Nannoptopoma Schaefer, 1996

Delapieve, Maria Laura S., A., Pablo Lehmann & Reis, Roberto E., 2017, An appraisal of the phylogenetic relationships of Hypoptopomatini cascudinhos with description of two new genera and three new species (Siluriformes: Loricariidae), Neotropical Ichthyology 15 (4), No. e 170079, pp. 1-38 : 22

Genus Nannoptopoma Schaefer, 1996

Nannoptopoma Schaefer, 1996: 915 . Type-species: Otocinclus spectabilis Eigenmann, 1914 . Type by original designation. Gender neuter.

Included species. Nannoptopoma spectabile (Eigenmann, 1914) and Nannoptopoma sternoptychum Schaefer, 1996 .

Diagnosis. Nannoptopoma is diagnosed as monophyletic based on two exclusive synapomorphies: distance between posterior process of coracoid and lateropterygium short, their tips touching or almost touching each other (char. 62.1); and two or three plates on single series of median abdominal plates (char. 89.1). In addition, there are three non-exclusive synapomorphies: anterior margin of mesethmoid rounded (char. 4.3); two median plates ventrally associated with second mid-ventral plate (char. 84.1); and one plate in lateral abdominal series (char. 88.1).

Comparisons. The species of Nannopoptopoma are further distinguished from other hypoptopomatins by a welldeveloped pectoral fin and by anterior displacement of the pelvic fin, such that the posterior tip of the pectoral-fin spine reaches to or surpasses the posterior tip of the first unbranched pelvic-fin ray (vs. pectoral spines never reaching the tip of the unbranched pelvic-fin). Nannoptopoma can be further distinguished from all other genera by possessing only one lateral abdominal plate and two or three plates in a single series of median abdominal plates (vs. different plate configurations). Nannoptopoma is also distinguished from Hypoptopoma by having the greatest width of body at the cleithrum (vs. at the eyes); the caudal peduncle is rounded in cross section (vs. vertically oval); the pectoral-fin spine has no serrations in its inner margin (vs. serrae present); the adipose fin is always absent (vs. usually present); and the dorsal profile of the head and body is slightly convex from the snout tip to the dorsal-fin origin (vs. profile straight).