The New Papers Walk Among Us

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

Hi All -

   A few that I don't think have been mentioned yet:

Fajardo, R.J., Hernandez, E., and O'Connor, P.M. 2007. Postcranial skeletal 
pneumaticity: a case study in the use of quantitative microCT to assess 
vertebral structure in birds. Journal of Anatomy 211(1):138-147. doi: 
10.1111/j.1469-7580.2007.00749.x.

ABSTRACT: Limb elements in birds have been characterized as exhibiting a 
reduction in trabecular bone, thinner cortices and decreased bending 
strength when pneumatized, yet it is unclear if these characteristics 
generalize to the axial skeleton. Thin section techniques, the traditional 
gold standard for bone structure studies, have most commonly been applied to 
the study of avian bone. This destructive technique, however, makes it 
subsequently impossible to use the same samples in experimental testing 
systems that allow researchers to correlate structure with the mechanical 
properties of the bone. Micro-computed tomography (µCT), a non-destructive 
X-ray imaging technique, can be used to assess the effect of pneumatization 
on vertebral cortical and trabecular bone through virtual extraction and 
structural quantification of each tissue type. We conducted a preliminary 
investigation of the application of µCT methods to the study of cortical and 
trabecular bone structure in a small sample of pneumatic and apneumatic 
thoracic vertebrae. The sample consisted of two similar-sized anatids, Aix 
sponsa (n = 7) and Oxyura jamaicensis (n = 5). Volumes of interest were 
created that contoured (outlined) the boundaries of the ventral cortical 
bone shell, the trabecular compartment and the whole centrum (cortical bone 
+ trabecular bone), and allowed independent structural analysis of each 
volume of interest. Results indicated that bone volume fraction of the whole 
centrum was significantly higher in the apneumatic O. jamaicensis than in 
the pneumatized A. sponsa (A. sponsa = 36%, O. jamaicensis = 48%, P < 0.05). 
In contrast, trabecular bone volume fraction was similar between the two 
species. The ventral cortical bone shell was approximately 23% thinner (P < 
0.05) in A. sponsa (0.133 mm) compared with apneumatic O. jamaicensis (0.172 
mm). This case study demonstrates that µCT is a powerful non-destructive 
imaging technique that may be applied to the three-dimensional study of 
avian bone. The preliminary results suggest that pneumatic and apneumatic 
vertebrae of comparably sized avian species differ in relative bone volume, 
with the largest difference apparent at the level of the cortex, and not 
within trabecular bone. The presence of relatively thin cortices in 
pneumatic vertebrae is consistent with previous studies contrasting 
diaphyseal cortical bone between pneumatic and apneumatic long bones. 
Methodological issues related to this and any comparative µCT study of bone 
structure are discussed.



Nudds, R.L., Dyke, G.J., and Rayner, J.M.V. 2007. Avian brachial index and 
wing kinematics: putting movement back into bones. Journal of Zoology 
272(2):218-226. doi: 10.1111/j.1469-7998.2006.00261.x.

ABSTRACT: The relationship between wing kinematics, wing morphology and the 
brachial index of birds (BI=humerus length/ulna length) was examined. BI was 
found to differ between three groups of birds, which were classified on the 
basis of similar wing kinematics. In addition, a comparative analysis of a 
large dataset, using phylogenetically independent contrasts, suggested a 
significant, albeit weak, correlation between BI and four measures of wing 
morphology (wing loading, wing area, wing length and aspect ratio). Although 
wing kinematics and wing morphology are both correlated with BI in birds, 
the dominant selective pressure upon this ratio is probably wing kinematics. 
The previously identified clade specificity of BI within Neornithes is most 
likely because birds with similar BIs fly with kinematic similarity and 
closely related birds have similar flight styles. A correlation between BI 
and wing kinematics means that it may be possible to characterize the wing 
beat of fossil birds. A more robust relationship between wing morphology and 
BI may emerge, but only after the relationship between wing kinematics and 
BI is quantified. A comparative and quantitative study of wing-bone anatomy 
and wing kinematics is a priority for future studies of avian wing-skeleton 
evolution and functional morphology.



Nudds, R.L. 2007. Wing-bone length allometry in birds. Journal of Avian 
Biology 38(4):515-519. doi: 10.1111/j.2007.0908-8857.03913.x.

ABSTRACT: A comparative analysis using both independent contrasts (CAIC) and 
a species level analysis was used to investigate the allometric scaling of 
avian wing-bone lengths. Total arm (ta=humerus+ulna+manus) scaled with 
positive allometry as body mass (M)0.37-0.39. Similarly, and in accordance 
with previous studies, wing-span (b) was positively allometric, but CAIC 
suggested a lower allometric exponent (M0.35) than found using species as 
independent data points (M0.39). Contrary to previous studies, individual 
wing-bones appear to scale with similar exponents against M and scale 
isometrically with ta. In addition to a general trend for larger birds to 
have longer wings, wing-bones and ta, their ta was a larger proportion of 
their b. A detailed study of primary feather length and elbow joint angle 
across a wide range of bird species and bird size, however, is required 
before a conclusive explanation for this increase in ta relative to b in 
larger birds can be established. Scaling equations are presented that can be 
used to predict M, ta and b from individual wing-bone lengths, which may be 
of use to palaeontologists wishing to reconstruct whole animals from single 
bones.



