NMMB-P37710, 1 specimen, 152.7 mm SL, off Dong-gang fishing port (ca. 22°22′22″N, 120°27′34″E), Pingtung, southwestern Taiwan, northern South China Sea, 12 March 2023, collected by H.-C. Ho.

Meristic and morphometric characters are provided in Tables 1–2. Dorsal-fin rays 92, originating over 5^th vertebra. Pectoral-fin rays 27/29. Pelvic-fin rays 2/2. Anal-fin rays 73, originating below 21^st dorsal-fin ray and 15^th vertebra. Caudal-fin rays 4 (upper lobe) + 4 (lower lobe). Preopercular spines 2. Gill rakers on outer face of first gill arch 2 + 1 + 6 = 9. Pseudobranchial filaments 7. Precaudal vertebrae 13; caudal vertebrae 39 (not including ural centra); total vertebrae 52 (not including ural centra). Pyloric caeca 15.

Body compressed and elongated, depth at dorsal-fin origin 5.3 in SL, at anal-fin origin 5.4 in SL. Head length 4.5 in SL. Eye window small, horizontal width 5.1 in HL; snout rounded, its length 3.9 in HL, extending before premaxilla; interorbital space narrow, width 4.5 in HL; postorbital length 1.6 in HL.

Mouth large, upper-jaw length 1.8 in HL; posterior end of maxilla truncated, exceeding beyond vertical through posterior margin of eye window. Two nostrils, anterior nostril forming short tube and situated at about midline of snout; posterior nostril larger than anterior one, situated right in front of eye and lower than horizontal through anterior nostril. Symphysis of premaxillae forming notch, edentate. Premaxilla, dentary, vomer, and palatine with villiform teeth. Vomerine tooth patch triangular, slightly concave at both sides anteriorly. Palatine tooth patch rather broad, gradually thinner anteriorly. Opercle with one strong spine, its end not exceeding beyond flap of opercle.

Gill rakers rod-shaped, somewhat laterally compressed, covered with small teeth on tips and inner surfaces; rakers on outer row of first arch longest; inner surface of first arch and both inner and outer surfaces of second to fourth arches short; fifth ceratobranchail with bump-like rakers on outer face and single, long and slender tooth patch on inner face. Oval tooth patch present on upper ends of second and third epibranchials. Triangular tooth patch on second and third pharyngobranchials. Oval, somewhat rectangular tooth patch on fourth pharyngobranchial. Two basibranchials: anterior one elongated and posterior one oval.

Small cycloid scales present on head, body, and dorsal-and anal-fin bases, all embedded under skin. Lateral line single, situated at upper one-fifth of body; originating from upper part of gill opening and indistinct on posterior portion of body.

Pectoral fin short, its length 1.5 in HL, its tip slightly pointed, not reaching vertical through anus. Pelvic-fin length 1.2 in HL, rather short, its tip not reaching anus. Caudal fin rounded, slightly pointed.

(Fig. 1C). First neural spine short, length about half of second neural spine; bases of first-two neural spines not thickened; parapophysis developed on seventh to 13^th vertebra; pleural ribs present on third to 12^th vertebra, and with epipleural on anterior five pleural ribs; epineurals absent. Anal-fin pterygiophores anterior to first haemal spine 5.

Figure 1. 

Neobythites australiensis Nielsen, 2002, NMMB-P37710, 152.7 mm SL. A. Fresh condition. B. Preserved condition. C. X-radiograph.

Sagittal otolith (Fig. 2) oblong, length 25.1% HL, length/depth ratio 1.84. Both dorsal and ventral margins smoothly curved, with small lobes forming crenation on antero-dorsal and both antero- and postero-ventral margins; distal surface slightly concave; proximal surface slightly convex. Sulcus groove mesial, shallow, horizontal, and archaesulcoid; its length 21.2% HL; both colliculums present, with ostial colliculum elongated and caudal colliculum oval; both crista superior and crista inferior poorly developed; rostrum absent; excisura absent; dorsal depression very shallow; ventral depression absent.

Figure 2. 

Right sagittal otolith of Neobythites australiensis Nielsen, 2002, 8.5 mm otolith length, taken from NMMB-P37710, 152.7 mm SL. A. Distal view. B. Proximal view. Scale bar = 1 mm.

