Oreonectes polystigmus, Du, Li-Na, Chen, Xiao-Yong & Yang, Jun-Xing, 2008

Du, Li-Na, Chen, Xiao-Yong & Yang, Jun-Xing, 2008, A review of the Nemacheilinae genus Oreonectes Günther with descriptions of two new species (Teleostei: Balitoridae), Zootaxa 1729, pp. 23-36 : 30-32

Oreonectes polystigmus sp. nov.

Fig. 7

Holotype: KIZ 2001060507, 57.7 mm SL, 68.6 mm TL, from Dabu Village, Guilin City, Guangxi Zhuang Autonomous Region, China, June 2001, donated by Mr. Lan Jiahu, Guangxi Du’an County Animal Husbandry and Aquaculture Bureau, April 2003.

Paratypes: 9 ex. KIZ 2001060502–06, 35.1–53.6 mm SL, 42.2–64.5 mm TL; KIZ 2001060508–10, 42.0– 46.4 mm SL, 50.2–55.9 mm TL. Location and date are the same as for the holotype.

Diagnosis: Anterior and posterior nostrils separated by short distance; anterior nostril elongated into barbel-like structure; tip of anterior nostril reaching middle of posterior nostril; caudal fin rounded; body and belly completely covered by scales; lateral line incomplete, with 6–8 pores; cephalic lateral-line system with 7 supraorbital, 4+7 infraorbital pores; sexual dimorphism observed: males have genital papilla located immediately posterior to anus; gonad opens at end of fleshy prominence.

Description: Body elongate and compressed; head compressed; snout pointed; snout shorter than postorbital portion of head; mouth inferior; lip surface smooth; lower lip with notch, completely interrupted by longitudinal groove; jaws completely covered by lips; formalin-preserved specimen has dark brown spots on upper lip; three pairs of barbels, inner rostral barbel reaching vertical of posterior margin of eye, outer barbel reaching almost vertically of branchiostegal rays, maxillary barbel reaching vertical of pectoral-fin origin, barbels with brown spots; anterior and posterior nostrils separated by short distance, anterior nostril tube-like; distal margin of nostril tube truncate, reaching middle of posterior nostril; eyes normal.

Distal margin of dorsal fin rounded; dorsal-fin origin posterior to pelvic-fin origin; predorsal length 57.0– 64.1% (59.5) SL; pectoral fin reaches about 1/2 distance to pelvic fin; distal margin of pelvic fin reaches anus; distance from anus to anal-fin origin is 1.5 times longer than eye diameter; less developed caudal-adipose keel on caudal-peduncle; caudal-peduncle length 1.1–1.5 (1.3) times longer than depth; caudal fin rounded; whole body covered by tiny scales, excluding head; lateral line incomplete, with 6–8 pores; cephalic lateral-line system with 7 supraorbital, 4+7 infraorbital pores; vertebra 4+30~33 (3). Air-bladder has two chambers, posterior chamber developed, filling body cavity, connected with anterior chamber by long, slender tube; intestine straight. Fin ray counts: P, 10; D, 6–7; V, 6; A, 5; C 14–15.

Color pattern (preserved in formalin): Body yellowish brown with many irregularly shaped spots, dorsal fin and caudal fin with irregular spots on rays, other fins hyaline or rays with black.

Sexual dimorphism: Males have genital papilla located immediately posterior to anus; gonad opens at end of fleshy prominence.

Distribution: Known from the Dabu Village, Guilin City, Guangxi Zhuang Autonomous Region, China.

Etymology: From Greek poly and stigma, meaning numerous marks, in reference to the presence of numerous dark brown spots on the body of this species. Gender masculine.

Remark: From the body shape, this species appears to be most closely related to O. platycephalus and shares the following characteristics: dorsal-fin origin posterior to pelvic-fin origin; body and belly completely covered by scales; cephalic lateral-line system with 2+2 supratemporal and 7 preoperculomandibular pores; caudal fin rounded.

However, it can be distinguished from O. platycephalus by the following characteristics: cephalic lateralline system with 7 supraorbital versus 8; 4+7 infraorbital versus 3+10; lateral line incomplete, with 6–8 pores versus 16–18; body with many different spots versus body plain; posterior portion of air-bladder developed, filling the body cavity versus reduced, reaching the vertical of pectoral-fin base.

Figures

FIGURE 7. Oreonectes polystigmus (holotype KIZ 2001060507, 57.7 mm SL), (a) lateral and (b) ventral views.