RESEARCH ARTICLE Rediscovery and redescription of the endangered Hypostomus subcarinatus Castelnau, 1855 (Siluriformes: Loricariidae) from the Rio São Francisco basin in Brazil Cla ´ udio Henrique Zawadzki ID 1 *, Iago de Souza Penido 2 , Jose ´ Carlos de Oliveira 3 , Tiago Casarim Pessali 4 1 Universidade Estadual de Maringa ´ . Departamento de Biologia. Nu ´ cleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (Nupe ´ lia), Maringa ´ , Parana ´ , Brazil, 2 Universidade Estadual de Maringa ´ . Programa de Po ´ s-Graduac ¸ ão em Biologia Comparada, Maringa ´ , Parana ´ , Brazil, 3 Universidade Federal de Juiz de Fora. Instituto de Ciências Biolo ´ gicas. Departamento de Zoologia, Rua Jose ´ Lourenc ¸o Kelmer, Juiz de Fora, Minas Gerais, Brazil, 4 Museu de Ciências Naturais da PUC Minas, Belo Horizonte, Minas Gerais, Brazil * chzawadzki@hotmail.com Abstract Hypostomus subcarinatus Castelnau, 1855 is rediscovered in the Lagoa da Pampulha, an urban lake in the Rio das Velhas basin (Rio São Francisco system) in the state of Minas Gerais, southeastern Brazil. Herein, H. subcarinatus is redescribed and diagnosed from its congeners based on characters such as blue-tan dorsal fin in live specimens, slender bicus- pid teeth, dentaries angled more than 90 degrees, moderate keels along lateral series of plates, small roundish dark spots, one plate bordering supraoccipital, by having nuptial odontodes mainly on pectoral, dorsal and caudal-fin rays, and long anal-fin unbranched ray. The rediscovery of H. subcarinatus more than 160 years after its original description was an unexpected event, because the Lagoa da Pampulha is an artificial, silted and polluted urban lake. The lake is located in downtown Belo Horizonte, the third largest urban agglomeration in Brazil with a population exceeding 5.9 million inhabitants. Introduction The loricariid Hypostomus subcarinatus was described by Castelnau [1] from a vague type locality stated as “des rivière de la province des Mines” [streams from the state of Minas Gerais]. Therefore, it was hypothetically associated with Eastern Brazilian coastal drainages and to the Rio São Francisco basin [2]. However, despite some ichthyological survey efforts in these systems [3,4], no scientific record of H. subcarinatus was undoubtedly stated for more than 160 years. This historical lack of records of H. subcarinatus lead to some hypotheses, a) an erroneous locality designation in the original description by Castelnau; b) species rarity or endemicity to specific locations; c) several ongoing populational extinction processes; or d) imprecise identifications. PLOS ONE | https://doi.org/10.1371/journal.pone.0207328 March 12, 2019 1 / 15 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Zawadzki CH, Penido IdS, de Oliveira JC, Pessali TC (2019) Rediscovery and redescription of the endangered Hypostomus subcarinatus Castelnau, 1855 (Siluriformes: Loricariidae) from the Rio São Francisco basin in Brazil. PLoS ONE 14 (3): e0207328. https://doi.org/10.1371/journal. pone.0207328 Editor: Roberto E. Reis, Pontificia Universidade Catolica do Rio Grande do Sul, BRAZIL Received: October 25, 2018 Accepted: February 19, 2019 Published: March 12, 2019 Copyright: © 2019 Zawadzki 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 Statement: All relevant data are within the manuscript and its Supporting Information files. Funding: This work was supported by Coordenac ¸ão de Aperfeic ¸oamento de Pessoal de Nı ´vel Superior granted to BsC Iago de Souza Penido. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.