Sternopygus sabaji, new species, is described from the Atlantic drainages of the Guiana Shield region of South America using traditional methods of morphometrics and meristics and microcomputed tomography (µCT) scans for osteological analysis. The new species is diagnosed from all other species of Sternopygus by the lack of dentition on the anteroventral surface of the endopterygoid and by the possession of a wider mouth. It further differs from its congeners by the following combination of characters: reduced humeral spot with low-contrast and poorly defined margins, possession of a light-colored mid-lateral stripe along posterior portion of lateral line, possession of 1–3 dark saddle-like markings along dorsum of smaller individuals, and a relatively low precaudal vertebrae count. This work provides the first description of a species of Sternopygus that is endemic to the Guiana Shield, joining S. astrabes and S. macrurus in elevating the species richness of the clade in that region to three species and the total number of valid Sternopygus to ten species.

Etymology.—This species is named in honor of Dr. Mark Henry Sabaj, of the Academy of Natural Sciences, Philadelphia, for his many contributions to the exploration and understanding of Neotropical aquatic diversity. The authors also acknowledge his role in collecting and photographing the specimens of the type series and his help to the authors in obtaining specimen loans for this study. 

Distribution.— Sternopygus sabaji is known from the Marowijne (Maroni) and Essequibo drainage basins where it is found sympatrically with S. macrurus and possibly another undescribed member of the genus (Fig. 10).

 

 

Kevin T. Torgersen and James S. Albert. 2022. A New Species of Sternopygus (Gymnotiformes: Sternopygidae) from the Atlantic Coast of the Guiana Shield. Ichthyology & Herpetology. 110(4), 714-727. DOI: 10.1643/i2022013