Three more loaches described

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Scientists have described three more loaches from the balitorine genus Gastromyzon.

The new fish, which have been named Gastromyzon scitulus, G. crenastus and G. farragus, were found in southern Sarawak, Borneo, and have just been described in the journal Zootaxa.

Tan and Leh, who described the new species, say that like other Gastromyzon that are endemic to Borneo, these fish are obligate bottom dwellers than spend their lives stuck to rocks where they graze on the biocover.

Gastromyzon scitulus is said to be similar to G. ctenocephalus (a species commonly sold as borneensis in the UK trade) but has a black body with lots of evenly spaced light brown spots.

The head of scitulus is darker with lots of cream spots that spread to the pelvic and pectoral fins. The tail has iridescent blue streaks and there are 57-58 scales in the lateral line series.

G. farragus looks similar to ocellatus but has a dark brown body and 9-10 thin cream bars on its back, plus spots and blotches on its flanks.

The head of farragus is dark with fine cream spots, the tail is reddish in colour and it has 52-55 scales in the lateral line series.

The final of the three species described, G. crenastus, is currently the smallest known Gastromyzon species, with the largest fish recorded measuring just 3cm in length.

Tan and Leh say it is similar to G. ridens but has a black body and 6-8 thin pale bars or spots on the dorsal surface, and cream spots or blotches on the head. The head of crenastus is said to be truncate when viewed from above and it has more lateral line scales than most other species with around 60-65 in the lateral line series.

Tan and Sulaiman described three other Gastromyzon species - Gastromyzon cranbrooki, G. aeroides and G. venustus - in a paper in Zootaxa last week.

For more details see the paper: Tan HH and Leh, CUM (2006) - Three new species of Gastromyzon (Teleostei: Balitoridae) from southern Sarawak. Zootaxa 1126: 1-19 (2006).