Plectranthias clavatus, Wada & Senou, 2024

Wada, Hidetoshi & Senou, Hiroshi, 2024, Plectranthias clavatus, a New Perchlet from Japan and Guam, with a Review of the Distributional Records of P. kamii (Perciformes: Serranidae: Anthiadinae), Bulletin of the Kanagawa Prefectural Museum (Natural Science) 53, pp. 113-126 : 114-123

Plectranthias clavatus sp. nov.

(New English name: Club Perchlet; new standard Japanese name: Ichimonji-hanadai)

( Figs. 1–6 , 8 ; Table 1)

Plectranthias kamii (not of Randall, 1980): Randall, 1980: 141 (in part: Guam); Kuiter, 2004: 113, unnumbered fig. (in part: Guam); Konishi, 2021: 210, uppermost fig. (photographic record: KPM-NR 86810) (in part: Sagami Bay, Japan)

Plectranthias sp. : Koeda et al., 2021b: 17, fig. 7A (underwater photograph: Shoho Sea Mount, Nishi-Shichito Ridge, Japan)

Holotype. KPM-NI 13878 , 176.0 mm SL, Okinoyama Bank Chain , southeast of Sagami Bay, Japan, 200 m depth, 13 Mar. 2004, line fishing, collected by H. Hoshiyama, donated by M. Miyazawa.

Paratypes. 4 specimens: FAKU 147672, 199.6 mm SL, off Inatori , Higashi-izu , Kamo, Shizuoka Prefecture, southwest of Sagami Bay, Japan, 200 m depth, 15 Feb. 2020, line fishing, collected by M. Okamoto; KPM-NI 48915, 153.1 mm SL, Hachijo-jima Island , Izu Islands, Tokyo, Japan, 200 m depth, 20 July 2018, line fishing, collected by Y. Tsuda; KPM-NI 77590, 131.3 mm SL, Naka-no-kurose, Hachijo-jima Island , Izu Islands, Japan, 386 m depth, 21 Aug. 2023, line fishing, collected by R / V Takunan , donated by K. Hashimoto; ZUMT 66348, 155.8 mm SL, collected with KPM-NI 77590 .

Non-type specimens. 2 specimens: BPBM 5845, paratype of Plectranthias kamii , 174.4 mm SL, Guam, Mariana Islands, details described in Randall (1980); ZUMT 40628, 188.3 mm SL, Japan (details unknown), collected before 1952 (see Koeda et al., 2022).

Photographic record (non-type). KPM-NR 86810, off Yawatano , Ito, Shizuoka Prefecture, southwest of Sagami Bay, Japan, 100 m depth, 20 Feb. 2003, line fishing, M. Okamoto .

Diagnosis. A species of Plectranthias with the following combination of characters: dorsal fin with 10 spines and 17–18 (mode 17) soft rays; pectoral-fin rays 13–14 (13), all branched except for uppermost ray simple; principal caudal-fin rays 9 + 8; lateral line complete, with 35–36 (35) pored scales; 5.5 and 16–17 (17) scale rows above and below lateral line respectively; 6–7 (6) diagonal rows of large scales on cheek between eye and corner of preopercle; circumpeduncular scales 15; ca. 8 rows of large predorsal scales, single row of small scales extending to posterior two-thirds of interorbital area, tip not reaching line through posterior nostrils ( Fig. 4 ); body deep, its depth at pelvic-fin origin 37.8–40.7 % (mean 39.1 %) of SL, greatest depth 39.6–42. 2 % (41.2 %) of SL; third dorsal-fin spine longest, its length 36.5–45.9 % (41.9%) of BDP; anal-fin soft rays short, its longest ray length 47.9–59.1 % (53.5 %) of BDP; no scales on chin, branchiostegal membranes, infraorbital bones, maxilla, mandibles or snout; posterior margin of preopercle serrated, ventral margin with 2 antrorse spines; short flaps at tips of second and third dorsal-fin spines; 3 large orange-red saddles on dorsal edge of body; single orange-red stripe on posterior four-fifths of lateral body, saddles and stripe well-separated when fresh. Maximum size of species ca. 200 mm SL.

Description. Data for the holotype presented first, followed by paratype data in parentheses if different. Counts and measurements are given in Table 1. Characters given in the diagnosis are not repeated.

