Cypselurus oligolepis georgii, Shakhovskoy & Parin, 2022

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 : 32-37

Cypselurus oligolepis georgii subsp. nov.

Synonymy and bibliography.

Cypselurus oligolepis (non Bleeker). Parin 1984: EXOC Cyp 11 (description, figures, distribution; western Indian Ocean; in part).

Material examined. Fifteen specimens 39–145 mm SL.

Full morphological study. ZMMU P-24451 (holotype), (1, 145 mm SL), road of Suez , 5.06.1957 . IORAS 03986 (2, 117– 139 mm SL), 13°03’N 42°58’E, 6.11.1963 . IORAS 03987 (1, 95 mm SL), 19°19’N 38°35’E, 21.10.1963 . IORAS 03988 IORAS (paratypes), (2, 111– 123.5 mm SL), 13°14’N 42°59’E, 16.10.1960 . IORAS 03989 (3, 76.5– 113 mm SL), 14°05’N 42°20’E, 15.10.1960 . IORAS 03990 (paratypes), (3, 39– 76 mm SL), 14°05’N 42°20’E, 15.10.1960 . IORAS 03991 (1, 71.5 mm SL), Gulf of Aden , late 1962 . IORAS 03992 (1, 111.5 mm SL), 12°35’N 44°45’E, 31.08.1964 .

Partial morphological study. IORAS uncat.* (1, 56 mm SL), 19°40’N 38°41’E, 13- 14.10.1960 .

Holotype ( Fig. 10 ) ZMMU P-24451, diesel-electric ship “ Ob ”, Cruise 2, Suez road, 5 June 1957, depth 12 m, silt bottom, captured with dip-net at surface, collectors: Barsukov and Permitin. Length 145 mm SL (male), D 12, A 9, P I 15, Spred 25, Str 8½, Sp.br 24 (6 + 18), Vert 41 (25 + 16). Measurements (in % SL): aA 78.5, aD 70.4, aV 56.0, cV 31.5, pV 41.3, c 24.7, po 10.9, o 7.6, ao 5.2, io 9.5, Hc 17.7, H 18.7, h 7.5, Dc 27.9, lP 62.8, lP 1 37.1, lV 31.4, lD 19.3, lA 10.1, HD -, HA 7.6?, p 15.3. Body dark dorsally, silvery ventrally. Head with small dark specks on gill covers and under eyes ( Fig. 10b ). Pectoral fins brown to 8 th ray with large pale tip, small “mirror” to 5 th –6 th ray and very narrow pale posterior edging ( Fig. 10c ). Tip of pectoral fin reaching 10 th dorsal-fin ray. Pelvic fins pale, their tip reaching the last anal-fin ray. Dorsal fin gray (pale brownish anteriorly), tip of last dorsal-fin ray behind middle of caudal peduncle but not reaching origin of caudal-fin upper lobe. Anal fin pale, 1 st anal-fin ray beneath 6 th dorsal-fin ray; second anal-fin ray longest. Caudal fin pale brown, slightly darker near base, with two large dark specks on lower lobe proximally. Lower jaw shorter than upper jaw; teeth small, numerous, tricuspid and conical, arranged in 2–3 rows on lower jaw and in 2–4 rows on upper jaw. Palatine teeth numerous.

Paratypes. IORAS 03988 , two specimens 111 and 123.5 mm SL, 13°14’N 42°59’E, 16 October 1960 . IORAS 03990 , three specimens 39, 56 and 76 mm SL, 14°05’N 42°20’E, 15 October 1960 .

Description. Meristic and morphometric characters are given in Tables 1–5 , 8 and 10. D 11–12, A 7–8 (rarely 9), P I 14–15, Spred 24–26 (usually 25), Str 8½–9 (usually 8½), Sp.br 20–25 (5–7 + 15–19), Vert 39–41 (24–26 + 14–16). Snout relatively short, upper jaw not pointed anteriorly. Lower jaw usually shorter than upper jaw or of equal size; in juveniles occasionally lower jaw slightly longer. Jaw teeth numerous, small (usually not visible with the naked eye), tricuspid and with additional cusps, sometimes with small admixture of conical teeth. In juveniles <75 mm SL conical teeth prevail, but teeth with additional cusps sometimes also present. Jaw teeth arranged in 2–4 rows. Palatine teeth always present, usually numerous.

In fish 39–145 mm SL, body elongate to rather deep; greatest body depth 4.8–5.7 in SL and nearly unchanged with growth. Body width 1.10–1.32 and depth of caudal peduncle 2.18–3.00 in greatest body depth. Greatest head depth decreasing with growth: in juveniles 39–95 mm SL it fits 4.8–5.25 in SL and in fish 100–145 mm SL— 5.2– 5.8 in SL. Head length 3.5–4.15 in SL and 0.94–1.19 in dorso-caudal distance. Eyes relatively small, eye diameter slightly decreasing with growth ( Fig. 6a, e ): in juveniles 39–95 mm SL, eye 9.35–11.6 in SL, 2.45–3.15 in с, 1.2–1.3 in io and 1.1–1.5 in po; in fish 100–145 mm SL, eye 11.75–13.9 in SL, 3.0– 3.5 in с, 1.2–1.3 in io and 1.35–1.6 in po.

