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Trapalcochelys, new turtle from Cretaceous of Argentina, and other non-dino papers



From: Ben Creisler
bcreisler@gmail.com


A number of new and recent non-dino papers that may be interest:

Juliana Sterli, Marcelo S. de la Fuente & Ignacio A. Cerda (2013)
A new species of meiolaniform turtle and a revision of the Late
Cretaceous Meiolaniformes of South America.
Ameghiniana 50(2): 240-256
http://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/582

A new species of meiolaniform turtle, Trapalcochelys sulcata gen. nov.
sp. nov. is described, based on material from the late Campanian–early
Maastrichtian Allen Formation, Patagonia (Argentina). The postcranial
remains recovered are described macroscopically (e.g., external
morphology) and microscopically (e.g., histological sections of the
shell). Trapalcochelys sulcata gen. nov. sp. nov. shares with other
meiolaniforms the presence of sulci strongly curved anteriorly among
marginal scales, and dermal bones ornamented with small foramina. This
new species differs from the other Late Cretaceous meiolaniform from
Patagonia —Patagoniaemys gasparinae— in the general size and in the
shape of neural 1. The shell-bone histology is characterized by a
diploe structure, in which well developed internal and external
compact bone layers frame an area of cancellous bone. Compact bone is
mostly composed by interwoven structural fiber bundles. The abundance
of structural fibers in the internal cortex and the presence of large
pipe-like vascular spaces in the cancellous bone are the most
distinctive histological features observed for T. sulcata. All
meiolaniform turtle remains of the Upper Cretaceous of South America
are exhaustively revised. The known South American record of Upper
Cretaceous meiolaniforms is restricted to Argentina and in this
revision six localities with outcrops bearing these fossils have been
identified. Meiolaniforms are confirmed as a component of the late
Campanian–early Maastrichtian South American Allenian tetrapod
assemblage.

===

M. Jimena Trotteyn & Ricardo N. Martínez (2013)
Primer registro de displasia coxofemoral en un rincosaurio del
Triásico superior. [First record of coxofemoral dysplasia in a late
Triassic rynchosaur.]
Ameghiniana 50(2):  217-226
http://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/510

Paleopathology deals with diseases that have left evidence in the
fossil record. This field includes the identification of the
pathology, and its consequences that on the animal that suffered it.
We present the first record of a coxofemoral dysplasia in an Upper
Triassic rhynchosaur, being also the first identification of this
pathology in the fossil record. The specimen is an incomplete
skeleton, partially articulated, of Hyperodapedon sanjuanensis (Sill),
from the Ischigualasto Formation (Carnian–Norian). Rhynchosaurs were
herbivores with a widespread geographical distribution, low species
diversity and a stratigraphic range restricted to Triassic outcrops.
The abnormalities described consist of atrophy of the sacrum and
pelvis, sclerosed structures in some dorsal vertebrae, and deformation
of the left femur. These features are presently characteristic of
acetabular dysplasia in dogs. Acetabular dysplasia is a multifactorial
disease appearing in the earliest stages of development and increasing
throughout life, triggering a secondary joint osteoarthritis in the
adult animal and leading to total disability of the affected limb. The
advanced stage of the disease affecting the studied specimen reveals a
pace known as “fourth grade claudication”, stage in which the affected
limb stops supporting the body-weight, moving the center of gravity
and loading the body-weight onto the other legs. Finally, the adult
stage reached by the specimen —despite the severity of their
condition— may suggest complex survival strategies in Hyperodapedon
sanjuanensis, which need confirmation by future analyses.

==

This item from April somehow got overlooked. I thought I sent a
posting, but here it is now in any case:

Yanhong Pan, Jingeng Sha, Zhonghe Zhou & Franz T. Fürsich (2013)
The Jehol Biota: Definition and distribution of exceptionally
preserved relicts of a continental Early Cretaceous ecosystem.
Cretaceous Research (advance online publication)
doi: http://dx.doi.org/10.1016/j.cretres.2013.03.007
http://www.sciencedirect.com/science/article/pii/S0195667113000566

Fossils from the “Jehol Biota” have been studied for nearly 90 years,
and the term “Jehol Biota” has been extensively used and is well known
today, largely thanks to the discovery of feathered dinosaurs,
angiosperms, and numerous other exceptionally preserved fossils in the
Lower Cretaceous of northeastern China. Ironically, however, what
exactly the Jehol Biota represents and how it is defined has hardly
been discussed. The lack of a precise definition of the Jehol Biota
has hindered our understanding of such important issues as its
palaeodiversity, its spatial and temporal distribution, and the
pattern of radiation of the biota. In this paper, we propose that the
Jehol Biota is defined by using a palaeoecological concept, and by
combining ecological and taphonomic aspects, i.e., as organisms that
lived in the Early Cretaceous volcanic-influenced environments of
northeastern China, and were buried in lacustrine and rarely fluvial
sediments, where most turned into exceptionally preserved fossils. The
relationship between the Jehol Biota and the Jehol Group is also
clarified. According to the revised definition, the Jehol Biota is so
far only discovered in deposits of the Yixian and Jiufotang formations
of western Liaoning, adjacent Inner Mongolia, and northern Hebei, and
the Huajiying Formation of northern Hebei. Temporally it ranges from
the Barremian to Aptian, i.e., for at least 10 Ma (130–120 Ma).


==
Non-Mesozoic but may be of interest:

Xijun Ni, Daniel L. Gebo, Marian Dagosto, Jin Meng, Paul Tafforeau,
John J. Flynn & K. Christopher Beard (2013)
The oldest known primate skeleton and early haplorhine evolution.
Nature 498: 60–64 (06 June 2013)
doi:10.1038/nature12200
http://www.nature.com/nature/journal/v498/n7452/full/nature12200.html

Reconstructing the earliest phases of primate evolution has been
impeded by gaps in the fossil record, so that disagreements persist
regarding the palaeobiology and phylogenetic relationships of the
earliest primates. Here we report the discovery of a nearly complete
and partly articulated skeleton of a primitive haplorhine primate from
the early Eocene of China, about 55 million years ago, the oldest
fossil primate of this quality ever recovered. Coupled with detailed
morphological examination using propagation phase contrast X-ray
synchrotron microtomography, our phylogenetic analysis based on total
available evidence indicates that this fossil is the most basal known
member of the tarsiiform clade. In addition to providing further
support for an early dichotomy between the strepsirrhine and
haplorhine clades, this new primate further constrains the age of
divergence between tarsiiforms and anthropoids. It also strengthens
the hypothesis that the earliest primates were probably diurnal,
arboreal and primarily insectivorous mammals the size of modern pygmy
mouse lemurs.