WARD, A.B.; University of Massachusetts Amherst: Kinematics of the pectoral fins in batfishes (Ogcocephalidae) during aquatic walking

Several independent radiations of benthic fishes have modified pectoral and/or pelvic fins that allow them to walk along the bottom. Members of Lophiiformes, in particular, have highly modified pectoral (and, to a lesser extent, pelvic) musculoskeletal systems. Previous work indicates that Antennarius employs its pectoral and pelvic fins in a diagonal sequence gait during aquatic walking. However, little work has focused on other benthic walking families of Lophiiformes including Ogcocephalidae, the walking batfishes. Within the walking batfishes are two groups defined by presence or absence of an �elbow�. The �elbow� is considered the joint between the radials and the fin rays. Whereas in most teleost fish the only parts of the pectoral fin that can be seen are the fin rays, in the �elbowed� batfish, the portion of the fin that contains the proximal radials can also be seen externally. Therefore the proximal radials are not contained within the body wall in �elbowed� batfish. This study sought to describe and compare the walking behavior of two genera within Ogcocephalidae which differ in presence or absence of an �elbow�: Ogcocephalus and Halieutichthys . Results indicate a wider variety of gait types including a bound-like gait that has not been described in Antennarius . This kinematic study will provide an initial understanding of aquatic walking in batfishes as well as provide the background for a larger study of the morphology, development and function of the fins in pediculate fish. This work was funded by a Sigma Xi GIA to ABW and NSF IBN 9875245 to ELB.