When fresh (Fig. 1A), body somewhat purplish, with brown reticulate patterns on head and body. Dorsal fin dusky, with pale vermicular patterns. Anal fin dusky, without any ocellus, its anterior potion rather pale. Pectoral, pelvic, and caudal fins dusky. When preserved (Fig. 1B), body color similar fresh but slightly paler. Single ocellus on dorsal fin, covering 19^th‒35^th dorsal-fin rays, with central blotch covering 21^st‒30^th dorsal-fin rays; anterior dorsal fin with single black blotch, covering 1^st‒4^th dorsal-fin rays. Oral cavity, including underside of tongue, lower gill arches, and rakers pale or scattered with sparse melanophores; pyloric caeca pale. Mouth roof behind vomer, inner face of opercle, and upper gill arches dusky. Peritoneum black.

Originally described from northwestern Australia. Although Uiblein and Nielsen (2023) described the previous record from the Pacific Ocean (Okamoto et al. 2011) as N. japonicus, the presently reported specimen from Taiwan confirmed the occurrence of this species and suggested a wide distribution in the west Pacific and east Indian Ocean. Inhabits depths down to 350 m (Nielsen 2002).

The presently reported specimen was identified as Neobythites australiensis in having one ocellus on the dorsal fin, situated posterior to a vertical through the anus; a black blotch on anterior dorsal fin; no ocellus on the anal fin; two preopercular spines; short pelvic fins, their tips not reaching anus (Nielsen 2002).

However, there are a number of differences compared to the previous record (Tables 1–2). The Taiwanese specimen has slightly fewer pseudobranchial filaments (7, vs. 8‒11); fewer caudal vertebrae (39, vs. 40‒41); shorter head length (22.0% SL, vs. 23.5‒24.5% SL); shorter postorbital length (13.5% SL, vs. 14.0‒15.5% SL); shorter predorsal length (24.2% SL, vs. 24.5‒27.5% SL); shorter preanal length (41.7% SL, vs. 43.0‒49.5% SL); and longer anterior gill filaments (7.7% SL, vs. 6.7‒7.4% SL). These minor differences are considered as intraspecific variations. The condition of 29 pectoral-fin rays on right side of our specimen is higher than other known specimens (26‒27).

Among species recorded in Taiwan, N. australiensis most resembles N. unimaculatus in having one ocellus on the dorsal fin (vs. none or more than one in other species), however, N. australiensis is readily distinguishable from N. unimaculatus in having a blotch situated at the anterior most dorsal-fin rays (vs. blotch absent; Nielsen 2002; this study); dorsal-fin rays 88‒92 (vs. 99‒106); anal-fin rays 73‒75 (vs. 83‒92); total vertebrae 52‒54 (vs. 57‒62).

NMMB-P37712, 1 specimen, 158.9 mm SL, off Daxi fishing port (ca. 24°53′37″N, 121°55′26″E), 30 Jan 2023, collected by J.-F. Huang.

Meristic and morphometric characters are provided in Tables 1–2. Dorsal-fin rays 92, originate over 5^th vertebra. Pectoral-fin rays 27/27. Pelvic-fin rays 2/2. Anal-fin rays 75, originate below 21^st dorsal-fin ray and 15^th vertebra. Caudal-fin rays 4 (upper lobe) + 4 (lower lobe). Preopercular spines 2. Gill rakers on outer face of first gill arch 3 + 1 + 8 = 12. Pseudobranchial filaments 4. Precaudal vertebrae 13; caudal vertebrae 40 (not including ural centra); total vertebrae 53 (not including ural centra).

Body compressed and elongated, depth at dorsal-fin origin 5.0 in SL, at anal-fin origin 5.2 in SL. Head length 4.4 in SL. Eye window small, horizontal width 5.3in HL; snout rounded, its length 4.1 in HL, extending before premaxilla; interorbital space narrow, width 4.1 in HL; postorbital length 1.6 in HL. Mouth large, upper-jaw length 1.9 in HL; posterior end of maxilla truncated, exceeding beyond vertical through posterior margin of eye window. Two nostrils, anterior nostril forming short tube and situated at about midline of snout; posterior nostril oval, larger than anterior one situated in front of eye and lower than horizontal through ventral margin of eye window. Symphysis of premaxillae forming notch, edentate. Premaxilla, dentary, vomer, and palatine with villiform teeth. Vomerine tooth patch triangular, slightly concave at both sides anteriorly. Palatine tooth patch rather broad, slightly widened at middle portion. Opercle with one strong spine, its end not exceeding beyond flap of opercle.

Gill rakers rod-shaped, somewhat laterally compressed, covered with small teeth on tips and inner surfaces; rakers on outer row of first arch longest; inner surface of first arch and both inner and outer surfaces of second to fourth arches short; fifth ceratobranchail with bump-like rakers on outer face and single, long and slender tooth patch on inner face. Oval tooth patch present on upper ends of second and third epibranchials. Triangular tooth patch on second and third pharyngobranchials. Oval, somewhat rectangular tooth patch on fourth pharyngobranchial. Two basibranchials: anterior one slender and elongated, with anterior portion wider than rest; posterior one oval.

