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New sauropod limb paper
From: Ben Creisler bh480@scn.org
In case this paper has not been mentioned yet:
Bonnan, M.F. 2004. Morphometric analysis of humerus and
femur shape in Morrison sauropods: implications for
functional morphology and paleobiology. Paleobiology 30
(3): 444-470.
Morphometric analyses of sauropod limbs have the potential
to illuminate functional aspects of sauropod locomotion
and paleobiology. However, analyses of sauropod limb
dimensions typically show few discernible morphological
trends because of large size differences among the
individuals in a sample. For sauropods, combined analyses
of both limb dimension and shape may be more desirable.
Numerous humeri and femora from Apatosaurus , Diplodocus ,
and Camarasaurus provide an opportunity to explore and
compare limb morphology in contemporaneous, sympatric
sauropods. Thin-plate splines were used to analyze
landmark-based shape differences in combination with
traditional morphometrics. The aims of the analysis were
(1) to determine if humerus and femur shape were
significantly different among the genera; (2) to determine
where shape changes occurred; and (3) to infer the basic
functional implications of the shape differences using an
Extant Phylogenetic Bracket approach. Few differences were
detected among the genera using traditional morphometric
analyses, and linear regression revealed a predominantly
isometric relationship between most measurement variables
and element size. Thin-plate splines revealed significant
shape differences among the taxa. Apatosaurus > humeri and
femora were the most robust, with expanded regions for
muscle insertion and more distally placed deltopectoral
and caudofemoral landmarks. Diplodocus humeri and femora
were gracile, with more proximally located landmarks of
muscular insertion. Camarasaurus humeri were surprisingly
gracile, with a less extensive deltopectoral crest, but
had more robust femora similar to those of Apatosaurus .
Few differences distinguished juvenile from adult
specimens. These data suggest some locomotor differences
were present among the three genera.