New Papers of the Damned

["Jerry D. Harris" <jharris@dixie.edu>]

Just in time for Halloween (thanks, Mary!):


de Souza Carvalho, I., de Vasconcellos, F.M., and Simionato Tavares, S.A. 
2007. Montealtosuchus arrudacamposi, a new peirosaurid crocodile 
(Mesoeucrocodylia) from the Late Cretaceous Adamantina Formation of Brazil. 
Zootaxa 1607:35-46.

ABSTRACT: We describe a new species of Peirosauridae (Crocodyliformes, 
Mesoeucrocodylia), Montealtosuchus arrudacamposi gen. nov. et sp. nov., from 
the Late Cretaceous (Turonian-Santonian) strata of the Bauru Basin, Brazil. 
Montealtosuchus was found at the outskirts of Monte Alto County in reddish 
sandstones of the Adamantina Formation. This specimen is exquisitely 
preserved with skull, mandible, postcranial and exoskeletal elements in 
articulation that provides critical information of the anatomy of this 
group. The occurrence of Peirosauridae in the Adamantina Formation 
(Turonian-Santonian) widens the chronostratigraphic range of this 
Mesoeucrocodylia taxon in Brazil. Recent analysis suggests that the 
Peirosauridae is restricted to the Late Cretaceous deposits of South 
America.



Butler, R.J., Upchurch, P., and Norman, D.B. 2007. The phylogeny of the 
ornithischian dinosaurs. Journal of Systematic Palaeontology. doi: 
10.1017/S1477201907002271.

ABSTRACT: Ornithischia is a familiar and diverse clade of dinosaurs whose 
global phylogeny has remained largely unaltered since early cladistic 
analyses in the mid 1980s. Current understanding of ornithischian evolution 
is hampered by a paucity of explicitly numerical phylogenetic analyses that 
consider the entire clade. As a result, it is difficult to assess the 
robustness of current phylogenetic hypotheses for Ornithischia and the 
effect that the addition of new taxa or characters is likely to have on the 
overall topology of the clade.
The new phylogenetic analysis presented here incorporates a range of new 
basal taxa and characters in an attempt to rigorously test global 
ornithischian phylogeny. Parsimony analysis is carried out with 46 taxa and 
221 characters. Although the strict component consensus tree shows poor 
resolution in a number of areas, application of reduced consensus methods 
provides a well-resolved picture of ornithischian interrelationships. 
Surprisingly, Heterodontosauridae is placed as the most basal group of all 
well-known ornithischians, phylogenetically distant from a stem-defined 
Ornithopoda, creating a topology that is more congruent with the known 
ornithischian stratigraphical record. There is no evidence for a 
monophyletic 'Fabrosauridae', and Lesothosaurus (the best-known 'fabrosaur') 
occupies an unusual position as the most basal member of Thyreophora. Other 
relationships within Thyreophora remain largely stable. The primitive 
thyreophoran Scelidosaurus is the sister taxon of Eurypoda (stegosaurs and 
ankylosaurs), rather than a basal ankylosaur as implied by some previous 
studies.
The taxonomic content of Ornithopoda differs significantly from previous 
analyses and basal relationships within the clade are weakly supported, 
requiring further investigation. 'Hypsilophodontidae' is paraphyletic, with 
some taxa (Agilisaurus, Hexinlusaurus, Othnielia) placed outside of 
Ornithopoda as non-cerapodans. Ceratopsia and Pachycephalosauria are 
monophyletic and are united as Marginocephalia; however, the stability of 
these clades is reduced by a number of poorly preserved basal taxa.
This analysis reaffirms much of the currently accepted ornithischian 
topology. Nevertheless, instability in the position and content of several 
clades (notably Heterodontosauridae and Ornithopoda) indicates that 
considerable future work on ornithischian phylogeny is required and causes 
problems for several current phylogenetic definitions.



Snively, E., and Russell, A.P. 2007. Craniocervical feeding dynamics of 
Tyrannosaurus rex. Paleobiology 33(4):610-638. doi: 10.1666/06059.1.

ABSTRACT: Tyrannosaurus rex and other tyrannosaurid theropods exerted high 
bite forces, and large muscle attachments suggest that the tyrannosaurid 
neck was a concomitantly powerful component of the feeding apparatus. We 
examine accelerative and work-generating capacity (WGC) of neck muscles in 
adult Tyrannosaurus rex, using a 3-D vector-based method that incorporates 
aspects of muscle force generation, reconstruction of muscle morphology and 
moment arms, and rotational inertias of the head and neck. Under 
conservative assumptions, radial accelerations of the head by large 
superficial muscles (M. transversospinalis capitis, M. complexus, and M. 
longissimus capitis superficialis) enabled rapid gaze shifts and imparted 
high tangential velocities to food sufficient for inertial feeding. High WGC 
by these and deeper muscles under eccentric contraction indicate high 
efficacy for tearing flesh, especially with the head and neck in an extended 
posture. Sensitivity analyses suggest that assigned density of the 
antorbital region has substantial effects on calculated rotational inertia, 
and hence on the accuracy of results. However, even with high latitude for 
estimation errors, the results indicate that adult T. rex could strike 
rapidly at prey and engage in complexly modulated inertial feeding, as seen 
in extant archosaurs.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jerry D. Harris
Director of Paleontology
Dixie State College
Science Building
225 South 700 East
St. George, UT  84770   USA
Phone: (435) 652-7758
Fax: (435) 656-4022
E-mail: jharris@dixie.edu
and     dinogami@gmail.com
http://cactus.dixie.edu/jharris/

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