Lutjanus bengalensis ( Bloch 1790 )

Iwatsuki, Yukio, Al-Mamry, Juma M. & Heemstra, Phillip C., 2016, Validity of a blue stripe snapper, Lutjanus octolineatus (Cuvier 1828) and a related species, L. bengalensis (Bloch 1790) with a new species (Pisces; Lutjanidae) from the Arabian Sea, Zootaxa 4098 (3), pp. 511-528 : 521-523

Lutjanus bengalensis ( Bloch 1790)

English name: Bengal snapper

Figures 1 C, 2B, & 3B‒C; Table 1

Holocentrus bengalensis Bloch 1790: 102 , pl. 246, fig. 2 (Type locality: Bay of Bengal, eastern Indian Ocean). Mesoprion pomacanthus Bleeker 1855: 407 (in part, Type locality: Ambon Island, Molucca Islands, Indonesia).? Genyoroge bengalensis ; Günther 1859: 178 (Red Sea).

Lutjanus bengalensis ; Kyushin et al. 1977: 68, unnumbered photograph (in part, Andaman Sea); Allen & Talbot 1985: 21, pl. I, E–I, F. (in part, as L. octolineatus in plate, Andaman Sea and Indonesia); Allen 1985: 61, pl. XII, 45 (in part, as L. octolineatus in plate, Andaman Sea and Indonesia); Iwatsuki et al. 1999: 316, fig. 1A (Iye Isl., Okinawa, Japan): Iwatsuki & Satapoomin 2009: 136, unnumbered underwater photograph (Andaman Sea).

Lectotype: ZMB 303, 94 mm SL, Bengal, Bay of Bengal, eastern Indian Ocean.

Non-type specimens (n =17): MUFS 10452‒104568, 7 specimens, 165‒190 mm SL, Nago, Okinawa Island, Ryukyu Islands, Japan; MUFS 12267, 139 mm SL, Malaysia; MUFS 18621, 129 mm SL and MUFS 18886, 2 specimens, 129‒132 mm SL, Makassar (Ujung Pangdang), South Sulawesi, Indonesia; MUFS 42884‒42885, 2 specimens, 51‒54 mm SL, Indian Ocean (purchased by aquarium shop but presumably Seychelles); MUFS 40234, 112 mm SL, Meitsu, Miyazaki, Japan; RMNH PISC. 38327 (lectotype of Mesoprion pomacanthus , designated herein), 30 mm SL (37+ mm TL), Ambon Island, Molucca Islands, Indonesia, removed from RMNH 5521; RMNH PISC. 38328 (paralectotype of M. pomacanthus ), same locality as the lectotype of M. pomacanthus , removed from RMNH 5521; SU 26900 at CAS, 112 mm SL, Philippines.

Photographic voucher specimens. KAUM-I. 12266‒12267, 2 specimens, 130‒142 mm SL, Malaysia; KAUM-I. 54316, 96 mm SL, Kagoshima, Japan.

Diagnosis. A species of Lutjanus with the following combination of characters: Dorsal fin XI, 13 or 14 (usually 13); anal fin III, 8; pectoral-fin 16 or 17; lateral-line scales 47‒50; horizontal scale rows above lateral line 8 or 9; scale rows above lateral line rising obliquely toward dorsal profile; predorsal scales extending forward nearly to level of just above anterior edge of orbit; scale rows on cheek 8‒11; no subocular extension of cheek scales; gill rakers on first arch 7 or 8 + 15‒17 = 22‒25; tongue smooth, without teeth; preopercular notch developed just above angle; interopercular knob inconspicuous; the first blue stripe running from above anterior edge of eye ending below the 7‒9th dorsal-fin spine base; the third stripe usually running from middle of upper part of opercle or anterior edge of upper opercle to below posterior fourth of soft portion of dorsal fin, reaching the last soft dorsalray base.

Description. Meristic counts and proportional measurements as percentages of standard length (SL), plus two diagnostic characters in coloration and squamation of subocular extension for the lectotype and non-type specimens of Lutjanus bengalensis are shown in Table 1.

