Labeo pierrei

Labeo: from the Latin labeo, meaning 'one with lips', in allusion to the remarkably thick, fleshy lips in members of this genus.

pierrei: in honor of “Pierre” who collected the type specimen, with no other information provided.

Known from throughout the Mekong river system in southern China, Laos, Thailand, Cambodia, and Vietnam, the Dong Nai river system in Vietnam and possibly the Chao Phraya basin in Thailand.

Type locality is 'Vietnam: Bien Hoa Province: rapids on the Dung-nai', which corresponds to the Dong Nai watershed.

Mostly inhabits main river channels and large, deep tributaries. It undergoes seasonal migrations, moving upstream into the Sekong, Sesan, and Srepok rivers in May and June, at the onset of the wet season, and returning downstream during the dry months between November and February.

This species can be distinguished by the following characters: juveniles with brown body and dark marking at base of caudal-fin; 37-42 + 3-4 lateral line scales; 11½ branched dorsal-fin rays; 7½ scale rows between lateral line and dorsal-fin origin; 20-25 predorsal scales; dorsal-fin relatively small with anterior branched rays shorter than head in juveniles, slightly longer than head in adults.

The genus Labeo is an enigmatic grouping containg more than 100 species which is critically in need of revision. Members occur throughout much of Africa and Asia, and they are considered members of the tribe Labeonini within the putative cyprinid subfamily Cyprininae or simply the subfamily Labeoninae (name varies with author). According to the most recent phylogenetic research, this grouping is further divided into four subtribes; Labeoina, Garraina, Osteochilina, and Semilabeoina (Yang et al., 2012). Among these, Labeo is included in the Labeoina alongside Bangana sensu stricto (which includes the genus Nukta), Cirrhinus sensu stricto, Cirrhinus microlepis (which is of a different genetic lineage to other Cirrhinus species), Gymnostomus, and Incisilabeo.

Thirty Labeo species were used in the study, and the genus was found to be polyphyletic, although all were nested within the Labeoina clade (Yang et al., 2012). Labeo boggut, L. bata and L. bata var. formed a clade with Incisilabeo behri, Schismatorhynchos nukta, and Bangana dero (the type species of the genus) and B. sp. Salween. All other Labeo species comprised a group referred to as Labeo sensu stricto which also includes Gibelion catla, and the authors recommended that the latter be synonymised with Labeo, although this does not appear to have been widely accepted (eg. Kottelat, 2013).