Plectranthias japonicus (Steindachner)

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 : 67-68

Plectranthias japonicus (Steindachner)

Figures 1 , 7 , 25 ; Tables 1–16, 19

Common name: Japanese Perchlet

Paracirrhites japonicus Steindachner in Steindachner & Döderlein 1883b: 25 (type locality: Japan).

Plectranthias japonicus .— Sainsbury et al. 1985: 337 (diagnosis, colour photo, off Northern Territory).— Allen 1985: 2508 (checklist, Western Australia).— Paxton et al. 1989: 506 (checklist).— Hutchins 2001: 30 (checklist).— Allen et al. 2006: 990 (checklist).— Larson et al. 2013: 102 (checklist).— Anderson 2018: 29 (checklist).— Parenti & Randall 2020: 26 (checklist).

Sayonara satsumae Jordan & Seale 1906: 145, fig. 3 (type locality: Yamakawa, Japan).— Paxton et al. 1989: 507 (checklist, North West Shelf).

Sayonara mitsukurii Smith & Pope 1906: 469 , fig. 3 (type locality: Kagoshima, Japan).

Diagnosis. The following combination of characters distinguishes P. japonicus from congeners: segmented dorsal rays 14–16, usually 15; fourth or fifth dorsal spine longest; pectoral rays 15–17, usually 16; lateral line complete, consisting of 30–35 tubed scales; posterior preopercle with 17–40 serrations, which continue around corner of bone to posteroventral edge; no antrorse serrations on ventral edge of preopercle; margins of subopercle and interopercle serrate.

Remarks. A relatively large Plectranthias species (largest specimen 129 mm SL), P. japonicus is known in Australia from the North West Shelf and Arafura Sea ( Figure 7 ). Outside of Australia, it is known from southern Japan, Taiwan, and southern Indonesia ( Randall 1980; Gloerfelt-Tarp & Kailola 1984; Lee 1990).

We add the following new observations: scales with basal cteni; vertebrae 10+16; supraneurals 2; predorsal formula 0/0/2/1+1; dorsal pterygiophores in interneural spaces 9–13 1/1/1+1/1+1/1+1 or 1/1/1+1+1/1/1+1; 6–13 trisegmental pterygiophores associated with dorsal fin; terminal dorsal pterygiophore in interneural space 17–18; 4–6 trisegmental pterygiophores associated with anal fin; terminal anal pterygiophore in interhaemal space 4–5; ribs present on vertebrae 3 through 10; epineurals present on vertebrae 1 through 9–11; 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.

Morphometric data are summarised in Table 19.

Material examined. Australia. AMS I.21835-020, 81.3 mm SL, Northern Territory, Arafura Sea , 09°21′S, 132°12′E, 156–164 m, otter trawl, FRV Soela , 15 Nov 1980 (field number SO7/80/36); CSIRO H 2548-02 , 101 mm SL, CSIRO H 2548-10 , 3 : 56.9–129 mm SL, Western Australia, northwest of North West Cape , 21°44.7′S, 113°52.3′E to 21°44.5′S, 113°52.5′E, 290–320 m, Engel trawl, P. Last, FRV Southern Surveyor , 24 Jan 1991 (field station number SS0191/8); NTM S.13147-005, 99.3 mm SL, Northern Territory, Arafura Sea , 9°47′S, 130°26′E, 255 m, D. Evans, 9 Dec 1990; NTM S.13577-005, 71.4 mm SL, Northern Territory, Arafura Sea , 9°5.1′S, 133°39.7′E, 165–176 m, R.S. Williams , 20 Oct 1992. Japan. CAS-SU 9259, 123 mm SL (holotype of Sayonara satsumae Jordan & Seale, 1906; radiograph only), Kagoshima Prefecture, near Kagoshima, Yamagawa, K. Mitsukuri; USNM 55617 , 70 mm SL (holotype of Sayonara mitsukurii Smith & Pope 1906 ; radiograph only), Kagoshima, H.M. Smith, 16 Jun 1903 .

Figures

FIGURE 1. Radiograph of anal fin of Plectranthias japonicus, CSIRO H 2548-10, 129.2 mm SL, showing bisegmental (consisting of undifferentiated proximal + middle radials and a separate distal radial) and trisegmental pterygiophores (consisting of separate proximal, middle and distal radials). Abbreviations: dr, distal radial; mr, middle radial; pr, proximal radial. Scale bar = 5 mm. Radiograph by J.J. Pogonoski.

FIGURE 7. Australian distribution records for Plectranthias sp. 1 (open circle), P. bennetti (closed circle) and P. japonicus (closed triangles).

FIGURE 25. Plectranthias japonicus, CSIRO H 2548-02, 101 mm SL, freshly dead, northwest of North West Cape, Western Australia, Australia. Photo by G. Johnson, CSIRO.