Small cycloid scales present on head, body, and dorsal-and anal-fin bases, all embedded under skin. Lateral line single, situated at upper one-fifth of body; originating from upper part of gill opening and indistinct on posterior portion of body.

Pectoral fin short, its length 1.5 in HL, its tip slightly pointed, not reaching vertical through anus. Pelvic-fin length 1.3 in HL, rather short, its tip not reaching anus. Caudal fin rounded, slightly pointed.

(Fig. 3C). First neural spine short, length about half of second neural spine; bases of first-two neural spines not thickened; parapophysis developed on eighth to 13^th vertebra; pleural ribs present on third to 12^th vertebra, and with epipleural on anterior seven pleural ribs epineurals absent. Anal-fin pterygiophores anterior to first haemal spine 4.

Figure 3. 

Neobythites japonicus Uiblein et Nielsen, 2023, NMMB-P37712, 158.9 mm SL. A. Fresh condition, photo by J.-F. Huang. B. Preserved condition. C. X-radiograph.

Sagittal otolith (Fig. 4) oblong, length 24.1% HL, length/depth ratio 1.82. Both dorsal and ventral margins smoothly curved, with small lobes forming crenation on antero-dorsal and both antero- and postero-ventral margins; distal surface slightly concave; proximal surface slightly convex. Sulcus groove mesial, shallow, horizontal, and archaesulcoid; its length 19.1% HL; both colliculums present, with ostial colliculum elongated and caudal colliculum oval; both crista superior and crista inferior poorly developed; rostrum absent; excisura absent; dorsal depression very shallow; ventral depression absent.

Figure 4. 

Right sagittal otolith of Neobythites japonicus Uiblein et Nielsen, 2023, 8.7 mm otolith length, taken from NMMB-P37712, 158.9 mm SL. A. Distal view. B. Proximal view. Scale bar = 1 mm.

When fresh (Fig. 3A), body pale, and somewhat purplish, with brown reticulate patterns on head and body, some of which forming blotches. Dorsal fin dusky, with irregular-sized pale blotches. Anal fin dusky, without any ocellus, its anterior potion rather pale. Both margins of dorsal and anal fins whitish. Pectoral, pelvic, and caudal fins dusky. When preserved (Fig. 3B), body color similar fresh but slightly paler. Two ocelli present on dorsal fin, anterior one covering 1^st‒11^th dorsal-fin rays, with central blotch covering 4^th‒9^th dorsal-fin rays; posterior one covering 21^st‒35^th dorsal-fin rays, with central blotch covering 23^rd‒33^rd dorsal-fin rays. Oral cavity, including underside of tongue, lower gill arches, and rakers pale or scattered with sparse melanophores. Mouth roof behind vomer, upper gill arches, and inner face of opercle dusky. Peritoneum black.

Originally described from the Okinawa Island, Japan (Okamoto et al. 2011; Uiblein and Nielsen 2023). The presently reported specimen represents the second specimen other than the holotype and the southernmost record of this species. Inhabits depths down to ca. 100 m (Okamoto et al. 2011).

The presently reported specimen was identified as N. australiensis before Uiblein and Nielsen (2023) described N. japonicus. It was soon re-identified as N. japonicus in having two ocelli on the dorsal fin, the first situated at anterior-most dorsal-fin rays and the second situated posterior to a vertical through the anus; no ocellus on the anal fin; two preopercular spines; short pelvic fins, their tips not reaching anus (Uiblein and Nielsen 2023).

However, there are still a number of minor differences comparing to the holotype (Tables 1–2). The Taiwanese specimens have fewer pseudobranchial filaments (4, vs. 6); more caudal vertebrae (40, vs. 39); shorter preanal length (43.0% SL, vs. 44.5% SL); and longer anterior gill filaments (7.6% HL, vs. 7.0% HL). These differences are considered as intraspecific variations.

Among species recorded in Taiwan, N. japonicus mostly resembles N. bimaculatus in having two ocelli (sometimes three) on the dorsal fin (vs. one or more than two in other species). However, N. japonicus is readily distinguishable from N. bimaculatus in having the anterior ocelli situated at the anteriormost dorsal-fin rays and the posterior ocelli situated at the middle portion of the dorsal fin (vs. both ocelli at the middle portion of the dorsal fin, sometimes a third ocellus present (Nielsen 1997, 2002; this study); dorsal-fin rays 91 (vs. 99‒106); anal-fin rays 75 (vs. 83‒92); total vertebrae 53 (vs. 57‒62).