Kinematics of terrestrial walking in balitorid loaches


SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY
2021 VIRTUAL ANNUAL MEETING (VAM)
January 3 – Febuary 28, 2021

Meeting Abstract


BSP-2-7  Sun Jan 3 18:00 – 18:15  Kinematics of terrestrial walking in balitorid loaches Crawford, CH*; Cerrato-Moralse, CL; Webber-Schultz, AC; Hart, PB; Randall, ZS; Chakrabarty, P; Page, LM; Suvarnaraksha, A; Flammang, BE; New Jersey Institute of Technology; Rutgers University; Rutgers University; Louisiana State University; Florida Museum of Natural History; Louisiana State University; Florida Museum of Natural History; Maejo University; New Jersey Institute of Technology chc24@njit.edu

Balitorid loaches exhibit morphological adaptations to living in fast flowing rivers and streams, including robust pectoral and pelvic girdles. These adaptations may also facilitate the terrestrial locomotion seen in the family. We collected high-speed video of walking in six balitorid species, Balitora sp., Cryptotora thamicola, Homalopteroides sp., Homalopteroides modestus, Homalopteroides smithi, and Pseudohomaloptera sexmaculata in the field, and one, Homaloptera parclitella in the laboratory. Videos were digitized using DeepLabCut (DLC), with 29 points digitized for each fish. Using the DLC output, we analyzed the duty factor, paired diagonal couplet overlap, fin rotation, body curvature, and distance (in body lengths) traveled over time and per step cycle. Walking performance varies among the balitorids analyzed here. The range of fin rotation for all species was greater in the pelvic fins than pectoral fins (p<0.0001 for each species). Cryptotora thamicola had significantly greater fin rotations than all other species in the pectoral fins while the greatest pelvic fin rotation was seen in C. thamicola and Homalopteroides sp. Duty factor was greatest in C. thamicola and all four species in the Balitorinae subfamily had a higher duty factor than the three Homalopteroidinae species. The same pattern between subfamilies was seen in the overlap between paired diagonal couplets. Cryptotora thamicola traveled the greatest body lengths per stride, although stride rate was lower than other species resulting in reduced body lengths per second. Here we examine the walking kinematics of recently collected balitorids and compare those with previous studies of terrestrial tetrapodal walking.

the Society for
Integrative &
Comparative
Biology