AVIS-IBIS

Birds of Indian Subcontinent

Intraspecific Variation in the Hindlimb Muscles of the Ivory-Billed Woodcreeper and the Blue Jay, with a Review of Other Species

Publication Type:Journal Article
Year of Publication:1993
Authors:RAIKOW, ROBERTJ, Bledsoe, AH, Syed, T, Glasgow, AG
Journal:The Condor
Volume:95
Issue:3
Date Published:1993
ISBN Number:00105422
Keywords:Corvidae, Cyanocitta, Cyanocitta cristata, Furnariidae, Garrulus, Garrulus glandarius, Xiphorhynchus, Xiphorhynchus flavigaster
Abstract:Systematists have long used myology in phylogenetic studies of birds, but have only recently begun to assess the extent of intraspecific variation in muscles and the potentially disruptive effect of such variation on investigations of phylogeny. We provide information on the Ivory-billed Woodcreeper (Xiphorhynchus flavigaster) and the Blue Jay (Cyanocitta cristata), and integrate these results with those of previous studies. Bilateral dissection of 19 specimens of X. flavigaster revealed seven major variants in six different muscles. Ten of the 19 specimens (52.6%) possessed variant muscles; of these, four were unilateral and seven bilateral. Overall, 1.6% of the individual muscles varied from their species-typical states. Six of the 11 variants were found in M. flexor cruris lateralis, suggesting an association with that muscle. The 26 specimens of C. cristata exhibited a different pattern. Major variations occurred in only three muscles, but for each of these a typical condition could not be ascribed because variation was extensive and polymorphic. Analysis of similar information for a total of 14 species of passerine birds indicated that variation is common enough that many individuals in a sample can be expected to possess at least one variant muscle. However, the probabilities of error in designating species-typical conditions from bilateral dissection of single specimens were low (0.00-0.06), suggesting that intraspecific variation does not significantly compromise phylogenetic analyses of myological data. Simulation experiments are needed to test this hypothesis.
URL:http://www.jstor.org/stable/1369593
Short Title:The Condor
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