Scoloplax baskini , INPA 28658, holotype, 14.4 mm SL. Photo by R. R. de Oliveira. 

Scoloplax baskini , INPA 28658, holotype, 14.4 mm SL. Photo by R. R. de Oliveira. 

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A new species of Scoloplax is described from small tributaries of rio Aripuanã, rio Madeira drainage, Amazonas State, Brazil. The new species can be distinguished from its congeners by several morphological features, such as ventral midline plates with two longitudinal parallel rows of odontodes not covered by skin, pectoral and pelvic fins with al...

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Context 1
... to caudal peduncle. Ventrolateral plates 8-9. Ventral midline plates 4-6, bearing odontodes along lat- eral margins forming two longitudinal rows (Fig. 5). Total ver- tebrae 25-27 (n=10). Coloration. Body overall brownish, more pigmented laterally with wide longitudinal dark brown stripe along lower region of trunk from pectoral to caudal fin ( Figs. 1-2). Mid-ventral plate series less pigmented. Dorsal part of body pale except for three narrow dark saddles. First saddle faint, at dorsal fin origin; other two saddles darker and evenly spaced between dorsal and caudal fins. Ventral portion of body pale, cream- colored, sometimes with dark pigment concentrated along lateral edges and more ...
Context 2
... the presence of two parallel rows of odontodes on the ventral midline plates, starting posterior to vent and reaching the caudal peduncle (Fig. 5). The holotype of S. dolicholophia and conspecific specimens deposited at INPA also have two rows of odontodes on the ventral midline plates, although not clearly illustrated in Schaefer et al. (1989: fig. 10a). This feature, however, differs between the two species. In S. dolicholophia the rows of odontodes are largely concealed by skin with only their tips visible, whereas in S. baskini these odontodes are completely exposed and conspicuous, not skin ...

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