Short Barbelled Catfish

Dorsal spines (total): 1; Dorsal soft rays (total): 7; Analspines: 0; Analsoft rays: 20 - 22

Inhabits river. Feeds exclusively on small fishes including clupeids, chandids and melanotaeniids.

Inhabits river. Feeds exclusively on small fishes including clupeids, chanids and melanotaeniids.

Arius augustus

USNM 217065, Holotype, Fly 75–17, 342 mm.

USNM 217066, Paratypes, Fly 75–17, 2: 288–308 mm.

USNM 217067, Paratype, Fly 75–6, 412 mm.

USNM 217068, Paratypes, Fly 75–25, 2: 91.0–101.7 mm.

Arius augustus, only one specimen of which was caught in the Upper Fly, is fairly common in large tributaries of the Middle Fly, where it attains 500–600 mm. This piscivorous species is readily distinguished from all other New Guinea Arius by its extremely short barbels, very small eyes, distinctive, graceful form, and vivid blue coloration in life. It is broad headed and broad mouthed; tooth band of upper jaw entirely or almost entirely included when mouth is closed. Maxillary barbel extending posteriorly a maximum of half the distance from its origin to that of pectoral spine. Eyes slightly dorsolateral, 24–39 in specimens 91–412 mm (negatively allometric). Gill rakers on first gill arch 21; gill rakers absent on posterior face of first and second gill arches. Upper limbs of gill arches without epithelial thickenings; pharyngeal roof with thin, low-lying longitudinal folds, without well-developed lobes or valves projecting into branchial passage. Dorsum of head smooth or finely granular and broadly rounded from side to side, with a narrow median groove (sometimes indiscernible). No nuchal hump. Pectoral fin with 11 segmented rays. Anal fin pterygiophores 20–21. Caudal fin deeply forked, caudal peduncle relatively slender. Free vertebral centra 49–51 (3: 288–308 mm). Color in life: dorsum vivid sky blue with violaceous hues, ventrum milk white.

Arius augustus is perhaps most closely related to A. leptaspis. The shape of the head and mouth is almost identical in these two species and unlike that in other ariids inhabiting the rivers of central-southern New Guinea.

The short barbelled catfish (Nemapteryx augusta) is a species of catfish in the family Ariidae. It was described by Tyson R. Roberts in 1978, originally under the genus Arius. It inhabits the Fly River in Papua New Guinea. It reaches a maximum standard length of 60 cm (24 in). Its diet consists of bony fish in the families Chanidae, Clupeidae and Melanotaeniidae.