Enneapterygius olivaceus, Dewa & Tashiro & Motomura, 2023

Dewa, Yuna, Tashiro, Satokuni & Motomura, Hiroyuki, 2023, A new species of the genus Enneapterygius (Perciformes: Tripterygiidae) from Japan and the Philippines, with a synopsis and synonymy of related species, Zootaxa 5374 (3), pp. 333-360 : 334-342

Enneapterygius olivaceus n. sp.

[New English name: Olive Green Triplefin; new standard Japanese name: Uguisu-hebigimpo]

Figures 1–6 ; Tables 1 , 6 , 7

Enneapterygius sp. 3 : Tashiro, 2019: 306, unnumbered fig. (Yoro-jima island, Amami Islands, Japan).

Holotype. KAUM –I. 101347, male, 19.3 mm SL, off Shinaha Beach , Chabana , Yoron-jima island, Amami Islands, Japan, 27°24′36″N, 128°24′57″E, 1–1.8 m, 28 June 2017, B. Jeong.

Paratypes. 27 specimens (13.7–25.1 mm SL). JAPAN : AMAMI ISLANDS: Yoro-jima island : KAUM –I. 89018, female, 22.7 mm SL, south of Yoro Port , 28°02′47″N, 129°10′03″E, 2 m, 11 May 2016 , K. Koeda. Okinoerabu-jima island : KAUM –I. 122097, female, 13.7 mm SL, Yakomo Beach, China, 27°20′04″N, 128°32′49″E, 0.5–1.5 m, 22 Oct. 2018 , H. Motomura et al.; KAUM –I. 159890, female, 18.5 mm SL, KAUM –I. 159908, male, 15.6 mm SL, Wanjo Beach, Wadomari, 27°20′04″N, 128°38′06″E, 0.5–1 m, 24 Aug. 2021 , B. Jeong et al. Yoron-jima island : KAUM –I. 101346, male, 18.5 mm SL, same data as holotype ; KPM-NI 22709 , male, 24.3 mm SL, Maehama Beach , 0.5–3 m, 20 Aug. 2008 , M. Watai. OKINAWA ISLANDS: Okinawa-jima island : KAUM –I. 28561, male, 23.3 mm SL, Minatogawa, Urasoe, 26°16′35″N, 127°42′06″E, 1 m, 14 Apr. 2010 , M. Meguro; KAUM –I. 32069, male, 21.8 mm SL, KAUM –I. 32072, female, 15.1 mm SL, off Kushi, Nago, 26°30′30″N, 128°01′32″E, 9 July 2010 , Y. Sakurai; KAUM –I. 35705, male, 20.0 mm SL, Naha, 26°32′03″N, 128°05′45″E, 28 Oct. 2010 , Y. Sakurai; KAUM –I. 41904, male, 22.5 mm SL, Nago, 26°31′N, 128°02′E, 19 Apr. 2011 , Y. Sakurai. Sesoko-jima island : URM-P 18596, 3 males, 17.9–25.1 mm SL, 4 May 1977 . Senaga-jima island : KAUM –I. 32462, female, 17.9 mm SL, west coast of island, 26°10′25″N, 127°38′30″E, 0.5 m, 2 Jan. 2010 , Y. Sakurai. Tokashiki-jima island : KPM-NI 21313 , male, 22.0 mm SL, south of Tokashiku Beach , 6 Mar. 2008 , A. Kishimoto. YAEYAMA ISLANDS: Ishigaki-jima island : KAUM –I. 62878, female, 21.5 mm SL, KAUM –I. 62879, male, 16.9 mm SL, KAUM –I. 62885, male, 19.0 mm SL, KAUM –I. 62886, 16.9 mm, KAUM –I. 62887, male, 15.8 mm SL, KAUM –I. 62888, male, 14.9 mm SL, KAUM –I. 62896, male, 15.5 mm SL, KAUM –I. 62897, female, 14.7 mm SL, KAUM –I. 62898, male, 14.4 mm SL, off Osaki, 24°08′44″N, 124°06′43″E, 0.5–2 m, 18 July 2014 , T. Yoshino & S. Tashiro. PHILIPPINES : USNM 273903 , female (1 of 8), 16.7 mm SL, Maloh, Negros Oriental, Negros Island , 09°03′06″N, 122°59′42″E, 18 May 1979 , H. Fehlmann et al.; WAM P. 31397-012, male, 20.3 mm SL, south of Talampulan Island, Calamian Islands , 12°06′N, 119°51′E, 3–5 m, 11 Feb. 1998 , G. Allen.

