Cypselurus opisthopus crockeri Seale, 1935

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 : 45-46

Cypselurus opisthopus crockeri Seale, 1935

Synonymy and bibliography.

Cypselurus crockeri Seale, 1935: 350 , pl. 22 fig. 1 (original description; near Rennell I. between Kungava Bay and Tuhangango). Munro 1958: 137 (New Guinea; listed). Parin 1961a: 49, 52 (listed as probable synonym of Cypselurus opisthopus ). Munro 1967: 117 (New Guinea; listed).

Cypsilurus crockeri . Fowler 1949: 58 (description [after Seale 1935]).

Cypselurus opisthopus . Parin 1961a: 49–52 (description; western Pacific; in part).

Material examined. Twelve specimens 134–183 mm SL.

Full morphological study. IORAS 04417 (1, 162 mm SL), Madang , New Guinea, 8- 12.04.1966 . IORAS 04071 (1, 180 mm SL), 6°16’S 153°44’E, 27- 28.07.1957 . IORAS 04205 (1, 167 mm SL), 5°49’S 152°53’E, 20.07.1957 . IORAS 04091 (1, 164.5 mm SL), Ninigo Is. , 17- 18.05.1971 . IORAS 04098 (1, 134 mm SL), 5°49’S 152°53’E, 20.07.1957 . IORAS 04104 * (1, 145 mm SL), 6°16’S 153°44’E, 27- 28.07.1957 . IORAS 04109 (1, 164 mm SL), 8°10’S 163°00’E, 4.06.1971 . CAS 5506 * (holotype, 147 mm SL), Solomon Islands, near Rennell Island , flew on deck between Kungava Bay and Tuhangango, 17.06.1933 . ZMUC uncat (4, 161– 183 mm SL), 4°25’S 160°00’E, 6- 7.10.1951 .

Holotype. The holotype of C. o. crockeri was studied by the second author5. Its characters are given below [see also description of the holotype in the work of Seale (1935)].

5 The photos of the holotype are available at CAS website: https://researcharchive.calacademy.org/research/Ichthyology /

Types/index.asp?xAction=getrec&close=true&TypeID=1784

CAS 5506, yacht “Zaca”, Solomon Islands, near Rennell Island, flew on deck on 17.06.1933 between Kungava Bay and Tuhangango. Length 147 mm SL (gonads removed). D 12, A 8, P I 13, Spred 33, Str 7, Sp.br 24 (5 + 19), Vert 45 (30 + 15). Measurements (in % SL): aA 78.7, aD 72.8, aV 63.6, cV 1 42.5, pV 35.5, c 21.9, po 10.2, o 7.4, ao 4.2, io 9.1, H 16.6, h 7.4, Dc 24.6, lP -, lV 36.8, lD 18.5, lA 9.7, HD 21.4, HA 8.8, p 14.2. Body and head brown. Chin barbel absent. Pectoral fins brown, somewhat paler near lower margin. Tips of pectoral fins broken. Pelvic fins dark brown (nearly black), paler along inner margin. Tip of pelvic fin protruding beyond origin of caudal-fin lower lobe. Dorsal fin black, its middle and posterior rays much elongated (6th ray the longest), tips of penultimate rays protruding beyond tip of the last ray. First anal-fin ray beneath 3rd–4th rays of dorsal fin. Caudal fin crossed with dark bands: one on upper lobe and two on lower one (both lobes are broken). Jaw teeth heavily damaged, but it is evident that they were arranged in about 3 rows, some lower jaw teeth tricuspid.

Differential diagnosis. Cypselurus o. crockeri differs from C. o. opisthopus (see Tables 8, 14) in more anal-fin rays (usually 9 vs. usually 8), upper gill rakers (e.br usually 7–8 vs. usually 6–7), total (usually 44–45 vs. usually 43–44) and precaudal (usually 30 vs. usually 28–29) vertebrae, as well as in shorter snout ( Figs. 11b , 15 ) and more densely pigmented pelvic fins ( Fig. 16 ). Cypselurus o. crockeri seems to have retarded metamorphosis as compared with C. o. opisthopus : elevated dorsal fin with dark brown lobe (so called “Parexocoetus-stage”) and juvenile-type pigmentation of body and fins are retained up to 147 mm SL (holotype of C. o. crockeri ); also, a fish 134 mm SL (IORAS 04098) has a fragment of chin barbel and a fish 145 mm SL (IORAS 04104) still retains the bony base of chin barbel on the lower jaw symphysis.

Despite these differences, we do not assign C. o. crockeri full species rank because we suspect that it is not reproductively isolated from C. o. opisthopus . However, this matter requires further study.

Figures

FIGURE 11. Size variation of morphometric characters (in % SL) in Cypselurus opisthopus opisthopus (□—Indian Ocean, ◊—Philippines, ∆—New Guinea) and C. o. crockeri (●). (A)—postventral distance (pV); (B)—snout length (ao); (C)—pelvicfin length (lV); (D)—dorsal-fin height (HD); (E)—anal-fin height (HA); (F)—body width (p).

FIGURE 15. Cypselurus opisthopus crockeri. (A)—134 mm SL, IORAS 04098, 5°49’S 152°53’E; (B)—167 mm SL, IORAS 04205, same place; (C)—180 mm SL, IORAS 04071, 6°16’S 153°44’E.

FIGURE 16. Pelvic fins of Cypselurus opisthopus crockeri. (A)—134 mm SL, IORAS 04098, 5°49’S 152°53’E; (B)—167 mm SL, IORAS 04205, same place; (C)—180 mm SL, IORAS 04071, 6°16’S 153°44’E; (D)—183 mm SL, ZMUC uncat., 4°25’S 160°00’E.