Scolopsis meridiana, Nakamura & Russell & Moore & Motomura, 2018

Nakamura, Jumpei, Russell, Barry C., Moore, Glenn I. & Motomura, Hiroyuki, 2018, Scolopsis meridiana, a new species of monocle bream (Perciformes: Nemipteridae) from northern Australia, Zootaxa 4500 (2), pp. 222-234 : 223-230

Scolopsis meridiana n. sp.

[New English name: Sahul Monocle Bream]

( Figs. 1 , 2 , 4A , 5A , 6 ; Tables 1–2)

Scolopsis taeniopterus (not of Cuvier): Sainsbury et al. 1985: 213, unnumbered fig. (Arafura Sea, Northern Territory, Australia).

Scolopsis taenioptera (not of Cuvier): Allen et al. 2006: 1249 (in part; Exmouth Gulf, Western Australia to North Palm Island, Queensland, Australia); Hung et al. 2017: 8, fig. 3 (West Papua, Indonesia and Queensland, Australia).

Holotype. CSIRO H 4029-01 , 194.8 mm SL, north of Dampier Archipelago , Western Australia, Australia, 20°23′07ʺ–24ʹ08ʺS, 116°31ʹ00ʺ–32′03ʺE, st. no. SS0895/56, 37– 38 m depth, Frank & Bryce demersal trawl, A. Graham and G. Yearsley on FRV Southern Surveyor, 28 Aug. 1995.

Paratypes. 29 specimens, 81.9–226.4 mm SL, all from Australia. AMS IB. 4170, 108.9 mm SL, North Palm Island , Queensland, 18°33′S, 146°30′E, G. Coates, 15 Aug. 1952 ; AMS I. 21945-001, 3 specimens, 115.4–129.1 mm SL, Arafura Sea , Northern Territory, 11°24′S, 134°58′E, engel trawl, RV Soela, 19 Nov. 1980 ; AMS I. 21946- 001, 172.7 mm SL, Arafura Sea , Northern Territory, 10°53′S, 135°00′E, engel trawl, RV Soela, 19 Nov. 1980 ; AMS I. 21957-013, 2, 94.9–132.7 mm SL, Arafura Sea , Northern Territory, 11°47′S, 136°16′E, prawn trawl, RV Soela, 22 Nov. 1980 ; AMS I. 33311-011, 2, 84.7–117.5 mm SL, Exmouth Gulf , Western Australia, 22°05′S, 114°15′E, N. Coleman, 12 Sept. 1972 ; KAUM –I. 118133, 168.0 mm SL, KAUM –I. 118134, 193.7 mm SL, west of Bedout Island, Northwest Shelf , Western Australia, 19°34′S, 118°25′E, 36 m, bottom trawl, CSIRO, 6 Sept. 1995 ; KAUM –I. 118135, 140.0 mm SL, Gulf of Carpentaria, Queensland, bottom trawl, R. Hobbs , Sept. 1977 ; NTM S. 11613-025, 224.4 mm SL, northwest of Cape Wessel, Arafura Sea , Northern Territory, 10°15′S, 136°20′E, bottom trawl, W. Houston on Pair Trawler Byio, 10 Mar. 1985 ; NTM S. 11654-027, 187.2 mm SL, north of Cape Wessel, Arafura Sea, Northern Territory, 10°25′S, 136°38′E, 64 m, bottom trawl, R. Williams on Pair Trawler Bzddd Ann Hae , 1 Feb. 1985 ; NTM S. 11923-005, 81.9 mm SL, northwest of Bedout Island, Northwest Shelf , Western Australia, 19°22′S, 118°48′E, 61 m, bottom trawl, NT Fisheries Observers, 21 June 1986 ; NTM S. 15131-002, 167.3 mm SL, Timor Sea , Northern Territory, 11°19′S, 128°15′E, 70 m, gill net, R. Williams, 9 Oct. 1996 ; NTM S. 15254-002, 226.4 mm SL, NTM S. 15254-003, 192.9 mm SL, north of Rosemary Island, Dampier Archipelago , Western Australia, 20°23′S, 116°32′E, 37–38 m, bottom trawl, CSIRO, 28 Aug. 1995 ; NTM S. 16591-021, 189.1 mm SL, west of Penguin Shoal, Holothuria Banks , Western Australia, 12°59′S, 125°36′E, 67 m, bottom trawl, NT Fisheries Observers, 27 June 1988 ; NTM S. 16990-002, 211.2 mm SL, Sahul Banks, Timor Sea , Western Australia, 11°55′S, 125°58′E, 86 m, bottom trawl, RV Soela, 13 July 1980 ; QM I. 20425, 3, 122.3– 128.2 mm SL, off Cairns , Queensland, 17°S, 146°E, 25 m, Queensland Fisheries Services, 25 Apr. 1982 ; QM I. 26804, 143.6 mm SL, Finders Island, Princess Charlotte Bay , Queensland, 14°10′S, 144°15′E, D. Tuma, 1 Dec. 1990 ; WAM P.34074- 008, 162.5 mm SL, Thevenard Island, Pilbara , Western Australia, 21°29′S, 115°05′E, 18 m, trawl, RV Naturaliste, 13 June 2013 ; WAM P.34221-019, 3, 95.3–139.7 mm SL, Cape Preston, Pilbara , Western Australia, 20°41′S, 116°19′E, 20 m, trawl, RV Naturaliste, 25 June 2013 .

