Meeting Abstract
The transition from swimming to walking was an important event in the evolution of tetrapods. Many extant aquatic and semi-aquatic species have been studied to understand the adaptions resulting from changes in environmental conditions. For example, epaulette sharks (Hemiscyllium ocellatum) have been noted to develop abnormal coloration and patterns during early development following exposure to elevated temperatures. Aquatic locomotion in this species has been categorized into three gaits: slow-to-medium walking, fast walking, and swimming. Here, we described kinematic differences between neonate (n=6) and juvenile (n=6) sharks hatched and reared in the laboratory. Neonates retain nutrition from an internal yolk while juveniles forage for worms, crustaceans, and small fishes. We hypothesized that changes in diet and feeding habits would affect gait performance between neonates and juveniles. Using video tracking software, we examined movement from 13 anatomical landmarks along the fins, girdles, and body mid-line. We calculated kinematic variables to identify characteristic movements and quantify coordination of the different gaits for each shark. Neonates and juveniles differed in a variety of kinematic variables. Notably, the juveniles were more coordinated in their movements. This study provides information about the impact of life history stage on aquatic locomotor performance in epaulette sharks. With a baseline understanding of regular locomotion patterns in this species, we can further investigate how environmental perturbations and climate change could alter their locomotion.
