Cypselurus persimilis, Shakhovskoy & Parin, 2024

Shakhovskoy, Ilia B. & Parin, Nikolay V., 2024, A review of the flying fish genus Cypselurus (Beloniformes: Exocoetidae). Part 3. Revision of the subgenus Cypselurus sensu stricto with descriptions of one new species and four new subspecies and reinstatement of Cypselurus crockeri Seale and Exocoetus socotranus Steindachner, Zootaxa 5473 (1), pp. 1-125 : 72-80

Cypselurus persimilis sp. nov.

Cypselurus persimilis is very similar to C. opisthopus and C. naresii , and in the collections examined and in previous publications it was usually misidentified as one of these two species.

Synonymy and bibliography.

Cypselurus opisthopus (non Bleeker). Parin 1961a: 49–52 (description; western Pacific; in part). Dalzell 1993: 22–29, figs. 2–6 (fishery, biology; Camotes Sea, Philippines; in part). Parin 1996: 302, 306 [359, 363] (distribution; western Pacific; in part).? Jayakumar et al. 2019: 698–701, figs. 1–3 (description of a specimen, molecular systematics (COI); Vizhinjam, India).

Cypselurus naresii (non Günther).? White et al. 2013: 98, fig. 28.7 (short description; Indonesia).

Cypselurus oligolepis (non Bleeker).? Panakkool-Thampan et al. 2018: 176, fig. 2a (photograph; host of Glossobius auritus Bovallius ; 11°51’N 75°22’E).

Material examined. One hundred specimens 129–180.5 mm SL. We compared samples from three areas: the Indian Ocean, New Guinea and adjacent waters and Philippines and adjacent waters (like for C. opisthopus , Wallace’s line was used as a border between the latter two areas).

Indian Ocean. Full morphological study. IORAS 04141 (1, 160 mm SL), Mungallore , India, 6.09.1979 . IORAS 04187 (1, 174 mm SL), 10°18’S 110°23’E, 31.10- 1.11.1959 . IORAS 04081 (1, 129 mm SL), 7°17’S 105°07’E, 16.07.1962 . SIO 61-721 (1, 176 mm SL), 10°33’S 124°16’E, 12.04.1961 .

Partial morphological study. NTM S.11316.002* (paratype) (1, 149 mm SL), Sandy Islet, Scott Reef, WA, 25.02.1984 . SIO 73-193 * (1, 155 mm SL), 12°12’S 122°58’E, 5.01.1973 . URM P9267 * (1, 146 mm SL), Phuket, Andaman Sea . URM P9268 * (1, 154 mm SL), same place . URM P14731 * (1, 152 mm SL), same place .

New Guinea and adjacent waters. Full morphological study. IORAS 04281 (1, 160 mm SL), Bongu, Maclay (Rai) Coast, 13.02.1977 . IORAS 04282 (1, 152 mm SL), same data . IORAS 04283 (paratype) (1, 175.5 mm SL), same data . IORAS 04284 (1, 158 mm SL), same data . IORAS 04285 (1, 177 mm SL), same data . IORAS 04286 , (1, 156.5 mm SL), same data . IORAS 04405 (1, 162 mm SL), ~ 2°N 132°E, 30- 31.03.1966 . IORAS 04412 (1, 169 mm SL), ~ 4°S 145°E, 7.04.1966 . IORAS 04420 (1, 168 mm SL), 4°00’N 130°00’E, 6.02.1966 . IORAS 04421 (1, 144.5 mm SL), 1°30’S 140°01’E, 18.01.1966 . IORAS 04425 (1, 145.5 mm SL), same data . IORAS 04427 (1, 156 mm SL), ~ 1°S 140°E, 17.01.1966 . IORAS 04435 (1, 131 mm SL), 6°28’S 128°19’E, 9.04.1973 . IORAS 04145 (1, 174.5 mm SL), 3°50’S 151°32’E, 10.05.1971 . IORAS 04068 (1, 180.5 mm SL), 6°16’S 153°44’E, 28- 29.07.1957 . IORAS 04069 (1, 175.5 mm SL), same place, 27- 28.07.1957 . IORAS 04070 (1, 147 mm SL), same place, 28- 29.07.1957 . IORAS 04073 (1, 172 mm SL), same data . IORAS 04074 (1, 164.5 mm SL), same place, 27- 28.07.1957 . IORAS 04076 (1, 161 mm SL), 8°39’S 153°22’E, 23.08.1957 . IORAS 04077 (1, 152 mm SL), 1°02’N 141°59’E, 9.04.1958 . IORAS 04235 (1, 144.5 mm SL), 5°49’S 152°53’E, 20- 21.07.1957 . IORAS 04110 (1, 140 mm SL), 2°57’S 131°10’E, 22.03.1975 . ZIN 4782 * (1, 137 mm SL), Amboina, 1858 . ZMMU P-24610 (holotype, 179.5 mm SL), 6°16’S 153°44’E, 28.07.1957 . ZMUC uncat. (22, 153– 179.5 mm SL), 4°25’S 160°00’E, 6- 7.10.1951 .