Senter, P. 2007. A method for distinguishing dromaeosaurid manual unguals 
from pedal 'sickle claws'. Bulletin of the Gunma Museum of Natural History 
11:1-6.

ABSTRACT: The manual unguals and pedal "sickle claws" of dromaeosaurid 
dinosaurs are easily confused. To find a method for distinguishing them. I 
compared the manual and pedal unguals of the dromaeosaurids Microraptor 
zhaoianus, Bambiraptor feinbergi, Velociraptor mongoliensis and Deinonychus 
antirrhopus. I found that the dorsal edge of a dromaeosaurid manual ungual 
arches higher than the articular facet when the latter is held vertically, 
whereas the same does not occur in a pedal "sickle claw". Also. the flexor 
tubercle of a dromaeosaurid manual ungual is much more pendant than that of 
a pedal "sickle claw". Application of these findings shows that 
disarticulated unguals of Utahraptor and Pyroraptor pertain to the foot, as 
does an ungual referred to Dromaeosaurus, whereas disarticulated unguals of 
Achillobator and Unenlagia pertain to the hand. This method is applicable 
only to Dromaeosauridae. because the unguals of other theropod taxa exhibit 
different morphologies.



Tumarkin-Deratzian, A.R. 2007. Fibrolamellar bone in wild adult Alligator 
mississippiensis. Journal of Herpetology 41(2):341-345. doi: 
10.1670/0022-1511(2007)41[341:FBIWAA]2.0.CO;2.

ABSTRACT: Histological examination of long bones from wild American 
Alligators (Alligator mississippiensis) reveals weakly defined growth zones 
and extensive fibrolamellar bone formation in both healthy and stressed 
adult individuals. The discovery of this tissue in wild adults of variable 
health status challenges three current assumptions concerning fibrolamellar 
bone in crocodylians: first, that it can only be formed in juveniles; 
second, that it occurs only in captive animals; and third, that it occurs 
only in individuals experiencing optimal physiological conditions. This 
highlights the need for further detailed study of bone microstructural 
diversity among modern crocodylians. Moreover, these results have 
potentially far-reaching implications for studies of fossil archosaurs, 
which often draw on extant crocodylian models, and for the phylogenetic 
significance of fibrolamellar bone within Archosauria as a whole.



Zelenkov, N.V. 2007. The structure and probable mechanism of evolutionary 
formation of the foot in piciform birds (Aves: Piciformes). Paleontological 
Journal 41(3):290-297. doi: 10.1134/S0031030107030082.

ABSTRACT: The foot structure of piciform and coraciiform birds is examined 
in detail. Certain similarity in foot structure between woodpeckers and 
woodhoopoes is shown and provides the basis for the model of the 
evolutionary formation of the zygodactyl foot. It is shown that African 
mousebirds and the Madagascan Leptosomus discolor are probably the closest 
relatives of piciforms. A brief review of fossil groups presumably belonging 
to the piciform stem is provided.



Candeiro, C.R.A. 2007. Paleogeographic distribution of the terrestrial 
squamate reptiles from the Cretaceous of Brazil. Bioscience Journal 
23(1):65-74.

ABSTRACT: The terrestrial squamates from Brazil are the Early Cretaceous 
Olindalacerta brasiliensis and Tijubina pontei from Ceará State; the Late 
Cretaceous Pristiguana brasiliensis from Minas Gerais State, Ophidia indet. 
and Aniloidea from São Paulo State. Squamates were widespread in western 
Gondwana and Laurasia landmasses, and iguanids and mainly snakes widely 
distributed in southern South America.



Lastly, I haven't seen this one, but it's out:

Veldmeijer, A.J., Signore, M., and Bucci, E. 2007. Predator-prey interaction
of Brazilian Cretaceous toothed pterosaurs: a case example, pp. 295-308 in:
A.M.T. Elewa, ed., Predation in organisms: a distinct phenomenon. Berlin,
Springer-Verlag.

ABSTRACT. This chapter presents an overview of evidence of predator-prey 
relationships in pterosaurs, with a focus on the Cretaceous (Santana 
Formation) pterosaurs from Chapado do Araripe, northeastern Brazil. The 
examples from the fossil record of pterosaurs as prey is scanty; the 
situation of pterosaurs as predators is not much better. However, especially 
for pterosaurs as predator, secondary evidence provides much insight in the 
life of these extinct predators. Here, we present a simple geometric model 
that proves the suggested way of predations of the toothed and crested taxa 
of the Anhangueridae.


This book 
(http://www.springer.com/west/home/geosciences?SGWID=4-10006-22-173679911-detailsPage=ppmmedia|toc) 
also has in it a chapter entitled "Predation tactics in flightless birds and 
non-avian dinosaurs," but I've been unable to determine the author or page 
numbers (though it looks like the last article in the book).  If anyone has 
access to the book, please let us know!

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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/

"Trying to estimate the divergence times
of fungal, algal or prokaryotic groups on
the basis of a partial reptilian fossil and
protein sequences from mice and humans
is like trying to decipher Demotic Egyptian with
the help of an odometer and the Oxford
English Dictionary."
              -- D. Graur & W. Martin (_Trends
                  in Genetics_ 20[2], 2004)