Diagnosis. A species of Enneapterygius ( Fig. 1 ) with the following combination of characters: 11–13 (modally 12) second dorsal-fin spines; 8–10 (9) third dorsal-fin rays; I, 16 or 17 (16) anal-fin rays; i–v + 3–7 + vi–viii = 14–17 (15) pectoral-fin rays; 12–14 (13) pored lateral-line scales; 18–22 (20) notched lateral-line scales; 30–32 (31) scale rows in longitudinal series; 1–3 (2) scales above 1st pored lateral-line scale; 2 or 3 (2) scales below 1st notched lateral-line scale; 8 circumpeduncular scales; mandibular pore formula 3–4 + 1 + 3–4 (usually 3 + 1 + 3); head long, its length 28.4–33.0% (mean 31.4%) of SL; upper jaw long, its length 9.5–13.1% (11.4%) of SL; 1st spine of first dorsal fin longer than that of 2nd dorsal-fin, its length 11.2–15.5% (13.6%) of SL; anterior nostril tentacle unbranched; orbital tentacle large, leaf-shaped, the edge rounded, its length slightly less than or subequal to pupil diameter, its width almost half of its length; body generally olive-green, head, including eye, snout, lips, cheek, opercle, and pectoral-fin base dense black in nuptial males; body generally yellowish-white, with scattered brownish-orange pigmentation particularly along scale margins, darker on lateral surface forming indistinct A-shaped or X-shaped bars in pale males and females; pectoral-fin rays flecked with broad brown pigmentation forming ca. 4 or 5 vertical bands on fin; anal fin generally black, with translucent margin in nuptial males; grayish pigmentation on central region of anal-fin rays in pale males and females; caudal fin semi-transparent, white with grayish rays.

Description. Data for the holotype are presented first, followed by paratype data in parentheses if different from holotype. Detailed counts and morphological measurements given in Tables 1 , 6 , and 7. Cephalic sensory-pore system illustrated in Fig. 2 .

Dorsal fin III, XI, 10 ( III, XI –XIII, 8–10); anal fin I, 16 (16 or 17); pectoral fin iii + 5 + vii = 15 [i–v + 3–7 + vi–viii = 14–17 (iii + 5 + vii = 15 in holotype and 2 paratypes, iii + 4 + vii =14 and iv + 4 + vii = 15 in 3 paratypes, i + 7 + vi = 14, ii + 5 + viii = 15, ii + 6 + vii = 15, and v + 3 + vii in 2 paratypes, and i + 6 + viii = 15, i + 7 + vii = 15, ii + 5 + vii = 14, ii + 6 + viii = 16, iii + 5 + vi =14, iv + 5 + vii = 16, and iv + 6 + vii = 17 in single paratype specimens)]; 31 (30–32) scale rows in longitudinal series; 2½ scales below 2nd dorsal-fin; mandibular pore formula 3 + 1 + 3 (4 + 1 + 4 in single paratype).

Body moderately elongate, slightly compressed anteriorly, progressively more compressed posteriorly. Dorsal profile of snout straight, moderately steep. Mouth slightly oblique; posterior margin of maxilla extending slightly beyond anterior margin of pupil; anterior tip of upper jaw below level of lower margin of orbit (lateral view). Anterior nostril a membranous tube with a small thin unbranched tentacle; anterior nostril at level of middle of eye, slightly closer to eye than to upper lip; posterior nostril opening circular, without membranous tube ( Fig. 2 ). Eye oriented dorsolaterally; broad leaf-like tentacle on posterodorsal margin of eye, its length longer than nasal tentacle and subequal to pupil diameter ( Fig. 2 ). Interorbital space narrow, its width less than pupil diameter. Opercular margin slightly pointed, reaching to below base of 3rd spine of first dorsal fin.

