Cobitis striata fuchigamii Nakajima, 2012

Nakajima, Jun, 2012, Taxonomic study of the Cobitis striata complex (Cypriniformes, Cobitidae) in Japan, Zootaxa 3586, pp. 103-130 : 113-115

Cobitis striata fuchigamii Nakajima , subsp. nov.

( Figs. 3B, 4C, D, 5B, 6B)

Onga form of Cobitis striata (middle race): Nakajima et al. 2008: 13, fig. 2F; Onga form of middle race of Cobitis striata complex: Kitagawa et al. 2009: 12, fig. 2D; Cobitis striata (the Onga form of the middle race): Nakajima et al. 2011b: 320, fig. 1C; Cobitis sp. 3 subsp. 2: Nakajima et al. 2012: 92, fig. 3b.

Holotype. TKPM-P17341 , male, 64.8 mm SL, Japan: Kakenouma River, Onga River system, Iizuka , Fukuoka Pref., Kyushu , 12. XII. 2010, J. Nakajima.

Paratypes. MPM-FI1501, 1 male, 55.6 mm SL, same data as holotype ; KPM-NI29503 , 1 male, 57.2 mm SL, Kuro R., Onga R. s., Yahatanishi-ku, Fukuoka Pref., Kyushu , 9. VI. 2005, J. Nakajima; JNC042, 1 male, 56.0 mm SL, Hikosan R., Onga R. s., Oto, Fukuoka Pref., Kyushu , 24. VI. 2008, J. Nakajima; FKUN33734 , 1 female, 63.4 mm SL, Chuganji R., Onga R. s., Kawasaki, Fukuoka Pref., Kyushu , 24. IV. 2004 , J. Nakajima.

Non-type specimens. 3 males, 47.4–59.5 mm SL, Kakenouma R., Onga R. s., Iizuka , Fukuoka Pref., Kyushu , 17. V. 2008, J. Nakajima ; 2 females, 51.2, 61.1 mm SL, Kakenouma R., Onga R. s., Iizuka , Fukuoka Pref., Kyushu , 10. XII. 2003, J. Nakajima ; 2 males and 2 females, 49.6–59.5 mm SL, Hikosan R., Onga R. s., Oto , Fukuoka Pref., Kyushu , 24. VI. 2008, J. Nakajima ; 1 male and 1 female, 59.5, 79.5 mm SL, Kuro R., Onga R. s., Yahatanishi-ku , Fukuoka Pref., Kyushu , 16. V. 2005, J. Kawahara .

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, 50–70 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. 6B); PMN commonly 13; line L3 formed by sharp longitudinal line, reaching to caudal base; line L4 formed by narrow longitudinal line, reaching beyond dorsal fin, narrower than L 3 in male of non-spawning season; line L5 organized in 11–14 roundish, oblong 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 1.0 mm; karyotype diploid.

Description. Lateral view in Figure 3B illustrate body shape, form and position of fins. Morphometric and meristic data for 10 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. 6B). The first branched soft ray of pectoral fin longer than the other rays; 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: 64.8 mm SL male, 79.5 mm SL female.

Coloration. Male in the non-spawning season ( Figs. 3B, 4C). Body yellowish white with light brown pigmentation in fresh specimens. Clear streak running from the tip of snout to the occiput, crossing to the eye. Upper part of head covered with some amorphous spots, these spots often stringed. Opercle and snout covered with some large amorphous patterns. Body pigmentation organized in one middorsal and four lateral zones. Line L1 consisting of a series of 10–16 saddles or oval-shaped blotches. Line L2 formed by convex semicircular spots, only present on the middorsal body, reaching dorsally to interspaces of L1. Line L3 formed by sharp longitudinal line, reaching to caudal base. The posterior part of L3 often intermissive. Line L4 formed by narrow longitudinal line, reaching beyond dorsal fin, narrower than L3. Latter part of L4 often interrupted. Line L5 organized in 11–14 blotches from upper part of the pectoral fin to the caudal-fin base; blotches roundish, frequently oblong 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 caudal base faint or missing.

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

Female ( Fig. 5B). Appearance similar to males in the non-spawning season. But line L4 often formed by longitudinal jagged line, reaching anterior anal-fin base, broader or as wide as L3. Latter part of L4 often interrupted. Lines L3 and L5 tend to be developed with broad stripes in spawning season in large individual.

Sexual dimorphism. Males have roundish lamina circularis at the base of the pectoral fin, but females do not. Generally the body size of the female is larger than that of the male. The L4 of the male tends narrower than that of the female.

Egg diameter. 0.96 ± 0.09 mm (females, N = 4; collected from the Onga River system, Fukuoka Prefecture)

Karyotype. Diploid. ( Kitagawa et al. 2009)

Distribution. Onga River system, 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. Although the spawning ecology is unknown, it is suggested that this subspecies needs a well-vegetated zone as a spawning site ( Nakajima et al. 2011b).

Etymology. The subspecific name is dedicated to Mr. Nobuyoshi Fuchigami, discoverer of this spined loach in the Onga River system.

Remarks. The genetic features have been already reported by Kitagawa et al. (2009). This is a subspecies endemic to the Onga River system.

Japanese name. Onga-suji-shima-dojyô.