A new species of Gymnotus, from the G. pantherinus species-group, is herein described from the rio Jucuruçu basin, a coastal river drainage located in the southern part of Bahia state, northeastern Brazil. Gymnotus capitimaculatus sp. n. differs from all congeners by having an pair of round blotches anteriorly positioned or under vertical passing through eye, on ventral portion of the head. Furthermore, Gymnotus capitimaculatus also differs from all members of the G. pantherinus species-group by having the following unique combination of characters states: tail with an unique series of bands or round spots; precaudal portion of trunk without bands but either with rounded and/or vermiculated spots; forty-five precaudal vertebrae; nine scales above lateral line at mid-body; anal-fin base length 75.2 – 78.6 % of TL; anus-anal fin length 101.4 – 122.8 % of HL; and branchial opening 38.5 – 45.0 % of HL.

Recent statements from the Brazilian federal government indicate that impacting economic activities, particularly commercial shrimp farming, are being encouraged in mangrove areas in the near future. Alterations of the National Action Plan and legal instruments that partially protected mangrove ecosystems have created an even weaker legal framework than previously existed. Such changes are leading Brazil far from the global call to conserve mangroves and from the Aichi targets and United Nations Sustainable Development Goals. Unfortunately, the loss of mangrove ecosystems and their ecosystem services will negatively impact living standards for Brazilians in coastal areas.

A new species of Gymnotus Linnaeus is described from Riacho Cambiriba a clear water stream, tributary of the Rio de Contas basin, Bahia, northeastern Brazil. The new species is a member of the G. carapo species-group, which is characterized by the presence of a transparent patch near the posterior end of the anal fin and two (vs. one) laterosensory pores in the dorso-posterior region of the preopercle bone. Gymnotus interruptus may be diagnosed by a unique combination of morphometric and meristic characters: wider interorbital distance (44.6 – 45.9% of STO); 9 scales above lateral line at midbody; 23 – 28 ventrally oriented lateral line rami; 37 – 40 pored lateral line scales to first ventral ramus of lateral line; shorter snout (29.6 – 30.5% of STO). Gymnotus interruptus, the first record of a gymnotiform fish from the rio de Contas basin, may be easily distinguished from G. carapo or G. bahianus, two congeners also occurring in northeastern Brazil, by its colour pattern, in which the pale interbands, anterior to vertical through first ventral lateral line ramus, are ventrally and/or dorsally fragmented, allowing union of adjacent dark bands