Diagnosis |
Characterized by 2 large teeth on the supraoral bars, the presence of only 2 points on the central pair of lateral tooth plates, and the presence of a row of posterial teeth (Ref. 27547). Dorsal fins arise far back on body, the anterior dorsal lower than the posterior, the fins higher in males; lower lobe of caudal fin is somewhat larger than upper, the fin joined to both dorsal and anal fins; anal fin small, in males represented only by a low ridge (Ref. 27547). Color ranges from brown to olive to grayish above, paler below (Ref. 27547). The non-anadromous form rarely grows larger than 18 cm (Ref. 27547). Other adult diagnostic features: 11.0-62.5 cm TL. Wet weight of individuals 14.5-35.0 cm TL, 3.2-87.7 g. Body proportions, as percentage of TL (based on 63 specimens measuring 13-46 cm TL): prebranchial length, 7.3-21.3; branchial length, 7.8-20.8; trunk length, 21.9-56.3; tail length, 24.6-30.8; eye length, 0.7-3.7; disc length, 4.5-7.7. Intestinal diameter up to 13 mm. Urogenital papilla length, as a percentage of branchial length, in 6 spawning males measuring 33.9-40.1 cm TL, 14.6-19.5. Trunk myomeres, 65-77 [Kucheryavyi et al. (2007) reported counts of 63-85 for 19 downstream migrants and 55-79 for 87 anadromous individuals from Utkholok River Basin, Kamchatka]. Dentition: supraoral lamina, 2 unicuspid, rarely bicuspid, teeth; infraoral lamina, 6-10 teeth, usually 8 (as few as 5), the lateralmost tooth on either end usually bicuspid, the internal ones unicuspid; usually 3, rarely 4 endolaterals on each side; endolateral formula typically 2-2-2 with variant formulae, 2-2-1, 2-2-2-2, 2-2-2-1; 3 rows of anterials; first row of anterials, 3 unicuspid teeth; total number of anterials, 20-33 teeth [5-43 according to Kucheryavyi et al. (2007) and as low as 11 according to Iwata et al. (1985), which may be due to regional effects, but this requires further investigation]; exolaterals absent; single row of posterials, 12-28 teeth; transverse lingual lamina, 13-18 teeth, the median one greatly enlarged; longitudinal lingual laminae each with 10-14 teeth. Velar tentacles, 5-7, with tubercles and with the single median tentacle shorter than the lateral tentacles immediately next to it, and with dorsal velar wings on either side, each consisting of a single tentacle. Body coloration (live) of recently transformed adults brown on dorsal and lateral aspects and silvery on ventral aspect, while upstream spawning migrants have a yellowish olive dorsal aspect, becoming lighter on the lateral aspects, and dull yellowish on the ventral aspect. Lateral line neuromasts unpigmented. Gular region unpigmented. Second dorsal fin with a dark blotch near the apex. Extent of caudal fin pigmentation, 1% to <25% (29% of specimens), 25% to <75% (57%) or, 75% or more (14%). Caudal fin shape, spade-like. Oral fimbriae, 87-112. Oral papillae, 12-22 (Ref. 89241). |