Meeting Abstract

P2.169  Tuesday, Jan. 5  Pectoral and pelvic fin coupling during augmented punting in the freshwater stingray, Potamotrygon laticeps MACESIC, L.J.*; BLEVINS, E.; Florida Atlantic University; Harvard University lmacesic@fau.edu

Punting, a form of aquatic locomotion performed by stingrays and hippos alike, involves depressing paired limbs into the substrate, then pushing off and gliding until the next limb depression cycle. In batoids (skates and rays), punting is performed either entirely with the pelvic fins, termed true punting, or in concert with the pectoral fins, termed augmented punting. The freshwater stingray, Potomotrygon laticeps, performs the latter, pairing pectoral fin undulation, a common swimming locomotion, with pelvic punts. We used high-speed video to quantify the motor patterns of the pectoral and pelvic fins during this locomotion to test whether the fins acted synchronously to generate a uniform thrust vector. We filmed ventrally to quantify pelvic fin punting cycles and laterally to quantify the maximum and minimum amplitude of each pectoral undulation (i.e. crest and trough of each wave). We found that the start and end of each pelvic cycle coupled with both the maximum and minimum amplitude of a single pectoral undulation within individuals (n=4; p<0.05, p<0.01, respectively). Moreover, the minimum amplitude, likely the thrust generating portion of the wave, coincided with the end of the pelvic fin thrust for all rays (p<0.01). This may be an efficient thrust generator, as pectoral undulation could add to the thrust generated by the pelvic fins. There was no consistency of timing in maximum pectoral fin amplitude among the rays (p=0.64). Pectoral fin undulation frequency during punting (mean=2.25Hz±0.56SD) was similar to previously published values during swimming for the blue-spot stingray (mean=2.32Hz±0.42SD), which suggests that the pectoral fin motor pattern may be fixed regardless of the type of locomotion being performed.