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Llallawavis, new terror bird from Argentina + Biarmosuchian from Zambia + more non-dino stuff



Ben Creisler
bcreisler@gmail.com


A number of recent and not so recent non-dino papers that may be of interest:


Llallawavis, new terror bird from Miocene of Argentina (free pdf)

Already posted on the DML a few weeks back:

http://dml.cmnh.org/2015Mar/msg00102.html


The new issue of Journal of Vertebrate Paleontology is now out and the
pdf is free:


http://www.tandfonline.com/doi/full/10.1080/02724634.2014.912656#abstract

News story:

http://phys.org/news/2015-04-exceptionally-fossil-voice-ancient-terror.html

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In open access (free pdf);


Christian A. Sidor (2015)
The first biarmosuchian from the upper Madumabisa Mudstone Formation
(Luangwa Basin) of Zambia.
Palaeontologia Africana 49: 1-7
URI: http://hdl.handle.net/10539/17373
http://wiredspace.wits.ac.za/handle/10539/17373


This contribution reports the first occurrence of a biarmosuchian
therapsid from the upper Madumabisa Mudstone Formation of the  Luangwa
Basin of northeastern Zambia. Although incomplete, the fossil
preserves diagnostic features of post-Biarmosuchus  biarmosuchians,
such as the presence of a preparietal bone and parasagittal ridges on
the basicranial rami of the pterygoids, that allow  its unambiguous
referral to this group. Based primarily on the record of dicynodonts,
the upper Madumabisa Mudstone assemblage  can be correlated with the
Cistecephalus Assemblage Zone of South Africa. During this interval,
the tetrapod faunas of the Karoo and  Luangwa basins were remarkably
similar and likely characterized by frequent biotic interchange.


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Not yet mentioned:

Lariosaurus from Germany (free pdf)


Cajus G. Diedrich (2014)
Marine Lariosaurus (Sauropterygia) records from the Middle Triassic of
the Germanic Basin: stratigraphic and paleobiogeographic importance
for Tethyan and Germanic Basin correlation.
Albertiana 42: 22–32
http://paleo.cortland.edu/Albertiana/issues/42/Diedrich_2014_Alb42.pdf


The stratigraphically oldest Lariosaurus skeleton in Europe is of L.
teutonicus (Diedrich, 1996) from the shallow marine lagoon deposits of
the Lower Muschelkalk (Bithynian) of Borgholzhausen (NW Germany) in
the Germanic Basin, possibly being synonymous with the (?)Pelsonian
Chinese L. xingyiensis (Rieppel et al., 2003). Younger remains of L.
buzzii Tschanz, 1989 were collected as isolated skulls and postcrania
in the German Upper Muschelkalk (Illyrian/Fassanian) sites Bad Sulza
and Bayreuth, mainly in the oolithic or shallow marine facies.
Lariosaurus buzzii is also recorded in a few younger
(Fassanian/Longobardian boundary) northern Tethys black-shale-lagoon
deposits of the Swiss/Italian locality Monte San Giorgio by complete
skeletons. The species L. balsami Curioni, 1841 seems to represent the
stratigraphically youngest records in the late Longobardian of the
northwestern Tethys (Austria, Italy, Switzerland). Lariosaurus is
known from a complete Middle Triassic European record with possibly
only three valid species and was distributed along the Pangaean coasts
between Europe and Asia in lagoon and shallow marine
paleoenvironments, where they probably smaller hunted fish and
juvenile pachypleurosaurs.


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Recent Triassic References (free pdf)


Geoffrey Warrington (2014)
New Triassic literature.
Albertiana 42: 56–85
http://paleo.cortland.edu/Albertiana/issues/42/Warrington_2014_Alb42.pdf

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Permian extinction papers

M. O. Clarkson, S. A. Kasemann, R. A. Wood, T. M. Lenton, S. J.
Daines, S. Richoz, F. Ohnemueller, A. Meixner, S. W. Poulton & E. T.
Tipper (2015)
Ocean acidification and the Permo-Triassic mass extinction.
Science 348 (6231): 229-232
DOI: 10.1126/science.aaa0193
http://www.sciencemag.org/content/348/6231/229.abstract


Ocean acidification triggered by Siberian Trap volcanism was a
possible kill mechanism for the Permo-Triassic Boundary mass
extinction, but direct evidence for an acidification event is lacking.
We present a high-resolution seawater pH record across this interval,
using boron isotope data combined with a quantitative modeling
approach. In the latest Permian, increased ocean alkalinity primed the
Earth system with a low level of atmospheric CO2 and a high ocean
buffering capacity. The first phase of extinction was coincident with
a slow injection of carbon into the atmosphere, and ocean pH remained
stable. During the second extinction pulse, however, a rapid and large
injection of carbon caused an abrupt acidification event that drove
the preferential loss of heavily calcified marine biota.