Diagnosis. A species of Scolopsis with the following combination of characters: no antrorse spine below eye; dorsal scaled area on head reaching anteriorly to between anterior margin of eye and anterior nostril; bony opercular ridge and lower limb of preopercle without scales; lateral-line scales 46–48; pectoral-fin rays 17–18; upper part of pectoral-fin base with reddish blotch when fresh; two blue bands across dorsum of snout; 18–20 brown diagonal lines on body in preserved specimens; posterior nostril usually elongate horizontally, its horizontal diameter 100.0–155.6% (mean 114.8%) of vertical diameter; caudal peduncle deep, its depth 11.4–13.1% (12.2%) of SL; pre-dorsal-fin length 31.4–36.4% (33.9%) of SL.

Description. Counts and proportional measurements (as percentages of SL) are given in Table 1. Selected frequency distribution counts are given in Table 2. Data for the holotype are presented first, followed by paratype data (if different).

Body oblong, compressed, deepest at about pelvic-fin origin, dorsal profile increasing from snout tip to dorsalfin origin, arching gently between origins of 1st and 10th dorsal-fin spines, thereafter decreasing to caudal peduncle. Ventral profile of body lowering from lower-jaw tip to pelvic-fin origin, straightening parallel to body axis from pelvic-fin origin to anus, and thereafter lifting to caudal peduncle. Dorsal-fin origin slightly anterior to posteriormost point of opercle, ending posterior to posteriormost point of anal-fin base. First to 4th dorsal-fin spines gradually lengthening, 4th to 10th spines of similar length. Sixth dorsal-fin soft ray longest (6th or 7th). All dorsal-fin soft rays not filamentous. Uppermost point of pectoral-fin base slightly posterior to posteriormost point of opercle. Lowermost point of pectoral-fin base anterior to pelvic-fin origin. Posterior tip of pectoral fin pointed, reaching to vertical through central region of dorsal-fin base. Pelvic-fin origin posterior to dorsal-fin origin. Posterior tip of depressed pelvic fin extending beyond anus, not reaching anal-fin origin (reaching anal-fin origin in some paratypes). Anal-fin origin below 2nd dorsal-fin ray origin, ending below 7th dorsal-fin ray origin (7th or 8th). First anal-fin spine shortest, 2nd and 3rd spines of similar length. Caudal-fin forked, upper lobe longer than lower lobe. Posterior tip of both lobes of caudal fin pointed, not filamentous. Anus oblong, anterior to anal-fin origin. Eye and pupil round. Lower margin of eye above a line from snout tip to uppermost part of pectoral-fin base. Nostrils paired, positioned close together, anterior to orbit. Anterior and posterior nostrils long vertically and horizontally, respectively. Anterior nostril round with small dermal flap on anterior edge. Snout pointed. Posterior tip of maxilla not reaching to vertical through anterior margin of eye (extending beyond anterior margin of eye in a few paratypes). Distinct suborbital spine posteriorly directed. Small antrorse spine below eye absent. Posterior margin of suborbital and preopercle serrated. Scales ctenoid; both lips, snout, area around eye and preopercle scaleless. Lateral line complete, originating above opercle, extending to central part of caudal-fin base. Both jaws with small conical teeth, forming dense teeth bands. Canine teeth absent. Upper limb gill rakers long, slender. Lower limb gill rakers short, rounded.

