Niwaella Nalbant, 1963

Chen, Yifeng & Chen, Yongxia, 2005, Revision of the genus Niwaella in China (Pisces, Cobitidae), with description of two new species, Journal of Natural History 39 (19), pp. 1641-1651 : 1643-1644

Genus Niwaella Nalbant, 1963

Niwaella Nalbant 1963, p 362 –363 (type species: Cobitis delicata Niwa, 1937 ) (Gifu Prefecture, Kuzuri Honsu, Japan).

Brief description

Body small, elongated and laterally compressed. Abdomen rounded, dorsal surface and abdomen almost parallel. Head small, slightly compressed, snout bluntly rounded. Anterior nasal tube slightly distant from the posterior orifice, and near eyes. Mouth small, inferior, on surface of lips with numerous transverse wrinkles, the upper lip broad, continuous with the lower lip; whole aspect of mouth resembles a sucker. Six barbels, of which two are rostral, two maxillary and two maxillo-mandibular; barbels short and subequal. Eyes located on upper part and middle of head. Eye interorbital width equal to or slightly longer than eye diameter. Suborbital spine relatively thick and curved, reaching the inferior of the middle of eye. Anus close to anal fin. Caudal peduncle truncated, adipose crests developed. Tip of caudal fin slightly emarginate.

Lateral line short, not exceeding length of pectorals. No scales on head and sides of head. Body scales are small, sometimes hardly visible, round, or oval, with a large, almost central or eccentric (being closer to the base) focal area. There are 23–26 radial grooves and few supplementary radial grooves. The radial grooves in the front and on the side of scale are broad and sparse, while at the base of scale are close spaced. The circular striae are relatively scarce.

Dorsal fin situated on second half of body, anal fin situated on second half of the space between pelvic fin and tail fin. Pelvic fin approximately on the same line, or slightly behind of, insertion with dorsal fin. Six branched rays in the dorsal fin, five branched rays in the anal fin.

Body pale yellowish. Head sprinkled with many black spots, a black stripe visible from nape through eye to first barbel insertion. Dorsal body colour pattern has angular black stripes. Small scattered dark speckles or large dark blotches on the dorsolateral surface, and a dark stripe or rounded black spots along the lateral midline, or some blotches below the lateral midline. There are three or four striations on the caudal fin and dorsal fin, and a conspicuous dark spot or thick dark striation on upper part of caudal base.

No sexual dimorphism; the second pectoral ray has no osseous process at the base in males.

Remarks

This genus comprises few species in the subfamily Cobitinae . The characters typical of the group are: (1) sucker-like mouth with short and subequal barbels; (2) on surface of lips numerous transverse wrinkles; (3) suborbital spine relatively thick and curved, opposite the caudal processes; (4) dorsal fin situated on second half of body; (5) a strong carina between dorsal and caudal fins; (6) six branched rays in the dorsal fin; (7) five branched rays in the anal fin; (8) scales small, round or oval, with a large focal area, 23–26 radial grooves and few supplementary radial grooves, circular striae scarce; (9) no sexual dimorphism and the second pectoral ray without an osseous process at the base in males.

Distribution and habitat

At present Niwaella are known in China, Japan and South Korea. In China three species are known, in Xinjiang River, Cao’ejiang River and Yongjiang River, respectively. Those loaches usually inhabit the upper parts of rivers and streams with stony bottoms, especially clear forming rapids.