Minous radiatus, Matsunuma & Motomura, 2018

Matsunuma, Mizuki & Motomura, Hiroyuki, 2018, Three new species of the Indo-Pacific stingfish genus Minous (Synanceiidae: Minoinae) with redescriptions of M. trachycephalus (Bleeker 1855) and M. pictus Günther 1880, Zootaxa 4455 (2), pp. 201-257 : 237-240

Minous radiatus sp. nov.

New English name: Radial Stingfish

Figures 21A–C , 22A–F , 23A–D , 25 , 26 ; Tables 1–5, 8, 9

Minous pictus not of Günther 1880: Eschmeyer et al. 1979: 467, figs. 1, 8a (Arafura Sea, Philippines, Vietnam, Hong Kong and Taiwan; in part; description and synonymy); Matsuura et al. 2001: 106 (off Hainan Island, China; listed; specimen: NSMT- P 54646); Motomura 2011: 71, unnumbered fig. (Terengganu, Malaysia, South China Sea; short description; specimens: KAUM–I. 17160 and others); Motomura 2013: 85, unnumbered fig. ( Thailand, Gulf of Thailand; short description; specimens: KAUM–I. 33224 and others).

Holotype. KAUM –I. 39286, 89.6 mm SL, off Da-xi , Yilan, northeastern Taiwan, bottom trawl, 6 July 2011.

Paratypes. 53 specimens, 57.2–106.5 mm SL: Taiwan: BSKU 50386 , 78.3 mm SL, Da-xi, Yilan, 23 Apr. 2012 ; BSKU 123088, 106.2 mm SL, BSKU 123089 , 101.9 mm SL, Dong-gang, Pingtung, 29 Mar. 2017 ; KAUM– I. 20411, 66.7 mm SL, Da-xi, Yilan, H.-C. Ho, bottom trawl, 18 Nov. 2007; KAUM –I. 83843, 93.2 mm SL, KAUM –I. 83844, 87.1 mm SL, KAUM –I. 83845, 91.4 mm SL, KAUM –I. 83846, 79.8 mm SL, Dong-gang, Pingtung, less than 100 m depth, H.- C. Ho, 20 Feb. 2016 ; NMMB-P28592 (formerly KAUM–I. 17752), 76.5 mm SL, collected with KAUM–I. 20411. China: FAKU 100030 , 4 specimens, 71.0– 83.1 mm SL, FAKU 100429, 85.4 mm SL, Gulf of Tonkin ; NSMT-P 54646 , 106.5 mm SL, 100 km off Sanya , south coast of Hainan Island, 70–80 m depth, K. Matsuura ; SAIAB 38438, 80.4 mm SL, China (no precise locality), Jan. 1988. Thailand (Gulf of Thailand): KAUM –I. 23221, 87.5 mm SL, KAUM –I. 23222, 89.0 mm SL, Gulf of Thailand , off east coast of Malay Peninsula, bottom trawl ; KAUM –I. 24083, 66.8 mm SL, KAUM –I. 24084, 67.4 mm SL, KAUM –I. 24085, 67.0 mm SL, KAUM –I. 44182, 62.6 mm SL, Gulf of Thailand , bottom trawl ; KAUM–I. 33224, 97.1 mm SL, off Chantha Buri, bottom trawl. Malaysia (Terengganu, east coast of Malay Peninsula ): KAUM –I. 17160, 75.6 mm SL, off Terengganu, 05°53′N, 102°28′E, trawl, 5 Jan. 2009 ; KAUM–I. 17195, 82.0 mm SL, off Terengganu, 05°53'N, 102°28'E, trawl, 5 Jan. 2009. Malaysia (Sabah, Borneo): KAUM –I. 12297, 102.1 mm SL, KAUM –I. 12298, 81.1 mm SL, KAUM –I. 12299, 84.2 mm SL, KAUM –I. 12300, 83.7 mm SL, KAUM –I. 12315, 83.5 mm SL, KAUM –I. 12316, 75.8 mm SL, KAUM –I. 12317, 86.2 mm SL, KAUM –I. 12424, 73.6 mm SL, KAUM –I. 12461, 85.6 mm SL, KAUM –I. 22119, 85.4 mm SL, KAUM –I. 22120, 81.9 mm SL, KAUM –I. 22121, 79.1 mm SL, KAUM –I. 22122, 74.2 mm SL, KAUM –I. 22123, 62.6 mm SL, KAUM –I. 49279, 72.9 mm SL, KAUM –I. 49378, 96.1 mm SL, off Kota Kinabalu, Sabah, 06°00′N, 116°07′E; KAUM –I. 22353, 81.7 mm SL, KAUM –I. 22354, 68.1 mm SL, KAUM –I. 22355, 60.6 mm SL, KAUM –I. 22367, 59.2 mm SL, KAUM –I. 22368, 62.1 mm SL, KAUM –I. 22369, 59.5 mm SL, KAUM –I. 22370, 57.2 mm SL, off Sulaman Bay, Tuaran, Sabah, 06°04′21″– 07′08″N, 115°57′08″–116°01′70″E, 34.7–35.0 m depth, S. A. Jaaman, bottom trawl ; ZRC 4308 , 80.6 mm SL, South China Sea , 06°15′N, 116°15′E, 44–50 m depth, SEAFDEC, RV Changi, trawl, 22 Apr. 1973 . Philippines: USNM 272200 , 3 specimens, 67.7–79.3 mm SL, vicinity of Samar and Leyte, Visayan Sea, E. O. Murdy, Oct. 1979 . South China Sea (no precise locality): ZRC 206 , 84.1 mm SL, east coast of Malay Peninsula, FMS Truwler Tongkol, Sept. 1926 .