Pectoral fins relatively short, their length increasing noticeably with growth ( Fig. 6c ): in juveniles 39–95 mm SL pectoral fin fits 1.6–1.85 in SL and in fish 100–145 mm SL— 1.55–1.6 in SL. Tip of pectoral fin reaching end of dorsal-fin base or slightly beyond (in juveniles <100 mm SL reaching middle of dorsal-fin base). The first pectoral-fin ray unbranched, its length 2.6–3.35 in SL, 1.65–1.95 in lP. Base of pelvic fins much closer to posterior margin of head than to origin of caudal-fin lower lobe (cV/pV = 0.68–0.80). Pelvic fin length strongly decreasing with growth ( Fig. 6d ): in juveniles 39–95 mm SL pelvic fin 2.5–3.1 in SL and 1.34–1.87 in lP; in fish 100–145 mm SL, 2.92–3.32 in SL and 1.86–2.08 in lP. Tip of pelvic fin in juveniles 39–71.5 mm SL protruding beyond middle of caudal peduncle (reaching origin of caudal-fin lower lobe in smaller fish); in fish 76–111.5 (117) mm SL protruding beyond end of anal-fin base but not reaching middle of caudal peduncle; in larger fish (113–145 mm SL) reaching last or penultimate anal-fin ray.

Anal-fin origin far behind dorsal-fin origin—1 st anal-fin ray beneath 5 th –6 th (very rarely 7 th) dorsal-fin ray. Dorsal fin with 3–5 rays more than anal fin. Height of dorsal fin in fish 55–125 mm SL fits 7.41–9.34 in SL. Height of anal fin in a juvenile 39 mm SL fits 9.52 in SL, in fish 75–145 mm SL, 12.34–14.49 in SL. The 2 nd ray of dorsal and anal fins longest (in juveniles <76 mm SL sometimes 3 rd ray the longest). Tip of last dorsal-fin ray protruding beyond middle of caudal peduncle, but not reaching origin of caudal-fin upper lobe (reaching only in the smallest juvenile examined, 39 mm SL). Middle and posterior dorsal-fin rays not elongated (tips of penultimate rays not protruding behind tip of last ray).

Pigmentation. Body of juveniles 39–95 mm SL brown or pale brown, somewhat paler ventrally ( Fig. 11a–d ). Body bands usually absent, but occasional specimens 39–76 mm SL with 2–3 dark bands on ventral side of body: near pectoral-fin base, between pectoral and pelvic fins and near pelvic-fin base. Larger fish (≥ 100 mm SL) with typical flying fish “pelagic” pigmentation of body.

Underside of head pale in juveniles. Only fish ≤ 71.5 mm SL with rather numerous melanophores on bases of branchiostegal rays. Fish ≥ 103.5 mm SL with sparse small dark specks on gill covers and under eyes.

Pectoral fins in juveniles 39–71.5 mm SL dark brown with pale tip and a row of 2–8 pale spots proximally ( Fig. 12a–c ). Pectoral fins in fish 76–111.5 mm SL dark brown (sometimes brown) to 9 th –11 th ray with very broad pale tip and pale “mirror” reaching 1 st –2 nd (in fish> 100 mm SL usually reaching 3 rd –4 th) ray ( Fig. 12d–e ). In fish 113–145 mm SL ( Fig. 12f ) pectoral fins brown or dark brown to 8 th –9 th ray with pale tip (the tip narrower than in smaller fish), small barely discernible “mirror” (in some fish the “mirror” is quite clear-cut and reaching 5 th –7 th ray) and very narrow pale posterior edging.

Pelvic fins in juveniles 39–71.5 mm SL dark brown with two pale spots ( Fig. 13a ) and usually with pale area near proximal part of 6 th ray. In juveniles 76–76.5 mm SL pigmentation begins to disappear proximally and along inner margin of the fin ( Fig. 13b ). In fish 95–113 mm SL pelvic fins only with dark spot distally between 3 rd –5 th rays ( Fig. 13c ). In fish 117–145 mm SL pelvic fins pale ( Fig. 13d ).

Dorsal fin of juveniles 39–76 mm SL covered with brown melanophores, especially densely in upper and posterior portions; last dorsal-fin ray pale. In fish ≥ 76.5 mm SL dorsal fin gray (in fish 76.5–90 mm SL tips of middle rays brown), usually with pale brown tinge.

Anal fin of juveniles 39–76.5 mm SL with large brown spot posteriorly, anterior part of the fin paler or entirely unpigmented. In fish ≥ 95 mm SL anal fin pale.