Body oval, laterally compressed. Upper profile of head nearly straight, forming an angle of ca. 30° to body axis. Dorsal profile rising from snout tip to seventh dorsal-fin spine base, thereafter gradually lowering to end of dorsal-fin base. Ventral profile lowering from lower-jaw tip to midpoint of abdomen, subsequently rising slightly to anal-fin origin (slightly rising or parallel to anal-fin origin). Ventral contour of anal-fin base rising. Dorsal and ventral profiles of caudal peduncle slightly concave. Branchiostegal rays 7. Vertebrae 10 + 16; supraneurals 3, all similar in length; formula for configuration of supraneural bones, anterior neural spines and anterior dorsal pterygiophores 0/0+0/2/1+1; no trisegmental pterygiophores associated with dorsal and anal fins; ribs present on third to tenth vertebrae.

Dorsal-fin origin dorsal to third pored lateral-line scale; dorsal profile of dorsal fin incised between spinous and soft-rayed portions; all soft rays branched, seventh longest, last two joined basally. Anal fin rounded with third soft ray longest; second spine longest and stoutest. Caudal fin truncate, uppermost portion slightly extended. Pectoral fin oval; lower 7 pectoral-fin rays slightly thickened, with membranes between thickened rays incised; eighth ray longest (eighth or ninth ray longest), just reaching vertical through posterior second anal-fin spine base. Pelvic fins short, reaching about half of abdomen, second soft ray longest.

Mouth large, slightly oblique, posterior margin of maxilla reaching vertical through posterior edge of pupil; maxilla expanded posteriorly; supramaxilla absent; upper jaw with band of villiform teeth, 8–9 rows wide anteriorly, reducing to 3–4 rows posteriorly, with 2 pairs of canine teeth at front of jaw (pair or 2 pairs at front of jaw); lower jaw with band of villiform teeth, 5 rows wide at symphysis, reducing to single row posteriorly, with 3 pairs of canine teeth on mid-side of jaw (2 or 3 pairs on mid-side of jaw); vomer with compressed V-shaped band of 2–3 rows of sharp-tipped conical teeth; palatine with a band of 1–2 rows of small, sharp-tipped conical teeth; ectopterygoid and mesopterygoid edentate; tongue narrow, pointed and edentate. Opercle with 3 flat spines, middle spine longest, upper spine partially concealed by scales; preopercle with single vertical open groove; 22 or 25 (23–34) serrae on posterior margin of preopercle; 1 or 6 (0–6) serrae on posterior margin of interopercle; 2 or 3 (1–5) serrae on posterior margin of subopercle; 3 or 5 (1–9) serrae on posttemporal; lower margin of lacrimal smooth without serrae. Anterior nostril positioned at middle of snout, tubular with small flap on posterior rim, not reaching posterior nostril when depressed; posterior nostril at anterior border of orbit, with small flap.

Scales ctenoid with peripheral cteni only; lateral line complete, broadly arched over pectoral fin following body contour to caudal-fin base; no auxiliary scales on head or body; dorsal fin with intermittent row of scales along base; anal fin with low thick scaly sheath basally, with some small scales extending on to fin membranes anteriorly; caudal fin with scaly basal sheath, small scales extending on to basal third to half of fin membranes; pectoral fins with basal sheath, small scales extending on to fin membranes.

Coloration when fresh ( Fig. 1 ). Body pinkish-white with three large orange-red saddles on dorsal half of body, posteriormost saddle consisting of three small interconnecting saddles. Single orange-red stripe on posterior four-fifths of body mid-laterally, not connected with saddles above. Cheek with single indistinct dull yellow blotch. Single small orange-red blotch on surface of pectoral-fin base. Dorsal surface of head and nape, and tip of lower jaw orange-red. Dorsal-fin spinous portion orange-red with white area between first to fourth spines; anterior surface of first dorsal-fin spine black. Proximal half of dorsal-fin soft rayed portion, anal fin, and caudal fin orange-red, distal half translucent white (translucent white or orange-red), distal edge with indistinct black margin. Pectoral fin pinkish-white (orange-red). Pelvic fin pinkish-white with single indistinct red blotch.

Coloration when preserved ( Fig. 2 ). Body uniformly yellowish-brown with four indistinct dark saddles and single stripe replacing orange-red saddles and stripe of fresh specimens. Dark markings on body becoming indistinct with time, almost absent after 20+ years. Indistinct dark margin on distal edge of dorsal-fin soft rayed portion, anal fin, and caudal fin. Anterior surface of first dorsal-fin spine black.

Etymology. The specific name “ clavatus ”, meaning “club”, is proposed in reference to the stripe on the lateral surface of the body that characterizes the species. New English and standard Japanese names are also proposed in relation to this coloration.

