Hisonotus devidei, a new species from the SAo Francisco basin, Brazil (Siluriformes: Loricariidae)

Abstract

A recent expedition to headwaters of the Rio Pandeiros, a left-bank tributary of the Rio SAo Francisco revealed the presence of a fourth species of Hisonotus from that basin. Hisonotus devidei sp. nov. differs from congeners by the presence of conspicuous dark blotches of distinct shapes irregularly arranged along lateral and dorsal surfaces of the body and scattered throughout all fins, by possessing small plates in lateral portions of the abdomen and adjacent areas between pelvic fins without development of dermal plates and by morphometric ratios. The putative phylogenetic placement of the new species is discussed based on morphological comparisons with species of related Hypoptopomatinae genera and the Hisonotus species diversity within the Rio SAo Francisco Basin is compared with that of adjacent basins.