Rhinogobius jangshiensis, Chen & Chen & Wang, 2024

Rhinogobius jangshiensis new species

(ẬẔ吻ṞẊ)

( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Materials examined

Holotype. NTOUP-2015-04-301, 33.6 mm SL, Field station no. 2015-03-1 B, Shianya village, Shihliu township, Jangpushi in the Jangshi basin, Jangpu County, Janchou City, Fujian Province, PR China, Coll. I-S. Chen, 10 Mar. 2015.

Paratypes: NTOUP-2015-04-302, 6 specimens, 28.6–30.0 mm SL, other data same as holotype.

Diagnosis

Rhinogobius jangshiensis can be well distinguished from all other congeners by the unique combination of the following features: (1) fins rays: second dorsal fin rays I/8; anal fin rays I/7; pectoral fin rays modally 17; (2) squamation: longitudinal scale series 28–30 (modally 29); perdorsal scales 9–10 (modally 9); (3) vertebral count 27; and (4) specific colouration: cheek with 4 main oblique black stripes in male; branchiostegal membrane grayish blue with about 26–32 rounded, brilliant orange red spots in male; caudal fin gray with some light rounded spots and basal black spotted patch and large central yellow mark in adult male.

Description

Body proportions in Table 1 View TABLE 1 . Body cylindrical anteriorly, compressed posteriorly. Head rather large, somewhat depressed in male. Eye large, dorsolateral. Snout pointed. Cheek fleshy in male. Lips thicks. Mouth oblique, rear edge extending to vertical of anterior margin of eye in male, but not reaching the vertical in female. Both jaws with 3–4 rows of conical teeth, outer jaws enlarged. Tongue margin rounded. Anterior nostril in short tube and posterior nostril round. Gill opening restricted, extending ventrally near vertical midline of opercle. Vertebral count 11 + 16 = 27 (in all 7 specimens).

Fins.— D1 VI, D2 I/8; A I/7; P 16–17 (modally 17); V I/5+I/5 (distribution frequency in Table 1 View TABLE 1 ). D1 rounded, 3 rd and 4 th rays longest, with rear tip while depressed extending just to D2 origin in male, but not reaching the point in female. Origin of A inserted below second branched rays of D2. The rear tips of D2 and A rays when depressed fall well short of procurrent rays of C. P moderate large and oblong, its rear tip near reaching vertical line through anus. V rounded, spinous rays with somewhat pointed membrane lobe. C elliptical, rear edge rounded.

Scales.— Body with moderately large ctenoid scales, anterior region of predorsal area naked; posterior dorsal area and belly cycloid. LR 28–30 (modally 29); TR 9–10 (modally 9); PreD 9–10 (modally 9); and SDP 8. Head and prepelvic region naked. Anterior edge of midpredorsal squamation reaching or near the midline of upper end of gellopening.

Values in parenthese are the average.

Head lateral-line system

Canals: Nasal extension of anterior oculoscapular canal with terminal pore σ located in between anterior and posterior nostrils. The gap between two oculoscapular canals is less than the length of posterior oculoscapular canal. Anterior interorbital sections of oculoscapular canal with paired poreλ. A single pore κin near rear of interorbital region. Pore ω present near posterior, dorsal margin of eye. Lateral section of anterior oculoscapular canal with pore α and terminal pore ρ. Posterior oculoscapular canal with two terminal pores θ and τ. Preopercular canal with three pores γ, δ and ε.

Sensory papillae: Row a extending to vertical midline of orbit. Row b length about equal to eye diameter.

Rows c, d longer. A single cp papilla. Row f paired. Anterior edge of row oi connected to lower region of row ot.

Colouration of fresh preserved material.—( Fig. 1 View FIGURE 1 and Fig. 3 View FIGURE 3 )

Body light brown to yellowish brown. Side of body with 6 major grayish brown blotches and 4–5 longitudinal rows of grayish brown lines. Dorsal region of body with 5–6 major grayish blotches. Caudal fin base with a rather short blackish brown bar. Head grayish brown to yellowish brown. Dorsal side of snout with a pair of deep red stripes united to snout tip, another gray stripe below eye in male, but two grayish black bar below eye in female. Lips and dorsal snout orange brown. Cheek grayish brown with four oblique grayish black stripes in male but yellowish brown spotless in female. Branchiostegal membrane grayish blue with about 26–32 rounded, brilliant orange red spots in male, but pale brown and spotless in female.

First dorsal fin broad grayish brown band darkening anteriorly, outer margin orange in male, but translucent with distal orange yellow mark in female. Second dorsal fin with oange background and three basal longitudinal rows of deep brown spots in male; but translucent with three basal longitudinal grayish brown spots and pale margin in female. Anal fin orange with distal gray to black margin. Pectoral fin gray with basal creamy yellow band and its base with longitudinal deep brown bar in upper part and basal brown rim in male; but translucent and its base with longitudinal brown bar in female. Caudal fin gray with some light rounded spots and basal black spotted patch and large central yellow mark in adult male, but translucent with 4–5 vertical rows of blackish brown spots in female. Pelvic fin gray to grayish black in male; but whitish in female.

Etymology.— The specific name, janshiensis , refers to the collecting type locality: the small tributary in “Janshi” basin, Janpu County, Janchou City, Fujian Province, PR China.

Distribution.— This new species is, thus far, only found in the small tributary of Janpushi, Janshi basin near Shianya village, Janpu County, Janchou City, Fujian Province, PR China. It occurs in shallow-water riffles and front region of pools (depth 20–60 cm depth) with substratum of large pebbles with slow to moderate flowing water.

Remarks.— The new species, Rhinogobius janshiensis , is rather similar to R. longyanensis Chen et al., 2008 than any other congeneric fluvial species in Fujian Province by overall colouration pattern in male. However, Rhinogobius janshiensis can be well separate from R. longyanensis by the following features ( Tables 2 View TABLE 2 , 3 View TABLE 3 ): (1) longitudinal scale rows: 28–30 (modally 29) vs. usually 30–31; (2) predorsal scales: modally 9 vs. 7; (3) cheek pattern: four main oblique black lines vs. three oblique black line in male; and (4) caudal fin with central yellow mark vs. without such mark in male.

This new species also somewhat similar to R. lingtongyanensis Chen et al., 2022 . The new species can be well separate from R. lingtongyanensis by the following features: (1) vertebral count 27 vs. 26; (2) predorsal scales: modally 9–10 vs. 5–6; (3) cheek pattern: four main oblique black lines vs. five oblique black line in male; (4) branchiotegal membrane with several red spots vs. entirely spotless in male; (5) caudal fin with central yellow mark vs. without such mark in male.