Cypselurus neglectus neglectus ( Bleeker, 1865 )

Shakhovskoy, Ilia B. & Parin, Nikolay V., 2022, A review of the flying fish genus Cypselurus (Beloniformes: Exocoetidae). Part 2. Revision of the subgenus Poecilocypselurus Bruun, 1935 with descriptions of three new species and five new subspecies and reinstatement of Exocoetus apus Valenciennes and E. neglectus Bleeker, Zootaxa 5117 (1), pp. 1-109 : 67-72

Cypselurus neglectus neglectus ( Bleeker, 1865)

Material examined. Seventy-one specimens 24–160.5 mm SL.

Tonkin Bay. Full morphological study. IORAS 04007 (1, 160.5 mm SL), Tonkin Bay, 22.04.1960. IORAS 04008 (1, 154 mm SL), Tonkin Bay. IORAS 04009 (1, 157 mm SL), Tonkin Bay . IORAS 04010 (1, 147 mm SL), 20°20’N 108°46’E, 7.07.1961. IORAS 04011 (1, 152 mm SL), Tonkin Bay . IORAS 04012 (2, 128– 160.5 mm SL), Tonkin Bay . IORAS 04013 (6, 83– 117 mm SL), 20°00’N 107°40’E, 12.08.1961. IORAS 04014 (3, 145– 152 mm SL), Tonkin Bay . IORAS 04015 (1, 149 mm SL), Tonkin Bay , 6.08.1961. IORAS 04016 (2, 112– 152 mm SL), Tonkin Bay . IORAS 04017 (2, 113– 145 mm SL), 19°00’N 106°30’E, 13.08.1961. IORAS 04018 (1, 149 mm SL), Tonkin Bay .

Partial morphological study. IORAS 04018 (1, 64 mm SL), Tonkin Bay . IORAS 04019 (1, ~ 24 mm SL), 20°20’N 108°46’E, 7.07.1961 . IORAS uncat.* (2, 74– 135 mm SL), 20°10’N 108°47’E, 14.08.1961 .

Other areas. Full morphological study. IORAS 04020 (1, 157 mm SL), Danang, Vietnam, 18.04.1980 . IORAS 04021 (1, 143.5 mm SL), Singapore . IORAS 04022 (1, 147 mm SL), 2°04’N 106°15’E, 6.03.1975 . IORAS 04023 (1, 39 mm SL), 1°58’N 105°53’E, 13.07.1971 . IORAS 04024 (1, 33.5 mm SL), 3°04’N 109°28’E, 13.06.1971 . IORAS 04025 (1, 133 mm SL), 1°58’N 105°53’E, 13.06.1971 . IORAS 04026 (1, 141 mm SL), 2°09’N 106°09’E, 6- 7.03.1975 . IORAS 04027 (1, 109 mm SL), 0°00’ 135°10’E, 3.04.1966 . IORAS 04028 (2, 37– 52 mm SL), Kieta Harbour , Bougainville, 9- 10.01.1966 . IORAS 04029 (2, 35–47.5), Surabaya , 13– 15.10.1959 . AMS uncat. (2, 33– 34 mm SL), Sek Harbour , 21.09.1971 . AMS uncat. (1, 43 mm SL), Madang , 11.08.1971 . CAS 81124* (1, 137.5 mm SL), 12°33’N 101°16’E, 27.10.1957 . CAS 81190 (1, 83 mm SL), 10°02’N 109°48’E, 24.09.1960 . FRSKU 44256 (1, 135 mm SL), Gulf of Thailand, 30.10.1970 . SIO 61-634 (1, 65 mm SL), 12°04’N 101°59’E, 11.02.1961 . SOSC Ref.No. 190 (9, 125–149), 6°30’N 118°45’E, 27.01.1965 . SIO 65-40 (1, 142 mm SL), Gulf of Thailand . ZMUC P341008 (1, 148 mm SL), 9°59’N 107°23’E, 11.04.1929 . ZMUC uncat (1, 142 mm SL), 4°25’S 160°00’E, 6- 7.10.1951 . ZMUC uncat. (1, 156 mm SL), 7°00’N 103°18’E, 8.06.1951 .