Color when fresh. Based on color photograph of holotype (CSIRO H 4019-01; Fig. 1A ). Head and body reddish-brown dorsally, silver-white ventrally. Two blue bands across dorsum of snout, connecting eyes; upper and lower bands above posterior nostril and below anterior nostril, respectively. Blue band on suborbital from anteroventral margin of orbit to upper-jaw lip. Oblique, broad, indistinct, yellowish band from upper opercular margin to posterior portion of upper jaw. Twenty purplish-brown diagonal lines on lateral body surface below lateral line; yellowish dorsally between diagonal lines. Dorsal-fin membrane pale yellow, with a blue horizontal line running from basal membrane anteriorly to middle of membrane posteriorly. Distinct reddish blotch at upper end of pectoral-fin base. Pectoral fin yellow. Pelvic and anal fins white, without lines or spots. Four indistinct yellowish longitudinal stripes on caudal peduncle. Caudal fin pale red, with yellowish upper margin; central area yellowish with small dark margined bluish blotches.

Color of preserved specimens ( Fig. 1B ). Head pale yellow, with three black bands radiating from orbit. Body pale yellow, with brown diagonal lines below lateral line.

Distribution. Currently known from northern Australia (Exmouth Gulf, Western Australia to North Palm Island, Queensland) ( Fig. 2 ) and West Papua, Indonesia ( Hung et al. 2017). Collection data indicate capture depths of 18– 86 m.

Etymology. The specific name “ meridiana ” is derived from Latin meaning “south”, in reference to the southern distribution of the species, relative to that of S. taenioptera , with which it has been confused.

Comparisons. Scolopsis meridiana ( Fig. 1 ) is most similar to S. taenioptera ( Fig. 3 ), both species having the scaled area on the head extending anteriorly to between the anterior margin of the eye and anterior nostril, the bony opercular ridge and lower limb of the preopercle without scales, 16–18 pectoral-fin rays, 46–49 lateral-line scales, the upper part of the pectoral-fin base with a reddish blotch when fresh ( Figs. 1A , 3A, C ), and a small antrorse spine absent below the eye. However, S. meridiana differs from the latter in having two bands across the dorsum of the snout ( Fig. 4A ) (vs. single band in S. taenioptera ; Fig. 4B ), and 18–20 yellow diagonal lines on the lateral body surface when fresh ( Fig. 1A ), such lines becoming brown after preservation ( Fig. 1B ) (vs. very obscure yellow diagonal lines on the body when fresh, subsequently lost after preservation; Fig. 3 ). Posterior nostril shape also separates the two species, being oval ( Fig. 5A ) and horizontally elongated, respectively [horizontal diameter 100.0–155.6% (mean 114.8%) of vertical diameter in S. meridiana , vs. vertically elongated ( Fig. 5B ), 58.3–106.3% (83.0%) in S. taenioptera ( Fig. 6A )]. In addition, the caudal-peduncle depth of S. meridiana [11.4–13.1% (12.2%) of SL] tends to be greater than that of S. taenioptera [9.3–12.8% (11.5%)] ( Fig. 6B , Table 1), and pre-dorsal-fin length of S. meridiana [31.4–36.4% (33.9%) of SL] shorter than that of S. taenioptera [32.6–38.4% (35.6%)] ( Fig. 6C , Table 1).

Hung et al. (2017) provided independent nuclear and mitochondrial support for the two lineages in the S. taenioptera complex to be recognised as full species. Although the actual genetic distances were not presented, the conclusions of Hung et al. (2017) were based on an Automatic Barcode Gap Discovery (ABGD) analysis ( Puillandre et al. 2012). ABGD compares intra- and interspecific pairwise distances (viz., barcode gap) and is therefore directly based on distance measures. This approach is favourable given that recent genetic studies have shown that many currently recognized species in Nemipteridae (e.g., Nemipterus peroni , N. japonicus , Parascolopsis inermis , Scolopsis vosmeri , and S. monogramma ) exhibit high intraspecific diversity but this variability likely represents species complexes ( Ravitchandirane et al. 2012; Farivar et al. 2017; Hung et al. 2017). That said, the branch lengths between S. taenioptera and S. meridiana lineages presented in Hung et al. (2017; fig. S2) are consistent with, or greater than, the branch lengths between other sister species that appear to be well resolved and stable (e.g., Nemipterus nemurus and N. zysron ; Pentapodus caninus and P. emeryii ; P. paradiseus and P. setosus ).

Synonymies. Scolopsis taenioptera was originally described as Scolopsides taeniopterus , based on a single specimen from Java, Indonesia. The dried holotype, registered as RMNH.PISC D. 333, is deposited at Naturalis Biodiversity Center, Leiden, the Netherlands. Although the Naturalis fish collection is currently inaccessible due to building renovation and the holotype was unavailable at the time of this study, the specimen was examined by BCR several years ago. Because the type locality (Java, Indonesia) of Scolopsides taeniopterus is included within the distribution range of the species considered here as Scolopsis taenioptera ( Fig. 2 ), the holotype and specimens treated here as S. taenioptera are regarded as conspecific.