Distribution. Plectranthias clavatus sp. nov. was collected from 100–386 m depth in Sagami Bay and the Hachijo-jima Island, Izu Islands, Japan, and Guam ( Fig. 5 ). In addition, an individual was observed at 406 m depth on the Shoho Sea Mount, Nishi-Shichito Ridge, southern Japan ( Koeda et al., 2021b). All individuals were collected from over rocky substrate.

Remarks. Plectranthias clavatus sp. nov. and P. kamii can be easily distinguished from all other congeners by the following combination of characters: dorsal fin rays X, 17–18, pectoral-fin rays 13–14, all branched except for uppermost ray simple; lateral line complete, with 34–38 pored scales; 4.5–5.5 and 16–20 scale rows above and below lateral line respectively; 6–7 diagonal rows of large scales on cheek between eye and corner of preopercle; body deep, its greatest depth more than 34.4 % of SL; third dorsal-fin spine longest; no scales on chin, branchiostegal membranes, infraorbital bones, maxilla, mandibles or snout; anterior end of predorsal scales not reaching line through posterior nostrils; posterior margin of preopercle serrated, ventral margin with 2 antrorse spines ( Table 1; Figs. 1 , 4 , 7 ; Randall, 1980, 1996; Randall & Hoese, 1995; Anderson, 2008; Heemstra & Randall, 2009; Wu et al., 2011; Williams et al., 2013; Bineesh et al., 2014; Allen & Walsh, 2015; Gill et al., 2016, 2021; Shepherd et al., 2018, 2020; Wada et al. 2018, 2020; Tang et al., 2020; Fricke, 2021; Koeda et al., 2021a; this study).

Plectranthias clavatus is most similar to P. kamii , widely distributed in the East Indian to Central Pacific Oceans ( Peristiwady et al., 2018; Gill et al., 2021), in sharing the abovementioned morphological characters. However, P. clavatus has a deeper body, its depth at the pelvic-fin origin 37.8–40.7 % (mean 39.1 %) of SL [vs. 34.4–37.5 % (36.1 %) of SL in P. kamii ], shorter third dorsal-fin spine, its length 36.5–45.9 % (41.9 %) of BDP [vs. long, 46.7–62.7% (53.7%) in P. kamii ], shorter anal-fin soft rays, its longest ray length 47.9–59.1 % (53.5 %) of BDP [vs. long, 59.4–73.9 % (64.4 %) in P. kamii ], three large orange-red saddles on dorsal edge of body (vs. 7 saddles in P. kamii ), single orange-red stripe on posterior four-fifths of mid-lateral body when fresh (vs. single longitudinal row of 4–5 irregular-shaped yellow blotches in P. kamii ), and saddles and stripe separated (vs. saddles and blotches partially connected in P. kamii ) ( Table 1; Figs. 1 , 6 , 7 , 8 ; Randall, 1980; Peristiwady et al., 2018; Koeda, 2019; Tang et al., 2020; Gill et al., 2021; Koeda et al., 2021b).

The base color of the body in P. clavatus and P. kamii is usually pinkish-white when fresh ( Figs. 1 , 7 ; Peristiwady et al., 2018; Koeda, 2019; Tang et al., 2020; Gill et al., 2021; Koeda et al., 2021b), but occasionally these species are more reddish and the patterns on lateral body appear more yellowish ( Kuiter, 2004; Ishikawa, 2012).

Distributional records of Plectranthias kamii

According to the key to species of Plectranthias provided by Randall (1980, 1996), P. clavatus has probably been misidentified in the literature as P. kamii . Therefore, previous distributional records of such are reassessed here ( Fig. 5 ).