Diagnosis. A species of Minous distinguished from other congeners by the following combination of characters: 1st dorsal-fin spine much shorter than 2nd dorsal-fin spine, their bases close together; dorsal-fin rays X or XI, 11–13 (modally XI, 12), total rays 22 or 23 (23); anal-fin rays II or III, 8–11 (II, 10), total rays 11–13 (12); lateral-line tubes 16–19 (17); width between interorbital ridges 1.4–3.7% (mean 2.9%) of SL; pelvic-fin base length 12.2–16.6% (14.4%) of SL; body brownish dorsally, reddish ventrally, with oblique alternating dark and light stripes; pectoral fin inner surface largely yellow, with narrow dark stripes along rays and small dark spots, blotches or broken stripes on membranes between rays.

Description. Pectoral-fin rays 12, lowermost ray free from membrane; pelvic fin rays I, 5. Vertebrae 11 + 15 = 26. Other meristics and morphometrics shown in Tables 1–5, 8. Body oblong, moderately compressed laterally, without scales ( Fig. 22A–C ). Lateral-line tubes continuous, except for posteriormost isolated tube on caudal peduncle; each tube with a pore opening to short dermal tube on posterior end, short cirri associated with pore. Single slit-like pore opening above pectoral-fin base behind gill opening, associated with simple relatively long tentacle (subequal to maximum pore diameter).

Head moderately large, exposed bony surface relatively smooth; interorbital space shallow, interorbital ridges developed, moderately separated from each other; occipital pit relatively shallow. Anterior and posterior lacrimal spines sharp, posterior spine longer than anterior spine, anterior spine canted anteroventrally, posterior spine

posteriorly (or posteroventrally); suborbital ridge with numerous small spines; preopercle with 5 spines, uppermost spine behind end of suborbital ridge longest, lower 3 spines blunt, plate-like; 3 sensory pores on underside of dentary; small pore on each side of symphysial knob; lateral and ventral surfaces of anterior portion of lower jaw with many cirri or tentacles; a pair of relatively long tentacles between middle and posteriormost sensory pore, tips not reaching posterior margin of maxilla when laid flat.

Snout blunt; dorsal profile of snout relatively steep, forming angle of ca. 50° (ca. 40–50°) to horizontal axis of head and body. Mouth moderately large, slightly oblique, forming angle of ca. 30° to horizontal axis of head and body; posterior margin of maxilla just reaching a vertical through mid-orbit. Lower jaw tip slightly projected anteriorly when mouth closed. Symphyseal gap separating premaxillary teeth bands very narrow, less than width of each band; both jaws with a band of small, conical teeth, ca. 7 (or 6) and ca. 4 (or 5) teeth rows at widest portions of upper and lower jaw, respectively; 2 small elongate patches of small conical teeth on vomer; palatine teeth absent.

Eye moderately large, with many tentacles on dorsal portion, longest tentacle branched, tips extending slightly beyond dorsal contour of orbit. Eye set relatively low on head, dorsal contour of orbit (about one-fifth of orbit) extending beyond a line between snout tip and dorsal-fin origin. Preocular, supraocular and postocular (surrounding orbit) relatively smooth.