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R. Hofmann, L.A. Buatois, R.B. MacNaughton & M.G. Mángano (2015)
Loss of the sedimentary mixed layer as a result of the end-Permian extinction.
Palaeogeography, Palaeoclimatology, Palaeoecology 428: 1–11
doi:10.1016/j.palaeo.2015.03.036
http://www.sciencedirect.com/science/article/pii/S0031018215001674

Highlights
the sedimentary mixed layer was absent after the end-Permian mass extinction
mixed layer demise was a result of extinct infauna and not
environmental exclusion
reduced mixing could may have caused anoxic signatures in sediments
reduced mixing could be reflected in geochemical cycling of Carbon and Sulphur
reduced mixing as outcome of the extinction was a strong control on the recovery

Abstract

The end-Permian mass extinction resulted in the most dramatic
degradation of marine bottom communities during the Phanerozoic. One
result of this extinction was the long-recognized, extreme reduction
in bioturbation of the Early Triassic seafloor. Several lines of
evidence (i.e., preferential preservation of epifaunal and very
shallow-tier infaunal trace fossils; paucity of mid- and deep-tier
trace fossils; absence of mottled bioturbation textures; dominance of
cohesive substrates; widespread occurrence of microbially induced
sedimentary structures in open-marine environments; ecological
composition of Early Triassic communities) show that the reduction in
bioturbation was so extreme that the sedimentary mixed layer was
eradicated at an interregional scale for the only time since it was
established in the early Palaeozoic. The consequences of this for
ecosystem function and geochemical cycling must have been profound and
yet they have received little consideration. Biogenic mixing of
sediments is fundamental to geochemical cycling in extant marine
ecosystems, and it also governs ecologically limiting factors such as
nutrient fluxes, benthic primary production, and availability of
ecospace. The collapse of biogenic sediment mixing during the Early
Triassic must have affected geochemical properties of sediments and
the seawater, as reflected in the geologic record of the sulphur
cycle. Additionally, many of the proxies traditionally used to infer
Early Triassic seawater anoxia may rather reflect poor sediment
oxygenation arising from the extinction of bioturbators. Because of
its impact on seawater and sediment chemistry, the loss of the mixed
layer may have been an important, but hitherto little-considered
constraint on the recovery from the end-Permian mass extinction.

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Giant salamander bite mechanics

Josep Fortuny , Jordi Marcé-Nogué, Egon Heiss, Montserrat Sanchez,
Lluis Gil & Àngel Galobart (2015)
3D Bite Modeling and Feeding Mechanics of the Largest Living
Amphibian, the Chinese Giant Salamander Andrias davidianus
(Amphibia:Urodela).
PLoS ONE 10(4): e0121885.
doi:10.1371/journal.pone.0121885
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0121885

Biting is an integral feature of the feeding mechanism for aquatic and
terrestrial salamanders to capture, fix or immobilize elusive or
struggling prey. However, little information is available on how it
works and the functional implications of this biting system in
amphibians although such approaches might be essential to understand
feeding systems performed by early tetrapods. Herein, the skull
biomechanics of the Chinese giant salamander, Andrias davidianus is
investigated using 3D finite element analysis. The results reveal that
the prey contact position is crucial for the structural performance of
the skull, which is probably related to the lack of a bony bridge
between the posterior end of the maxilla and the anterior
quadrato-squamosal region. Giant salamanders perform asymmetrical
strikes. These strikes are unusual and specialized behavior but might
indeed be beneficial in such sit-and-wait or ambush-predators to
capture laterally approaching prey. However, once captured by an
asymmetrical strike, large, elusive and struggling prey have to be
brought to the anterior jaw region to be subdued by a strong bite.
Given their basal position within extant salamanders and their
“conservative” morphology, cryptobranchids may be useful models to
reconstruct the feeding ecology and biomechanics of different members
of early tetrapods and amphibians, with similar osteological and
myological constraints.

**


http://www.redorbit.com/news/science/1113368242/world%E2%80%99s-largest-amphibian-feeds-on-prey-approaching-from-the-side-040915/
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