Meeting Abstract

P3.82  Saturday, Jan. 5  A comparative study of osmoregulatory physiology in freshwater and estuarine watersnakes BABONIS, L.S.*; CAMPBELL, C.C.; LILLYWHITE, H.B.; Univ. of Florida, Gainesville; Univ. of Florida, Gainesville; Univ. of Florida, Gainesville babonis@ufl.edu

In contrast with the marine sea snakes, watersnakes in the genus Nerodia are not known to have functional salt glands. Despite this presumed physiological difference, at least two species of watersnake are known to utilize marine/estuarine habitats; the remaining members of this genus occupy freshwater habitats. Little is known about the osmoregulatory physiology of estuarine watersnakes especially as it relates to habitat use. Using histology and immunohistochemistry, we examined the cellular and biochemical anatomy of the cephalic region of two species of watersnake: Nerodia fasciata (freshwater) and N. clarkii (estuarine). Additionally, we compared rates of water loss of N. fasciata and N. clarkii during acclimation to each of the following salinities: 0, 50, and 100% seawater. Through these comparative studies of osmoregulation in freshwater and estuarine snakes we examine the possibility for physiological divergence consistent with habitat divergence. This study demonstrates the necessity for further investigations into the physiological limitations of habitat use in marine and estuarine species.