Dorsal-fin origin behind occipital pit, surrounded by parietal spine clefts; 1 st spine relatively short, thin, much shorter than 2nd spine, its length 33% (26–44%) of 2nd spine length, their bases close together; 3rd spine almost subequal or slightly longer than 2nd spine, its length 97–131 % of 2nd spine length (based on paratypes); 3rd to 6th spines gradually becoming longer posteriorly, remaining posterior spines subequal in length; membranes on anterior spinous portion well incised, remaining membranes moderately incised; 2nd and 3rd spines not associated with dermal flaps. Dorsal contour of soft-rayed portion of dorsal fin rounded, longest soft ray length subequal to 2nd spine length; last soft ray attached to caudal peduncle by broad membrane. Anal-fin origin below 11th (9th or 10th) dorsal-fin spine base; spines tiny, covered with skin; longest anal-fin soft ray length subequal to longest dorsal-fin soft ray length; last soft ray attached to caudal peduncle by broad membrane. Pectoral fin rounded, moderately large, 4th (or 5th) ray longest, its tip almost reaching a vertical through middle of anal-fin base, but not reaching end of anal-fin base; lowermost ray long, slightly thickened, free from membrane, its base well separated from base of above membrane associated rays, its tip reaching (or extending slightly beyond in specimens <60 mm SL) a vertical through anal-fin origin when depressed. Pelvic-fin origin below 4th dorsal-fin spine base, spine covered with skin, last soft ray attached to abdomen by broad membrane, end of pelvic-fin base not reaching level of anus; 4th (or 3rd) soft ray longest, its tip not reaching (slightly extending beyond in specimens <60 mm SL) a vertical through anal-fin origin when depressed. Caudal fin moderately long, posterior margin slightly rounded. All segmented rays in dorsal, anal, pectoral, pelvic and caudal fins unbranched.

Fresh coloration, based on color photographs of fresh specimens [KAUM–I. 12315, 23221, 23222, 24083, 24084, 24085, 49297 and 39286 (holotype)] ( Fig. 23 ). Head and body brownish dorsally, reddish ventrally, posterior portion of maxilla and ventral portions of head and chest whitish; body with oblique alternating dark and light stripes centrally and dorsally, extending onto dorsal fin, pattern becoming net-like in specimens> 80 mm SL, including holotype; eye yellow, pupil black. Dorsal fin coloration same as that of dorsum, without blotches; spine tips tinged with black. Anal fin reddish with large blackish distal portion. Pectoral fin outer surface black (brownish-red) with irregular, poorly defined lighter bands; inner surface largely yellow dorsally, rays tinged with black (brownish) with small elongate black blotches (sometimes forming broken lines in paratypes) on membranes; ventral portion dusky red (pale red); lowermost free ray dark red ( Fig. 23B, D, F ); axil with large white blotches. Pelvic fin dark red, blackish (brownish) distally. Caudal fin reddish without markings.

Coloration of preserved specimens, based on all specimens ( Fig. 22A–C ). Head and body creamy-white, brownish dorsally, with oblique alternating dark and light stripes centrally and dorsally, extending onto dorsal fin, forming net-like pattern in large specimens, including holotype. Tips of dorsal-fin spines tinged with black. Anal fin creamy-white, blackish distally. Pectoral fin outer surface black (pale brown) with many irregular pale bands; inner surface with large pale creamy-white portion with black tinged rays and irregularly shaped black blotches on membranes, blackish distally; lowermost free ray dusky (creamy-white). Pelvic fin dusky creamy-white, largely blackish (brownish) distally. Caudal fin entirely pale creamy-white, dusky distally, without markings.

Etymology. The name of species radiatus is derived from Latin meaning radial, in reference to the dark stripes radiating along the rays on the pectoral fin inner surface, thereby distinguishing the species from M. pictus , its most closely related congener.

Distribution. Minous radiatus is distributed in the northwestern Pacific Ocean, including the east coast of the Malay Peninsula, Gulf of Thailand, Vietnam, southern and northeastern Taiwan, northeastern Borneo and the Philippines ( Fig. 10 ). Sampling data for three specimen lots recorded their collection by trawl at depths of 34.7– 80 m.

Remarks. Although M. pictus has previously been recorded from the western Pacific Ocean from the Arafura Sea north to Taiwan ( Eschmeyer et al. 1979), the present examination of supposed M. pictus specimens representing a widespread distributional range, indicated that they comprised two distinct species, one from northwestern Australia and south of New Guinea, and the other in the northwestern Pacific Ocean. Since the lectotype of M. pictus (designated herein) from south of New Guinea is identical with the Australian and New Guinean taxon, the northwestern Pacific Ocean taxon is described herein as M. radiatus sp. nov. Detailed comparisons of M. radiatus with M. pictus are provided under M. pictus .