Body oblong to moderately deep, greatest depth 2.4 – 2.8, head length 2.5‒2.8 in SL; snout length 2.6‒3.4, eye diameter 3.0‒4.2, interorbita1 width 4.5‒5.4, maxilla length 2.2‒2.9 and preorbital depth 5.1‒7.3, in head length; head relatively small with pointed snout; snout-forehead profile weakly rounded; pair of small nostrils rounded anteriorly and somewhat ovate posteriorly, in anterior and posterior openings on each side of snout, with very low flap on outer edge of anterior nostril; body scales rising obliquely above lateral line; body, opercle and preopercle with finely ctenoid scales; parietal, frontal, interorbital and rear edge of preopercle scaly; preopercular margin finely serrate (serrae increasing in size ventrally); sharp, flattened, flexible projection at middle of opercular margin, with blunt bony spine (mostly covered by scales) immediately above, its base; margins of opercle, interopercle and subopercle smooth; preopercular notch and interopercular knob well developed; vomerine tooth patch crescent-shaped without a posterior extension (similar small-sized lateral canine teeth present in 1 row on both right and left branches); tongue smooth without granular teeth; upper jaw with dagger-like very short canine tooth, on each side anteriorly, with smaller canines between it and symphysis; remaining lateral portion of upper jaw with a series of ~10 visible smaller embedded canines, lower jaw with ~10 small embedded canine teeth on each side of jaws, most not visible when mouth closed; dorsal-fin outline very weakly incised, fourth or fifth spines longest, remaining spines gradually decreasing in length; profile of soft dorsal-fin relatively low and weakly rounded; pectoral fins pointed, caudal fin emarginate.

Color in life, based on SAIAB’s Indian Ocean specimens (2 specimens, SAIAB 82483 and uncatalogued 1815#6, 94 and 105 mm SL, respectively, Sodwana Bay, South Africa) and Pacific specimens (MUFS 10452‒10458, 7 specimens, 165‒190 mm SL and uncatalogued photographs from Japan): head and body generally bright yellow on upper half and white ventrally, sometimes with reddish tinge, often after death; upper side with four dark-edged blue stripes, uppermost stripe extending from interorbital to middle of spinous dorsal fin, the second from upper rear edge of eye to anterior part of soft dorsal-fin base, third stripe from posterodorsal margin of preopercle or middle of upper part of opercle to area posteriorly on body a short distance anterior to base of last soft dorsal-fin rays, and lowest stripe from just above of middle of maxilla across lower edge of eye, extending through middle preopercle and opercle to anterior third of caudal peduncle just below lateral line; median fins yellow; pectoral and pelvic fins whitish; iris yellow.

Color in alcohol: generally yellowish tan (including fins), with 4 brown or bluish stripes as noted above.

Distribution. Lutjanus bengalensis is widely distributed in the Indo-West Pacific ( Allen & Talbot 1985; this study) and is currently known from South Africa, Seychelles, Indonesia, Malaysia, Philippines and Japan, on the basis of specimens examined. The species is also confirmed from the following areas by photographic vouchers and references ( Kyushin et al. 1977; Allen & Talbot, 1985; Shen 1993; Chen 1996; Randall & Lim 2000; E. Heemstra pers. comm.; U. Satapoomin pers. comm.): Mozambique, Madagascar, Kenya, Saya de Malha Bank (southwestern area off the Chagos Archipelago), Andaman Sea (Similan Island), Taiwan and China. Furthermore, photographic vouchers (E. Heemstra, pers. comm.) show the species from the following localities: southern and northern Mozambique, Madagascar and South Africa (Sodwana Bay and Cape Vidal), plus a photograph that might be the species from Zanzibar, Tanzania. However, records of the distribution of L. bengalensis from the Middle East, including the Red Sea, may have been erroneous ( Allen & Talbot 1985), because L. bengalensis was confused with L. sapphirolineatus n. sp., described below in this study.

In occurrence notes on L. bengalensis from the western Pacific, Allen & Talbot (1985) and Allen (1985) reported one record of this species from Ambon, Indonesia. An underwater photograph clearly showing a school of snappers ( Allen & Erdmann 2012), as L. kasmira , was taken at Mios Kon, Raja Ampat Islands, West Papua, Indonesia (by M. Allen), and could be the easternmost record of L. bengalensis (A. Ryanskiy, pers. comm.); there are no gray (or narrow reddish) stripes on the abdomen, and no dusky upper pectoral-fin rays.

In the northwestern Pacific, the species was firstly reported from Okinawa Island, Japan ( Iwatsuki et al. 1999). Currently this species is very common from southern Japan (Ryukyu Islands, and ranging as far north as the Kii Peninsula ( Kimura et al. 2008), Tokai District, and Kanto District near Tokyo, observed by the first author), as well as Taiwan and southern China. However, during the period 1983-1995, the first author visited southwestern Asia ( Philippines, Indonesia, Singapore and Taiwan) several times, but identified only one specimen (ca. 15 cm TL, not kept) of this species at the Chinese fish market in Singapore; it seemed a rare species from the Pacific at that time. The distributional range of L. bengalensis as well as L. xanthopinnis is likely to extend northwards, southwestern Japan from the northwestern Pacific presumably due to global warming ( Iwatsuki et al. 2015).

