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New Cretaceous bird and other papers
From: Ben Creisler bh480@scn.org
New Cretaceous bird and other papers
Here are the citations and abstracts for some new papers
(one not so new but maybe of interest).
Varricchio, David J. 2002. A new bird from the Upper
Cretaceous Two Medicine Formation of Montana.
Canadian Journal of Earth Sciences 39(1): 19-26
Abstract: A partial humerus, ulna, and radius compose the
type specimen of a new bird, Piksi barbarulna, new genus
and species, from the Late Cretaceous (Campanian) Two
Medicine Formation of western Montana. This
ornithothoracine taxon differs from all other birds in
having an enlarged dorsal epicondyle and a reduced ventral
condyle on the humerus with corresponding modifications on
the articular surface of the ulna. Among modern birds,
Piksi is most similar to galliforms, but the paucity of
unambiguous characters and its unusual morphology defy
placement within any extant "order" and strongly questions
any neornithine affinities. Instead, Piksi appears to have
a fairly basal position within Ornithothoraces. Several
morphologic features of Piksi occur in phylogenetically
diverse but morphologically similar birds, such as
galliforms, tinamous, and some columbiforms. The new bird
comes from an inland, relatively dry paleo-environment.
Atypical for a Cretaceous avian record dominated by
waterfowl, Piksi appears to represents a heavy-bodied
ground bird. Searching of inland depositional environments
may yield new and ecologically distinct avian varieties.
Haring-E , Kruckenhauser-L , Gamauf-A , Riesing-MJ &
Pinsker-W. 2001. The complete sequence of the
mitochondrial genome of Buteo buteo (Aves, Accipitridae)
indicates an early split in the phylogeny of raptors
MOLECULAR-BIOLOGY-AND-EVOLUTION. OCT 2001; 18 (10) : 1892-
1904
AB: The complete sequence of the mitochondrial (int)
genome of Buteo buteo was determined. Its gene content and
nucleotide composition are typical for avian genomes. Due
to expanded noncoding sequences, Buteo possesses the
longest mt genome sequenced so far (18,674 bp). The gene
order comprising the control region and neighboring genes
is identical to that of Falco peregrinus, suggesting that
the corresponding rearrangement occurred before the
falconid/accipitrid split. Phylogenetic analyses performed
with the nit sequence of Buteo and nine other nit genomes
suggest that for investigations at higher taxonomic levels
(e.g., avian orders), concatenated rRNA and tRNA gene
sequences are more informative than protein gene sequences
with respect to resolution and bootstrap support.
Phylogenetic analyses indicate an early split between
Accipitridae and Falconidae, which, according to molecular
dating of other avian divergence times, can be assumed to
have taken place in the late Cretaceous 65-83 MYA.
Christiansen-P. 2002. Mass allometry of the appendicular
skeleton in terrestrial mammals.
JOURNAL OF MORPHOLOGY. FEB 2002; 251 (2) : 195-209.
AB: Most analyses on allometry of long bones in
terrestrial mammals have focused on dimensional allometry,
relating external bone measurements either to each other
or to body mass. In this article, an analysis of long bone
mass to body mass in 64 different species of mammals,
spanning three orders of magnitude in body mass, is
presented. As previously reported from analyses on total
skeletal mass to body mass in terrestrial vertebrates, the
masses of most appendicular bones scale with significant
positive allometry. These include the pectoral and pelvic
girdles, humerus, radius+ulna, and forelimb. Total
hindlimb mass and the masses of individual hindlimb bones
(femur, tibia, and metatarsus) scale isometrically.
Metapodial mass correlates more poorly with body mass than
the girdles or any of the long bones. Metapodial mass
probably reflects locomotor behavior to a greater extent
than do the long bones. Long bone mass in small mammals
(<50 kg) scales with significantly greater positive
allometry than bone mass in large (>50 kg) mammals,
probably because of the proportionally shorter long bones
of large mammals as a means of preserving resistance to
bending forces at large body sizes. The positive
allometric scaling of the skeleton in terrestrial animals
has implications for the maximal size attainable, and it
is possible that the largest sauropod dinosaurs approached
this limit.