Meeting Abstract

P1.116  Wednesday, Jan. 4  Fish out of water: Evaluating the use of substrate during terrestrial excursions ALUCK, R/J*; WARD, A/B; Adelphi University; Adelphi University robertaluck@mail.adelphi.edu

Vertebrate body shapes are extremely diverse ranging from spheroidal to highly elongate. In fishes, body elongation is due primarily to changes in the axial skeleton. Most frequently, elongate fish species have more vertebrae than non-elongate relatives. Increases in vertebral number tend to occur region-specifically with most groups of elongate ray-finned fishes having an increased caudal vertebral number. When comparing habitats of elongate and non-elongate fishes, elongate species are often found in habitats with a great deal of vertical structure. Many elongate species are also known to move onto land for short excursions either to feed or to move between bodies of water. Previous studies have demonstrated that individuals may use “push-points” in their environment to generate forward momentum. In this study, we examined the use of substrate during terrestrial excursions by two elongate fish species that differed in their type of axial elongation (Polypterus senegalus and Gymnallabes typus) to determine whether relative body proportion affected how successfully a fish could locomote terrestrially. Individuals moved through an array of pegs with one of the pegs instrumented with two uniaxial strain gages to measure force of pushing. We found that contact times and pushing force differed in the two species. These results provide a greater understanding of how extreme changes in body shape may affect locomotion.