Remarks. A lectotype, ZMB 303, was designated by Paepke (1999) and we confirm this specimen as the lectotype ( Fig. 1 C, 94 mm SL, Bengal, Bay of Bengal, India) of Holocentrus bengalensis Bloch 1790 . Unfortunately, we did not have the opportunity to examine the paralectotypes, ZMB 300 (1 specimen) and ZMB 33057 (1, right side skin).

Lutjanus bengalensis has long been confused with L. octolineatus , but careful examination of the lectotype of this species shows a blue stripe on the upper part of opercle, 11 dorsal-fin spines and no suborbital extension of cheek scales (vs. no stripe on upper part of opercle, 12 dorsal-fin spines and the presence of a suborbital extension of cheek scales in L. octolineatus ; Figs. 1‒3 ), discussed above under Remarks for L. octolineatus .

Bleeker (1855) described Mesoprion pomacanthus on the basis of five specimens (38‒48 mm in total length, Bleeker’s measurement, from snout tip to tip of caudal fin). However, Bleeker (1874; Bleeker 1876–1877) subsequently recognized M. pomacanthus as a junior synonym of Lutjanus bengalensis ( Bloch 1790) . Bleeker’s (1873) description of L. bengalensis was based on 20 specimens, 43‒265 mm TL. The smallest of the five syntypes of M. pomacanthus (38 mm TL) was apparently already lost in 1873. According to M. van Oijen (pers. comm.), there are presently 28 of the 29 specimens of L. bengalensis listed/recorded in Bleeker (1873) in the collection of Naturalis Biodiversity Center (RMNH). The original Bleeker jar bought at the auction of the Bleeker collection (in December 1879) now contains 24 specimens. At the time of the auction, it contained 25 specimens ( Hubrecht 1879). Later, three specimens from the Series B‒E must have been added as 28 specimens are recorded in the RMNH register. Two specimens identified by G.R. Allen (WAM) as L. kasmira ( Forsskål 1775) were removed from RMNH 5521 in 1978 and registered as RMNH 27825 in this report. One of these two specimens is Bleeker’s largest specimen of L. bengalensis from which Bleeker removed the pharyngeal jaws for the description (Bleeker 1873). Moreover, RMNH 5521 contained four syntypes of M. pomacanthus ; two specimens 35 (42+) and 37 (44+) mm, identified by Allen & Talbot (1985) as L. kasmira (now registered as RMNH PISC. 38326), and two specimens 30 (37+) and 36 (43+) mm, identified by Allen & Talbot (1985) as L. bengalensis (now registered as RMNH PISC.38327 and RMNH PISC.38328, respectively). Allen & Talbot (1985) identified these specimens solely on the basis of the number of dorsal-fin spines. In order to avoid further confusion, we here designate the specimen of 30 mm SL (37+ mm TL), RMNH PISC.38327 as the lectotype of Mesoprion pomacanthus ; the three other syntypes becoming the paralectotypes.

In addition, Fricke (1999) placed Labrus octovittatus Lacepéde 1801 (p. 430, 477, pl., 22, fig. 2; Type locality: Grand Ocean) in synonymy of L. bengalensis although Allen & Talbot (1985) did not note this nominal species. The figure clearly shows presumably?X, probably 14 in dorsal-fin rays (as counted as IX, but the first short dorsalfin spine may have been missed or overlooked and not drawn) and presence of the third stripe, beginning from the middle of upper part of opercle. Such characters strongly suggest L. kasmira ( Forsskål 1775) , (see diagnostic characters of Allen & Talbot 1985). The two characters could not be applied to L. octolineatus (with XII, 12 or 13 dorsal-fin rays) and L. sapphirolineatus n. sp. (with the third stripe beginning just from upper rear edge of eye, through upper part of opercle, to upper part of caudal peduncle; see each diagnosis of the two species).

Figures

FIGURE 1. Type specimens of Lutjanus octolineatus (A, B) and L. bengalensis (C): A. MNHN 0000 - A 5446 (no label attached with a blue glass plate), 122 mm SL, lectotype of Diacope octolineata, Mauritius, Mascarenes; B. MNHN 0000 - 7046 (holotype of Diacope octovittata), 137 mm SL, Mauritius, Mascarenes; C. ZMB 303, lectotype of Holocentrus bengalensis), 94 mm SL, Bengal, Bay of Bengal, eastern Indian Ocean.