A new species assigned to the genus Trichomycterus from the area of the waterfalls of Tabay stream, Paraná River basin, Misiones, Argentina, is described. Trichomycterus ytororo sp. nov. is distinguished from all other species in the genus by the presence of 31–35 dorsal procurrent caudal-fin rays and the combination of some external characters such as: coloration, number of pectoral–fin rays and pores of the laterosensory canals. The new taxon belongs to a presumably monophyletic group of species composed of T. crassicaudatus, T. igobi, and T. stawiarski based on the presence of 24 or more thickly ossified and rigid procurrent caudal-fin rays with a slender distal tip extending along the tips of at least ten neural spines.
Citation: Terán GE, Ferrer J, Benitez M, Alonso F, Aguilera G, Mirande JM (2017) Living in the waterfalls: A new species of Trichomycterus (Siluriformes: Trichomycteridae) from Tabay stream, Misiones, Argentina. PLoS ONE 12(6): e0179594. https://doi.org/10.1371/journal.pone.0179594
Editor: Zuogang Peng, SOUTHWEST UNIVERSITY, CHINA
Received: April 11, 2017; Accepted: May 29, 2017; Published: June 22, 2017
Copyright: © 2017 Terán et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper and its Supporting Information files.
Funding: This work was supported by Fondo para la Investigación Científica y Técnica (PICT–2011–0992 to JMM), http://www.agencia.mincyt.gob.ar/frontend/agencia/fondo/foncyt; Consejo Nacional de Investigaciones Científicas y Técnicas (PIP–11420110100301 to JMM), http://www.conicet.gov.ar/; and Conselho Nacional de Desenvolvimento Científico e Tecnológico (Proc. 152354/2016-6 to JF), http://cnpq.br/web/guest/pagina-inicial. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Trichomycteridae is a monophyletic group comprising seven monophyletic subfamilies (Copionodontinae, Glanapteryginae, Sarcoglanidinae, Stegophilinae, Trichogeninae, Tridentinae, and Vandelliinae) and the recognized non–monophyletic subfamily Trichomycterinae as presently conceived [1,2,3,4,5]. Among the eight genera of Trichomycterinae, Bullockia Arratia, Chang, Menu-Marque & Rojas, Eremophilus Humboldt, Hatcheria Eigenmann, and Rhizosomichthys Miles, are monotypic based on autapomorphies; Scleronema Eigenmann is a monophyletic group including three psamophyly species; Ituglanis Costa & Bockmann and Silvinichthys Arratia were proposed to allocate species previously included in Trichomycterus Valenciennes; and lastly, Trichomycterus lacks any diagnostic character being demonstrably non-monophyletic assemblage of species [2,3,4,5].
Trichomycterus is currently the largest genus within Trichomycteridae, containing over 170 valid species , which are distributed in practically all South America, Costa Rica and Panamá in Central America , and even found in an offshore island in the Pacific Ocean . Its geographical distribution ranges from lowlands of the Atlantic forest in southern Brazil, to mid-elevation streams on both sides of the Andean cordilleras, as well as the Patagonian region in Argentina . Most species inhabit fast-flowing streams . Their range of habitats is also remarkably diverse, including unusual freshwater habitats, such as sand-bottom streams, semipermanent pools, high-altitude Andean streams, and desolate creeks in Tierra del Fuego .
During recent samplings in northeastern Argentina we collected specimens of a remarkable new species of Trichomycterus from waterfalls in the Paraná River basin, which are described herein as a new species. The new taxon exhibits conspicuous characters that indicate a close relationship with T. crassicaudatus Wosiacki & de Pinna, T. igobi Wosiacki & de Pinna, and T. stawiarski (Mir