Research Training Program

James Morgan
Fort Valley State University
Fort Valley, Georgia

Neal Woodman, Ph.D.
Supervising Scientist
Vertebrate Zoology - Mammals

“10 weeks of unforgettable enjoyment; a lifetime of wishing it was week 1”.

Skeletal Morphology of Mammals; Soricid Feet in Relation to Phylogeny

Shrews are small insect-eating mammals of the Family Soricidae. Variation in the bones of the forefeet of small-eared shrews has been used previously to help understand classification and relationships among species. Variations in the forefeet show different adaptations are needed for a range of environments and will help scientists better understand the natural world. Few skeletons of shrews are available for study, so digital x-rays were used to closely observe the forefeet of 101 dried skins in which the bones of the forefeet were preserved. These specimens included eight species of shrews that are assumed to represent distinct lineages. The types are C. p.parva, C. p.floridana, C. nigrescens, C. mera, C. meridensis, C. mexicana, C. goldmani, and C. goodwini. The left hand of each specimen was digitally x-rayed, the resulting image edited, and the bones measured using Photoshop computer software. This study, focused primarily on the bones of digit III (middle finger) because digit III of all specimens appeared most variable. This variation is useful in distinguishing among species and groups of species. For example, C. meridensis has a long metacarpal (middle palm bone) relative to all other taxa. The length of the distal phalanx relative (bone of the fingertip) to the length of the middle phalanx (middle finger bone) distinguished three groups of species. In four species (C. p.parva, C. mexicana, C. goldmani, C. goodwini), the distal phalanx is less than 90% the length of the middle phalanx. In C. meridensis, the distal phalanx is greater than 100% but less than 120% and in C. mexicana, C. goldmani, and C. goodwini; the distal phalanx is more than 150%.

This research was supported by a grant from the National Science Foundation Research Experiences for Undergraduates program, Award Number DBI-0243512.

Letter of gratitude