Cobitis striata hakataensis Nakajima, 2012

Nakajima, Jun, 2012, Taxonomic study of the Cobitis striata complex (Cypriniformes, Cobitidae) in Japan, Zootaxa 3586, pp. 103-130 : 115-116

Cobitis striata hakataensis Nakajima , subsp. nov.

( Figs. 3C, 4E, F, 5C, 6C)

Hakata form of Cobitis striata (middle race): Nakajima et al. 2008: 13, fig. 2G; Hakata form of middle race of Cobitis striata complex: Kitagawa et al. 2009: 12, fig. 2E, F; Cobitis sp. 3 subsp. 3: Nakajima et al. 2012: 92, fig. 3c.

Holotype. TKPM-P17342 , male, 58.0 mm SL, Japan: Tatara River, Kasuya, Fukuoka Pref., Kyushu , 12. XII. 2010, J. Nakajima.

Paratypes. JNC005, 1 male, 54.4 mm SL, same data as holotype; JNC041, 1 male, 60.4 mm SL, Tatara R., Kasuya, Fukuoka Pref., Kyushu , 23. V. 2005, J. Nakajima; KPM-NI29504 , male, 55.0 mm SL, Tatara R., Kasuya, Fukuoka Pref., Kyushu, 18. V. 2008, J. Nakajima; MPM-FI1502, 1 male, 48.8 mm SL, same data; FKUN33756 , 1 female, 87.4 mm SL, Naka R., Minami-ku, Fukuoka, Fukuoka Pref., Kyushu, 20. IV. 2005, J. Nakajima; JNC006, 1 male, 59.1 mm SL, Muromi R., Nishi-ku, Fukuoka, Fukuoka Pref., Kyushu, 13. V. 2010. E. Miyamura .

Non-type specimens. 1 male and 2 females, 56.4–63.4 mm SL, same data as holotype ; 1 male and 2 females, 64.0– 69.7 mm SL, Muromi R., Nishi-ku, Fukuoka, Fukuoka Pref., Kyushu , 5. VI. 2006, J. Nakajima ; 2 males, 65.0, 65.7 mm SL, Tatara R., Kasuya, Fukuoka Pref., Kyushu , 23. V. 2005, J. Nakajima ; 1 male and 1 female, 52.6, 55.5 mm SL, Tatara R., Kasuya, Fukuoka Pref., Kyushu , 18. V. 2008, J. Nakajima .

Diagnosis. This subspecies is distinguishable from other Japanese striated spined loaches by the following characteristics: body size moderate, the mature size about 50–60 mm SL in males, 55–80 mm SL in females; lamina circularis at the base of the pectoral fin of adult male simple roundish plate, the upper segments of the first branched soft ray narrow and weak ( Fig. 6C); PMN commonly 13; line L3 formed by incomplete longitudinal line, reaching to caudal base; line L4 formed by longitudinal jagged weblike line, reaching to postanal body, broader than L 3 in male of non-spawning season; line L5 organized in 11–14 roundish or ovoid blotches in non-spawning season; caudal fin and dorsal fin with 3–4 arcuate bars; upper spot at the caudal base jet-black comparable in size to eye diameter; lower spot at caudal base faint or missing; egg yolk diameter approximately 1.0mm; karyotype diploid.

Description. Lateral view in Figure 3C illustrate body shape, form and position of fins. Morphometric and meristic data for 11 males and 5 females are summarized in Table 2. Dorsal-fin rays iii, 7; anal-fin rays iii, 5; pectoral-fin rays i, 7–8; pelvic-fin rays ii, 6; caudal-fin rays 8+8. Body elongate, laterally compressed. Head and snout elongated. Interorbital space narrow, convex. Caudal peduncle relatively compressed. Mouth small, inferior, arched with fleshy lips; lower lip divided with two well-developed lobes; upper lip with transverse wrinkles on surface. Barbels, 3 pairs, first on rostora, second on maxillae, third on maxillomandibula; each barbel well developed, length of maxillary barbel same as eye diameter; length of rostral and mandibular barbels shorter than that of maxillary barbel. Lateral line short, reaching the central region between the pectoral-fin base and the tip of the fin. PMN commonly 13 (range, 13–14). Very small cycloid scales on the trunk. Lamina circularis at the base of the pectoral fin of adult male simple roundish plate ( Fig. 6C). The first branched soft ray of pectoral fin longer than the others; pectoral fin of the male relatively longer than that of the female. The upper segments of the first branched soft ray of pectoral fin narrow and weak. Dorsal-fin base equidistant from the base of the caudal fin and the tip of the snout. Pelvic-fin origin below first or second branched dorsal-fin ray. Anal fin not reaching caudal-fin base. Margin of anal and dorsal fins slightly roundish. Caudal fin slightly roundish. Largest recorded specimens: 65.7 mm SL male, 69.7 mm SL female.

Coloration. Male in the non-spawning season ( Figs. 3C, 4E). Body yellowish white with dark brown pigmentation in fresh specimens. Clear streak running from the tip of snout to the occiput, crossing to the eye. Upper part of head, opercle and snout covered with oval or amorphous shape spots. Body pigmentation organized in one middorsal and four lateral zones. Line L1 consisting of a series of 14–16, saddles or oval-shaped blotches, irregularly chained to each other. Line L2 formed by longitudinal jagged line, reaching to middorsal region, often fused with L1. Line L3 formed by incomplete longitudinal line, reaching to caudal base. Line L4 formed by longitudinal jagged weblike line, reaching to postanal body, broader than L3. Line L5 organized in 11–14 blotches from upper part of the pectoral fin to the caudal-fin base; blotches roundish or ovoid. Caudal fin and dorsal fin with 3–4 arcuate bars. Anal fin pigmented along the fin rays. Upper spot at the caudal base jet-black comparable in size to eye diameter, lower spot at the caudal base faint or missing.

Male in the spawning season ( Fig. 4F). Line L4 not visible or formed by faint longitudinal line, present only in anterior half of body. Lines L3 and L5 well developed with broad stripes from the upper part of the pectoral-fin base to the caudal-fin base.

Female ( Fig. 5C). Appearance similar to males in the non-spawning season, but number of blotches of line L5 tends to be more than in the male, line L5 of female organized in 11–17 blotches.

Sexual dimorphism. Males have roundish lamina circularis at the base of the pectoral fin, but females do not. Generally, the body size of females is larger than that of males.

Egg diameter. 0.98 ± 0.05 mm (females, N = 3; collected from the Tatara River system, Fukuoka Prefecture).

Karyotype. Diploid ( Kitagawa et al. 2009).

Distribution. Rivers flowing into Hakata Bay, northern Kyushu: Fukuoka Prefecture ( Nakajima et al. 2008).

Habitat and biology. This species inhabits sandy-mud bottoms of the middle and lower reach of rivers. Life histories are unknown.

Etymology. The subspecific name is derived from the popular common name of the Fukuoka City area in which the type locality is situated.

Remarks. The genetic features have been reported by Kitagawa et al. (2009).

Japanese name. Hakata-suji-shima-dojyô.