Cheilopogon formosus andamanicus, Shakhovskoy & Parin, 2019

Shakhovskoy, Ilia B. & Parin, Nikolay V., 2019, A review of the flying fish genus Cypselurus (Beloniformes: Exocoetidae). Part 1. Revision of the subgenus Zonocypselurus Parin and Bogorodsky, 2011 with descriptions of one new subgenus, four new species and two new subspecies and reinstatement of one species as valid, Zootaxa 4589 (1), pp. 1-71 : 26-30

Cheilopogon formosus andamanicus subsp. nov.

urn:lsid:zoobank.org:act:4EFE3E28-EDC4-49BE-BC10-5B9C2E1FB12B

( Figs. 2 , 3 , 9 , 10 ; Tables 1–7)

Cypselurus hexazona (non Bleeker). Parin & Bogorodsky 2011: 683–686 [658–660 in English translation] (in part; description, distribution).

Representatives of this subspecies were previously identified as C. hexazona both as juveniles and as adults (except for the specimens with spots on pectoral fins which were mainly identified as Cheilopogon spilopterus ).

Material examined. Forty three specimens 30–179 mm SL.

Full morphological study. ZMMU P-24079, holotype (1, 61 mm SL), 3°27’N 100°12’E, 2.11.1962 . IORAS 03410 (3, 101– 106.5 mm SL), Andaman Sea, 17.03.1964 . IORAS 03411 (4, 53– 64.5 mm SL), 6°04’N 98°29’E . ZMUC uncat. (13, 41– 156 mm SL), 6°06’N 96°00’E, 10.05.1951 .

Partial morphological study. IORAS 03411 (2, 53– 58 mm SL), 6°04’N 98°29’E . IORAS uncat* (1, 31 mm SL), 5°00’N 90°52’E, 11- 12.02.1961 . URM 9252 * (1, 149 mm SL), Phuket , Andaman Sea . URM P9161 * (1, 135 mm SL), same place . URM P9164 *, paratype (1, 116 mm SL), same place . URM P9253 * (1, 159 mm SL), same place . URM P9261 * (1, 158.5 mm SL), same place . URM P14733*, paratype (1, 169 mm SL), same place . URM P-9251* (1, 155 mm SL), same place. URM P-9254* (1, 168 mm SL), same place. URM P-9255* (1, 167 mm SL), same place. URM P-9256* (1, 173 mm SL), same place. URM P-9258* (1, 157 mm SL), same place. URM P- 9260* (1, 161 mm SL), same place. URM P-9262* (1, 165 mm SL), same place. URM P-9263* (1, 176.5 mm SL), same place. URM P-9264* (1, 168 mm SL), same place. URM P-9265* (1, 162 mm SL), same place. URM P- 9266*, paratype (1, 179 mm SL), same place . ZMUC P341377 , paratype (1, 30 mm SL), 4°41’N 98°13’E, 9.11.1929 . CAS 132113 ( SU 32113 )* (1, 112 mm SL), Singapore .

Holotype ( Fig. 9a ). ZMMU P-24079, R / V "Vityaz" Cruise 35, Sta. 5302, Sample 461, 3°27’N 100°12’E, captured with dip net and night light near the surface on 2.11.1962 at 19.00–19.10. The depth of capture place is 58 m. Juvenile, 61 mm SL. D 12, A 9, P I 13, Spred 29, Str 7½ (?), Sp.br 23 (6 + 17), Vert 40 (?). Measurements (in % SL): aA 78.8, aD 70.0, aV 59.1, cV 34.7, pV 40.6, c 24.9, po 11.3, o 9.5, ao 4.7, io 10.1, Hc 16.5, H 16.5, h 6.5, Dc 27.7, lP 70.4, lP 1 39.6, lV 39.0, lD 19.3, lA 11.6, HD -, HA 10.0, p 14.5. Body with five transverse bands: near the bases of pectoral and pelvic fins, between them, above the anus (very weak), and above the middle of anal-fin base. Head densely pigmented below eye and on gill cover. Pectoral fins dark brown with pale “mirror” reaching to upper edge of fin. Tip of pectoral fin reaches middle of caudal peduncle. Pelvic fins pale with dark brown spot on distal half between 2nd–5th rays, and with a few dots near bases of central rays. Tip of pelvic fin reaches origin of lower caudal-fin lobe. Dorsal fin (the ends of rays broken off) with dark spot centrally and dots at bases of anterior rays. Tip of last ray protrudes slightly beyond middle of caudal peduncle. Anal fin transparent, with an aggregation of dots between 3rd–8th rays near the lower margin of fin. First anal-fin ray beneath 5th–6th dorsal-fin ray. Caudal fin is pale with brown pigment only near its base and along rays of lower lobe, with an aggregation of melanophores (band) proximally. Lower jaw slightly longer than upper jaw; teeth relatively small, acute, conical (many teeth in the upper jaw recurved), arranged in two rows. Single tooth on anterior of palatines.

