Otocinclus flexilis Cope, 1894

A, Pablo Lehmann, Mayer, Fernanda & Reis, Roberto E., 2010, Re-validation of Otocinclus arnoldi Regan and reappraisal of Otocinclus phylogeny (Siluriformes: Loricariidae), Neotropical Ichthyology 8 (1), pp. 57-68 : 60

Otocinclus flexilis Cope, 1894

Fig. 2

Otocinclus flexilis Cope, 1894: 97 , pl. 8, fig. 13. Type locality: rio Jacuhy , Rio Grande do Sul [rio Jacuí, Brazil]. Lectotype: ANSP 21756 , 40.0 mm SL, designated by Schaefer (1997: 53).

Otocinclus fimbriatus Cope, 1894: 98 , pl. 9, fig. 16. Type locality: rio Jacuhy , Rio Grande do Sul [rio Jacuí, Brazil]. Syntypes: ANSP 212752 (4) andANSP 21585-97 (14).

Diagnosis. Otocinclus flexilis is distinguished from all other Otocinclus (except for O. xakriaba , O. affinis , O. hasemani , O. arnoldi , and O. mimulus ) by possessing an iris operculum and (except for O. xakriaba , O. arnoldi , and O. mimulus ) by having a lateral trunk coloration consisting of a series of 3-6 diffuse pigment blotches ( Fig. 2). An inconspicuous and not elevated patch of 0-10 (mode = 0, mean = 3.0) enlarged odontodes on the postero-dorsal parieto-supraoccipital tip, the pectoral skeleton with closed arrector fossae, and the presence of a triangular pigment mark at the dorsal-fin base distinguishes O. flexilis from O. xakriaba , which possesses an elevated patch of enlarged odontodes on the parietosupraoccipital, has an open arrector fossae, and lacks the dorsal-fin mark. From O. arnoldi and O. mimulus it is easily distinguished by having six branched pectoral-fin rays (vs. five branched rays) and few (0-10, mode = 0, mean = 3.0) not elevated enlarged odontodes on the parieto-supraoccipital tip (vs. 2-23, mode = 7, mean = 8.3) not elevated enlarged odontodes in O. arnoldi and 5-14, mode = 7, mean = 8.4 conspicuously elevated odontodes in O. mimulus ).

Distribution. Otocinclus flexilis is restricted to the laguna dos Patos drainage basin ( Fig. 5).