Lateral line discontinuous, with anterior series of pored scales and posterior series of notched scales; pored scale series ending below membrane between 9th and 10th spines of second dorsal fin; notched scale series beginning below second scale from last pored scale (or below last pored scale), ending at caudal-fin base; Body scales ctenoid; scales absent on head (including maxilla, interorbital space, preopercle and opercle), pectoral-fin base, pre-and inter-pelvic-fin region, and pre-dorsal-fin region; all fin membranes, except basal part of caudal fin, scaleless.

First dorsal fin triangular to trapezoid, its origin vertically above pre-opercular margin (midway between pre-opercular and opercular margins); 1st spine of first dorsal fin longest, thereafter becoming shorter posteriorly. Origin of second dorsal fin just above 5th (4th to 6th) pored lateral-line scale, 2nd or 3rd spine longest, thereafter becoming gradually shorter posteriorly, forming rounded margin. Third dorsal fin semicircular to trapezoid, its origin just above 19th and 20th longitudinal scales, 1st or 2nd ray longest, thereafter becoming gradually shorter posteriorly. Anal-fin membranous margin deeply incised between rays; anal fin origin just below 7th (6th to 8th) spine base of second dorsal fin, its posteriormost tip close to caudal-fin base. Pectoral fin relatively long, its posterior tip pointed and slightly beyond (or reaching) vertical through base of last spine of second dorsal fin; upper and lowermost pectoral-fin base level with bases of 1st spine of second dorsal-fin and 3rd spine of first dorsal fin, respectively. Pelvic fin origin just below vertical through base of 1st spine of first dorsal fin, its tip not reaching anus. Caudal fin rounded, its length similar to head length.

Coloration of nuptial males. Fresh coloration ( Fig. 1A, B ). Body generally olive green; scattered brownish-orange pigmentation particularly along scale margins; small indistinct white spots aligned horizontally on level of notched scale series. Head, including eye, snout, lips, cheek, and opercle, and pectoral-fin base dense black [dark gray with scattered melanophores]. Pre-pelvic region and undersurface of abdomen grayish. Orbital tentacle and iris brownish-orange, pupil black. Caudal-fin base with narrow whitish vertical bar. First dorsal fin black, with brownish-orange pigmentation between 1st and 2nd spine membranes. Second and third dorsal fins generally transparent, with two black longitudinal bands on fin margin and base, width of former ca. 1/2 length of spines, latter somewhat indistinct. Pectoral fin transparent, membranes between lower 6–8 rays black [translucent dark gray]. Pelvic fins black with white edges. Anal fin generally black, with translucent margin [translucent grayish with scattered white spots]; fin ray bases with 7 or 8 white spots aligned along lower margin of posterior body. Caudal fin semi-transparent, white with grayish rays and ca. 5 faint whitish bars.

Preserved coloration ( Fig. 1C ). Body yellowish-white. Blackish pigmentation in fresh condition clearly brownish in preserved specimens. Other pigmentation completely lost.

Live coloration ( Fig. 3 ). Similar to fresh coloration, but black pigmentation somewhat indistinct in life. Body yellowish-brown, with ca. 5 dusky oblique bars and flecked with whitish spots; lower half of head and pectoral-fin base with scattered melanophores; two yellowish-white stripes extending from lower margin of eye to isthmus. Iris brown with green lines radiating from pupil. Pupil black, margined by orange. First dorsal fin translucent white, membrane between 1st and 2nd spines cream. Second and third dorsal fins transparent with black spots.

Coloration of females. Fresh coloration ( Fig. 1D, E ). Body generally yellowish-white; scattered brownish-orange pigmentation particularly along scale margins, darker on lateral surface forming indistinct A-shaped or X-shaped bars; ca. 5 white spots, width subequal to pupil diameter, aligned horizontally on level of notched scale series. Cheek and opercle reddish-brown. flecked with golden blotch; reddish-brown stripes extending from tip of snout to anterior margin of eye, its width subequal to upper lip width. Pre-pelvic region and undersurface of abdomen whitish. Orbital tentacle and iris brownish-orange; pupil black margined with orange. Lower margin of posterior body with ca. 9 or 10 brownish-red spots aligned along anal-fin base. Caudal-fin base with narrow yellowish-white vertical bands. First dorsal fin transparent with scattered melanophores; brownish-orange or cream pigmentation between 1st and 2rd spine membranes. Second and third dorsal fins generally transparent, with 2 or 3 yellowish oblique bands irregularly; faint grayish longitudinal bands on fin margin and edge. Anal fin with grayish pigmentation on central region of fin rays; yellowish irregular blotches forming ca. 7 or 8 oblique bars on fin membranes. Pectoral fin translucent white, with yellowish blotches; fin rays flecked with broad brown pigmentation forming ca. 4 or 5 vertical bands on pectoral fin. Pelvic fins translucent white. Caudal fin translucent white with narrow yellowish vertical bars; fin rays dark brown. Coloration of the pale male is very similar.