Partial morphological study. CSIRO C.1089* (1, 175 mm SL), Cape St. George , New Ireland . SIO 77-180 * (1, 166 mm SL), 4°34’S 135°31’E, 30.07.1971 .

Philippines and adjacent waters. Full morphological study. IORAS 04066 (1, 140 mm SL), Philippines (Camotes Sea?) . IORAS 04095 (1, 151.5 mm SL), 7°39’N 121°32’E, 28.02.1975 . IORAS 04103 (1, 161 mm SL), 7°22’N 116°34’E, 2.03.1975 . IORAS 04106 (6, 153– 166 mm SL), 7°32’N 116°37’E, 10.06.1971 . SOSC Ref. No.190 (7, 143– 162 mm SL), 6°30’N 118°45’E, 27.01.1965 . ZMUC P34925 (1, 140 mm SL), 4°50’S 118°45’E, 17.08.1929 .

Partial morphological study. IORAS 04111 (1, ~ 130 mm SL), 5°57’N 123°40’E, 26- 27.02.1975 . CAS 49641 * (1, 137 mm SL), Sulu Sea: W of Basilan I, N of Pilas I., 6.05.1948 . CAS 49651 * (2, 156– 165 mm SL), near Monado , Celebes I., March 1948 . CAS 81807 * (1, 146 mm SL), 3°00’N 118°15’E, 1.08.1948 . CAS 81831 * (1, 154 mm SL), 6°56’N 121°45’E, 6.05.1948 . CAS 81832 * (5, 140– 148 mm SL), Siokun Bay, NW Zamboanga Peninsula, 11.03.1948 . CAS 81872 * (1, 140 mm SL), same place, 11- 12.03.1948 . CAS 82061 * (1, 146 mm SL), 7°27’N 121°43’E, 10.10.1947 . CAS 127269 * (1, 146 mm SL), Dumaguete , Philippines, 11.07.1931 . SOSC Ref. No. 190 (8, 144– 162 mm SL), 6°30’N 118°45’E, 27.01.1965 . URM P27993 * (1, 161 mm SL), Okinawa fish market . USNM 226707 * (1, 153 mm SL), 9°50’N 118°50’E, June 1978 . USNM 294609 * (paratype) (1, 150 mm SL), 5°50’S 118°10’E, 26- 28.03.1974 .

Holotype ( Fig. 32d ). ZMMU P-24610, R / V Vityaz, Cruise 25, Sta. 3663, sample 126, 6°16’S 153°44’E, 28 July 1957, captured with dip-net and night-light near surface. Length 179.5 mm SL (immature female). D 11, A 8, P I 14, Spred 29, Str 8½, Sp.br 24 (7 + 17), Vert 42 (28 + 14). Measurements (in % SL): aA 80.6, aD 74.6, aV 63.5, cV 40.6, pV 34.9, c 24.0, po 10.7, o 7.2, ao 5.1, io 9.2, Hc 17.4, H 20.2, h 7.8, Dc 24.0, lP 69.6, lP 1 41.1, lV 24.0, lD 15.7, lA 8.9, HD -, HA -, p 14.4. Body dark dorsally, silvery ventrally. Chin barbel absent. Dark specks on gill cover and under eye. Pectoral fins brown to 8th ray (proximally to 7th ray) with a pale tip and very narrow pale posterior edging. Tip of pectoral fin reaching middle of caudal peduncle. Pelvic fins pale, reaching slightly beyond end of anal-fin base. Dorsal fin gray (pale-brownish anteriorly), tip of its last ray protruding beyond middle of caudal peduncle but not reaching origin of caudal-fin upper lobe. Anal fin pale, its first ray beneath 5th–6th dorsal-fin ray. Caudal fin pale brown. Lower jaw shorter than upper jaw. Jaw teeth very small (not visible with the naked eye), mainly with additional cusps, a few conical and tricuspid teeth also present. Palatine teeth small, numerous.

