A new miniature species of cyprinid in the genus Boraras from southern Thailand has been formally named in a recent issue of the journal Zootaxa.
Cyprinid experts Kevin Conway and Maurice Kottelat name the new species Boraras naevus, a species occasionally imported in the aquarium trade as Boraras sp. "South Thailand".
Boraras naevus is known from peninsular Thailand, and superficially resembles B. maculatus.
It is distinguished from it in having a pronounced sexual dimorphism of the front blotch situated on the sides of the body, which is a small circular marking of roughly eye size or smaller in females and a large dorsoventrally oriented oval-shaped marking larger than the eye in males (vs. blotch similar in size and shape in both sexes); the absence of a midlateral stripe; the presence of red and black pigment along the front edge of the dorsal and anal fins of males in life; 9+8 principal caudal-fin rays; i,5,i pelvic-fin rays; 7 branched dorsal-fin rays; 24–26 body scales in the midlateral row; infraorbital 4 present; infraorbital 2 contacting both infraorbital 1 and infraorbital 3; and mesocoracoid present.
Boraras naevus inhabits swamps, and is named after the large sexually dichromatic blotch on the body (naevus=Latin for a blemish).
For more information, see the paper: Conway, KW and M Kottelat (2011) Boraras naevus, a new species of miniature and sexually dichromatic freshwater fish from peninsular Thailand (Ostariophysi: Cyprinidae). Zootaxa 3002, pp. 45–51.
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