Cheilopogon (Ptenichthys) katherinae, 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 : 46-52

Cheilopogon (Ptenichthys) katherinae sp. nov.

urn:lsid:zoobank.org:act:FA5312DB-2248-460B-A087-04072418261F

( Figs. 18 , 20–22 ; Tables 1–7, 10)

Cypselurus sp. Ben Tuvia & Steinitz 1952 (cited by: Fowler & Steinitz 1956): 5 (Eylath, Red Sea).

Cypsilurus socotranus (non Steindachner). Fowler & Steinitz 1956: 271–272 (description; Eylath, Red Sea).

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

Material examined. Fourteen specimens 51–212 mm SL.

Full morphological study. ZMMU P-24081, holotype (150.5 mm SL), 19°39’N 38°45’E, 11.06.1977 . IORAS 03432 (1, 51 mm SL), 17°43’N 39°20’E, 8.06.1977 . IORAS 03433 (1, 174.5 mm SL), 24°49’N 35°46’E, 21.10.1988 . IORAS 03434 , paratypes (3, 139, 139 and 142 mm SL), 19°39’N 38°45’E, 11.06.1977 .

Partial morphological study. IORAS uncat.* (3, 185– 197 mm SL), 14°05’N 42°20’E, 15.10.1960 . IORAS uncat.* (1, 187 mm SL), 19°40’N 38°41’E, 13- 14.10.1960 . IORAS uncat.* (1, 212 mm SL), 12°22’N 43°59’E, 5.03.1983 . SMF 213 * (1, 181 mm SL), Rotes Meer . USNM 294827 (1, 112 mm SL), 21°34’N 38°41’E, 17.05.1958 . ANSP 101711 6 (1, ~ 192 mm SL), Eylath , Red Sea .

Holotype ( Figs. 20a, b ). ZMMU P-24081, R / V "Vityaz", Cruise 61, Sta. 7630, 19°39’N 38°45’E, captured with night light on 11.06.1977. Female (immature), 150.5 mm SL. D 12, A 9, P I 14, Spred 31, Str 9, Sp.br 22 (5 + 17), Vert 44 (30 + 14). Measurements in % SL: aA 78.5, aD 71.2, aV 56.0, cV 32.0, pV 41.9, c 23.9, po 10.3, o 7.4, ao 4.7, io 8.0, Hc 17.2, H 18.5, h 7.1, Dc 26.7, lP 64.2, lP 1 34.6+, lV 34.0, lD 17.4, lA 10.7, HD 11.2, HA 6.7, p 13.9. Pectoral fins grayish brown with pale “mirror” to 4th ray. Tip of fin reaches 10th dorsal-fin ray. Pelvic fins transparent, their tip reaching end of anal-fin base. Dorsal fin is gray, tip of last ray reaching middle of caudal peduncle. Penultimate dorsal-fin rays not elongate. Anal fin transparent; first anal-fin ray beneath 6th–7th dorsalfin ray. Longest ray of dorsal fin the 2nd; 2nd and 3rd rays of anal fin longest. Caudal fin is grayish brown. Remnants of two pigment bands ventrally on body: in middle of pecto-ventral distance and near pelvic-fin base. Lower jaw longer than upper, teeth small, conical, some with additional cusps. No palatine teeth.

Paratypes. IORAS 03434 , three specimens 139, 139 and 142 mm SL , R / V "Vityaz", Cruise 61, Sta. 7630, 19°39’N 38°45’E, 11.06.1977 .

Description. The meristic and morphometric characters are given in Tables 1–7 and 10. D 11–13, A 8–10, P I 12–14 (usually I 14), Spred 30–34, Str 8–9½, Sp.br 20–24 (5–7 + 15–18), Vert 44–46 (29–30 + 14–17). Palatine teeth absent (only 1 out of 8 specimens with row of 3–4 teeth on anterior of palatines). Snout not oblong, upper jaw is slightly pointed at end. Lower jaw longer than upper or, rarely, equal. Jaw teeth very small, usually unicuspid, conical. Occasional specimens with some teeth with additional cusps.

Body of fish 139–212 mm SL elongate, greatest body depth 5.2–6.0 in SL. Body width 1.10–1.34 and depth of caudal peduncle 2.23–2.74 in greatest body depth. Greatest head depth and head length 5.8–6.25 and 4.0– 4.25 in SL, respectively. Head length 1.01–1.16 in dorso-caudal distance. Eyes large, their diameter 12.2–14.3 times in SL, 2.55–3.45 in c and 1.0– 1.15 in io.