Paratypes. IORAS 04283 , 175.5 mm SL, Bongu, Maclay Coast, anchorage, 13 February 1977 . USNM 294609, 150 mm SL, 5°50’S 118°10’E, 26-28 March 1974 . NTM S.11316.002, 149 mm SL, Sandy Islet , Scott Reef, W.A., 25 February 1984 .

Diagnosis. A small species of Cypselurus with few dorsal-fin rays and vertebrae. Body rather deep, head and eyes large, pectoral fins long, pelvic and dorsal fins short. Pelvic-fin base about midway between posterior edge of head and origin of caudal-fin lower lobe or closer to the latter. Jaw teeth mainly tricuspid and with additional cusps, palatine teeth usually present. Juveniles presumably with a short chin barbel and low dorsal fin. In adults, pelvic and anal fins usually pale. D 10–12, Spred 26–33, Str 6–8½, Vert 40–43 (26–29 + 13–16).

Description. Meristic and morphometric characters are given in Tables 1–7, 11 and 14. D 10–12 (usually 11)10, A 7–9 (usually 8), P I 12–14 (usually I 13), Spred 26–33 (usually 28–30), Str 6–8½ (usually 7–7½), Sp.br 20–26 (5–8 + 15–19), usually 22–24 (6–7 + 16–18), Vert 40–43 (26–29 + 13–16), usually 41–42 (27–28 + 14–15). Snout moderate, lower jaw usually shorter than upper jaw or of equal size (occasionally lower jaw slightly longer); upper jaw not pointed anteriorly ( Fig. 32 ). Smallest juvenile studied (129 mm SL, IORAS 04081) without a chin barbel. However, judging by photos on the Internet ( Fig. 33 ), juveniles ~ 20–50 mm SL, which we supposedly identified as C. persimilis , have a wide and short (not protruding beyond eye) dark chin barbel with a paler median keel and without pronounced triangular lobes basally.

Jaw teeth sparse to numerous, small to medium-sized (not visible or barely visible to naked eyes), tricuspid, with additional cusps and conical (in smaller fish conical teeth usually prevail while in larger fish—tricuspid and with additional cusps). Teeth arranged in 2–3 (rarely in 1 or 4) rows. Palatine teeth present (absent in 2 of 69 specimens studied), usually numerous.

Body rather deep, its depth 4.55–5.8 in SL. Body width 1.18–1.44 and caudal peduncle depth 2.29–3.00 in greatest body depth. Greatest head depth 5.1–6.3 in SL. Head length 3.75–4.3 in SL and 0.86–1.02 in dorso-caudal distance. Eyes large, eye diameter 10.85–15.4 in SL, 2.9–3.7 in head length, 1.0– 1.35 in interorbital width and 1.2–1.75 in postorbital distance.

Pectoral fins long ( Fig. 4c ), 1.4–1.6 in SL, tip of pectoral fin reaching from end of dorsal-fin base to middle of caudal peduncle (rarely slightly beyond). First pectoral-fin ray unbranched, its length ( Fig. 4d ) 2.2–2.7 in SL and 1.48–1.72 in lP. Pelvic-fin base about midway between posterior edge of head and origin of caudal-fin lower lobe or closer to the latter (cV / pV = 0.97–1.24, Fig. 4a ). Pelvic fin 3.2–4.15 in SL and 2.01–2.90 in pectoral fin, tip of pelvic fin reaching from end of anal-fin base to middle of caudal peduncle.

Anal-fin origin far posterior to dorsal-fin origin (1st anal-fin ray under 4th–6th dorsal-fin ray, usually under 5th–6th). Dorsal fin with 1–5 (usually 2–3) rays more than anal fin. Height of dorsal ( Fig. 4e ) and anal fins 8.05–11.1 and 12.5–16.95 in SL, respectively. Longest dorsal- and anal-fin ray—2nd or 3rd. Tip of last dorsal-fin ray reaching from middle of caudal peduncle to origin of caudal-fin upper lobe, penultimate rays not elongated ( Figs. 32 , 33 ).

