Rasbora tobana Ahl, 1934

Family:  Danionidae (Danios), subfamily: Rasborinae
Max. size:  3.53 cm SL (male/unsexed)
Environment:  benthopelagic; freshwater
Distribution:  Asia: Lake Toba, Sumatra, Indonesia.
Diagnosis:  Dorsal soft rays (total): 9-9; Anal soft rays: 7-7; Vertebrae: 31-32. Distinguished from all members of the Rasbora trifasciata-group by the following characters: a black midlateral stripe extending along the flank from the post-opercular region to the caudal-fin base and tapering anteriorly and terminating posteriorly at the black basicaudal spot as wide as the black stripe; male cephalic tubercles relatively slender and tall with the tubercle base relatively higher than the skin surface and appearing protruded with the epithelial cells smooth, and with the tubercles aggregated in a clumped plate; and a relatively large supraorbital with posterior margin almost reaching anterior lamina of fifth infraorbital and exceeding opening of dilatator fossa (vs. small supraorbital with posterior margin distantly separated from anterior lamina of fifth infraorbital and barely reaching opening of dilatator fossa). Can be further diagnosed from other members of this group in northwestern Sumatra by the following combination of characters: cranial superficial neuromasts (with basal plate of the neuromast confluent with the skin surface and surrounded by a peripheral groove); a conspicuous depression on the ventral margin of the maxilla notched by a deep lachrymal groove; the uniformly pigmented lachrymal region; the dorsomedial branch of the supraorbital canal extending toward the posterior margin of the frontal; the axial streak anteriorly terminating in the area between the vertical through the dorsal-fin origin and the pelvic-fin insertion; the presence of cephalic tubercles in both sexes; a transverse scale count anterior to the dorsal-fin origin and pelvic-fin insertion of K4/1/3K; 10 scales around ccaudal peduncle; a basal reticulation pattern comprised of networks of well-developed parenthesis-shaped bars on the midlateral surface of the body; the maximum vertical coverage of basal reticulation of three longitudinal scale rows; and the pelvic-fin rays i,7 (Ref. 85846). Description: Dorsal-fin rays ii, 7½; anal-fin rays ii, 5½; pectoral-fin rays i,13; pelvic-fin rays i, 7; basicaudal blotch relatively distinct; gill rakers on 1st gill arch 10-11; all scales perforated, 26-29 + 2-3; scales in lateral line series 27-30 + 2-3; black basicaudal spot on caudal-fin base; all fins hyaline except for slight yellow coloration on basal sections of dorsal- and caudal-fin rays (Ref. 94947).
Biology: 
IUCN Red List Status: Least Concern (LC); Date assessed: 09 January 2019 Ref. (130435)
Threat to humans:  harmless
Country info:   
 


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