Preserved coloration ( Fig. 1F ). Body uniformly yellowish-white. Cheek, nape, opercle and pectoral-fin base brown. Stripe on snout, A-shaped or X-shaped bars on lateral surface of body, pigmentation on first dorsal and anal fins, two longitudinal bands on second and third dorsal fins, and vertical bars on pectoral-fin retained as faint brown pigmentation. Pelvic fin generally translucent, white.

Distribution and habitat. Currently known only from southern Japan and the Philippines. The specimens examined in this study were collected from the southern part of the Ryukyu Islands (the Amami, Okinawa, and Yaeyama islands) and Talampulan and Negros islands, the Philippines ( Fig. 4 ).

Enneapterygius olivaceus n. sp. usually inhabits shallow rocky reefs in depths of 0.5–3 m. The specimen from Okinawa-jima island ( KAUM –I. 28561, male, 23.3 mm SL) was collected from the upper surface of the rock covered by short seaweed ( Fig. 3 ) .

Etymology. The specific name “ olivaceus ”, treated as a noun in apposition, is derived from Latin and refers to the olivaceous body color of specimens.

Remarks. Enneapterygius olivaceus n. sp. is most similar to Enneapterygius gracilis Fricke 1994 from northern Australia (see diagnosis in following species account), the two species sharing the following features: 11–13 (modally 12) second dorsal-fin spines; 8–11 (modally 9) third dorsal-fin rays; 12–14 (13) pored lateral-line scales; 1–2.5 (2) scales above 1st pored lateral-line scale; head long, its length 28.4–33.0%; 1st spine of the first dorsal fin longer than that of second dorsal fin, its length 10.8–17.9%; orbital tentacle large, leaf-shaped, its length slightly less than or subequal to pupil diameter; body with brownish bands in pale males and females; lower half of head and pectoral-fin base black in nuptial males; pectoral-fin rays flecked with brown pigmentation forming ca. 4 or 5 vertical bands ( Figs. 1 , 5A, B , 7 ; Tables 1 , 2 , 6 , 7 ). However, E. olivaceus n. sp. differs from E. gracilis in having slightly fewer notched lateral-line scales [18–22 (modally 20) in the former vs. 19–21 (21) in the latter] and scales below the 1st notched scale [2 or 3 (modally 2) vs. 3–3.5], a single symphyseal mandibular-pore (mandibular pore formula: 3 + 1 + 3) (vs. double symphyseal mandibular-pores, 3 + 2 + 3), black pectoral fins in nuptial males (vs. pectoral fin pale with brownish blotches in both sexes), and no distinct lines on the anal-fin membranes (vs. anal fin with 7–9 brownish oblique bands) ( Figs. 1 , 7 , 8 ; Tables 6 , 7 ). Although E. nanus also has a small number of scales below the 1st notched scale [2 or 2.5 (2)], the mandibular pore formula 3 + 1 + 3, and the anal fin with no oblique lines ( Fig. 12 , Tables 6 , 7 ), it clearly differs from E. olivaceus n. sp. in some morphometric characters, viz., E. olivaceus n. sp. has greater head length [28.4–33.0% (mean 31.4 %) of SL], 1st spine length of the first dorsal fin [11.2–15.5% (13.6%) of SL] than E. nanus [28.3–30.1% (29.5%) of SL, 8.2–10.5% (9.8%) of SL, respectively], and orbital tentacle (its length slightly shorter than or subequal to pupil diameter vs. slightly less than or subequal to half of pupil diameter in E. nanus ) ( Fig. 4A, C ), and the pectoral-fin rays flecked with broad brown pigmentation forming ca. 4 or 5 vertical bands (no distinct pigmentation on fin) ( Figs. 1 , 12 ). Moreover, the new species has been recorded from southern Japan and the Philippines, whereas E. nanus is likely endemic to the Marshall Islands ( Fig. 4 ; see E. nanus Remarks). In Japanese waters, E. olivaceus n. sp. co-occurs with E. minutus in the southern part of the Ryukyu Islands ( Fig. 4 ). However, the new species is clearly distinguished from E. minutus by some morphological characters and the color patterns of nuptial males (see E. minutus Remarks; Figs. 4 , 7 ; Tables 2 , 4 , 6 , 7 ).