Paratypes. URM P- 9266, 179 mm SL, Phuket, Andaman Sea . URM P 14733, 169 mm SL, Phuket, Andaman Sea . URM P 9164, 116 mm SL, Phuket, Andaman Sea . ZMUC P341377 , 30 mm SL, 4°41’N 98°13’E, 9.11.1929 .

Description. Meristic and morphometric characters are given in Tables 1–7. D 11–14, A 9–11, P I 12–14 (usually I 13), Spred 25–31 (usually 27–29), Str 7–8 (usually 7–7½), Sp.br 21–23 (5–6 + 15–17), Vert 40–42. Palatine teeth, if present (absent in about 50% of specimens), few in number: usually only 1–2 teeth anteriorly on palatines (often only on one side); only a few specimens with 3–4 teeth. In contrast with Ch. f. pseudospilopterus, palatine teeth already present in juveniles starting with 41 mm SL. Snout oblong, upper jaw pointed at tip. Lower jaw longer than upper; teeth unicuspid. Teeth of adults numerous, large (usually clearly visible with the naked eye), conical, usually recurved, and arranged in 2 or 3 rows near the symphysis. In juveniles, teeth are not as numerous (arranged in 1 or 2 rows), relatively small, conical or needle-shaped. At a length of about 60 mm SL, the teeth begin to recurve.

Body elongate, greatest body depth changing little with growth, 5.5–6.3 in SL. Body width 1.07–1.3, and depth of caudal peduncle 2.45–2.9 in greatest body depth. Greatest head depth and head length practically do not change with growth, 5.55–6.2 and 3.8–4.1 in SL, respectively. Head length 0.96–1.18 in dorso-caudal distance. Eyes large, eye diameter decreasing with growth: in juveniles 40–105 mm SL, 9.4–11.6 in SL, 2.4–2.95 in c and 1.0– 1.2 in io; in large fish 135–180 mm SL, 11.1–14.1 in SL, 2.9–3.5 in c, 1.0– 1.15 in io.

Pectoral fins relatively long, their length decreasing slightly with growth: in juveniles (40–105 mm SL), 1.35– 1.6 in SL, in large fish (135–180 mm SL), 1.45–1.6 in SL. Tip of pectoral fin reaches posterior part of dorsal-fin base – middle of caudal peduncle (occasionally farther). First pectoral-fin ray is unbranched, its length almost not changing with growth, 2.35–2.75 in SL and 1.5–1.8 in lP. Pelvic-fin base slightly closer to posterior edge of head than to beginning of lower caudal-fin lobe (cV / pV = 0.79–0.95); pelvic fins shift slightly posteriorly as fish grows ( Fig. 2a ). Length of pelvic fins decreases quite strongly from juveniles to adults, in juveniles (40–105 mm SL), 2.4–3.1 in SL and 1.6–2.15 in lP; in large fish (135–180 mm SL), 3.55–4.15 and 2.3–2.55, respectively. Tip of pelvic fin in small juveniles 40–55 mm SL reaches or extends slightly beyond origin of caudal fin lower lobe; in juveniles 55–75 mm SL it reaches from middle of caudal peduncle to origin of caudal fin lower lobe; in fish 75–110 mm SL it reaches from end of anal-fin base to middle of caudal peduncle; in fish 140 mm SL and over, from middle to end of anal-fin base (and only in one fish it reached no further than first third of anal fin).

Anal fin origin is far behind dorsal-fin origin (1st anal-fin ray under the 4th–7th dorsal-fin ray, usually under 5th or 6th). Dorsal fin with 2–4 rays more than anal fin. Heights of dorsal and anal fins decrease markedly with growth of fish ( Figs. 2e, f ). In juveniles (40–105 mm SL) HD 6.0–6.7 and HA 9.0– 13.1 in SL; in large fish (135– 180 mm SL) HD 7.9–10.6, HA 13.1–15.1 in SL. The longest ray in dorsal and anal fins is the 2nd or, occasionally, the 3rd one. Tip of last dorsal-fin ray reaches middle of caudal peduncle or protrudes slightly beyond it. Middle and posterior dorsal-fin rays not elongate (in juveniles of about 40–50 mm SL penultimate rays somewhat elongate and protrude slightly beyond last ray tip).

Pigmentation. Pigmentation of Ch. f. andamanicus similar to that of Ch. f. pseudospilopterus. However, there are some differences. Bands on body of Ch. f. andamanicus more pronounced (compare Figs. 5 and 10 ), and in juveniles up to 75 mm SL all 5–6 bands clearly visible (in Ch. f. pseudospilopterus 55–75 mm SL there are usually no more than 3–4 poorly discernible bands). Juveniles of Ch. f. andamanicus 80–100 mm SL were absent in our collections. However, in juveniles of about 100–115 mm SL the bands are no longer visible. Dark spots appear on pectoral fins much later, only in fish about 150 mm SL and more (in Ch. f. pseudospilopterus starting at 55 mm SL). Spots always few in number (1–5 spots), and in most fish (62.5%) more than 150 mm SL are absent. In juveniles of Ch. f. andamanicus pelvic fins slightly more intensively pigmented near base, and distal spot clearly visible up to 135 mm SL (in Ch. f. pseudospilopterus up to 115 mm SL).

