Amblyrhynchichthys micracanthus NG & KOTTELAT, 2004

Etymology

Amblyrhynchichthys: from the Greek amblús (Gr. ἀμβλύς), meaning ‘blunted’, rhýnchos (Gr. ῥύγχος), meaning ‘snout’, and ichthýs (Gr. ἰχθύς), meaning ‘fish’, in allusion to the comparatively blunt snout in members of this genus.

micracanthus: from the Greek mikrós (Gr. μικρός), meaning ‘small’ and ákantha (Gr. ἄκανθα), meaning ‘thorn’, in reference to this species’ relatively short dorsal spine when compared to the congener A. truncatus.

Classification

Order: Cypriniformes Family: Cyprinidae

Distribution

Native to the Mekong River catchment in Laos (where Vientiane province represents the upper limit of its range), Thailand, Cambodia, and Vietnam, and the Tapi, Chao Phraya, and Mae Klong river systems in Thailand.

Type locality is ’22 kilometers upstream from Phnom Penh, Tonle Sap River, Kandal Province, Cambodia’.

Habitat

A riverine species which also moves into areas of inundated forest during the wet season (June to September), while juveniles have  been observed in swamps and flooded fields.

Maximum Standard Length

150 – 200 mm.

Diet

Wild fish feed on periphyton, phytoplankton, zooplankton, and benthic algae.

NotesTop ↑

Prior to this species’ description, the genus comprised only a single species meaning older records of A. truncatus in mainland Indochina all refer to A. micracanthus.

A. micracanthus can be told apart from A. truncatus by the following combination of characters: snout more truncate with a straight (vs. gently rounded in A. truncatus) lateral profile; dorsal-fin spine shorter, measuring 15.5-25.7% SL (vs. 26.7-29.9%); a smaller eye when individuals of a similar size and larger than ca. 70 mm SL are compared, with a diameter measuring 28.7-34.9% HL (vs. 32.7-36.3%); 34-37 (vs. 39-40) gill rakers.

The genus Amblyrhynchichthys is distinguished from all other cyprinids by the following character combination: snout extremely blunt; nostrils located anteriorly; last simple dorsal-fin ray stout with serrations on the posterior edge; presence of a well-developed, hyaline eyelid.

References

1. Ng, H. H. and M. Kottelat , 2004 - Revue Suisse de Zoologie 111(2): 425-432
   Amblyrhynchichthys micracanthus, a new species of cyprinid fish from Indochina (Cypriniformes: Cyprinidae).
2. Kottelat, M., 2013 - Raffles Bulletin of Zoology Supplement 27: 1-663
   The fishes of the inland waters of southeast Asia: a catalogue and core bibiography of the fishes known to occur in freshwaters, mangroves and estuaries.
3. Kottelat, M., 2001 - WHT Publications, Colombo: 1-198
   Fishes of Laos.
4. Rainboth, W. J., 1996 - FAO, Rome: 1-265
   FAO species identification field guide for fishery purposes. Fishes of the Cambodian Mekong.
5. Roberts, T. R., 1989 - Memoirs of the California Academy of Sciences 14: i-xii + 1-210
   The freshwater fishes of western Borneo (Kalimantan Barat, Indonesia).