Partial morphological study. IORAS 04030 (1, 74 mm SL), 7°44’S 120°05’E, 15.03.1975 . IORAS uncat.* (1, 143 mm SL), 2°05’N 106°12’E, 6.08.1975 . AMS I.16747-010* (1, 50 mm SL), Madang Harbour, PNG, 30.09.1969 . CAS 81114* (1, 129 mm SL), 9°N 103°E, 22.08.1959 . CAS 81119* (1, 141 mm SL), 5°59’N 105°23’E, 23.06.1960 . CSIRO C.3096* (1, 145 mm SL), Möwe Harbour , New Britain, 2.01.1949 . HUMZ 90194 * (1, 160 mm SL), no data . ISH 5-1993 * (1, 100 mm SL), off Chumpon, Gulf of Thailand, 6.12.1993 . Institute of Marine Research ( Vietnam) No. 51789* (1, 117 mm SL), Can Bong, 1.08.1976 . USNM 135803 * # (1, 132.5 mm SL), Catbalogan, Samar I., 15.04.1908 .

Type material. BMNH 1866.5.2.34* (1, 165 mm SL), no data. RMNH 6975 * (2, 143– 187 mm SL), no data .

Description. Meristic and morphometric characters are given in Tables 1–5 and 9–10. D 10 –13 (usually 11–12), A 7–9 (usually 8), P I 13–15 (usually I 14), Spred 23–29 (usually 25–28), Str 8–9½ (usually 8½), Sp.br 21–25 (5–8 + 15–19), usually 22–24 (6–7 + 16–17), Vert 40–42 (25–28 + 14–17), usually 41 (26–27 + 14–15). Snout short ( Figs. 23 , 25 ), lower jaw shorter than upper or of equal size (rarely lower jaw slightly longer). Upper jaw not pointed anteriorly. Jaw teeth small to medium-sized (not visible or barely visible to the naked eye), mainly tricuspid and (or) with additional cusps (some specimens also have conical teeth). Juveniles <80 mm have mainly conical teeth. Teeth arranged in 2–5 rows, in juveniles in 1–3 rows. Palatine teeth always present, usually numerous (sparse in juveniles <40 mm SL).

Body elongate ( Figs. 23 , 25 ), greatest body depth changing slightly with growth: in juveniles 33–100 mm SL body depth 5.15–5.9 in SL and in fish 110–160 mm SL, 4.55–5.7 in SL. Body width 0.97–1.40 and caudal peduncle depth 2.01–2.81 in greatest body depth. Greatest head depth and head length not changing with growth, 5.1–6.0 and 3.8–4.4 in SL, respectively. Head length 0.95–1.22 in dorso-caudal distance. Eyes large, eye diameter decreasing strongly with growth ( Fig. 26a ): in juveniles 33–100 mm SL eye diameter 8.55–11.8 in SL, 2.05–2.9 in head length, 0.95–1.4 in interorbital width and 0.85–1.3 in postorbital distance; in fish 110–160 mm SL, 10.6–14.3 in SL, 2.75–3.35 in с, 1.0–1.3 times in io and 1.15–1.5 in po.

Pectoral fins relatively long, their length increasing with growth to about 100 mm SL, and afterwards nearly constant: in juveniles 33–100 mm SL pectoral fin 1.50–1.85 in SL; in fish 110–160 mm SL, 1.4–1.6 in SL. Tip of pectoral fin reaching from posterior half of dorsal-fin base to middle of caudal peduncle; in juveniles <80 mm SL from origin to middle of dorsal-fin base. First pectoral-fin ray unbranched, its length increasing with growth: in juveniles 33–100 mm SL it fits 2.65–3.30 in SL and 1.55–1.87 in lP; in fish 110–160 mm SL, 2.3–2.9 in SL and 1.53–1.85 in lP. Pelvic-fin base closer to posterior edge of head than to origin of caudal-fin lower lobe (cV / pV = 0.71–0.91); pelvic fins shifted slightly posteriorly as fish grows ( Fig. 26e ). Pelvic-fin length decreasing strongly from juveniles to adults ( Fig. 26c ): in juveniles 33–100 mm SL pelvic fin 2.3–2.8 in SL and 1.30–1.72 in lP; in fish 110–160 mm SL, 2.7–3.5 in SL and 1.74–2.21 in lP. Tip of pelvic fin of small juveniles 30–95 mm SL reaching (nearly reaching) origin of caudal-fin lower lobe or slightly beyond; in juveniles 95–135 mm SL reaching from end of anal-fin base to middle of caudal peduncle; in fish> 135 mm SL reaching from 1 st –3 rd posterior anal-fin ray to slightly beyond anal-fin base.

