From: Ben Creisler
bh480@scn.org
Not exactly a partridge in a pear tree, but here's a new
paper to unwrap:
Jesus Marugan-Lobon; Luis M. Chiappe; Shu'an Ji; Zhonghe
Zhou; Gao Chunling; Dongyu Hu; Qinjing Meng (2010)
Quantitative patterns of morphological variation in the
appendicular skeleton of the Early Cretaceous bird
Confuciusornis.
Journal of Systematic Palaeontology (advance online
publication)
DOI: 10.1080/14772019.2010.517786
http://www.informaworld.com/smpp/content~db=all~content=a9
31591597~frm=titlelink
Confuciusornis sanctus stands out among the remarkable
diversity of birds of the Jehol biota (Lower Cretaceous,
Liaoning Province, China). Its basal position in the
phylogenetic tree of birds, combined with the exceptional
number of well-preserved, largely complete and
articulated specimens, makes it a perfect model system
for studying the variation, development and life history
of early Mesozoic birds. A comprehensive morphometric
study (measurements of humerus, ulna, radius, femur and
tibia) previously identified two distinct size classes of
C. sanctus, while demonstrating the lack of statistical
support of the association between this size dimorphism
and the characteristic pair of long tail feathers present
in some specimens. Four plausible explanations were
discussed to account for the resultant size classes: the
existence of more than one species in the sample; sexual
size dimorphism; two size classes corresponding to
attritional death assemblages; and/or a particular growth
pattern similar to that inferred for non-avian dinosaurs.
Here we present an expanded statistical analysis based on
a larger sample of C. sanctus that substantiates previous
interpretations, but also addresses the statistical
association between the presence/absence of tail feathers
and fore- and hind-limb allometry. We discuss the
implication of the resulting quantitative patterns of
morphological variation to understand better
confuciusornithid taxonomy and the life history of C.
sanctus.