Rhinogobius baborinisanensis, Chen & Yeh, 2024

Chen, I-Shiung & Yeh, Ming-Fon, 2024, Two new freshwater gobiid species of Rhinogobius Gill, 1859 (Teleostei: Gobiidae) from Taiwan, Zootaxa 5550 (1), pp. 333-353 : 334-343

Rhinogobius baborinisanensis n. sp.

(ṮƜ吻Ṟğ)

Figs. 1–5

Materials examined

Holotype. —NTOUP-2021-12-651, 41.2 mm SL, coll. I-S. Chen, Dec. 14, 2021, small tributary of Dar-An River basin, Maioli County, Taiwan, ROC.

Paratypes.—NTOUP-2021-12-652, 11 specimens, 20.6–37.9 mm SL, collection date and other data same as holotype.

NTOUP-2022-04-255, 4 specimens, 39.9–45.6 mm SL, coll. I-S. Chen, April 15, 2022, small tributary of DarAn River basin, Maioli County, Taiwan, ROC.

NTOUP-2022-05-266, 5 specimens, 28.8–36.7 mm SL, coll. I-S. Chen, May 10, 2022, small tributary of DarAn River basin, Maioli County, Taiwan, ROC.

Diagnosis

Rhinogobius baborinisanensis can be well distinguished from all other congeners by the unique combination of the following features: (1) fins: second dorsal fin rays modally I/8; anal fin rays I/7; pectoral fin rays modally 17; (2) squamation: longitudinal scale series 32–33 (modally 33); perdorsal scales usually 13–14; (3) vertebral count 27; (4) rear edge of mouth: merely extending to or slightly beyond vertical of anterior margin of pupil in male and (5) specific colouration: Lateral body with 6–8 longitudinal rows of deep orange to orange red spots about 1/2–1/3 of pupil diameter in male. Cheek and opercle with 24–28 orange to reddish orange spots in male. Larger cheek spot about 1/2 of pupil diameter. Branchiostegal membrane gray with some yellowish green tone with larger 12–15 orange spots in male; but number of spots less than 5 in female. A middle, conspicuous grayish black mark mainly in front of second spine of first dorsal fin and its basal region with 7–9 orange or brown spots in male. Pectoral fin base with two rows (totally 7–10 spots) of orange to red orange spots which 3–4 larger orange spots on anterior row in male.

Description

Body proportions in Table 1 . Body rather slender, cylindrical anteriorly, compressed posteriorly. Head rather large, somewhat depressed in male. Eye large, dorsolateral. Snout pointed. Cheek rather fleshy in male. Lips thick. Mouth oblique, rear edge extending to or just beyond vertical of anterior margin of eye in male, but not reaching 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 small and restricted, extending ventrally to vertical midline of opercle. Vertebral count 10 + 17 = 27 (examined in all 7 larger specimens).

Fins.— D1 VI, D2 I/8–9 (modally I/8); A I/7–8 (modally 7); P 16–17 (modally 17); V I/5+I/5 (distribution frequency in Table 2 ). D1 rounded, 3 rd and 4 th rays slightly longer, with rear tip while depressed near or slightly extending beyond D2 origin in male; but not reaching this point in female. Origin of A inserted below second branched rays of D2. Rear tips of D2 and A fin rays extending far beyond procurrent rays of C in male. P moderate moderate large and oblong, rear tip not reaching vertical line through anus in male. V small and rounded, spinous rays with somewhat pointed membrane lobe. C elliptical, rear edge rounded.

Scales.— Body with moderately size ctenoid scales, anterior region of predorsal area naked; posterior dorsal area and belly cycloid. LR 32–34 (modally 33); TR 10–11 (modally 11); PreD 12–14 (usually 13–14); and SDP 10–11 (modally 10) (distribution frequency in Table 2 ). Head and prepelvic region naked. Anterior edge of midpredorsal squamation extending beyond the vertical of midline of opercle.

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SDP Vert 6 7 8 9 10 11 12 13 14 15 X 26 27 X R. baborinisanensis n. sp. 6 1 10.1 7 27.0 R.

2. (

macromaculatus n. sp. 4 1 8.2 5 27.0 R. candidianus 1 7 9 2 1 12.8 20 26.0 R. delicatus 1 14 4 2 10.3 21 26.0 R. formosanus 4 7 4 11.0 15 26.0 R. gigas 3 5 5 1 11.3 14 26.0 R. henchuenensis 11 9 10.5 20 26.0 R. lanyuensis 1 11 3 11.1 10 26.0 R. maculafasciatus 5 12 4 7.0 21 26.0 R. nantaiensis 412 4 11.0 20 26.0 R. rubromaculatus 14 1 8.1 15 27.0 R. similis 7 13 6.7 20 26.0 R. yangminshanensis

1 178.0 10 27.0

Head lateral-line system.—( Figure 2 )

Canals: Nasal extension of anterior oculoscapular canal with terminal pore σ located in between anterior and posterior nostrils. A single pore κ in near rear of interorbital region in lacking both with paired pore λ and pore ω. Lateral section of anterior oculoscapular canal with terminal pore α. No posterior oculoscapular canal. No preopercular canal.

