Potamotrygon pantanensis

Loboda, Thiago S., 2016, New records of two ocellated species of the genus Potamotrygon Garman, 1877 (Chondrichthyes: Myliobatiformes: Potamotrygonidae) for Paraguay and Bolivia., Ichthyological Contributions of PecesCriollos 45, pp. 1-8 : 5

Potamotrygon pantanensis . Morphometric data are given in Table 2.

As stated by Loboda & Carvalho (2013), some specimens of P. pantanensis show a very similar dorsal coloration as does P. motoro , but this species can be distinguished from other congeners by possessing a light brown or light gray dorsal coloration with bicolored ocelli and vermiculated markings with beige, yellow, or orange central area surrounded by a gray or dark gray contour, a clearly demarcated gray color area in the anterocentral ventral disc (which in some specimens may form a strip above the first pair of gill slits), tail relatively smaller (mean of distance between cloaca and tip around 73% DW) and broader (width in basis around 13% DW), presence of star-shaped dermal denticles only in the central area of dorsal disc, two or three rows of slender and curved pointed spines on the tail.

Male adult specimen AMNH 59875 from the Upper Amazon basin possess a very peculiar dorsal ocelli pattern in the central area of disc ( fig. 5 ) as a set of small ocelli fused in a big one, and very similar with the pattern of specimens of this species from the Paraná-Paraguay basin shown by Loboda & Carvalho (2013, fig. 31). The AMNH 59875 specimens also present tubercles in the rows of the tail and on the margins of the disc.

Figures

fig. 5. Potamotrygon pantanensis AMNH 59875, 263 mm DW, from Guaporé river, Bolivia, in dorsal (A) and ventral (B) views