Mastacembelus armatus (Lacepède, 1800)

[N]—Zig-zag eel

Taxonomy. Original description: Macrognathus armatus Lacepède, 1800: 283, 286 [locality unknown; no types known].— Afghanistan synonyms: Macrognathus caudatus McClelland, 1842; Macrognathus hamiltonii McClelland, 1843; Mastacembelus manipurensis Hora, 1921; Mastacembelus marmoratus Cuvier, 1832; Rhynchobdella polyacantha Bloch & Schneider, 1801; Mastacembelus ponticerianus Cuvier, 1832; Mastacembelus venosus Valenciennes, 1838 .—Revisions: None.—Illustration: Day (1876a: pl. 73, fig. 3).

Status in Afghanistan. First record from Afghanistan by Day (1876a); confirmed by Coad (1981: 17; 2014: 309; 2015: 229).—Afghanistan materials: FMNH.

Distribution and habitat. Distribution in Afghanistan: Kabul River.—General distribution: South Asia, Southeast Asia, East Asia: Pakistan, India and Myanmar to Thailand;? China and? Taiwan.—Habitat: This species inhabits freshwater areas in plains and hills. The adults live in highland streams to lowland wetlands and are usually found in streams and rivers with a sand, pebble, or boulder substrate. They seldom leave the bottom except when disturbed. This species also occurs in still waters, both in coastal marshes and dry zone tanks. Sometimes it stays partially buried in a fine substrate, although they generally favor rivers, tanks, and streams with a rocky substrate and may be found in flowing or still water. During the day, this species remains hidden under rocks, with only the rostral appendage showing. In some poorly oxygenated streams, it rises to the surface intermittently for air. A nocturnal fish, it hunts on the substrate for insects, worms, crustaceans, and fish. This spiny eel feeds mainly on insects, insect larvae, worms, and sometimes fish. Freshwater.

Economic importance. Commercially important.

Conservation. Conservation status in Afghanistan: Unknown.—IUCN: LC (Fernado et al. 2019).—Threats: EUT.— Moderate sensitivity to human activities.—Keystone species.—Decline status: Stable.—Moderate priority for conservation action.

Remarks. See Gholamhosseini et al. (2022) for molecular systematics of this species.