (Crocodyliformes, Upper Cretaceous) of the Bauru Basin, Brazil.
Cretaceous Research (advance online publication)
doi: https://doi.org/10.1016/j.cretres.2017.07.003
http://www.sciencedirect.com/science/article/pii/S0195667117301908


Highlights

Montealtosuchus arrudacamposi was a Cretaceous Crocodyliformes of terrestrial habits.
It possessed more slender anterior limbs than the living crocodyliforms
The 3D analysis of the skeleton of M. arrudacamposi, showed that this species presented a more vertical position of its anterior limbs.
M. arrudacamposi had cursorial habits, allowing him to wander in terrestrial environments in search of his prey.

Abstract

Montealtosuchus arrudacamposi, a Peirosauridae from the Upper Cretaceous of the Bauru Basin, was a Crocodyliformes of terrestrial habits. The fossils analyzed in this study belong to the pectoral girdle (scapula and coracoid) and anterior appendicular skeleton (humerus, radius, ulna, carpals, radiale, ulnale, metacarpals and phalanges). In this study we infer the locomotion habits of M. arrudacamposi. A morphometric, morphofunctional and 3D reconstruction of the elements of the pectoral girdle and the anterior limbs of M. arrudacamposi were performed. For a better understanding of the most plausible pectoral girdle and anterior limb posture, the studied bones were virtually disarticulated and articulated on 3D reconstruction.

The herein results obtained indicate the structures present a relatively thin and elongated aspect, thus allowing an interpretation that M. arrudacamposi possessed more slender anterior limbs than living crocodyliforms. This condition allowed for an adducted stance and cursorial habits that would enable movement through terrestrial environments for prey searching.

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A. Pérez-García (2017)
The Iberian fossil record of turtles: an update.
Journal of Iberian Geology (advance online publication)
DOI: 10.1007/s41513-017-0016-4
https://link.springer.com/article/10.1007/s41513-017-0016-4

Purpose

The record of fossil turtles of the Iberian Peninsula is abundant and diverse, considering both the Mesozoic and the Cenozoic forms. The knowledge about the Iberian representatives has been significantly improved through the studies carried out in recent years. More than a third of the species nominated in the Iberian record have been described in the 21st century, corresponding to more than half of the currently valid species defined there. These recent studies allowed to recognize unknown lineages for the Iberian record, to refute several attributions or the validity of several taxa, to raise new hypotheses about the palaeobiogeographical and biostratigraphic distributions of several linages, as well as to provide new data on their dispersal events to Europe and, more specifically, to the Iberian Peninsula. Several previous determinations were not reviewed so far, and the validity of several taxa was not evaluated. Thus, the hypotheses about their systematic positions were not updated.

Methods

The information on the diversity of the Iberian turtles is collected and evaluated here. Some synonyms are supported or proposed here, the phylogenetic position of several forms is revised, and all the Iberian taxa, which are revised here, are figured.

Results

The evolutionary history of the turtles of the Iberian Peninsula, from the Upper Jurassic to the present, is compiled, evaluated and synthesized for the first time.

Conclusions

The palaeobiogeography and the information on the origin of each of the lineages of turtles recognized here are considered, as well as the knowledge on their temporal distributions.


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Eudald Mujal , Guillem Iglesias, Oriol Oms , Josep Fortuny , Arnau Bolet & Josep Manel Méndez (2017)
Rhynchosauroides Footprint Variability in a Muschelkalk Detrital Interval (Late Anisian–Middle Ladinian) from the Catalan Basin (NE Iberian Peninsula).
Ichnos (advance online publication)
doi:  http://dx.doi.org/10.1080/10420940.2017.1337571   
http://www.tandfonline.com/doi/full/10.1080/10420940.2017.1337571


The Middle Triassic successions of coastal and distal alluvial systems are often characterized by the presence of the tetrapod ichnotaxon Rhynchosauroides. Nevertheless, few studies paid attention on the paleoenvironmental implications of this widely distributed ichnogenus. The finding of a new Rhynchosauroides-dominated tracksite opens the window to the use of such footprints in paleoenvironmental studies. The tracksite is located in the active quarry of Pedrera de Can Sallent, at Castellar del Vallès (Catalan Basin, NE Iberian Peninsula). The footprints were recovered from the Middle Muschelkalk detrital unit, composed of a claystone-sandstone-gypsum succession from a sabkha setting of late Anisian-middle Ladinian age. This unit was deposited during a short regression interval within the main Middle Triassic transgression represented by the Muschelkalk facies. The ichnoassociation is composed of Rhynchosauroides isp., and a single, partially preserved, undetermined large footprint. Among Rhynchosauroides specimens, three different preservation states were recognized, corresponding to substrates in (1) subaqueous conditions (surfaces with scarce, deformed, and deeply impressed ichnites), (2) occasionally flooded (mostly trampled surfaces, footprints commonly well preserved), and (3) subaerial exposition (surfaces with few footprints, sometimes corresponding to faint impressions or only preserved by claw marks). The footprint morphological variations of Rhynchosauroides are correlated to substrate rheology and further to the environmental conditions. Rhynchosauroides is a characteristic morphotype that often dominates in the Anisian-Ladinian coastal and distal alluvial settings of several European tracksites. Therefore, these ichnoassociations in such environments, awaiting further detailed analyses, may constitute a distinct ichnocoenosis.

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Spencer G. Lucas (2017)
Permian tetrapod biochronology, correlation and evolutionary events.
The Permian Timescale: Geological Society, London, Special Publication 450 (advance online publication) 
doi: https://doi.org/10.1144/SP450.12
http://sp.lyellcollection.org/content/early/2017/05/08/SP450.12


The most extensive Permian tetrapod (amphibian and reptile) fossil records from the western USA (New Mexico to Texas) and South Africa have been used to define 11 land vertebrate faunachrons (LVFs). These are, in ascending order, the Coyotean, Seymouran, Mitchellcreekian, Redtankian, Littlecrotonian, Kapteinskraalian, Gamkan, Hoedemakeran, Steilkransian, Platbergian and Lootsbergian. These faunachrons provide a biochronological framework with which to assign ages to, and correlate, Permian tetrapod fossil assemblages. Intercalated marine strata, radioisotopic ages and magnetostratigraphy were used to correlate the Permian LVFs to the standard global chronostratigraphic scale with varying degrees of precision. Such correlations identified the following significant events in Permian tetrapod evolution: a Coyotean chronofaunal event (end Coyotean); Redtankian events (Mitchellcreekian–Littlecrotonian); Olson's gap (late Littlecrotonian); a therapsid event (Kapteinskraalian); a dinocephalian extinction event (end Gamkan); and a latest Permian extinction event (Platbergian–Lootsbergian boundary). Problems of incompleteness, endemism and taxonomy, and the relative lack of non-biochronological age control continue to hinder the refinement and correlation of a Permian timescale based on tetrapod biochronology. Nevertheless, the global Permian timescale based on tetrapod biochronology is a robust tool for both global and regional age assignment and correlation. Advances in Permian tetrapod biochronology will come from new fossil discoveries, more detailed biostratigraphy and additional alpha taxonomic studies based on sound evolutionary taxonomic principles.