The distribution records of P. kamii were confirmed from the descriptions and figures in the following publications and/or from direct examination of specimens shown in the references in this study: Japan (later discussion); northern and southern Taiwan ( Chen & Shao, 2002; Koeda, 2019; Tang et al., 2020); Sulawesi, Indonesia ( Peristiwady et al., 2018); Coral Sea, Lord Howe Island and Christmas Island, Australia ( Gill et al., 2021); and Moorea, Society Islands ( Randall, 1996; this study). In Japanese waters, this species is recorded from Sagami Bay ( Ishikawa, 2012; this study), Irouzaki, southernmost Izu Peninsula ( Senou, 2013; this study), Cape Omaezaki (this study), Kii Peninsula ( Fukui, 1999; Ikeda & Nakabo, 2015), Kii Canal ( Ikeda & Nakabo, 2015; this study), Cape Muroto ( Senou, 2005), Hyuga Nada Sea ( Iwatsuki et al., 2017; this study), Amakusa Nada Sea (this study), Goto Islands (this study), Koshiki Islands ( Fujiwara et al. 2017; this study), Taka-shima Island, Kagoshima Prefecture (this study), Uji Islands ( Motomura et al., 2016; Fujiwara et al. 2017; this study), Osumi Islands ( Kaburagi, 2016; Fujiwara et al., 2017; Motomura & Harazaki, 2017; Kimura et al., 2017; Jeong & Motomura, 2021; Motomura, 2023; this study), Ryukyu Islands [Tokara Islands ( Furuhashi & Motomura, 2022), Amami Islands ( Fujiwara et al., 2017; Sakurai, 2019; this study), Okinawa Islands ( Yoshino, 1972; Miura, 2012), Yaeyama Islands ( Yoshino, 1972; Shimose, 2021), and somewhere in the Ryukyu Islands ( Randall, 1980; this study)], Zunan Islands ( Kuriiwa et al., 2014; this study), and Ogasawara Islands ( Randall et al., 1997). A paratype of P. kamii from Palau ( Randall, 1980: USNM 219329) and a non-type specimen of P. kamii reported by Randall et al. (2005) from Marshall Islands (USNM 371628) represent an undescribed species that differs from both P. clavatus and P. kamii , and is currently under study (Wada and Hata, unpublished).

For the following locations, it was not possible to determine from the information provided in the publications whether the records were based on P. clavatus or P. kamii : New Caledonia ( Fourmanoir, 1982; Rivaton et al., 1990; Fricke et al., 2011: no registered specimens shown); Samoa ( Wass, 1984: based on one specimen, BPBM 22721). Given the limited current distribution of P. clavatus along the eastern edge of the Philippine Sea Plate ( Fig. 5 ), these records are more likely to be P. kamii , which is widely distributed in the East Indian to Central Pacific Oceans.

Comparative materials. Plectranthias kamii : 38 specimens, 121.7–291.5 mm SL. JAPAN: Sagami Bay: KPM-NI 39928, 182.3 mm SL, Miura, Kanagawa Prefecture, 28 Oct. 2015; Cape Omaezaki: KPM-NI 28889, 214.9 mm SL, 200–250 m depth, 9 July 2011; Kii Canal: FAKU 65967, 227.3 mm SL, 250 m depth, 1 Dec. 1997; Hyuga Nada Sea: KAUM–I. 183718 (previously registered as MUFS 15924), 177.0 mm SL, Meitsu, Nango, Miyazaki Prefecture, 8 July 1998, referenced by Iwatsuki et al. (2017), but details undescribed (Wada, unpublished); Goto Islands: FAKU 79115, 179.6 mm SL, FAKU 79116, 178.0 mm SL, FAKU 79119, 160.5 mm SL, FAKU 79120, 184.4 mm SL, FAKU 79121, 174.7 mm SL, FAKU 79122, 172.1 mm SL, FAKU 79123, 171.4 mm SL, FAKU 79141, 162.1 mm SL, FAKU 79142, 185.1 mm SL, FAKU 79143, 135.1 mm SL, FAKU 79144, 168 mm SL, 31 July 1987; Amakusa Nada Sea: ZUMT 65206, 235.6 mm SL, ZUMT 65207, 173.8 mm SL, off Ushibuka, Kumamoto, 1 Dec. 1994; Koshiki Islands: KAUM– I. 52252, 231.7 mm SL, KAUM–I. 52253, 210.4 mm SL, KAUM–I. 52254, 212.7 mm SL, KAUM–I. 52255, anomaly individual, 291.5 mm SL, 12 Nov. 2012; KAUM–I. 58815, 238.7 mm SL, 27 Jan. 2014; Taka-shima Island: KAUM–I. 98262, 121.7 mm SL, 28 Feb. 2017; Uji Islands: KAUM–I. 33981, 217.1 mm SL, 340 m depth, 19 Nov. 2011; KAUM–I. 46926, 200.5 mm SL, 340 m depth, 29 Dec. 2011; Osumi Islands: KAUM– I. 1654, 230.3 mm SL, KAUM– I. 1655, 188.8 mm SL, off Yakushima Island, 30 Jan. 2007; KAUM–I. 56985, 207.2 mm SL, KAUM–I. 56986, 214.9 mm SL, Tanega-shima Island, 9 Nov. 2013; KAUM–I. 97950, 197.7 mm SL, Kuroshima Island, 150–200 m depth, 20 Feb. 2017; Amami Islands: KAUM–I. 60920, 183.8 mm SL, Yoron-jima Island, 5 May 2014; KAUM– I. 128533, 219.9 mm SL, Amami-oshima Island, 31 Jan. 2019; KAUM–I. 149521, 213.6 mm SL, Amami-oshima Island, 5 Jan. 2021; Ryukyu Islands (details unknown): BPBM 19639, holotype of Plectranthias kamii , 214.0 mm SL, details described in Randall (1980); KAUM–I. 93789, 209.3 mm SL, 3 Sept. 2016; KPM-NI 70977, 212.6 mm SL, 25 Sept. 2021; Zunan Islands: NSMT-P 64813, 147.8 mm SL, Hoei Seamount, 9–10 Sept. 2002, listed in Kuriiwa et al. (2014); MOOREA: BPBM 24784, 207.0 mm SL, details described in Randall (1996): 4 photographs: JAPAN: Sagami Bay: KPM-NR 92368, Okinose, Yokosuka, 120 m depth, June 2004; KPM-NR 193065, Sunosaki, southernmost of Boso Peninsula, 250–300 m depth, 27 Jan. 2018; Izu Peninsula: KPM-NR 92367, Irouzaki, Minami-izu, 100 m depth, May 2004; Cape Omaezaki: KPM-NR 74403, 200–250 m depth, 12 June 2011.

