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Xinjiangchelys (turtle, Jurassic of China) revised + turtle magnetic navigation (free pdf)



Ben Creisler
bcreisler@gmail.com

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

Haiyan Tong, Zhiming Dong and Tao Wang (2015)
A revision of Xinjiangchelys oshanensis (YE, 1973), and new material
from the Middle Jurassic of Lufeng, Yunnan Province, China.
Bulletin de la Société Géologique de France 186(1): 43-49
doi: 10.2113/gssgfbull.186.1.43
http://bsgf.geoscienceworld.org/content/186/1/43.abstract

Xinjiangchelys oshanensis (YE, 1973) was originally described as
Plesiochelys oshanensis YE, 1973 from the Jurassic Upper Lufeng series
of Eshan, Yunnan Province, China. The species was based on a single
specimen (IVPP V4444), a damaged shell with articulated carapace and
plastron. This species was later referred to as Xinjiangchelys?
oshanensis and X. oshanensis respectively, but has never been revised
and often overlooked in the studies of Asian Mesozoic turtles. In this
paper, we provide the systematic revision of X. oshanensis (YE, 1973)
after new restoration of the specimen. Five additional shells from the
Middle Jurassic Chuanjie Formation of Lufeng, Yunnan Province, China
are referred to this species. Our study confirms the validity of the
species and its assignment to the genus Xinjiangchelys. The study of
the new material completes the shell morphology of X. oshanensis and
provides additional information about its age.


========

Daniel Hontecillas, Alexandra Houssaye, César Laplana, Paloma Sevilla,
Juan Luis Arsuaga, Alfredo Pérez-González, Enrique Baquedano &  Fabien
Knoll (2015)
Reworked marine pythonomorph (Reptilia, Squamata) remains in Late
Pleistocene cave deposits in central Spain.
Cretaceous Research 54: 188–202
doi:10.1016/j.cretres.2014.12.010

Highlights

We study new isolated vertebrae and teeth of a Late Cretaceous marine
pythonomorph found as reworked elements at the Late Pleistocene
Calvero de la Higuera karstic complex in Madrid (Spain).
We establish four morphotypes in teeth according to the position of
the carinae and the ornamentation of the crown enamel.
We establish two possible morphotypes in teeth according to the slope
of the crown apex.
The dorsal vertebrae have similar sizes and features to the
pythonomorph incertae sedis Carentonosaurus mineaui.
The absence of any other fossil reptile material suggests that the
teeth found may also belong to Carentonosaurus. If this is confirmed,
they will be the first described teeth for this taxon.

Abstract

Three sites at the Calvero de la Higuera complex (Camino Cave,
Navalmaíllo Rock Shelter, and Buena Pinta Cave), near the village of
Pinilla del Valle (Madrid, Spain), are known for their record of
Neanderthals and other Late Pleistocene mammals. Occasionally, they
also yield much more ancient reworked remains, which come from the
Upper Cretaceous dolomites and carbonatic sandstones in which these
caves and shelters are developed. These are mostly teeth of sharks and
rays and vertebrae and teeth of bony fishes, but several reptile
vertebrae and teeth have also been found. These reptile remains, which
we describe here, likely belong to the pythonomorph incertae sedis
Carentonosaurus cf. mineaui. This taxon is known from several outcrops
in the southwest of France but is rare on the Iberian Peninsula;
indeed, only a few remains possibly related to the genus have been
found (in the Cabaña Formation, Asturias, Spain). The pythonomorph
remains discussed here are the first fossils of marine reptiles from
the Madrid region. Should the assignment to Carentonosaurus be
confirmed, the teeth would provide novel data on the characteristics
of this rather poorly known taxon, and might help clarify its
phylogenetic relationship within Pythonomorpha.
===


J. Roger Brothers & Kenneth J. Lohmann (2015)
Evidence for Geomagnetic Imprinting and Magnetic Navigation in the
Natal Homing of Sea Turtles.
Current Biology (advance online publication)
DOI: http://dx.doi.org/10.1016/j.cub.2014.12.035
http://www.cell.com/current-biology/abstract/S0960-9822(14)01638-8

Free pdf:

http://www.cell.com/current-biology/pdf/S0960-9822(14)01638-8.pdf

Highlights

Sea turtle nesting density varies with slight changes in Earth’s magnetic field.
Results imply that sea turtles locate nesting beaches using geomagnetic cues.
Turtles likely imprint on the unique magnetic signature of their natal beach.
Similar mechanisms may explain natal homing in diverse long-distance migrants.

Summary

Natal homing is a pattern of behavior in which animals migrate away
from their geographic area of origin and then return to reproduce in
the same location where they began life. Although diverse
long-distance migrants accomplish natal homing, little is known about
how they do so. The enigma is epitomized by loggerhead sea turtles
(Caretta caretta), which leave their home beaches as hatchlings and
migrate across entire ocean basins before returning to nest in the
same coastal area where they originated. One hypothesis is that
turtles imprint on the unique geomagnetic signature of their natal
area and use this information to return. Because Earth’s field changes
over time, geomagnetic imprinting should cause turtles to change their
nesting locations as magnetic signatures drift slightly along
coastlines. To investigate, we analyzed a 19-year database of
loggerhead nesting sites in the largest sea turtle rookery in North
America. Here we report a strong association between the spatial
distribution of turtle nests and subtle changes in Earth’s magnetic
field. Nesting density increased significantly in coastal areas where
magnetic signatures of adjacent beach locations converged over time,
whereas nesting density decreased in places where magnetic signatures
diverged. These findings confirm central predictions of the
geomagnetic imprinting hypothesis and provide strong evidence that
such imprinting plays an important role in natal homing in sea
turtles. The results give credence to initial reports of geomagnetic
imprinting in salmon and suggest that similar mechanisms might
underlie long-distance natal homing in diverse animals.


News stories:


http://news.nationalgeographic.com/news/2015/01/150115-loggerheads-sea-turtles-navigation-magnetic-field-science/

http://www.cbsnews.com/news/how-sea-turtles-find-their-way-home-from-thousands-of-miles-away/