Figures

FIGURE 1. Photographs of fresh (A, B, D, E) and preserved (C, F) specimens of Enneapterygius olivaceus n. sp. A–C KAUM–I. 101347, holotype, male, 19.3 mm SL, Yoron-jima Island, Amami Islands, Japan; D–F KAUM–I. 62897, paratype, female, 14.7 mm SL, Ishigaki-jima Island, Yaeyama Islands, Japan.

FIGURE 2. Illustrations of the cephalic sensory pore system of Enneapterygius olivaceus n. sp. (KAUM–I. 101347, holotype, male, 19.3 mm SL). Dorsal (A), lateral (B), and ventral (C) views of head. Bar represents 1 mm.

FIGURE 3. Male of Enneapterygius olivaceus n. sp. (KAUM–I. 28561, male, 23.3 mm SL, Okinawa-jima Island, Okinawa Islands, Japan) before and after capture. Underwater photo by M. Meguro.

FIGURE 4. Distributional map of five species of Enneapterygius examined in this study.

FIGURE 5. Orbital tentacle shape of A Enneapterygius olivaceus n. sp., KAUM–I. 101347, holotype, male, 19.3 mm SL, Yoron-jima Island, Japan; B E. gracilis, AMS I. 25500-005, male, 19.5 mm SL, Western Australia; C E. nanus, NSMT-P 54443, male, 14.3 mm SL, Eroj Island, Marshall Islands; D E. minutus, lectotype, BMNH 1961.10.20.1, female, 20.4 mm SL, Apia, Western Samoa. Bars represent 1 mm

FIGURE 6. Lengths of A head, B upper jaw, and c 1st spine length of first dorsal-fin (% standard length) relative to standard length in five species of Enneapterygius. Yellow triangles, orange circles, red diamonds, blue squares, and a green star indicate E. gracilis, E. minutus, E. nanus, E. olivaceus n. sp., and E. philippinus, respectively

FIGURE 7. Photographs of preserved specimens of Enneapterygius gracilis. A NTM S. 10431-027, holotype, male, 19.7 mm SL, Northern Territory, Australia; B AMS I. 17060-043 (1), paratype, male, 19.9 mm SL, Western Australia; C AMS I. 17060- 043 (3), paratype, female, 19.5 mm SL; D NTM S. 10431-034, paratype, female, 16.5 mm SL, Northern Territory

FIGURE 8. Illustrations of mandibular pore system of Enneapterygius gracilis and Enneapterygius minutus. A double symphyseal mandibular-pores (3 + 2 + 3) (Enneapterygius gracilis, AMS I. 25500-005, male, 19.5 mm SL), B single symphyseal mandibular-pore (mandibular pore formula: 3 + 1 + 3) (Enneapterygius minutus, BMNH 1961.10.20.1, female, 20.4 mm SL) Bars represent 1 mm

FIGURE 12. Photograph of the holotype of Enneapterygius nanus (USNM 142233, male, 15.8 mm SL, Rujoru Island, Eniwetok Atoll, Marshall Islands)

Tables

TABLE 1. Counts and morphometric measurements (as % of SL) of specimens of Enneapterygius olivaceus n. sp.

