Homatula guanheensis sp. nov. (Teleostei: Nemacheilidae), a new species of loach from Henan Province, China

Background The genus Homatula belongs to the order Cypriniformes and family Nemacheilidae. Nichols (1925) set up the genus as a subgenus of Barbatula by the type species of Nemacheilus potanini. Currently, it is recognised as a valid genus. Nineteen valid species have been already reported in the drainage of the Yellow, Yangtze, Pearl, Lancang, Red and Nujiang Rivers. H. variegata, H. longidorsalis, H. berezowskii and H. potanini are distributed in the Yangtze River drainage in China. H. laxiclathra is mainly distributed in the Weihe River, a tributary of the Yellow River. The remaining species are mainly distributed in the rivers of Yunnan Province. New information Homatula guanheensis sp. nov., a new species, is described from the Guanhe River of the HanJiang River drainage (a tributary of the Yangtze River), Xixia County, Henan Province, China. It can be distinguished from its congeners by a combination of the following characters: the vertical brown bars on the body are wider than their interspaces, numbering 19-22; predorsal body partially scaled; the lateral line complete; adipose crest on caudal peduncle not reaching forward; the position of the anal-fin origin and the intestinal form. The new species displays distinct molecular divergence in the Cytochrome oxidase I (COI) and Cytochrome b (Cyt b) genes.