Pigmentation. Body with typical “pelagic” pigmentation. Head with small, dark specks ( Fig. 32e ) on gill cover and under eye (in some fish also on body), but the specks probably covered with iridocytes in life. Pectoral fins ( Fig. 34a–c ) pale brown to dark brown (sometimes nearly black) to 7th–9th ray (pigmentation usually extending one ray lower distally than proximally, occasionally a subtle “mirror” present) with a pale tip and a narrow pale posterior edging. In few fish pigmentation is faded proximally. Pelvic fins of the smallest fish studied (129 mm SL, see Fig. 34d ) dark brown between 2nd–4th rays. In fish> 130 mm SL pelvic fins pale, though sometimes, especially in fish <150 mm SL, sparse pigmentation is retained between fin rays ( Fig. 34e–h ).

Dorsal fin gray to pale-brownish, in the smallest fish 129 mm SL with black pigmentation along upper margin posteriorly ( Fig. 32 ). Anal fin translucent. Caudal fin ( Fig. 32 ) pale brown to brown, usually with slightly darker base and/or tip of upper lobe; in the smallest fish 129 mm SL both lobes of caudal fin with paler bands.

Coloration in life. Photos of live juveniles that we identified as C. persimilis are presented in Figure 33 .

Maximum size. The maximum length of C. persimilis in the material examined was 180.5 mm SL (IORAS 04068, immature female). The largest male was 172 mm SL (IORAS 04073).

10 There is an abberant specimen (IORAS 04110) with a mutation—it has only 5 dorsal-fin rays supported by 6 skeletal elements. We excluded all mutation-related counts and measurements of this specimen (D, D-A, aD, Dc, lD) from the data pool.

Intraspecific variation. The samples from different areas differ slightly in some counts and measurements ( Tables 1–7, 11, 14) but we do not regard these differences as taxonomically significant. However, the population from the Indian Ocean (and especially from waters of western India) is worth further taxonomic study based on more representative material.

Comparative remarks. Cypselurus persimilis differs from C. hiraii in many meristic (Vert, Vert.pc, D, A, Spred, Str, Sp.br, h.br, see Tables 1–6) and morphometric (aD, aV, pV, c, o, io, Hc, H, h, Dc, lV, lD, see Tables 7, 14 and Fig. 4 ) characters, as well as in morphology of jaw teeth (mainly with additional cusps and tricuspid vs. mainly conical) and pigmentation of head (dark specks on head sides usually numerous vs. usually scarce or absent).

Cypselurus persimilis is very similar to both C. naresii and C. opisthopus , being somewhat intermediate in morphology, and distinguishing from these species is difficult task. Adults of C. persimilis differ from C. naresii in pigmentation of pelvic fins (usually pale vs. usually pigmented distally), anal fin (unpigmented vs. usually with black dots [except C. n. socotranus ]) and head (dark specks on head sides usually numerous vs. usually scarce or absent), shorter pelvic fins (except C. n. socotranus , Fig. 35a ) and smaller body length (maximal size 180.5 vs. 258 mm SL). Putative juveniles of C. persimilis ( Fig. 33 ) differ from juveniles of C. naresii in chin barbel morphology, pigmentation of pectoral (pigmented to 11-th ray) and pelvic (with pale anterior edge) fins and head’s lower surface (pale anteriorly and posteriorly), shorter pectoral fins and their first ray.

Adults of C. persimilis differ from C. opisthopus in fewer vertebrae (Vert 40–43, usually ≤ 42 vs. 42–45, usually ≥ 43; Vert.pc 26–29, usually ≤ 28 vs. 28–30, usually ≥ 29) and pectoral-fin rays (13–15, usually ≤ 14 vs. 13–16, usually ≥ 15, see Tables 1, 6), smaller dorso-caudal distance and larger head (index Dc/c 0.86–1.02, usually <0.97 vs. 0.90–1.20, usually> 0.97, Fig. 35b ), longer pectoral fins and their first ray (in fish ≥ 140 mm SL tip of pectoral fin usually protruding beyond dorsal-fin base, lP 62.3–70.5, usually> 66.0% SL, lP1 38.0–45.2, usually> 40.0% SL in C. persimilis vs. tip usually reaching from middle to end of dorsal-fin base, lP 57.7–67.0, usually <66.0% SL, lP1 32.3–44.1, usually <40.0% SL in C. opisthopus , see Figs. 4c–d , 35c ), more anterior position of pelvic-fin base (pV 32.1–38.2, usually> 34.0% SL vs. 29.3–37.5, usually <34.0% SL; index cV/pV 0.97–1.24, usually <1.17 vs. 1.04–1.46, usually> 1.17, see Fig. 4a ) and in pelvic-fin pigmentation (usually entirely pale vs. usually with vestigial dotted pigmentation). Putative juveniles of C. persimilis ( Fig. 33 ) differ from juveniles of C. opisthopus in chin barbel morphology, pigmentation of pectoral (much more intensive than in C. opisthopus ) and caudal (without wide dark stripe through fin-base) fins, much lower dorsal fin without a dark lobe.

