https://onlinelibrary.wiley.com/doi/abs ... /cne.25057
PDF: https://onlinelibrary.wiley.com/doi/epd ... /cne.25057
Abstract
Mochokid catfish offer a distinct opportunity to study a communication system transitioning to a new signaling channel because some produce sounds and others electric discharges. Both signals are generated using an elastic spring system (ESS), which includes a protractor muscle innervated by motoneurons within the protractor nucleus that also has a motoneuron afferent population. and S. nigriventris produce sounds and electric discharges, respectively, and their ESSs show several morphological and physiological differences. The extent to which these differences explain different signal types remains unclear. Here, we compare ESS morphologies and behavioral phenotypes among five mochokids. Synodontis grandiops and S. nigriventris were compared with S. eupterus that is known to produce both signal types, and representative members of two sister genera, Microsynodontis cf. batesii [moderator comment: ] and , for which no data were available. We provide support for the hypothesis that peripheral and central components of the ESS are conserved among mochokids. We also show that the two non‐synodontids are only sonic, consistent with sound production being an ancestral character for mochokids. Even though the three sound producing‐only species differ in some ESS characters, several are similar and likely associated with only sound production. We propose that the ability of S. eupterus to generate both electric discharges and sounds may depend on a protractor muscle intermediate in morphology between sound producing‐only and electric discharge‐only species, and two separate populations of protractor motoneurons. Our results further suggest that an electrogenic ESS in synodontids is an exaptation of a sound producing ESS.
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- Keywords: Animal vocalizations; Neural Pathways; Electric Fish; Comparative anatomy; Evolution