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New papers with free pdfs



From: Ben Creisler
bh480@scn.org

A few new articles that might be of interest to DML members. The pdfs are
free.


Sauropod diversity
Roger B. J. Benson and Philip D. Mannion (2011)
Multi-variate models are essential for understanding vertebrate
diversification in deep time.
Biology Letters (advance online publication)
doi: 10.1098/rsbl.2011.0460 
free pdf at:
http://rsbl.royalsocietypublishing.org/content/early/2011/06/16/rsbl.2011.04
60.abstract

Statistical models are helping palaeontologists to elucidate the history of
biodiversity. Sampling standardization has been extensively applied to
remedy the effects of uneven sampling in large datasets of fossil
invertebrates. However, many vertebrate datasets are smaller, and the issue
of uneven sampling has commonly been ignored, or approached using pairwise
comparisons with a numerical proxy for sampling effort. Although most
authors find a strong correlation between palaeodiversity and sampling
proxies, weak correlation is recorded in some datasets. This has led
several authors to conclude that uneven sampling does not influence our
view of vertebrate macroevolution. We demonstrate that multi-variate
regression models incorporating a model of underlying biological
diversification, as well as a sampling proxy, fit observed sauropodomorph
dinosaur palaeodiversity best. This bivariate model is a better fit than
separate univariate models, and illustrates that observed palaeodiversity
is a composite pattern, representing a biological signal overprinted by
variation in sampling effort. Multi-variate models and other approaches
that consider sampling as an essential component of palaeodiversity are
central to gaining a more complete understanding of deep time vertebrate
diversification. 


Jacqueline M. T. Nguyen, Martyna Molak, Karen H. Black, Erich M. G.
Fitzgerald, Kenny J. Travouillon, and Simon Y. W. Ho (2011)
Vertebrate palaeontology of Australasia into the twenty-first century
Biology Letters (advance online publication)
doi:10.1098/rsbl.2011.0549
free pdf at:
http://rsbl.royalsocietypublishing.org/content/early/2011/06/16/rsbl.2011.05
49.abstract

The 13th Conference on Australasian Vertebrate Evolution Palaeontology and
Systematics (CAVEPS) took place in Perth, Western Australia, from 27 to 30
April 2011. This biennial meeting was jointly hosted by Curtin University,
the Western Australian Museum, Murdoch University and the University of
Western Australia. Researchers from diverse disciplines addressed many
aspects of vertebrate evolution, including functional morphology,
phylogeny, ecology and extinctions. New additions to the fossil record were
reported, especially from hitherto under-represented ages and clades. Yet,
application of new techniques in palaeobiological analyses dominated, such
as dental microwear and geochronology, and technological advances,
including computed tomography and ancient biomolecules. This signals a
shift towards increased emphasis in interpreting broader evolutionary
patterns and processes. Nonetheless, further field exploration for new
fossils and systematic descriptions will continue to shape our
understanding of vertebrate evolution in this little-studied, but most
unusual, part of the globe. 


Synapsid papers in Geodiversitas

New Permian synapsid taxa Ruthenosaurus and Euromycter from France:

Robert R. REISZ,Hillary C. MADDIN,Jörg FRÖBISCH, & Jocelyn FALCONNET (2011)
A new large caseid (Synapsida, Caseasauria) from the Permian of Rodez
(France), including a reappraisal of "Casea" rutena Sigogneau-Russell &
Russell, 1974. 
Geodiversitas 33(2): 227-246
DOI: 10.5252/g2011n2a2.
free pdf at:
http://www.mnhn.fr/museum/front/medias/publication/36313_g2011n2a2.pdf

The description of a new large caseid, Ruthenosaurus russellorum n. gen.,
n. sp. from the Early Permian (upper Cisuralian to lower Lopingian) of the
Rodez Basin, France, is based on a partial postcranial skeleton that was
initially collected at the same time as the holotype of "Casea" rutena
Sigogneau-Russell & Russell, 1974. Despite its distinctly larger size than
"C" rutena, the holotype of Ruthenosaurus n. gen. clearly represents an
immature individual, as shown most clearly by the lack of fusion of the
neural arches to their respective vertebral centra and incomplete
ossifi  cation of the ends of the limb elements, including the
absence of an ossifi  ed olecranon on the ulna. Nonetheless,
Ruthenosaurus n. gen. is diagnosed by several autapomorphic characters,
including dorsal vertebrae with anteriorly tilting neural spines and a
diamond-shaped outline in transverse section, a first sacral rib with
a dorsoventrally expanded distal head, and a low iliac blade with a poorly
developed anterior process. The new taxon is further distinguishable from
the only other known French caseid, "Casea" rutena, by the shape of the
distal part of the humerus, including an ectepicondylar notch rather than a
fully enclosed foramen, the specific shape of the ulna, and the
overall robustness of the specimen. The taxonomic status of "Casea" rutena
is discussed and it is concluded that this species should be moved into a
new genus named Euromycter n. gen. The occurrence of the large-sized
Ruthenosaurus n. gen. in France increases our knowledge about the early
diversity of this clade in Europe.


Marina Bento SOARES,Fernando ABDALA,Cristina BERTONI-MACHADO (2011)
A sectorial toothed cynodont (Therapsida) from the Triassic Santa Cruz do
Sul fauna, Santa Maria Formation, Southern Brazil. 
Geodiversitas 33 (2): 265-278. 
DOI: 10.5252/g2011n2a4.
free pdf at:
http://www.mnhn.fr/museum/front/medias/publication/36296_g2011n2a4.pdf

A sectorial toothed cynodont from the Triassic Santa Cruz do Sul fauna,
Santa Maria Formation, Parana Basin, southern Brazil, is described.The
taxon is represented by a tiny portion of a right lower jaw which preserves
partially the last postcanine. A comparative analysis of the postcanine
morphology of the Santa Cruz do Sul specimen with South American Triassic
cynodonts is made. The crown morphology of the Santa Cruz do Sul cynodont
is closer to that of the juvenile single specimen of cf. Probainognathus
from the Carnian Ischigualasto Formation and of juveniles of
Probainognathus jenseni Romer, 1970 from the Ladinian Chañares Formation in
Argentina. There are, however, some important dfferences between the tooth
of the new specimen and those of P. jenseni juveniles, and therefore we
provisionally assign the new Santa Cruz do Sul material to cf.
Probainognathus. The fauna of Santa Cruz do Sul, dominated by
traversodontid cynodonts, is now composed of a proterochampsid
archosauriform, three traversodontids and two sectorial toothed cynodonts
and we refer to it as Santacruzodon Assemblage Zone. We also propose the
name of Riograndia Assemblage Zone for the faunas from the Upper Triassic
Caturrita Formation, on the basis of the abundance yet restricted record of
this taxon in these faunas. A brief summary of the Brazilian Middle and
Upper Triassic biostratigraphy is presented within the framework of two
different time scales. 


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