Cypselurus persimilis differs from C. nossibe in fewer pectoral-fin rays (13–15, usually ≤ 14 vs. 15–17), fewer transverse scales (6–8½, usually ≤ 7½ vs. 8–9, usually ≥ 8½), shorter dorsal fin originating more posteriorly (lD 14.3–17.7 vs. 18.0–21.2% SL; aD 72.3–75.9 vs. 68.4–72.2% SL; Dc 21.8–25.5 vs. 26.0–28.4% SL), more posterior position of pelvic-fin base (index cV/pV 0.97–1.24 vs. 0.78–0.99), smaller eye (6.5–9.2, usually <8.5 vs. 8.5–10.8% SL) and pigmentation of pelvic fins (usually pale vs. pigmented).

Cypselurus persimilis differs from all species of the subgenus Poecilocypselurus in more posterior position of pelvic-fin base (index cV/pV 0.97–1.24, usually> 1.00 vs. 0.48–1.05, usually <1.00). Occasional specimens of C. neglectus shcherbachevi may be hard to distinguish from C. persimilis based on position of pelvic-fin base alone. In that case length of predorsal distance, dorso-caudal distance and dorsal-fin base, and number of predorsal and transverse scales should also be also taken into consideration.

Cypselurus persimilis seems to interbreed with C. naresii , as a putative hybrid was found: ZMUC uncat., 4°25’S 160°00’E, 6-7 October 1951, length 160 mm SL. D 10, A 7, P I 14, Spred 29, Str 7½, Sp.br 23 (6 + 17). Measurements (in % SL): aA 80.6, aD 73.8, aV 62.6, cV 36.9, pV 35.0, c 25.0, po 11.2, o 7.9, ao 5.0, io 9.3, Hc 17.5, H 19.0, h 7.6, Dc 24.3, lP 65.8, lP1 41.0, lV 31.3, lD 15.6, lA 8.0, HD 9.5, HA 6.2, p 13.8. Chin barbel absent. Numerous small dark specks on gill cover and under eye. Pectoral fins brown to 8th ray with a pale tip and a narrow pale posterior edging. Tip of pectoral fin protruding beyond dorsal-fin base but not reaching middle of caudal peduncle. Pelvic fins pale (one fin with a few dots between 3rd–4th rays distally). Dorsal fin gray, tip of its last ray protruding beyond middle of caudal peduncle but not reaching origin of caudal-fin upper lobe. Anal fin translucent with a few dots anteriorly, its first ray beneath 5th dorsal-fin ray. Caudal fin pale brown with slightly darker base. Lower jaw and upper jaw of equal size. Jaw teeth very small (not visible with the naked eye), mainly tricuspid, a few conical teeth also present; arranged in 2–3 rows in lower jaw and in 1 row in upper jaw. Palatine teeth present. Thus, this specimen has characters of both C. persimilis (pale pelvic fins, numerous dark specks on head sides) and C. naresii (long pelvic fins, anal fin with dark dots).

Etymology. The species name reflects extreme similarity in adult stage (a kind of triplets) of C. persimilis to C. naresii and C. opisthopus (from Latin “ persimilis ”—very similar).

Common name. The name “triplet flying fish” (Russian: “стрижехвост-блиЗнец”) is proposed here.

Biology. Females and males are mature starting at 155 and 140 mm SL, respectively. Mature and close to mature adults were captured in January (SOSC Ref. No.190, 6°30’N 118°45’E), February (IORAS 04283 & IORAS 04285, Bongu, New Guinea), March (IORAS 04103, 7°22’N 116°34’E; CAS 49651, near Monado, Celebes I.), April (SIO 61-721, 10°33’S 124°16’E), June (IORAS 04106, 7°32’N 116°37’E) and August (ZMUC P34925, 4°50’S 118°45’E). Thus, the spawning season is protracted for more than half a year, at least from January to August. It is interesting to note, that being captured at the same place (ZMUC uncat., 4°25’S 160°00’E, 6- 7.10.1951), nearly all adults of C. opisthopus were mature while all adults of C. persimilis were immature, and many of them were with flying fish eggs 11 in their buccal cavity. It seems probable that adults of C. persimilis may form mixed aggregations with spawning adults of C. opisthopus and feed on their eggs (a form of interspecific competition?).