Sensory papillae: Row a extending just beyond 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 well separated to lower region of row ot.

Colouration while fresh.—( Figures 1 , 3–5 )

Body yellowish brown to brown. Side of body without distinct gray or brown blotches in male; but somewhat distinct 9–10 brown blotches along middle side in female. Lateral body with 6–8 longitudinal rows of deep orange to orange red spots about 1/2–1/3 of pupil diameter in male; orange to brown spots less than 1/3 of pupil diameter in female. Dorsal region of body with 5–6 indistinct gray blotches.

Head yellowish brown to brown. Cheek and opercle with 24–28 orange to reddish orange spots in male, with 10–12 small brown spots in female. Larger cheek spot about 1/2 of pupil diameter. Nape with many orange spots in male, with small brown spots in female. Snout on dorsal side with a pair of orange to brown stripe united at snout tip. Snout on lateral side with an infraorbital orange stripe in male; but orange brown to brown in female. Between the stripe with a wide, gray to blackish gray mark in female. Lips and dorsal snout pale brown. Branchiostegal membrane gray with some yellowish green tone with larger 12–15 orange spots in male; but number of spots less than 5 in female.

First dorsal fin in having pale brown with very thin orange margin on distally 1/5 area in front a smaller of third spine. A middle, conspicuous grayish black mark mainly in front of second spine of first dorsal fin in male, but another smaller spot in between second and third spines in female. Basal region of first dorsal fin with 7–9 orange or brown spots in male, 6–7 in female. Second dorsal fin pale with snow white band on distal 1/4–1/5 region, 5–6 longitudinal rows of orange spots in male; translucent with thin gray band, 4–5 longitudinal blackish brown spots in female.

Anal fin pale to orange with a distal grayish bane following with very narrow distal snow white margin. Caudal fin surrounding with posteriorly orange zone of fin membrane in male accompanying with 2–3 somewhat vertical rows of orange or reddish orange spots in basal region; with pale brown zone in female accompanying with 4 vertical rows of small orange brown spots. Both sexes with a narrow snow white margin. Caudal fin base with two grayish brown marks, upper one usually larger than lower one. Pectoral fin base with two rows (totally 7–10 spots) of orange to red orange spots which 3–4 larger orange spots on anterior row in male; with two rows (totally 6–8 spots) of smaller brown spots in female. In front of the base with modally 2 orange spots just behind opercle in male. Pelvic fin pale gray in male, whitish and more translucent in female.

Etyomolgy

The specific name “ baborinisanensis ” is referred to the type locality of tributaries of river drainage—Dar-An River running northward originating from “Babo Rinisan” mountain ridge which as a classical name for “Dar-Shue-Shan” mountain ridge, a branch of Shue-Shan mountain ridge, northern Taiwan.

Distribution

The new species is endemic species in fresh waters of Taiwan. It is merely well known for its distribution range includes several small tributaries of Dar-An River basin, Miaoli County, northern Taiwan.

Remarks

The new species, Rhinogobius baborinisanensis is rather similar to Rhinogobius rubromaculatus Lee & Chang, 1996 than any other congeneric species. However, they can be well distinguished from Rhinogobius rubromaculatus by the following features: (1) pectoral fin rays: modally 17 vs. 16; (2) predorsal scales usually 13–14 vs. 11; (3) scales between first dorsal fin origin to pectoral fin base modally 10 vs. 8; (4) longitudinal scales: modally 33 vs. modally 29; and (5) specific coloration: blotches of first dorsal fin: larger black blotch in front of the second spine and the height of dorsal fin blotch about 1/2 length of second spine in male vs. smaller bluish black blotch in front of third dorsal fin ray and the height of dorsal fin blotch less than 1/3 length of second dorsal fin ray in male; pectoral fin base: usually 4 orange spots in male in first row in male vs. 3 orange spots in first row in male.

Furthermore, the unpublished mitogenetic data of current new species has recently revealed that it has also shown the great mitogenetic divergence of mtDNA from the discrete species, Rhinogobius rubromacultatus Lee & Chang, 1996 (Chen et al. unpublished).

Figures

FIGURE 1. Rhinogobius baborinisanensis n. sp., A. holotype, 41.2 mm SL, B. paratype, 37.9 mm SL, Dar-An River basin, Miaoli County, Taiwan.

FIGURE 2. Head lateral-line system of Rhinogobius baborinisanensis n. sp., holotype, 41.2 mm SL, Dar-An River basin, Miaoli County, Taiwan. (Bar = 1 mm).

FIGURE 3. Head pigmentation pattern of Rhinogobius baborinisanensis n. sp., holotype, 41.2 mm SL, Maioli County, Taiwan.

FIGURE 4. Pigmentation pattern of Rhinogobius baborinisanensis n. sp., holotype, 41.2 mm SL, Miaoli County, Taiwan.

FIGURE 5. Ventral view of head of Rhinogobius baborinisanensis n. sp., holotype, 41.2 mm SL, Miaoli County, Taiwan.