Meeting Abstract

P3.154  Monday, Jan. 6 15:30  What a fine spine: ontogenetic changes in the vertebral column of the mangrove rivulus (Kryptolebias marmoratus) TIETBOHL, M.D.*; PERLMAN, B.M.; ASHLEY-ROSS, M.A.; Wake Forest University tietmd11@wfu.edu

Kryptolebias marmoratus is a unique quasi-amphibious fish with the ability to move over land via controlled jumps generated by the axial musculoskeletal system. As a part of a study of the ontogeny of terrestrial jumping ability, we examined the development of the caudal vertebrae, quantifying inter-vertebral as well as ontogenetic differences. We predicted isometric scaling of the linear dimensions of the vertebral centra and neural and hemal spines with growth. We also predicted, based on previous research with adult fish of multiple species, that neural and hemal spine angles would become more acute toward the tail. Five individuals were selected for each of six age groups (1, 2, 4, 8, 12, and 16 weeks post-hatching) and cleared and stained. The most posterior twelve vertebrae anterior to the terminal (hypural) vertebra were photographed using a stereomicroscope and the following variables were digitally analyzed: vertebrae length/height, neural/hemal spine angles relative to the long axis of the centrum, neural/hemal spine lengths, number of intervertebral joints spanned by the neural/hemal spines, and area of the hypurals. Ossification of the vertebral column was completed by week 4; spines were fully ossified by week 8. As predicted, centrum height and length increased with age, and from posterior to anterior position within the column. In contrast, spine length increased in the posterior direction as well as the number of joints spanned by the neural and hemal spines, increasing to 2-3 joints toward the tail. Neural and hemal spine angles became more acute toward the tail in all age classes. We would predict the jumping ability of these fish to improve with age as vertebral elements further ossify.