Rediscovery and redescription of the endangered Hypostomus subcarinatus Castelnau, 1855 (Siluriformes: Loricariidae) from the rio São Francisco basin in Brazil, with comments on the urban water conservation

Hypostomus subcarinatus Castelnau, 1855 is rediscovered in the Pampulha lake, an urban lake pertaining to the rio das Velhas basin in the rio São Francisco system in the state of Minas Gerais, southeastern Brazil. Herein, H. subcarinatus is redescribed and its diagnosis from the congeners is established due to characters such as blue tan dorsal fin in live specimens, slender bicuspid 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 longer anal-fin unbranched ray. The rediscovery of H. subcarinatus after more than 160 years after its original description was one unexpected event, because the Pampulha lake is an artificial, shallow and polluted urban lake. The lake is located in the downtown of municipality of Belo Horizonte, the third largest urban agglomeration in Brazil with a population exceeding 5.9 million inhabitants. In the light of this finding we address the importance of urban body waters to maintenance of fish biodiversity in the neotropics.