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Late Triassic aetosaur from Poland + Chinle archosauriform tooth + multibody analysis of Edingerella



Ben Creisler
bcreisler@gmail.com

A number of recent non-dino papers:


Mateusz Antczak (2015)
Late Triassic aetosaur (Archosauria) from Krasiejów (SW Poland): new
species or an example of individual variation?
Geological Journal (advance online publication)
DOI: 10.1002/gj.2691
http://onlinelibrary.wiley.com/doi/10.1002/gj.2691/abstract



An aetosaur discovery in Krasiejów (SW Poland), in Late Triassic
deposits, was first described by Sulej in 2010 as a new species
carrying the name Stagonolepis olenkae. However, new fossil material
suggests that its taxonomical position is not as clear as was
initially presumed. In the new material from the ‘Triassic’ site of
Krasiejów, the typical features of Stagonolepis robertsoni, described
by Walker in 1961 from the Elgin area of Scotland, were identified
(i.e. frontal/prefrontal width ratio), as well as features of S.
olenkae (i.e. angle between ventral edge of the maxilla and ventral
edge of the antorbital fenestra). However, distinct features from both
species, such as the shape of the canal at the dorsal surface of the
frontal, are present. Some of the variation is similar to sexual
dimorphism observed in recent amphibians and reptiles. These
variations, as well as the fact that the postcranial skeleton was
previously described as S. robertsoni by Lucas and co-workers in 2007,
suggest that the taxonomical affiliation of the Krasiejów aetosaur
(and/or the number of aetosaur species) should be re-considered.


==


Andres Lopez, Isabella St. Aude, David Alderete, David Alvarez, Hannah
Aultman, Dominique Busch, Rogelio Bustamante, Leah Cirks, Martin
Lopez, Adriana Moncada, Elizabeth Ortega, Carlos Verdugo & Robert J
Gay (2015)
An unusual archosauriform tooth increases known tetrapod diversity in
the lower Chinle Formation (Late Triassic) of southeastern Utah.
PeerJ PrePrints 3:e1358
doi: https://dx.doi.org/10.7287/peerj.preprints.1110v1
https://peerj.com/preprints/1110/

An unusual tetrapod tooth was discovered in the Late Triassic Chinle
Formation of southeastern Utah. The tooth was originally thought to
belong to Revueltosaurus but further investigations have rejected that
hypothesis. In this paper we compare MNA V10668 to other...n unusual
tetrapod tooth was discovered in the Late Triassic Chinle Formation of
southeastern Utah. The tooth was originally thought to belong to
Revueltosaurus but further investigations have rejected that
hypothesis. In this paper we compare MNA V10668 to other known fossil
teeth found in the Chinle Formation and identify the least inclusive
clade it may belongs to. Using data found in other publications and
pictures of other teeth, we compare this specimen to other Triassic
dental taxa. MNA V10668 shares some similarities with Crosbysaurus,
Tecovasaurus, and several other named taxa but possesses unique
characteristics not found in other diapsid teeth. We conclude that it
is most likely an archosauromorph and probably an archosauriform. This
increases the known diversity of tetrapods from the Chinle Formation
and represents the first tooth morphotype completely unique to Utah in
the Late Triassic Period.


====


Jordi Marcé-Nogué, Adam Kłodowski, Montserrat Sánchez, and Lluís Gil (2015)
Coupling finite element analysis and multibody system dynamics for
biological research.
Palaeontologia Electronica 18.2.5T: 1-14
http://palaeo-electronica.org/content/2015/1197-coupling-fea-and-msd

Flexible Multibody System Dynamics (FMSD) is a simulation technique
that can be used to study the behavior of the mechanical systems that
consists of one or more deformable bodies. A deformable body can be
modeled using a number of approaches while the floating frame of
reference formulation is a widely used approach. In that approach,
flexibility within Multibody System Dynamics (MSD) is described by
employing the Finite Element Analysis (FEA) with a modal reduction
approach. The applicability of an FMSD in the feeding mechanism of
vertebrate structures is tested in order to utilize the potential of
the method in biological research. Flexible Multibody System Dynamics
is explored studying the feeding mechanism in a skull of Edingerella
madagascariensis. Firstly, a static structural analysis is done using
FEA and secondly, dynamic solutions based on FMSD are obtained by
varying the number of deformation modes used in the modal reduction
analysis. The conclusion is that use of this approach is feasible and
efficient for the study of feeding mechanisms in vertebrate structures
when a dynamic response should be evaluated.

Edingerella madagascariensis (a basal capitosaurian from the Early
Triassic of Madagascar). The specimen is stored at the Museum National
d’Histoire Naturelle (MNHN) in Paris, with the labelling MSNM V2992
and was described in detail in (Maganuco, 2009), being the largest and
most well-preserved specimen recovered to date for this taxon.
Capitosaurians are Triassic temnospondyl amphibians characterized by
large, parabolic and heavy skulls as well as extensive pectoral
girdles, which have been widely studied using FEA (Fortuny et al.,
2011, 2012a, 2012b) but not using multibody approaches.