Meeting Abstract

43.3  Saturday, Jan. 5  Testing the generality of the cross-couplet locomotor system in marsupials REILLY, S. M.*; WHITE, T.D.; MCELROY, E.J.; Ohio University; Buffalo State College; Ohio University reilly@ohiou.edu

Extant placental mammals differ from marsupials and many more basal mammalian groups in having �epipubic� bones projecting into the abdominal wall. Previously we showed that these bones act one at a time with each trotting step to help stiffen the body diagonally between the fore and ipsilateral hind feet on the ground. This was accomplished by an asymmetical pattern of abdominal hypaxial muscle contraction. This cross couplet abdominal locomotory system was shown in two South American marsupials, Monodelphis domestica and Didelphis virginiana. To test the generality of this pattern we studied abdominal muscle function in another South American marsupial, Philander opossum. Comparisons of these three species will be discussed and initial comparisons to preliminary studies of several Australian marsupials will be presented. Supported by NSF grant IOB 0520100.