Three new species of South East Asian cyprinid have been described from Sumatra and Borneo in a taxonomic revision of the genus Eirmotus by ichthyologists Tan Heok Hui and Maurice Kottelat.
The new species are described based on comparisons with the type species, and until recently the only known member of the genus, Eirmotus octozona.
Eirmotus isthmus (from the lakes of central Sumatra and the Mentaya Drainage of southern Borneo) is distinguished from other species of Eirmotus by the shape and position of its mouth and by a combination of colour pattern features and meristic counts.
Its name is derived from the latin isthmus, meaning a narrow passage of land, in reference to the narrow dark bars on the body.
Eirmotus furvus (from coastal peat swamp forest of Sumatra) is distinguished from other species of Eirmotus by its wider dark body bars and a combination of meristic counts.
Its name is derived from the latin furvus, meaning dark black or dusky, in reference to its dusky appearance.
Eirmotus insignis (from the small streams and slowly flowing backwaters of the Kapuas drainage in Western Borneo and Belitun Island) is distinguished from other species of Eirmotus by features of its colour pattern and a combination of meristic counts.
Its name is derived from the latin insignis, meaning worth distinction or brilliant, in reference to its unique colour pattern.
Redescription of Eirmotus octozona
Tan and Kottelat also provide a redescription of Eirmotus octozona, a species commonly referred to as the false eightstripe barb or puntius in the aquarium trade.
This species, which is also the type species of the genus, was originally described in the American aquarist magazine Tropical Fish Hobbyist in 1959 by L. D. Schultz based on aquarium specimens reportedly collected from Central Thailand.
It can be distinguished from all other species by a combination of colour pattern and meristic patterns.
For more information on the genus Eirmotus, see the paper: Tan, H. H and Kottelat, M. Revision of the cyprinid fish genus Eirmotus, with description of three new species from Sumatra and Borneo. Raffles Bulletin of Zoology, 56(2): 423-433.