Anal-fin origin far behind dorsal-fin origin, 1st anal-fin ray beneath 4 th –7 th dorsal-fin ray (usually beneath 5 th –6 th). Dorsal fin with 2–5 rays more than anal fin. Height of dorsal and anal fins decreasing with growth ( Fig. 26d ): in juveniles 33–100 mm SL, HD 8.1–8.2 and HA 8.8–12.0 in SL; in fish 110–160 mm SL, HD 7.95–11.2 and HA 11.2–14.9 in SL. The 2 nd or 3 rd ray in dorsal and anal fins longest. Tip of last dorsal-fin ray reaching from middle of caudal peduncle to origin of caudal-fin upper lobe (rarely slightly further). Middle and posterior rays of dorsal fin not elongate, penultimate rays not protruding beyond tip of last ray (occasionally slightly protruding in juveniles).

Pigmentation. Body of juveniles ( Fig. 25a–d ) pale brown to dark brown, the ventral side usually darker than dorsal. Body bands usually absent (juveniles occasionally with 1–2 indistinct dark bands posteriorly). Adults with typical “pelagic” pigmentation.

Lower surface of head in juveniles 33–55 mm SL brown to dark brown with paler chin and distal parts of branchiostegal rays (in a single juvenile 39 mm SL rather pale with wide dark band under eyes). In fish> 60 mm SL, lower surface of head mainly pale; in juveniles 60–110 mm SL usually with weak aggregation of melanophores under eyes (on bases of branchiostegal rays). Adults with a few small dark specks ( Fig. 25f ) on gill covers and (or) under eyes.

Pectoral fins in juveniles 24–80 mm SL ( Fig. 27a–b ) brown or dark brown with pale tip (sometimes also with small pale spots near tips of 2 nd and 3 rd rays); without pale transverse band or a row of pale spots. In fish 80–115 mm SL, pigmentation disappearing at lower edge of the fin (below 9–12 th ray). In fish> 115 mm SL ( Figs. 23a , 27c ), pectoral fins dark gray to dark brown to 8 th ray (rarely to 7 th or 9 th) with broad pale tip and very narrow posterior pale edging; distally pectoral-fin pigmentation usually spreading one ray lower than proximally.

Pelvic fins in juveniles 24–80 mm SL ( Fig. 27d–e ) entirely brown or dark brown. In fish 80–100 mm SL, pigmentation begins to disappear starting with proximal part of the fin, along 1 st ray and between 5 th –6 th rays. In fish 100–120 mm SL, pelvic fins pale with a large dark spot between 2 nd –4 th rays distally. In fish ≥ 120 mm SL, pelvic fins pale ( Figs. 23a , 27f ), occasionally with few dots or a dark streak between some rays.

Dorsal fin in juveniles 33–80 mm SL covered with melanophores, more densely near bases of anterior rays and along upper margin of fin; posterior edge devoid of pigmentation. In fish 80–115 mm SL dorsal fin pale brownish with darker upper margin. In fish> 115 mm SL, dorsal fin gray, sometimes with yellowish or brownish tinge near fin base.

Anal fin in juveniles 33–85 mm SL covered with melanophores, mainly near fin base anteriorly and on posterior part of fin (sometimes aggregated there in a brown spot, see Fig. 23b ). In fish 85–90 mm SL (65 mm SL from Tonkin Bay) anal fin pale with weak pigmentation near tips of posterior rays. In fish> 110 mm SL, anal fin pale or translucent.

Caudal fin of fish 33–45 mm SL ( Fig. 25a ) pale, with pale brown to brown base and dots along lower lobe rays (except uppermost rays). In fish 45–100 mm SL ( Figs. 23b , 25b–d ), caudal fin usually with 1–3 dark bands on lower lobe and, in some fish, also with 1–2 bands on upper lobe. In fish> 100 mm SL, caudal fin gray to brown, usually with darker fin base and distal part of upper lobe ( Fig. 25e–f ).

