Meeting Abstract

P1.98  Friday, Jan. 4  Divergent feeding kinematics in two Amazonian cichlids BERG, CL*; CHOW, JS; MCGEE, MD; WAINWRIGHT, PC; University of California, Davis; University of California, Davis; University of California, Davis; University of California, Davis clberg@ucdavis.edu

The Amazon Basin represents a hotspot of fish diversity and contains the largest number of freshwater species in the world. In this study, we examine the kinematics of feeding in two Amazonian cichlids with similar habitats but divergent morphology, Pterophyllum scalare and Crenicichla strigata. P. scalare have deep heads with small mouths suitable for picking prey off the underside of floating vegetation. In contrast, C. strigata have elongate heads and large mouths, and are ambush predators that typically dart out from vegetation to strike at passing prey. Using a Fastec HiSpec 1 camera system, we recorded video at 2000 frames per second of multiple P. scalare and C. strigata, capturing small fish (Danio rerio, Tanichthys albonubes) introduced individually via a feeding tube. We then digitized each video with a custom modification of the program Dltdv3 in MATLAB, tracking eleven points on the fish and prey item throughout the duration of the strike. We analyzed kinematic patterns using mixed models and generated p-values for the fixed effects of size (head length) and species using 10,000 Markov Chain Monte Carlo samples in R. With the exception of a higher maximum jaw protrusion, P. scalare displayed less cranial kinesis than C. strigata, including smaller maximum gape, head elevation, and jaw rotation. However, P. scalare possessed both shorter timings and higher velocity movements for gape, head elevation, jaw protrusion, and lower jaw rotation. Our data suggests that despite their similar habitats, these cichlids exhibit extreme kinematic divergence.