Plectranthias kamii Randall

Gill, Anthony C., Pogonoski, John J., Moore, Glenn I. & Johnson, Jeffrey W., 2021, Review of Australian species of Plectranthias Bleeker and Selenanthias Tanaka (Teleostei: Serranidae: Anthiadinae), with descriptions of four new species, Zootaxa 4918 (1), pp. 1-116 : 68-71

Plectranthias kamii Randall

Figures 18 , 26–27 ; Tables 1–16, 22

Common name: Kami’s Perchlet

Plectranthias kamii Randall 1980: 141 , fig. 14, tab. 10 (type locality: Okinawa, Ryukyu Islands, Japan).— Anderson 2018: 29 (checklist).— Parenti & Randall 2020: 26 (checklist).

Plectranthias yamakawai [non Yoshino 1972].— Hobbs et al. 2014a: 194, tab. 1 (list, Christmas Island).

Diagnosis. The following combination of characters distinguishes P. kamii from congeners: dorsal rays X,17–18; third dorsal spine longest; pectoral rays 13; lateral line complete, with 32–38 tubed scales; scales below lateral line to origin of anal fin 16–20.

Description of Australian specimens. Dorsal rays X,18, all or all but first segmented rays branched; anal rays III,7, all segmented rays branched; pectoral rays 13/13, all but upper ray branched; pelvic fin I,5, all segmented rays branched; upper procurrent caudal-fin rays 7–8; lower procurrent caudal-fin rays 6; principal caudal-fin rays 9+8; branched caudal fin rays 8+7; total caudal-fin rays 30–31; lateral line complete with 34–37 scales; scales above lateral line to origin of dorsal fin 4–5; scales above lateral line to base of fifth dorsal spine 3–4; scales below lateral line to origin of anal fin 16–20; diagonal rows of scales on cheek 9–10, including 2 overlying preopercular canal; predorsal scales 19–20, extending to anterior interorbital area, at about vertical through anterior edge of eye; circumpeduncular scales 16; gill rakers 5–6+11–12=17, the upper 4–5 and lower 3–4 rudiments; pseudobranchial filaments 19–22; branchiostegal rays 7.

Vertebrae 10+16; supraneurals 3; predorsal formula 0/0+0/2/1+1; dorsal pterygiophores in interneural spaces 9–13 1/1/1+1/1+1/1+1; no trisegmental pterygiophores associated with dorsal fin; terminal dorsal pterygiophore in interneural space 18; no trisegmental pterygiophores associated with anal fin; terminal anal pterygiophore in interhaemal space 5; ribs present on vertebrae 3 through 10; epineurals present on vertebrae 1 through 10–11; parhypural and hypurals autogenous; well-developed hypurapophysis on parhypural; epurals 3; single uroneural (posterior uroneural absent); ventral tip of cleithrum with well-developed posteroventral process; proximal tip of first anal-fin pterygiophore near distal tips of parapophyses on vertebra 10.

Dorsal-fin spines with fleshy tabs on their distal tips, the tab on third spine longest; third dorsal spine longest; dorsal fin incised before first segmented-fin ray (tenth spine 57.3–58.1% length of first segmented ray); second anal-fin spine longest and stoutest; anal fin slightly pointed with second segmented ray longest; caudal fin emarginate; lower 6 pectoral fin rays thickened, with membranes between thickened rays deeply incised; eighth (counting from dorsal-most) pectoral ray longest, reaching vertical through base of second anal-fin spine; pelvic fins short, reaching about two-thirds way to anus, second segmented ray longest.

Morphometric data are summarised in Table 22 .

Mouth large, slightly oblique, posterior margin of maxilla reaching vertical through posterior edge of pupil; maxilla expanded posteriorly, with long, low, lateral ridge running parallel to dorsal margin; small splint-like supramaxilla present; mouth terminal; upper jaw with 2 fixed, short stout outer canines on either side of symphysis, flanked internally by villiform band with about 7–8 rows of depressible, smaller, sharp-tipped teeth, with inner rows becoming progressively longer and caniniform near symphysis, band reducing to 4 rows posteriorly, the teeth on outer row subequal to other rows, but slightly stouter and fixed; lower jaw with 2–3 short, stout fixed canines at front of jaw, a villiform band of about 5–6 rows of small depressible teeth at symphysis, teeth becoming progressively longer and more caniniform on inner rows near symphysis, two enlarged, curved canines on middle of jaw, band narrows to 2–3 rows posteriorly, the inner row teeth larger and slightly curved; vomer with chevron of 2–3 rows of sharp-tipped conical teeth; palatine with a band of 2–3 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 concealed by scales; preopercle with 26–30 serrations on posterior margin, and two enlarged antrorse spines ventrally; interopercle and subopercle smooth. Anterior nostril positioned at middle of snout, tubular with short posterior flap, barely reaching posterior nostril when appressed; posterior nostril at anterior border of orbit, with raised rim but no flap.

Scales ctenoid with peripheral cteni; lateral line broadly arched over pectoral fin following body contour to caudal-fin base; no scales on chin, branchiostegal membranes, maxilla, snout or infraorbital bones; no auxiliary scales on head or body; dorsal fin with low basal scale sheath of 2–4 scales along soft part of fin; anal fin with low basal scaly sheath posteriorly, with some small scales extending on to fin membranes; caudal fin with scaly basal sheath, with small scales extending on to basal third to half of fin membranes; pectoral fins with basal sheath and small scales extending on to fin membranes.