Although Scolopsis dubiosus was originally described by Weber (1913) on the basis of a single specimen (140 mm TL) from Makassar, Sulawesi, Indonesia, Nijssen et al. (1982) incorrectly regarded two specimens (ZMA 114.483 and ZMA 114.484) as syntypes of the species. The total lengths of ZMA 114.483 and ZMA 114.484 (ca. 150 mm and 220 mm, respectively) support the former being recognized as the holotype of S. dubiosus . That specimen was here identified as S. taenioptera , having a single brown band across the dorsum of the snout and lacking diagonal lines on the lateral body surface. ZMA 114.484, on the other hand, was identified here as Scolopsis monogramma (Cuvier in Cuvier & Valenciennes 1830), having 48 lateral-line scales, and 6 transverse scale rows between the lateral line and first dorsal-fin spine base, in addition to lacking a small antrorse spine below the eye.

Scolopsis siamensis , originally described by Akazaki (1962) from a single specimen (FAKU 29354) from the Gulf of Thailand, was regarded as a junior synonym of S. taenioptera by Wongratana (1978) and Russell (1990, 2001), its taxonomic status as a junior synonym being confirmed here by it having a single band across the dorsum of the snout and no diagonal lines on the lateral body surface (also see Table 1).

Distributional implications and populations. Hung et al. (2017) indicated that a distributional break, which separated two allopatric populations of S. taenioptera (identified here as S. meridiana and S. taenioptera ), apparently existed between Sundaland and Sahul Shelf during the Pleistocene ice age. Such a barrier was supported by the present study, the deep sea floor between Sundaland and the Sahul Shelf likely impeding gene flow between the two, relatively shallow water-inhabiting species ( Russell 1990, 2001).

Examination of an unpublished underwater photograph taken by G. Allen in Raja Ampat, West Papua, showed it has a single band across the dorsum of the snout and lacks distinct diagonal lines on the body, and is identifiable as S. taenioptera , although examination of voucher specimens is needed to confirm this identification. Molecular data for an individual (not retained) from West Papua given by Hung et al. (2017) indicate that it is S. meridiana , suggesting the two species may co-occur in West Papua or there may be distributional boundary within the West Papua region.

¹ Except Philippines.

Kakioka et al. (2017) indicated that Southeast Asian S. taenioptera included two lineages showing a clear phylogeographic break, one lineage from the Philippines and the other from Southeast Asia (Terengganu, Malaysia; Rayong, Thailand; and Ha Long Bay, Vietnam). Although the present examination of S. taenioptera specimens from these locations failed to establish significant morphological differences between them, a small difference in maximum width of the pre-orbital band was found [ Philippines population 3.5–8.0 % of HL (mean 5.8 %) vs other populations 2.7–6.3 % of HL (4.2 %)] ( Fig. 6D ), therefore giving small morphological support for two geographic populations of S. taenioptera in Southeast Asia.

Figures

FIGURE 1. Scolopsis meridiana n. sp. (CSIRO H 4029–01, holotype, 194.8 mm SL, north of Dampier Archipelago, Western Australia, Australia). A: fresh condition (photo by CSIRO); B: preserved condition.

FIGURE 2. Distribution records of Scolopsis meridiana n. sp. (diamonds) and S. taenioptera (circles), based on specimens examined in this study.

FIGURE 3. Scolopsis taenioptera. A–B: KAUM–I. 105120, 165.1 mm SL, off east coast of Bidong Island, Terengganu, Malaysia; C: UPVMI 1613, 138.2 mm SL, Miagao Fish Market, Panay Island, Philippines. A, C: fresh condition; B: preserved condition.

FIGURE 4. Dorsal view of snout. A: Scolopsis meridiana n. sp. (CSIRO H 4029–01, holotype, 194.8 mm SL); B: S. taenioptera (KAUM–I. 67573, 197.4 mm SL).

FIGURE 5. Posterior nostril. A: Scolopsis meridiana n. sp. (CSIRO H 4029–01, holotype, 194.8 mm SL); B: S. taenioptera (KAUM–I. 67573, 197.4 mm SL).

FIGURE 6. Relationships of (A) horizontal diameter of posterior nostril (% of vertical diameter of posterior nostril), (B) caudal-peduncle depth (% of SL), and (C) pre-dorsal-fin length (% of SL) to SL in Scolopsis meridiana n. sp. (diamonds) and S. taenioptera (circles). Star indicates holotype of S. meridiana. (D) Relationship of maximum width of pre-orbital band (% of HL) to SL in S. taenioptera from the Philippines (triangles) and Southeast Asia, except Philippines (circles).