Coloration in life. No data.

Maximum size. The maximum length of C. n. neglectus in our material was 160.5 mm SL (IORAS 04007, Tonkin Bay, female). The largest male was 157 mm SL.

Intrasubspecies variation. Fish from Tonkin Bay differ slightly from others in having more predorsal scales (usually 26–29 vs. usually 26–27), a smaller interorbital space (see Table 9) and paler pigmentation of anal fin in juveniles (the fin is mainly pale starting with 65 mm SL vs. 85 mm SL). We regard these differences to have no taxonomic significance.

Common names. The name “common neglected flying fish” (Russian: “обыкновенный ПриЗрачный стрижехвост”) is proposed here.

Biology. Males mature at 133 mm SL, females at 141 mm SL. Close to mature or mature fish were captured near Singapore in March (IORAS 04026) and June (IORAS 04025), in Gulf of Thailand in June (ZMUC uncat.), in Tonkin Bay in April (IORAS 04007) and August (IORAS 04015). The smallest juveniles, 24–35 mm SL, were captured east of Singapore in June (IORAS 04024), at Surabaya in October (IORAS 04029), in Tonkin Bay in July (IORAS 04019), in Sek Harbour in September (AMS uncat.). These data suggest C. n. neglectus spawns at least from March to August-September.

Distribution. The subspecies is distributed ( Fig. 28 ) from Singapore (IORAS 04021), Gulf of Thailand (ISH 5- 1993, off Chumpon) and Tonkin Bay (IORAS 04010, 20°20’N 108°46’E), through Indonesia (southernmost occurrences at Surabaya (IORAS 04029) and 7°44’S 120°05’E (IORAS 04030)), Philippines and New Guinea eastward to Melanesia (ZMUC uncat., 4°25’S 160°00’E).

Figures

FIGURE 23. Cypselurus neglectus neglectus: (A)—160.5 mm SL, IORAS 04007, Tonkin Bay; (B)—83 mm SL, IORAS 04013, Tonkin Bay. After Parin and Besednov 1965.

FIGURE 25. Cypselurus neglectus neglectus: (A)—33.5 mm SL, IORAS 04024, 3°04’N 109°28’E; (B)—47.5 mm SL, IO- RAS 04029, Surabaya; (C)—65 mm SL, SIO 61-634, 12°04’N 101°59’E; (D)—83 mm SL, CAS 81190, 10°02’N 109°48’E; (E)—128 mm SL, IORAS 04012, Tonkin Bay; (F)—149 mm SL, SOSC Ref.No.190, 6°30’N 118°45’E.

FIGURE 26. Size variation of morphometric characters (in % SL) in Cypselurus neglectus neglectus (+—Tonkin Bay, x—other areas) and C. n. shcherbachevi (□—Indonesia, ○—Andaman Sea, ∆—Bay of Bengal and Arabian Sea): (A)—eye diameter (o); (B)—snout length (ao), (C)—pelvic fin length (lV); (D)—dorsal fin height (HD); (E)—cephalo-ventral distance divided by postventral distance (index cV/pV); (F)—pelvic fin length divided by snout length (index lV/ao).

FIGURE 27. Pectoral (A–C) and pelvic (D–F) fins in Cypselurus neglectus neglectus: (A)—37 mm SL, IORAS 04028, Kieta Harbour, Bougainville; (B)—65 mm SL, SIO 61-634, 12°04’N 101°59’E; (C)—133 mm SL, IORAS 04025, 1°58’N 105°53’E; (D)—37 mm SL, IORAS 04028, Kieta Harbour, Bougainville; (E)—83 mm SL, CAS 81190, 10°02’N 109°48’E; (F)—126 mm SL, SOSC Ref.No.190, 6°30’N 118°45’E.

FIGURE 28. Distribution of Cypselurus neglectus neglectus (○), C. n. shcherbachevi (◊) and C. nossibe (∆). Filled symbols indicate capture location for fishes ≤ 100 mm SL, open symbols indicate capture location for fishes> 100 mm SL. Positions of holotypes marked with asterisk.