Rediscovery and redescription of the endangered Hypostomus subcarinatus Castelnau, 1855 (Siluriformes: Loricariidae) from the Rio São Francisco basin in Brazil

Hypostomus subcarinatus Castelnau, 1855 is rediscovered in the Lagoa da Pampulha, an urban lake in the Rio das Velhas basin (Rio Sao 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 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 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.