Colour in life (based on photos of freshly dead and live fishes from the Coral Sea, Lord Howe Island and Christmas Island; Figures 26–27 ): Head and body reddish pink to white, paler ventrally, marked with following yellow-brown to bright yellow blotches and bars: several small blotches dorsally on head, nape and snout tip; a short stripe from anterior edge of eye to middle of jaws; a diffuse oblique bar from posteroventral part of eye to preopercle angle; a diffuse blotch covering most of operculum; a curved stripe from posterior edge of eye to posterior part of nape and dorsal origin; an oblique bar extending from bases of fourth through sixth dorsal spines to just behind posterior edge of opercle; an oblique bar extending from bases of seventh through ninth dorsal spines to upper third of body; an oblique bar extending from bases of first through third segmented dorsal rays to upper third of body; a pupil-sized spot or short bar beneath bases of eighth through tenth segmented dorsal rays; a similar spot beneath terminal three or four dorsal segmented rays; a median spot on mid-dorsal part of caudal peduncle, a bar over posterior edge of caudal peduncle; a large elongate blotch mid-laterally below bars from seven through ninth dorsal spines and first through third segmented dorsal rays; smaller elongate mid-lateral blotch beneath middle part of soft dorsal fin; and elongate blotch over middle part of caudal peduncle; adjacent yellow-brown to bright yellow markings sometimes coalescing, sometimes overlain with small blue-grey to dark grey spots and blotches; eye pale pink to white, yellow-brown to orange where adjacent to yellow-brown to yellow stripes on head, with dark blue-grey to black crescent in front of pupil; dorsal fin reddish pink to white, with yellow-brown to bright yellow markings from body extending on to fins; first dorsal spine with dark grey basal spot; anal fin pale pink or white to orange; caudal fin pink to white dorsally and ventrally, pinkish hyaline to orange centrally; distal margins of caudal, soft dorsal and soft anal fins of larger specimen dusky grey; pelvic fins white to pink or orange, paler on fin spine; pectoral fins whitish hyaline to pink.

Colour in preservative ( Figure 27C ): Head and body pale tan; yellow-brown to bright yellow markings remain, becoming dusky brown; first dorsal spine with dusky brown basal spot; yellow-brown markings on fin remain, becoming dusky brown; fins otherwise pale tan, with distal margins of caudal, soft dorsal and soft anal fins dusky brown.

Remarks. A very large Plectranthias species (largest known specimen 34 cm total length, or approximately 280 mm SL; Figure 27A ), P. kamii was originally described from Okinawa, Ryukyu Islands (type locality), Palau and Guam. It has since been recorded from Samoa ( Wass 1984), Moorea ( Randall 1996), Taiwan ( Chen & Shao 2002), New Caledonia ( Fricke et al. 2011) and Sulawesi, Indonesia ( Peristiwady et al. 2018). We newly record this species from Australia on the basis of a specimen collected east of the Murray Islands, Coral Sea ( Figure 27C ), several individuals photographed from RV Falkor ROV SuBastian dives at Madgelaine Cays, Diamond Islet and Lihou Reef, Coral Sea ( Figure 26 ), an individual collected and photographed (but not retained) from near Lord Howe Island ( Figure 27A ), and a specimen collected from Christmas Island ( Figure 27B ). The last-mentioned was the basis for Hobbs et al. (2014a) record of P. yamakawai from Christmas Island. Although the specimen resembles P. yamakawai in having dark spots on the body, these are mostly arranged in and around yellow markings (versus evenly scattered over the upper body in P. yamakawai ; Figure 28 ). Moreover, the third dorsal spine is longest (versus the fourth in P. yamakawai ), and the specimen lacks the large pink to red spot (grey-brown in preservative) beneath the posterior part of the dorsal fin that is characteristic of P. yamakawai . The specimens and photographs agree well with published descriptions and photographs of P. kamii .

Allen & Walsh (2015) recorded a depth range of 183–280 m for P. kamii . All of the Australian specimens and observations were from deeper than 280 m: 350 m for the Lord Howe individual, 398 m for the Christmas Island specimen, 480 m for the Murray Islands specimen, and 465–534 m for the ROV SuBastian observations.

Material examined. Australia. QM I. 20683, 173 mm SL, Queensland, Coral Sea, east of Murray Islands , 9°53′S, 144°23′E, 480 m, trawl, C. Jones, Queensland Fisheries Service, 28 May 1983 ; WAM P.34014-001, 238.0 mm SL, Christmas Island , 10°29′S, 105°37′E, 398 m, S. Newman, 12 Mar 2014 . Taiwan. ASIZP 60270, 162 mm SL (radiograph), Pingtung, Hengchun, J.P. Chen, 9 Apr 1999 (radiograph from Shao, 2020).

Figures

FIGURE 18. Distribution records for Plectranthias ferrugineus n. sp. (closed circles; arrow indicates type locality), P. kamii (open circles; Australian records only, excluding Christmas Island) and P. winniensis (triangles; Australian records only).

FIGURE 26. Plectranthias kamii, photo from ROV SuBastian, 471 m, Magdelaine Cay, Coral Sea, Australia. Photo courtesy of Schmidt Ocean Institute, Visioning Coral Sea Marine Park expedition.

FIGURE 27. Plectranthias kamii, Australian specimens: A) freshly dead specimen, approx. 280 mm SL, not retained, south of Lord Howe Island; B) WAM P.34014-001, 238 mm SL, freshly dead, Christmas Island; C) QM I.20683, 173 mm SL, preserved, east of Murray Isles, Coral Sea. Photos by (A) Scott Wilson, (B) S. Newman & J.P. Hobbs, (C) A.C. Gill.

FIGURE 28. Plectranthias yamakawai, NMMB P-30833, 163 mm SL, preserved, Hou-bi-hu, Pingtung, Taiwan. Photo by A.C. Gill.