Matsubara’s (1943) report of M. trachycephalus from the Gulf of Tonkin, South China Sea, based on a 93.6 mm-SL specimen was subsequently regarded by Eschmeyer et al. (1979) as a misidentification of M. pictus (now restricted to Australia and New Guinea). Matsubara’s (1943) description being reminiscent of M. coccineus (also recorded from the South China Sea), as well as M. radiatus , the precise identification of his specimen cannot now be determined.

Three specimens from the Gulf of Tonkin (FAKU 100030, 3 of 4 specimens, 71.0– 77.2 mm SL; Fig. 22B ) possessed relatively large eyes (orbit diameter 16.1–16.5% of SL), compared with other similarly sized specimens, 72.9–79.8 mm SL (12.6–14.3% of SL). However, since other diagnostic features of the three specimens were closely consistent with other examples of M. radiatus , the orbital size differences are regarded as representing individual variations within the species.

Figures

FIGURE 10. Distributional maps of Minous trachycephalus (purple squares); M. groeneveldi sp. nov. (yellow stars); M. roseus sp. nov. (blue circles); M. andriashevi (gray downward triangles); M. pictus (yellow upward triangles); and M. radiatus sp. nov. (green diamonds). White arrowheads indicate type localities. Black arrowheads indicate photographic records (Lembeh Strait, North Sulawesi, Indonesia).

FIGURE 21. Pores above pectoral-fin base and associated skin flap in Minous roseus sp. nov. (A–D), M. trachycephalus (E) and M. groeneveldi sp. nov. (F). (A) NTM S.13974-005, paratype, 63.9 mm SL, Western Australia; (B) CSIRO CA1844, holotype, 72.1 mm SL, Western Australia; (C) NMV A29712-004, paratype, 40.6 mm SL, Western Australia; (D) NMV A29660-012, paratype, 33.5 mm SL, Western Australia; (E) KAUM–I. 33284, 70.4 mm SL, Gulf of Thailand; (F) NTM S.11031-002, holotype, 77.7 mm SL, Indonesia. Red arrowhead (in A) indicates pore location. Blue arrowheads indicate skin flaps (absent in M. trachycephalus). Right side, reversed in A–C. Bars indicate 0.5 mm.

FIGURE 22. Preserved specimens of Minous radiatus sp. nov. (A–C) and M. pictus (D–F) at different growth stages. (A) KAUM–I. 39286, holotype, 89.6 mm SL, Taiwan; (B) FAKU 100030, paratype, 1 of 4 specimens, 73.2 mm SL, China; (C) KAUM–I. 22367, paratype, 59.2 mm SL, Malaysia (Borneo); (D) CSIRO H1489-4, 101.8 mm SL, Australia; (E) NTM S.12977-004, 70.1 mm SL, Australia; (F) NTM S.12920-002, 57.3 mm SL, Australia.

FIGURE 23. Fresh specimens of Minous radiatus sp. nov.—lateral view (A, C, E);—pectoral fin inner surface (magnified) (B, D, F). (A, B) KAUM–I. 39286, holotype, 89.6 mm SL, Taiwan; (C, D) KAUM–I. 23222, paratype, 89.0 mm SL, Gulf of Thailand; (E, F) KAUM–I. 24084, paratype, 67.4 mm SL, Gulf of Thailand. Right side, reversed in D and F.

FIGURE 25. Pectoral fin inner surface in preserved specimens of Minous radiatus sp. nov. (A–C) and M. pictus (D–F). (A) NSMT-P 54646, paratype, 106.5 mm SL, China; (B) KAUM–I. 39286, holotype, 89.6 mm SL, Taiwan; (C) KAUM–I. 22370, paratype, 57.2 mm SL, Malaysia; (D) CSIRO H1489-4, 101.8 mm SL, Australia; (E) NTM S.12973-004, 77.2 mm SL, Australia (right side, reversed); (F) BMNH 1879.5.14.371, lectotype, 45.5 mm SL, Arafura Sea. Photo: Gota Ogihara (D).

FIGURE 26. Lectotype (A) and paralectotype (B) of Minous pictus, Arafura Sea, south of New Guinea. (A) BMNH 1879.5.14.371, 45.5 mm SL; (B) BMNH 1879.5.14.372, 36.6 mm SL (= M. trachycephalus).