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New Mesozoic bird papers

From: Ben Creisler

In case these new papers concerning Mesozoic birds have 
not been mentioned yet:

Alyssa Bell and Luis M. Chiappe (2011)
Statistical approach for inferring ecology of Mesozoic 
Journal of Systematic Palaeontology (advance online 
DOI: 10.1080/14772019.2010.525536 

The ability to identify the ecological role an organism 
plays is fundamental to modern ecology and is an 
important goal of palaeontological studies. Morphometrics 
has the potential to be a statistically robust means of 
furthering this goal, identifying ecomorphological trends 
within a group of organisms. The dramatic morphological 
and ecological diversity of modern and fossil birds makes 
them ideal for ecomorphological studies, and the vast 
increase in known Mesozoic avian diversity opens numerous 
possibilities for applying modern ecomorphology to 
enhance our understanding of avian diversification in the 
Mesozoic. This study presents a large morphometric 
database of modern birds analysed using a multivariate 
statistical approach, in order to identify correlations 
between ecology and morphology. These relationships were 
also examined in a number of Mesozoic birds in order to 
investigate both the ecological diversification of early 
birds as a whole and the specific ecological roles 
individual taxa may have played.  

Amanda R. Falk, Larry D. Martin and Stephen T. Hasiotis 
A morphologic criterion to distinguish bird tracks.
Journal of Ornithology (advance online publication)
DOI: 10.1007/s10336-011-0645-x

Few anatomical criteria have been proposed to distinguish 
bird tracks from dinosaur tracks. The most commonly used 
criterion is the angle of divarication between toes II 
and IV, which is usually greater in birds than dinosaurs. 
The angle of divarication as related to some skeletal 
feature in modern birds may provide additional 
information about the trackmaker and its evolutionary 
relationships. A total of 186 bird tarsometatarsi (11 
orders, 21 families, 39 genera, 41 species) from 8 
morphotypes?shorebirds, wading birds, perching birds, 
zygodactyl birds, birds of prey, ground foragers, webbed-
footed birds, and syndactyl birds?were sampled to test 
the hypothesis that the morphology of the distal end of 
the tarsometatarsus is the primary influence on the angle 
of divarication of the toes. Skeletal limb anatomy was 
also studied for correlations with stride length in an 
effort to predict pivot point height in birds from their 
trackways. Analysis shows a pronounced correlation 
between a large trochlea arc angle, and a small angle of 
divarication. Distinct differences in the trochlear arc 
angle and the angle of divarication could be correlated 
to such avian morphotypes as shorebirds, waders, ground 
foragers, and perching birds. No correlations between 
limb length and stride length could be established, and 
the equations commonly used for most vertebrate trackways 
did not hold for birds, most likely due to their unique 
hindlimb anatomy.