Microplecostomus forestii sp. n.

The new genus and species differs from all members of the Loricariidae by having (1) three hypertrophied bicuspid odontodes on the lateral portion of the body (character apparently present only in mature males – observed in the holotype, but not present in the paratypes) (Fig. 2a, b); and differs from all members of the Neoplecostominae by having (2) a large area without odontodes around the snout, observed in all specimens, Fig. 3 (vs. margin of snout bearing odontodes); and from all members of the Neoplecostominae, except Hirtella carinata Pereira, Zanata, Cetra & Reis, 2014, Pareiorhina carrancas Bockmann & Ribeiro, 2003 and Pareiorhina hyptiorhachis Silva, Roxo & Oliveira, 2013 by (3) the presence of a post-dorsal ridge on the caudal peduncle, see dorsal view of holotype in Figs 1, 4 (vs. the absence of a post-dorsal ridge). Microplecostomus forestii sp. n. differs from species of the genera Isbrueckerichthys, Neoplecostomus and Pseudotocinclus by (4) the absence of abdominal plates, Fig. 1 (vs. abdomen covered by pentagonal or hexagonal platelets); from Kronichthys by having (5) the tooth series in dentary and premaxillary rows straight (vs. tooth series strongly curved medially); from Neoplecostomus by (6) the absence of a conspicuous series of enlarged papillae just posterior to the dentary teeth (vs. presence of enlarged papillae); and from Pseudotocinclus by having (7) the caudal peduncle ellipsoid in cross section (vs. caudal peduncle square in cross-section).

The generic name is a combination of Greek, micro (mikrós) = small, related to the small size of the adult type-specimen, and plecostomus = a former generic name of species currently included in Loricariidae, also in reference to the small adult size of the type-species. A masculine name.