Dark Sea Catfish

Distinguished from all other species of Cathorops by the possession of the following features: gill rakers on first arch 16-18; anal fin with 19-20 rays; snout length 5.3-5.5% SL; and posterior margin of pectoral-fin spine with prominent serrations, except in Cathorops aguadulce, Cathorops kailolae, Cathorops multiradiatus, and Cathorops tuyra. Can be further differentiated from other congeners by the following combination of characters: distance from tip of snout to dorsal-fin origin 30.0-32.6% SL; distance from tip of snout to posterior margin of dorsomedian groove of neurocranium 17.9-19.1% SL; absence of fleshy papillae intercalated with gill rakers on first two arches; head length 22.3-23.0% SL; distance between lateral cornu of lateral ethmoid and external limb of supracleithrum 19.3-19.6% SL; distance between the anterior nostrils 3.6-4.4% SL; distance between posterior nostrils 4.4-5.1% SL; orbital diameter 4.5-5.0% SL; interorbital distance 11.1-12.1% SL; mouth width 8.9-9.7% SL; premaxilla width 5.1-5.8% SL; intense black pigmentation on pelvic fin; distance from tip of snout to pelvic-fin origin 46.2-49.1% SL; dorsal-fin spine length 17.2-18.1% SL; caudal-peduncle height 8.7-9.0% SL; width of cephalic shield at supracleithrum area 16.7-16.9% SL; and body width 19.6-20.1% SL (Ref. 75004).

Dorsal spines (total): 1; Dorsal soft rays (total): 7; Analsoft rays: 19 - 20

The Dark sea catfish (Cathorops melanopus) is a species of catfish in the family Ariidae. It was described by Albert Günther in 1864. It is a tropical, freshwater catfish which occurs in Guatemala. It reaches a total length of 23 cm (9.1 in).