Pectoral fins relatively long, their length increasing somewhat with growth: in fish 139–150.5 mm SL tip of fin reaches (or almost reaches) end of dorsal-fin base and lP 1.54–1.6 in SL; in larger fish (174.5–212 mm SL) tip of pectoral fin reaches from end of dorsal-fin base to middle of caudal peduncle, and lP 1.44–1.51 in SL. First pectoral-fin ray unbranched, its length almost not changing with growth, 2.65–2.95 in SL and 1.75–1.92 in lP. Pelvic-fin base much closer to posterior edge of head than to beginning of lower lobe of caudal fin (cV/pV = 0.74– 0.79). The length of pelvic fins 2.8–3.3 in SL and 1.85–2.3 in lP. Tip of pelvic fins reaches (almost reaches) end of anal-fin base or protrudes slightly beyond it.

Anal-fin origin far behind dorsal-fin origin, 1st anal-fin ray beneath 5th–7th dorsal-fin ray (usually 5th or 6th). Dorsal fin with 2–4 rays more than anal fin. Heights of dorsal and anal fins 8.3–10.1 and 13.3–16.4 in SL, respectively. Longest ray in dorsal and anal fins 2nd or 3rd. Tip of last dorsal-fin ray reaches middle of caudal peduncle. Central and posterior rays of dorsal fin not elongate.

Pigmentation. Fish 139–212 mm SL have the typical pelagic coloration: dark from above and pale from below. There are no body bands. Only some fish 139–150 mm SL show remnants of two bands: near pelvic-fin base and in middle of pecto-ventral distance. Gill covers usually with few small specks or large dots; absent below eye.

6. This specimen was studied by the first author basing only on photographs and X-ray photographs (by the courtesy of K.E. Bemis (VIMS)).

Pectoral fins ( Fig. 20b ) grayish-brown or gray with large pale “mirror” reaching to 3rd–4th (sometimes to 6th) ray, and usually with narrow pale posterior edge. In the smallest specimen of the type series (139 mm SL) the “mirror” reaching upper edge of fin. Pelvic fins transparent, and only some fish retaining remnants of pigmentation distally along the 3rd–4th rays ( Fig. 20c ). Dorsal fin gray; in fish 139–142 mm SL its upper margin blackish. Anal fin transparent. Caudal fin pale brown, and in fish 139–150 mm SL the posterior margin pale.

Coloration in life. No data.

Maximum size. The maximum length (SL) of Ch. katherinae in our materials was 212 mm (IORAS uncat., 12°22’N 43°59’E). The only male available at our disposal was 174.5 mm SL. The length of the largest female studied for sex and maturity was 187 mm SL.

Juveniles. Two juveniles 51 and 112 mm SL (the latter specimen in poor condition) were preliminarily identified as Ch. katherinae ( Fig. 21 ). A description of the smaller juvenile with some data for the larger specimen is given below.

The 51 mm SL juvenile is similar to large fish in measurements of body and fins (Table 10), worth noting only a higher value of body width (15.8% SL), more anterior position of pelvic fins (cV/pV = 0.68), much longer pelvic fins (44.9% SL) extending beyond origin of caudal fin lower lobe, and higher dorsal fin (17.2% SL), the penultimate ray of which is longer than the last one and reaches the beginning of the upper lobe of the caudal fin.

The jaw teeth are small and conical; palatine teeth absent. There is a pair of short, pointed barbels on the chin ( Fig. 21b ), nearly reaching the middle of the eye. The barbels consist of a thick stem with a narrow fringe along the outer (posterior) margin. The barbels are uniformly covered with dots and only near the base they are pale. In the 112 mm SL juvenile barbels are absent.

There are four distinct dark bands on the body ( Fig. 21a ): near the bases of pectoral and pelvic fins, between them and above the anus. The underside of the head is pale with only isolated dots below the eye; the gill covers are densely pigmented. The snout end and the space around the nostrils are covered with dots.

The pectoral fins are mottled ( Fig. 21c ), their proximal part and the lower edge of the distal part dark, with two rows of darker spots and with a paler band near the fin base. Distally the fins are generally pale with several dark streaks along the rays. In the 112 mm SL juvenile the pectoral fins are gray proximally and brown distally, with a pale “mirror” to the 5th–6th rays.

The pelvic fins ( Fig. 21d ) are brown with faded (paler) areas along the rays. The 112 mm SL juvenile has a similar pattern of pigmentation, but its intensity is noticeably less—the fin grayish.

The dorsal fin is covered with dots forming three oblique stripes: near the bases of the anterior rays, in central and postero-superior parts of the fin. The last ray is pale. The anal fin is brownish anteriorly between the 1st–3rd rays and there is a cluster of dots (forming a faint spot) on the rear of the fin, between the 4th–8th rays. In the 112 mm SL juvenile the dorsal fin is pale with some feint pigmentation along its upper margin; the anal fin is transparent.