	Holotype	Paratypes
	KAUM–I. 101347	n = 16	n = 11
	Japan	Japan and Philippines
	Male	Males	Females
Standard length (SL; mm)	19.3	14.4–25.2	13.5–22.7
Counts
Dorsal-fin rays	III, XI, 10	III, XI–XIII, 8–10	III, XI–XII, 9–10
Anal-fin rays	I, 16	I, 16–17	I, 16–17
Pectoral-fin rays	iii + 5 + vii = 15	i–v + 3–7 + vii–viii = 14–17	i–v + 3–7 + vi–viii = 14–16
Scale rows in longitudinal series	31	30–32	30–32
Pored lateral-line scales	13	12–14	12–13
Notched lateral-line scales	20	18–22	18–22
Scales above of 1st PLL	2	1–2½	2–3
Scales below 2nd dorsal fin	2½	2–3	2–3
Scales below of 1st NLL	3	2–3	2–3
Circumpeduncular scales	8	8	8
Mandibular pore formula	3 + 1 + 3	3 + 1 + 3	3 + 1 + 3 (rarely 4 + 1 + 4)
Measurements (% SL)
Body depth	20.3	19.3–22.8 (20.6)	17.3–22.1 (19.9)
Body width	20.6	17.4–22.8 (19.3)	16.7–20.4 (18.5)
Head length	28.4	29.2–33.0 (31.4)	28.7–32.3 (31.0)
Snout length	9.4	6.7–11.7 (9.9)	8.6–12.3 (10.0)
Orbit diameter	7.6	8.0–12.1 (9.9)	8.1–11.7 (10.2)
Interorbital width	2.4	1.2–3.4 (2.6)	1.2–2.8 (2.2)
Upper-jaw length	11.4	10.2–13.1 (11.7)	9.5–12.0 (10.9)
Postorbital length	13.7	12.1–15.5 (13.5)	11.6–13.8 (12.8)
Pre-1st-dorsal-fin length	25.2	23.5–28.4 (25.8)	23.9–28.4 (26.3)
Pre-2nd-dorsal-fin length	35.5	33.6–39.3 (36.5)	36.2–39.1 (37.7)
Pre-3rd-dorsal-fin length	69.1	66.8–71.8 (70.0)	69.3–73.3 (70.9)
Pre-anal-fin length	47.8	47.3–52.9 (49.3)	48.3–52.6 (50.9)
Anal-fin base length	39.1	38.8–43.0 (40.7)	36.2–41.3 (39.2)
Pre-pectoral-fin length	32.5	30.3–35.7 (32.4)	31.2–35.2 (33.0)
Pre-pelvic-fin length	24.5	21.9–27.7 (24.1)	21.7–26.6 (23.9)
Caudal peduncle length	13.2	11.0–15.3 (13.3)	10.8–15.1 (12.9)
Caudal peduncle depth	9.9	7.2–9.9 (8.8)	7.7–9.2 (8.5)
1st spine length of 1st dorsal fin	13.8	11.8–15.5 (14.0)	11.2–14.9 (12.7)
2nd spine length of 1st dorsal fin	12.2	10.5–14.7 (12.6)	9.5–13.5 (11.1)
3rd spine length of 1st dorsal fin	9.8	7.3–11.1 (9.4)	6.8–9.3 (8.2)
1st dorsal-fin base length	5.6	4.7–6.8 (5.8)	4.0–6.4 (5.3)
1st spine length of 2nd dorsal fin	12.6	10.0–14.2 (12.9)	11.4–14.0 (12.6)
2nd spine length of 2nd dorsal fin	13.4	12.6–16.0 (14.5)	12.5–14.7 (13.7)
3rd spine length of 2nd dorsal fin	13.7	13.1–16.1 (14.9)	12.8–15.0 (14.1)
2nd dorsal-fin base length	27.5	25.3–33.4 (29.2)	23.9–31.1 (28.3)
1st ray length of 3rd dorsal fin	14.6	11.9–18.5 (16.2)	13.4–18.1 (15.8)
2nd ray length of 3rd dorsal fin	13.7	13.8–18.4 (16.4)	14.2–17.2 (15.6)
3rd ray length of 3rd dorsal fin	13.2	13.2–17.8 (15.0)	12.7–16.1 (15.0)
3rd dorsal fin base length	20.1	15.3–19.0 (17.4)	16.4–19.1 (17.5)
Pectoral-fin length	32.3	30.1–39.4 (34.9)	29.6–39.9 (34.8)
1st ray length of pelvic fin	13.9	14.4–19.1 (16.7)	12.2–18.0 (15.8)
2nd ray length of pelvic fin	22.2	21.8–27.9 (25.1)	20.5–27.3 (24.7)

Means in parentheses