Strawberry Rasbora

description

Description. General body shape as in Figure 1. Morphometric and meristic data are listed in Table 1. Miniature species, largest specimen examined 12.7 mm SL (range 10.2 – 12.7 mm). Head and eye large, snout rounded, mouth small, terminal. Anterior nostril small, oval-shaped, separated from larger posterior nostril by a narrow, low strip of skin. Body compressed, deepest midway between occiput and dorsal-fin origin. Caudal peduncle slender. Dorsal fin origin situated roughly at mid-body, insertion of posteriormost dorsal-fin ray slightly anterior to vertical through anal-fin origin. Pelvic-fin origin situated anterior to vertical through dorsal-fin origin. Pectoral fin insertion situated low on flank. Caudal fin forked, upper and lower lobes rounded, upper lobe slightly longer than lower. holotype (ZRC 53120) and 10 paratypes (CMK 16459). Values for B. maculatus obtained from CMK 20696, BMNH 1985.12.18: 10 – 18, 1995.5.17.112 – 126, USNM 101267 and 229241. Morphometric values for B. micros taken from Kottelat & Vidthayanon (1993) with additional meristic data obtained from BMNH 2004.4.29.1 – 3. Boraras naevus Boraras micros Boraras maculatus Holotype Range Mean St. Dev. Range Range

Boraras naevus, a new species of miniature and sexually dichromatic freshwater fish from peninsular Thailand (Ostariophysi: Cyprinidae)

diagnosis

Diagnosis. Boraras naevus is distinguished from its congeners with a similar blotched color pattern (viz. B. maculatus and B. micros) by pronounced sexual dimorphism of the anteriormost blotch situated on the body side, which is a small circular marking of roughly orbit size or smaller in females and a large dorso-ventrally orientated oval-shaped marking larger than the orbit in males (vs. anteriormost blotch similar in size and shape in both sexes) and by its lower number of principal caudal-fin rays (9 + 8 vs. 9 + 9 in B. micros, 9 – 10 + 9 in B. maculatus). It is further distinguished from B. maculatus by its lower number of body scales in the midlateral row (24 – 26 vs. 26 – 29), and its lower number of pelvic-fin rays (i. 5. i vs. i. 6. i), and from B. micros by its higher number of body scales in the midlateral row (24 – 26 vs. 22 – 23), higher number of branched dorsal-fin rays (7 vs. 5 – 6), the presence of red and black pigment along the anterior edge of the dorsal and anal fins of males in life (vs. all fins transparent without red or black pigmentation in life in both sexes), the presence of infraorbital 4 (vs. infraorbital 4 absent), infraorbital 2 contacting both infra

Boraras naevus, a new species of miniature and sexually dichromatic freshwater fish from peninsular Thailand (Ostariophysi: Cyprinidae)

distribution

Distribution and habitat. We have examined material from the type locality, in a swampy area north of Surat Thani. The species is reported to have a wider distribution in the lower Tapi drainage, on the Gulf of Thailand slope of peninsular Thailand. It is suspected that most of its natural habitats (swamps) has been transformed into paddy fields. Additional populations, or another, similar species is known from the Andaman Sea slope of the Malay Peninsula near Trang.

Boraras naevus, a new species of miniature and sexually dichromatic freshwater fish from peninsular Thailand (Ostariophysi: Cyprinidae)

etymology

Etymology. From the Latin naevus, a spot, a mark on skin, a blemish, in allusion to the large sexually dichromatic blotch on the side of the body. A noun in apposition.

Boraras naevus, a new species of miniature and sexually dichromatic freshwater fish from peninsular Thailand (Ostariophysi: Cyprinidae)