The caudal fin is pigmented near its base and along the lower lobe rays, where there are two bands. In the 112 mm SL juvenile the caudal fin is pale brown.

Intraspecific variation. Specimens of the type series of Ch. katherinae 139–150.5 mm SL differ slightly from larger fish (174.5–212 mm SL) in shorter pectoral fins (62.4–64.8 vs 66.1–69.2% SL). We consider this difference a consequence of allometric growth, although it is also possible that the large specimens belong to another, undescribed, species. Furthermore, one specimen (IORAS 03433, 174.5 mm SL, 24°49’N 35°46’E) has a row of 3– 4 teeth on the palatines, while the other seven specimens examined had no palatine teeth. We regard this as intraspecific variation, although it is possible that this specimen may also belong to another species. To resolve these issues it is necessary to study a more representative collection of Ch. katherinae .

Etymology. The species is named in honor of Katherine Elliott Bemis (VIMS) to acknowledge her kind help with our work on this review.

Common names. The name “Katherine’s Red Sea flying fish” (Russian: “кpacнoмopcкий длиннoкpыл Кaтepины”) is proposed here.

Comparative remarks. Cheilopogon katherinae differs from Ch. intermedius occurring in Indo-West Pacific (for a description of this species see Parin 1961a; Parin & Lakshminayana 1993; Lakshminarayana 1993) in the pale pigmentation of pelvic fins, a smaller number of anal-fin rays (usually 9 vs usually 10), larger values of Spred, Str, pV and smaller values of cv/pV and cV. The 51 mm SL juvenile differs from the juveniles of Ch. intermedius of similar size (see Parin 1961a; Kovalevskaya 1975) in paler chin barbels with a narrower fringe, in darker pelvic and anal fins and base of pectoral fins, as well as in larger values of c, o, lP and lD.

Cheilopogon katherinae differs from Ch. furcatus (see Parin & Belyanina (1998) for a description of this species) in pigmentation of pectoral, pelvic, dorsal and anal fins, in a lower number of rays in dorsal, anal and pectoral fins, in smaller values of lD and lA. It differs from the Atlantic species Ch. melanurus (description of this species is given in Parin & Belyanina (2000)) in fewer rays in pectoral (13–15 vs. usually 16–17) and dorsal fins, higher value of aV and lower values of Dc, lD and HA. Cheilopogon katherinae is probably most closely related to Ch. melanurus or Ch. intermedius , because it is most similar to these species in pigmentation and morphometry. However, this issue requires a special study.

Cheilopogon katherinae can be easily confused with Ch. marisrubri , the other species occurring in the Red Sea. These two species have very similar pigmentation as adults. However, they can be distinguished by the length of the pelvic fins ( Fig. 18 ), the number of vertebrae and transverse scales (Str) and by other characters (see Tables 1–7).

TA BLE 10. Meristic and morphometric characters of flying fish Cheilopogon katherinae

Biology. All the specimens of this species studied (150–187 mm SL) were immature.

Distribution. Cheilopogon katherinae is endemic to the Red Sea ( Fig. 22 ), where it is widely distributed, penetrating northward to Eylath (Eilat) (ANSP 101711, ~ 192 mm SL, December 1949). This species has also been collected in the western part of the Gulf of Aden (IORAS uncat., 212 mm SL, 12°22’N 43°59’E, 5.03.1983).

Figures

FIGURE 18. Size variation of morphometric characters in flying fishes Cypselurus bosha (□), C. olpar (○), Cheilopogon formosus (x), Ch. marisrubri (+), Ch. katherinae (◊), Cheilopogon sp. 1 (∆) and Cheilopogon sp. 2 (▲). (A)—length of pectoral fin divided by length of pelvic fin (index lP/lV), (B)—length of pelvic fin (lV), (C)—greatest head depth (Hc).

FIGURE 20. Flying fish Cheilopogon katherinae. (A)—150.5 mm SL, ZMMU P-24081 (holotype), 19°39’N 38°45’E, lateral view; (B)—the same specimen, pectoral fin; (C)—142 mm SL, IORAS 03434 (paratype), 19°39’N 38°45’E, pelvic fin.

FIGURE 21. Juvenile of flying fish Cheilopogon katherinae (51 mm SL, IORAS 03432, 17°43’N 39°20’E). (A)—lateral view; (B)—close-up of barbel; (C)—pectoral fin; (D)—pelvic fin.

FIGURE 22. Distribution of flying fishes Cheilopogon katherinae (Δ), Cypselurus bosha (□) and C. olpar (○). Filled symbols indicate capture location for fishes ≤100 mm SL, open symbols indicate capture location for fishes>100 mm SL.