Coloration in life. In a juvenile 31 mm SL (IORAS uncat., 5°00’N, 90°52’E), bands on its body (except for the band near the caudal fin base), as well as a spot on pectoral fin base and a spot on dorsal fin were yellow at the time of capture.

Maximum size. The maximum length of Ch. f. andamanicus in our collections was 179 mm SL (URM P9266, Phuket (Andaman Sea)).

Etymology. The name " andamanicus " reflects distribution of this subspecies mainly in the Andaman Sea.

Common names. The name “Andaman toothy flying fish” (Russian: “aндaмaнcкий зyбacтый длиннoкpыл”) is proposed here.

Comparative remarks. Cheilopogon f. pseudospilopterus and Ch. f. andamanicus slightly differ in pigmentation of body and pectoral fins, in number of pectoral-fin rays (usually 13 vs. usually 14), in values of ao (in juveniles), H (in large fish), h and in maximum size (see Figs. 2b, c ; Tables 1, 6). We consider these differences sufficient to recognize them as distinct subspecies. The differences of these subspecies from Cheilopogon f. formosus are described above.

Biology. The only mature female of this subspecies examined, 176.5 mm SL, was captured near Phuket (capture date is unknown). In addition, one female 156 mm SL (captured 10.05.1951 at 6°06’N 96°00’E) was close to maturity. At the same station juveniles 40–50 mm SL were captured. An early juvenile 31 mm SL was captured 11- 12.02.1961 at 5°00’N 90°52’E. This suggests that Ch. f. andamanicus spawns at least from January to May.

Distribution. This subspecies is distributed ( Fig. 3 ) in the southern part of the Andaman Sea from Phuket, southwards through the Malacca Strait to Singapore (CAS 132113 (SU 32113), 112 mm SL). One juvenile, 31 mm SL, was captured west of the Nicobar Islands (IORAS uncat., 5°00’N 90°52’E, 11- 12.02.1961).

It is very likely that the ranges of all three subspecies of Ch. formosus are much wider than presented here ( Fig. 3 ) because we had few samples from coastal waters.

Figures

FIGURE 2. Size variation of morphometric characters in Cheilopogon formosus formosus (▲), Ch. formosus andamanicus (□), Ch. formosus pseudospilopterus (○) and Ch. spilopterus (x). (A)—postventral distance (pV); (B)—greatest body depth (H); (C)—lowest depth of caudal peduncle (h); (D)—length of anal fin base (lA); (E)—height of dorsal fin (HD); (F)—height of anal fin (HA). Note: for Ch. formosus formosus data from Kotthaus (1969) are included.

FIGURE 3. Distribution of flying fishes Cheilopogon formosus formosus (□), Ch. formosus pseudospilopterus (Δ), Ch. formosus andamanicus (◊), Ch. marisrubri (○), Cheilopogon (Ptenichthys) sp.1 (x) and Cheilopogon (Ptenichthys) sp. 2 (+). Filled symbols indicate capture location for fishes ≤100 mm SL, open symbols indicate capture location for fishes>100 mm SL.

FIGURE 5. Flying fish Cheilopogon formosus pseudospilopterus. (A)—25.5 mm SL, ZMUC uncat., Galathea, Sta. 383, 7°57’N 102°32’E; (B)—28 mm SL, ZMUC uncat., Galathea, Sta. 383, 7°57’N 102°32’E; (C)—36.5 mm SL, IORAS 03407 (paratype), 1°58’N 105°53’E; (D)—48 mm SL, IORAS 03407 (paratype), 1°58’N 105°53’E; (E)—81.5 mm SL, IORAS 03406, 4°28’N, 112°51’E; (F)—154 mm SL, CAS 81208, 9°05’N 100°48’E; (G)—150.5 mm SL, CAS 81203, 12°11’N 100°41’E, close-up of jaws.

FIGURE 9. Flying fish Cheilopogon formosus andamanicus. (A)—61 mm SL, ZMMU P-24079 (holotype), 3°27’N 100°12’E (drawing by G.N. Pokhilskaya); (B)—152 mm SL, ZMUC uncat., Galathea Sta. 326, 6°06’N 96°00’E; (C)—the same specimen, pectoral fin.

FIGURE 10. Juveniles of flying fish Cheilopogon formosus andamanicus (ZMUC uncat., Galathea Sta. 326, 6°06’N 96°00’E). (A)—27 mm SL; (B)—30 mm SL; (C)—32 mm SL; (D)—37 mm SL; (E)—42 mm SL; (F)—48 mm SL; (G)—77.5 mm SL.