title: Mechanosensation in an adipose fin.
abstract: Adipose fins are found on approximately 20% of ray-finned fish species. The apparently rudimentary anatomy of adipose fins inspired a longstanding hypothesis that these fins are vestigial and lack function. However, adipose fins have evolved repeatedly within Teleostei, suggesting adaptive function. Recently, adipose fins were proposed to function as mechanosensors, detecting fluid flow anterior to the caudal fin. Here we test the hypothesis that adipose fins are mechanosensitive in the catfish Corydoras aeneus. Neural activity, recorded from nerves that innervate the fin, was shown to encode information on both movement and position of the fin membrane, including the magnitude of fin membrane displacement. Thus, the adipose fin of C. aeneus is mechanosensitive and has the capacity to function as a 'precaudal flow sensor'. These data force re-evaluation of adipose fin clipping, a common strategy for tagging fishes, and inform hypotheses of how function evolves in novel vertebrate appendages.
authors.affiliation: Department of Organismal Biology and Anatomy, The University of Chicago, 1027 E. 57th Street, Chicago, IL 60637, USA braiello@uchicago.edu.
authors.forename: Brett R
authors.identifier: http://orcid.org/0000-0001-9034-0460
authors.initials: BR
authors.lastname: Aiello
authors.affiliation: Department of Organismal Biology and Anatomy, The University of Chicago, 1027 E. 57th Street, Chicago, IL 60637, USA tom.stewart@yale.edu.
authors.forename: Thomas A
authors.identifier: http://orcid.org/0000-0002-7965-5901
authors.initials: TA
authors.lastname: Stewart
authors.affiliation: Department of Organismal Biology and Anatomy, The University of Chicago, 1027 E. 57th Street, Chicago, IL 60637, USA.
authors.forename: Melina E
authors.identifier: http://orcid.org/0000-0001-5194-1220
authors.initials: ME
authors.lastname: Hale
mesh_terms: D050154:Adiposity; D058500:Animal Fins / Q000166:cytology / Q000502:physiology; D000818:Animals; D005075:Biological Evolution; D002397:Catfishes / Q000502:physiology*; D008465:Mechanoreceptors
keywords: Siluriformes; appendage; fishes; flow sensing; neurophysiology