Caudal fin of a 39 mm SL juvenile pale with pigmented base and dots along rays of lower lobe (both lobes broken). In juveniles 56–95 mm SL two dark bands (sometimes fused into a single very wide band) on lower lobe and 1–2 dark bands on upper lobe appear ( Fig. 11b–d ). In fish ≥ 103.5 mm SL ( Fig. 11e ) caudal fin brown to grayish brown or pale brown, usually with darker posterior margin of the fin and tip of upper lobe and paler area near fork.

Coloration in life. No data.

Maximum size. The largest specimen of C. o. georgii examined was 145 mm SL ( ZMMU P-24451, holotype, male); the largest female was 139 mm SL .

Intrasubspecies variation. No data.

Comparative remarks. Cypselurus o. georgii differs from all other subspecies of C. oligolepis (except C. o. persicus) in larger postorbital distance and smaller eye diameter (and, consequently, in higher index po/o, see Fig. 6e ), a somewhat slimmer caudal peduncle and higher number of pectoral-fin rays (usually 16 vs. usually 15). It differs most strikingly from C. o. persicus in shorter pectoral and pelvic fins ( Fig. 6c–d ) and fewer vertebrae and predorsal and transverse scales (Vert 39–41, Spred 24–26 and Str usually 8½ vs. Vert 42–43, Spred 26–30 and Str usually ≥ 9). In pelvic-fin length C. o. georgii is intermediate between C. o. oligolepis and C. o. apus ; in the number of rays in dorsal and anal fins C. o. georgii is closer to the latter subspecies and in pigmentation of juveniles closer to the former, though slightly differing in some details.

Etymology. The subspecies named after Georgy B. Shakhovskoy—a brother of the first author of this review, who was very helpful with figure preparation.

Common names. The name “Red Sea largescale flying fish” (Russian: “красноморский малочеШуйный стрижехвост”) is proposed here for C. o. georgii.

Biology. The only mature (running ripe) female of this subspecies examined ( IORAS 03986 , 139 mm SL) was captured on 6 November 1963 at 13°03’N 42°58’E; a maturing male 117 mm SL was also captured at this locality. The smallest juvenile of 39 mm SL ( IORAS 03990 ) was captured on 15 October 1960 at 14°05’N 42°20’E. These data suggest that spawning takes place at least from September to November .

Five of 15 fishes studied were heavily infested with isopods (Cymothoa), in the buccal cavity. The infestation deformed the head and such infested specimens usually had higher values of H and Hc.

Distribution. Cypselurus o. georgii is distributed ( Fig. 3 ) in the Red Sea from Suez (ZMMU P-24451) to Babal-Mandeb Strait, also entering the Gulf of Aden (IORAS 03991–03992).

Figures

FIGURE 3. Distribution of Cypselurus starksi (□), C. oligolepis oligolepis (○), C. o. persicus (◊), C. o. georgii ( ) and C . izumii (Δ). 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.

FIGURE 6. Size variation of morphometric characters (in % SL) in Cypselurus oligolepis (□— C. o. oligolepis, ○— C. o. apus, ∆— C. o. persicus, +—C. o. georgii), C. clariangulatus (◊) and C. izumii (x): (A)—diameter of eye (o); (B)—width of interorbital space (io); (C)—length of pectoral fin (lP); (D)—length of pelvic fin (lV); (E)—postorbital distance divided by diameter of eye (index po/o); (F)—pectoral fin length divided by pelvic fin length (index lP/lV).

FIGURE 10. Holotype of Cypselurus oligolepis georgii (145 mm SL, ZMMU P-24451, road of Suez): (A)—side view; (B)— close up of head; (C)—pectoral fin.

FIGURE 11. Cypselurus oligolepis georgii: (A)—39 mm SL, IORAS 03990, 14°05’N 42°20’E; (B)—56 mm SL, IORAS 03990, 14°05’N 42°20’E; (C)—71.5 mm SL, IORAS 03991, Gulf of Aden; (D)—76 mm SL, IORAS 03990, 14°05’N 42°20’E; (E)—113 mm SL, IORAS 03989, 14°05’N 42°20’E.

FIGURE 12. Pectoral fins in Cypselurus oligolepis georgii: (A)—39 mm SL, IORAS 03990, 14°05’N 42°20’E; (B)—56 mm SL, IORAS 03990, same place; (C)—71.5 mm SL, IORAS 03991, Gulf of Aden; (D)—76.5 mm SL, IORAS 03989, 14°05’N 42°20’E; (E)—111 mm SL, IORAS 03988, 13°14’N 42°59’E; (F)—123.5 mm SL, IORAS 03988, same place.

FIGURE 13. Pelvic fins in Cypselurus oligolepis georgii: (A)—71.5 mm SL, IORAS 03991, Gulf of Aden; (B)—76 mm SL, IORAS 03990, 14°05’N 42°20’E; (C)—103.5 mm SL, IORAS 03989, 14°05’N 42°20’E; (D)—117 mm SL, IORAS 03986, 13°03’N 42°58’E.