Meeting Abstract

P3.160  Sunday, Jan. 6  Functional morphology of cephalic protuberances in the oyster toadfish, Opsanus tau MARRANZINO, AN*; FRANK, MM; LINDEMANN, SD; GUIFFRIDA, BA; SIPPER, K; WEBB, JF; MENSINGER, AF; Regis Univ., Denver, CO; St. Olaf Coll., Northfield, MN; Univ. of Minnesota, Duluth; Wareham Middle School, MA; Northern Michigan Univ., Marquette; Univ. of Rhode Island, Kingston; Univ. of Minnesota, Duluth marra938@regis.edu

The oyster toadfish, Opsanus tau, is an important model organism for muscle and sensory physiology. However, the roles of two prominent anatomical features on the head of the fish remain unknown. These include multilobed protuberances, or cirri, that project primarily from the lower jaw and simpler, paired projections termed papillae that surround superficial neuromasts. Scanning electron microscopy (SEM) and light microscopy (LM) were used to investigate the morphology and potential functional significance of these structures. It has been proposed that the cirri serve a mechanosensory function, but both SEM and LM failed to reveal neuromasts. However, domed structures with apical microvilli seen with SEM, were determined to be bulbiformous organs using LM. These organs were similar to type II taste buds, suggesting a putative gustatory role for the cirri. O. tau has a reduced number of anterior canal neuromasts (which detect water acceleration). However, numerous superficial neuromasts (which serve as velocity detectors) are present, and flanked by linguiform protuberances. It has been proposed that these papillae protect the neuromasts from the loose sediment that characterizes the fish’s benthic habitat. The papillae may also channel water over the neuromasts, possibly allowing them to function as canal neuromasts. SEM revealed that hair cell orientation in these superficial neuromasts was parallel to the channel formed by the papillae, supporting this hypothesis. Supported by NSF REU 1005378 (AFM), and the Coll. Environment & Life Sciences, URI (JFW).