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Contact Information last updated July 1, 2004 |
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My research employs appendicular osteology and myology of vertebrates in studies of convergent evolution, of morphological adaptations related to locomotion, and of avian systematics. Most recently I have initiated what I hope to be a series of anatomical studies of facial musculature of octodontid rodents. I am presently also involved in a long-term project elucidating the phylogenetic relationships among birds of the order Psittaciformes (parrots). Each species is characterized by features of its hind limb musculature. Birds that share unusual characters are believed to have inherited them from a common ancestor, and therefore to be more closely related to one another than to other birds of this group. A comprehensive study of parrot systematics using modern approaches has never been undertaken, hence this is a very exciting and important project. Some of the students doing research in my lab have helped fill in "pieces of the puzzle" by dissecting the hind limbs of one or two species. Along with this, I have recently initiated an investigation of intraspecific variation in anatomical features of birds, specifically in their hind limb musculature. We know from experience in any anatomical teaching lab that it is not uncommon to find specimens that differ in some way from the condition described for that species. For example, almost every year in chordate morphology one or two students in the group of 20 will find that their cats have a double vena cava in the abdominal cavity. In "normal" cats this is a single vessel. There is good reason to suspect that such anomalies are present in other parts of the anatomy of other species. Human anatomy abounds with examples. This can cause serious problems for morphologists who are characterizing a species on the basis of anatomical features. Most preserved specimens of exotic animals are obtained from museum collections, and large sample sizes are seldom available. In addition, dissections are usually so time-consuming that a consideration of even five or ten individuals per species is impractical. Hence there is a danger of using an anomalous specimen to characterize a species and arriving at an erroneous phylogeny. The error might not be corrected for decades. The question we are asking is just how much variation can we expect in the hind limb musculature of one species? My students and I undertook the first step toward an answer by dissecting a series of 58 House Sparrows (readily available from supply houses). In the last few years six students have carried out the same dissection on a total of 49 specimens of Flickers.
Berman, Susan L. 2003. A desert octodontid rodent, Tympanoctomys barrerae, uses modified hairs for stripping epidermal tissue from leaves of halophytic plants. J. Morph. 257:53-61. Berman, S., Addesa, J., Hannigan, R., Restivo, V., and Rodrigues, J. 1998. Intraspecific variation in the hind limb musculature of the Northern Flicker. The Condor 100:574-579. Berman, S., Cibischino, M., Dellaripa, P., and Montren, L. 1990. Intraspecific variation of the hind limb musculature of the house sparrow. The Condor 92:199-204. Berman, S. 1985. Convergent evolution in the hind limb of bipedal rodents. Zeitschrift fuer Zoologische Systematik und Evolutionsforsschung 23:59-77. Berman, S. 1984. The hind limb musculature of the White-fronted Amazon (Amazona albifrons, Psittaciformes). The Auk 101:74-92. Berman, S., and R.J. Raikow. 1982. The hind limb musculature of the mousebird (Coliiformes). The Auk 99:41-57.
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