Plectranthias sp. : PALAU: USNM 219329, paratype of P. kamii ,191.0 mm SL, details described in Randall (1980): MARSHALL ISLANDS: USNM 371628, 198.4 mm SL, details described in Randall et al. (2005).

Figures

Fig. 1. Fresh specimens of Plectranthias clavatus sp. nov. from Japan.A: KPM-NI 13878, holotype, 176.0 mm SL, Sagami Bay, photo by H. Senou; B: KPM-NI 77590, paratype, 131.3 mm SL, Izu Is., photo by H. Wada; C: KPM-NI 48915, paratype, 153.1 mm SL, Izu Is., photo by H. Senou; D: ZUMT 66348, paratype, 155.8 mm SL, Izu Is., photo by H.Wada; E: FAKU 147672, paratype, 199.6 mm SL, Sagami Bay, photo by M. Okamoto.

Fig. 2. Preserved specimens of Plectranthias clavatus sp. nov. (all photos by H. Wada). A: KPM-NI 13875, holotype, 176.0 mm SL, Sagami Bay, Japan; B: KPM-NI 48915, 153.3 mm SL, paratype, Izu Is., Japan; C: FAKU 147672, paratype, 199.6 mm SL, Sagami Bay, Japan; D: BPBM 5845, paratype of P. kamii (identified as P. clavatus), 174.4 mm SL, Guam.

Fig. 3 Radiographs of Plectranthias clavatus sp. nov. (all taken by H. Wada).A: KPM-NI 13875, holotype, 176.0 mm SL, Sagami Bay, Japan; B: KPM-NI 48915, 153.3 mm SL, paratype, Izu Is., Japan.

Fig. 4. Squamation on interorbital space of Plectranthias clavatus sp. nov. (FAKU 147672, paratype, 199.6 mm SL). Stained with cyanine blue.Photo by H. Wada.

Fig. 5. Distribution ofPlectranthias clavatus sp. nov. (red circles) and P. kamii (blue diamonds). Open and closed symbols indicate type locality and other localities respectively.Green triangles indicate unassessed previous records ofP.kamii during this study.

Fig. 6. Relationships of (A) body depth at pelvic-fin origin (as % SL), (B) third dorsal-fin spine length (% BDP), and (C) longest analfin soft ray length (% BDP) with standard length (mm) in Plectranthias clavatus sp. nov. (red circles) and P. kamii (blue diamonds). Open and closed symbols indicate holotype and other specimens respectively.

Fig. 8 Diagnostic colorations of lateral surface of body in Plectranthias clavatus sp. nov. (A, B) and P. kamii (C, D). Enclosed area shown by blue lines indicates saddles. Enclosed area shown by green lines indicates stripe or blotches.A: KPM-NI 77590, paratype, 131.3 mm SL; B: KPM-NI 48915, paratype, 153.3 mm SL; C: KAUM–I. 60920, 183.6 mm SL; D: KPM-NI 28889, 214.9 mm SL.

Fig. 7. Fresh specimens of Plectranthias kamii from Japan. A: KAUM–I. 60920, 183.6 mm SL, Amami Islands, photo by KAUM; B: KPM-NI 39928, 182.3 mm SL, Sagami Bay, photo by H. Senou; C: KPM-NI 70977, 212.4 mm SL, Hachijo-jima I., photo by H. Wada; D: KPM-NI 28889, 214.9 mm SL, Cape Omaezaki, photo by H. Senou.