Distribution. Cypselurus persimilis is distributed mainly in neritic waters ( Fig. 36 ) from the western coast of India (IORAS 04141, Mungallore) to Solomon Islands (ZMUC uncat., 4°25’S 160°00’E) and from Okinawa (URM P27993) to north-western Australia (NTM S.11316.002, Sandy Islet, Scott Reef). Like C. naresii and C. opisthopus , this species is mainly absent in neritic waters above wide continental shelf. Broad gaps in the distribution of C. persimilis will probably be filled with increasing efforts to study the species. Suspected juveniles of C. persimilis ( Fig. 33 ), according to information provided by authors of the photographs, were found among aggregations of drifting objects (seaweeds and other floating debris).

A specimen from the Arabian Sea (Vizhinjam) previously identified by the first author of this review as C. opisthopus (see Jayakumar et al. 2019) we can now re-identify as C. persimilis (though with some reservations as it could also be C. neglectus shcherbachevi ). Panakkool-Thampan et al. (2018) provided a photo of a specimen captured at 11°51’N 75°22’E, probably also belonging to C. persimilis .

11 These eggs were very similar to that found in the ovaries of C. opisthopus : ~ 1.2–1.3 mm in diameter, envelope evenly covered with rather long (more than egg’s diameter) filaments.

Figures

FIGURE 4. Size variation of morphometric characters (in % SL) in Cypselurus hiraii (◊), C. opisthopus (∆), C. naresii (○), C. persimilis (+), C. angusticeps (□) and C. comatus (x): (A)—cephalo-ventral distance divided by postventral distance (index cV/ pV); (B)—dorso-caudal distance (Dc); (C)—pectoral-fin length (lP); (D)—length of the first pectoral-fin ray (lP1); (E)—height of dorsal fin (HD); (F)—length of chin barbel (Lcir).

FIGURE 32. Cypselurus persimilis sp. n. (A)—129 mm SL, IORAS 04081, 7°17’S 105°07’E; (B)—140 mm SL, IORAS 04110, 2°57’S 131°10’E; (C)—158 mm SL, IORAS 04106, 7°32’N 116°37’E; (D)—179.5 mm SL, ZMMU P-24610 (holotype), 6°16’S 153°44’E; (E)—157 mm SL (close up of head), IORAS 04106, 7°32’N 116°37’E.

FIGURE 33. Presumed juveniles of Cypselurus persimilis sp. n. (A)—length unknown (probably ~ 20–30 mm SL), Raja Ampat, Indonesia, 25.01.2018, photo by Sabine Templeton (CC-BY-NC, downloaded 31.05.2023 from www.inaturalist.org); (B)—estimated length ~ 50–70 mm TL, ~ 2°50’S 128°40’E, side view, photo by Ned DeLoach ©; (C)—same juvenile, view from below (with a reflection from water surface), photo by Ned DeLoach ©.

FIGURE 34. Pectoral (A–C) and pelvic (D–H) fins of Cypselurus persimilis sp. n. (A)—140 mm SL, IORAS 04110, 2°57’S 131°10’E; (B) & (G)—164.5 mm SL, IORAS 04074, 6°16’S 153°44’E; (C) & (H)—176 mm SL, ZMUC uncat., 4°25’S 160°00’E; (D)—129 mm SL, IORAS 04081, 7°17’S 105°07’E; (E)—144.5 mm SL, IORAS 04235, 5°49’S 152°53’E; (F)—158 mm SL, IORAS 04284, Bongu, New Guinea.

FIGURE 35. Size variation of morphometric characters (in % SL) in Cypselurus persimilis (+), C. naresii (○—C. n. naresii, C. n. ordinarius, C. n. septentrionalis and C. n. albitaenia; red circles—C. n. socotranus) and C. opisthopus (∆). (A)—pelvicfin length (lV); (B)—dorso-caudal distance divided by head length (index Dc/c); (C)—pectoral-fin length divided by pelvic-fin length (index lP/lV).

FIGURE 36. Distribution of Cypselurus persimilis sp. n. Open symbols indicate capture location for fishes> 100 mm SL; holotype position marked with asterisk; putative juveniles of C. persimilis (see Fig. 33) marked with red cross.