Meeting Abstract

P1.109  Saturday, Jan. 4 15:30  Interspecific variation in muscle fiber type composition and histological architecture characterizes cypriniform palatal organ HERNANDEZ, LP*; CHEN, AH; RADE, CM; COSTANTINI, K; OBERG, F; STAAB, KL; GEORGE WASHINGTON UNIVERSITY; GEORGE WASHINGTON UNIVERSITY; GEORGE WASHINGTON UNIVERSITY; GEORGE WASHINGTON UNIVERSITY; GEORGE WASHINGTON UNIVERSITY; MCDANIEL COLLEGE phernand@gwu.edu

Cypriniform fishes are characterized by a number of trophic novelties that have likely played an important role in the evolutionary success of this group. The palatal organ is a dorsal mass of exceedingly thin, complexly arranged muscle fibers within the roof of the buccopharyngeal cavity. Tied laterally to the branchial arches and caudally to the chewing pad it is coated in a taste bud-studded epithelium. In goldfish and carp this muscular pad is incredibly well innervated and produces localized protrusions that are used to trap edible items while bottom feeding. Thus far the palatal organ has only been investigated in those species with either a greatly hypertrophied vagal lobe or species with a greatly hypertrophied palatal organ. There is little comparative data on histological structure of the palatal organ across the whole of Cypriniformes. Moreover there is no data on the specific myosin isoforms that comprise the palatal organ. The general assumption has been that the function of the palatal organ is conserved across cypriniforms, and requires the careful sensory control of the vagal lobe to function properly. Few have considered the possibility that the palatal organ may have become adapted for different trophic functions during the course of cypriniform evolution. Here we present data on the histological structure and myosin identity of species within several major clades within Cypriniformes. Palatal organs from different species showed subtle but significant differences in both histological architecture and myosin profiles. Such differences suggest that the palatal organ may have become coopted for different functions during the course of cypriniform evolution.