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Dinosaur teeth from Junggar Basin (China), K/Pg acidic oceans, Triassic rib bones



From: Ben Creisler
bcreisler@gmail.com

A number of recent papers:

Oliver Wings, Thomas Tütken, Denver W. Fowler, Thomas Martin,
Hans-Ulrich Pfretzschner & Ge Sun (2014)
Dinosaur teeth from the Jurassic Qigu and Shishugou Formations of the
Junggar Basin (Xinjiang/China) and their paleoecologic implications.
Paläontologische Zeitschrift (advance online publication)
DOI: 10.1007/s12542-014-0227-3
http://link.springer.com/article/10.1007/s12542-014-0227-3



The Middle and early Late Jurassic Qigu and Shishugou Formations of
the southern and central Junggar Basin yielded teeth of theropods
(Theropoda indet.), sauropods (Eusauropoda indet.), and stegosaurs.
The dinosaur assemblage of the southern Junggar Basin is less diverse
and is represented by smaller forms than in the central part of the
basin. The microwear of the teeth of Eusauropoda indet. resembles that
observed in Camarasaurus and may have formed as a result of biting
through resistant woody materials. Carbon and oxygen isotope data of
the sauropod and theropod teeth indicate feeding within a C3-plant
ecosystem in a continental setting. Differences in enamel δ13C and
δ18O values between Eusauropoda indet. and the theropod teeth are
comparable to those observed in other herbivorous and carnivorous
vertebrates, and suggest at least partial preservation of original
dietary signals.



**


Sohsuke Ohno, Toshihiko Kadono, Kosuke Kurosawa,Taiga Hamura,
Tatsuhiro Sakaiya, Keisuke Shigemori, Yoichiro Hironaka, Takayoshi
Sano, Takeshi Watari, Kazuto Otani, Takafumi Matsui & Seiji Sugita
(2014)
Production of sulphate-rich vapour during the Chicxulub impact and
implications for ocean acidification.
Nature Geoscience  (advance online publication)
doi:10.1038/ngeo2095
http://www.nature.com/ngeo/journal/vaop/ncurrent/pdf/ngeo2095.pdf



The mass extinction event at the Cretaceous/Palaeogene boundary 65.5
Myr ago has been widely attributed to the Chicxulub impact, but the
mechanisms of extinction remain debated. In the oceans, near-surface
planktonic foraminifera suffered severe declines, in contrast to the
relatively high survival rates of bottom-dwelling benthic
foraminifera7. The vapour produced by an impact into Chicxulub’s
target rocks, which include sulphate-rich anhydrite, could have led to
global acid rain, which can explain the pattern of oceanic
extinctions. However, it has been suggested that most of the sulphur
in the target rocks would have been released as sulphur dioxide and
would have stayed in the stratosphere for a long time. Here we show,
from impact experiments into anhydrite at velocities exceeding 10 km
s−1, that sulphur trioxide dominates over sulphur dioxide in the
resulting vapour cloud. Our experiments suggest that the Chicxulub
impact released a huge quantity of sulphur trioxide into the
atmosphere, where it would have rapidly combined with water vapour to
form sulphuric acid aerosol particles. We also find, using a
theoretical model of aerosol coagulation following the Chicxulub
impact, that larger silicate particles ejected during the impact
efficiently scavenge sulphuric acid aerosol particles and deliver the
sulphuric acid to the surface within a few days. The rapid surface
deposition of sulphuric acid would cause severe ocean acidification
and account for preferential extinction of planktonic over benthic
foraminifera.


**

Nicole Klein & Oliver J.Sichelschmidt (2014)
Remarkable dorsal ribs with distinct uncinate processes from the early
Anisian of the Germanic Basin (Winterswijk, The Netherlands).
Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 271(3): 307-314
DOI: http://dx.doi.org/10.1127/0077-7749/2014/0391
http://www.ingentaconnect.com/content/schweiz/njbgeol/2014/00000271/00000003/art00005At

Isolated dorsal ribs of tetrapods from the Lower Muschelkalk (early
Anisian, Middle Triassic) of Winterswijk, The Netherlands, with a
distinct posteriorly located broad uncinate process are described.
Dorsal ribs with posteriorly directed uncinate processes are known
from various marine reptile groups such as the placodont Paraplacodus,
the Saurosphargidae, the enigmatic genus Eusaurosphargis, and the
eusauropterygian Bobosaurus. Their rib morphology is compared in
detail with the ribs from Winterswijk presented herein. Some of the
dorsal ribs from Winterswijk described resemble the morphology of
dorsal ribs of Eusaurosphargis, which is known from the Besano
Formation (Grenzbitumenhorizont, Anisian-Ladinian boundary, Middle
Triassic) of Northern Italy. The morphology of one of the ribs is
unique among the compared taxa. The slenderness of the rib, the
gracile and constricted rib head, the shape and extension of the
uncinate process, and its restriction to the proximal part of the rib
excludes saurosphargid or Eusaurosphargis affinities but does also not
fit to the morphology of dorsal ribs characteristic for Paraplacodus
or any other taxon known so far. Different anatomical positions can
also be excluded. Hence, this rib indicates the presence of an
additional yet unknown taxon in Winterswijk.