Plectranthias Bleeker

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 : 29-32

Plectranthias Bleeker

Plectranthias Bleeker 1873: 238 (masculine; type species Plectropoma anthioides G̹nther 1872 , by monotypy).

Paracirrhites Steindachner in Steindachner & Döderlein 1883b: 25 (masculine; type species Paracirrhites japonicus Steindachner 1883 in Steindachner & Döderlein 1883b by monotypy; preoccupied by Paracirrhites Bleeker 1874 , replaced by Isobuna Jordan 1907 ).

Sayonara Jordan & Seale 1906: 145 (feminine; type species Sayonara satsumae Jordan & Seale 1906 [= Paracirrhites japonicus Steindachner in Steindachner & Döderlein 1883b ] by original designation and monotypy).

lsobuna Jordan in Jordan & Herre 1907: 158 (feminine; type species Paracirrhites japonicus Steindachner 1883 in Steindachner & Döderlein 1883b by being a replacement name).

Xenanthias Regan 1908: 223 (masculine; type species Xenanthias gardineri Regan 1908 , by monotypy).

Zalanthias Jordan & Richardson 1910: 470 (masculine; type species Anthias kelloggi Jordan & Evermann 1903 , by original designation).

Pteranthias Weber 1913: 208 (masculine; type species Pteranthias longimanus Weber 1913 , by monotypy).

Serranops Regan 1914: 15 (masculine; type species Serranops maculicauda Regan 1914 , by monotypy).

Pelontrus Smith 1961: 364 (masculine; type species Pelontrus morgansi Smith 1961 by original designation and monotypy).

Zacallanthias Katayama 1964: 27 (masculine; type species Zacallanthias sagamiensis Katayama 1964 , by original designation and monotypy).

Diagnosis. The following combination of characters distinguishes Plectranthias from other serranid genera: dorsal fin with 10 (rarely 9) spines and 13–20 segmented rays, incised between the spinous and soft portions; pectoral rays 12–18; lateral line with 8–46 tubed scales; no auxiliary scales on head or body; scales with or without basal cteni; teeth on vomer in a V- or U-shaped patch; no teeth on tongue; gill rakers 3–10+7–22=12–31; total vertebrae 26 (rarely 27).

Remarks. We follow Randall (1980) in including Sayonara Jordan & Seale, 1906, lsobuna Jordan in Jordan & Herre, 1907, Xenanthias Regan, 1908 , Zalanthias Jordan & Richardson, 1910, Pteranthias Weber, 1913 , Serranops Regan, 1914 , Pelontrus Smith, 1961 and Zacallanthias Katayama, 1964 in the synonymy of Plectranthias . This is despite the lack of evidence for monophyly of the genus, and results from preliminary molecular studies that suggest the genus is not only non-monophyletic, but that some species are more closely related to the Serraninae than the Anthiadinae ( Smith & Craig 2007, but see Smith et al. 2018). We further note that some characters used to diagnose other anthiadine genera, such as presence or absence of basal cteni on scales, lateral-line development and pectoral-ray branching, vary among Plectranthias species. Although some authors have recognised Zalanthias as a valid genus (e.g. Smith & Craig 2007; Kharin & Balanov 2013), we feel that more extensive sampling of species and characters is needed before any classification changes are made.

The genus Hypoplectrodes Gill, 1862 is well represented in southern Australian waters and is easily confused with Plectranthias . Heemstra & Anderson (1983) distinguished Hypoplectrodes (as Ellerkeldia Whitley, 1927 , a junior synonym; see Anderson & Heemstra 1989) from Plectranthias solely on the basis of vertebral counts, with Hypoplectrodes typically having one more vertebra (27 versus 26 in Plectranthias ). The monotypic Australian genera Epinephelides Ogilby, 1899 and Othos Castelnau, 1875 also resemble Plectranthias but were not considered by Heemstra & Anderson (1983). We confirm counts of 10+17 vertebrae for all Australian Hypoplectrodes , Othos and Epinephelides based on the examination of radiographs of the following specimens (number of specimens in parentheses): E. armatus ( Castelnau, 1875) , AMS I.20233-011 (4), AMS I.20233-071 (1), AMS I.20245-015 (1); H. annulatus (G̹nther, 1859), AMS I.17234-001 (1), AMS I.19901-034 (1), AMS I.22559-001 (1); H. cardinalis Allen & Randall, 1990 , AMS E.2492 (1), AMS I.12403 (1), AMS I.18476-001 (1 paratype) , CSIRO H 6381-07 (1) , CSIRO H 6381-08 (1) ; H. jamesoni Ogilby, 1908 , AMS I.17773-001 (1), AMS I.19237-002 (1), AMS I.19246-001 (1), CSIRO H 6727-04 (1) , CSIRO H 7678-03 (1) , CSIRO H 7679-02 (1) ; H. maccullochi ( Whitley, 1929) , AMS I.19700-016 (4), CSIRO CA 680 (1) ; H. nigrorubrum (Cuvier in Cuvier & Valenciennes, 1828) , AMS I.19103-024 (2), AMS I.20239–015 (1); H. wilsoni ( Allen & Moyer, 1980) , AMS I.20233-010 (3 paratypes); H. sp. nov. (C.D. Roberts ms) , AMS I.17260-001 (1), AMS I.18428-001 (1), AMS I.20774-001 (1), AMS I.22756-001 (1), CSIRO H 8032-01 (1) ; and Othos dentex (Cuvier in Cuvier & Valenciennes, 1828) , WAM P.4136-001 (2), WAM P.4071-001 (1), USNM 177012 (1).

Most other anthiadines have 26 vertebrae, the typical count for Plectranthias species. Aside from Epinephelides , Othos and Hypoplectrodes , a count of 27 has been otherwise recorded from one species of the genus Caprodon Temminck & Schlegel, 1843 by Kharin & Dudarev (1983), from the holotype of Plectranthias bilaticlavia Paulin & Roberts, 1987 and from some specimens of P. japonicus by Katayama (1959; as Sayonara satsumae ). Pinheiro et al. (2018) recorded a count of 10+17 vertebrae for their new species Tosanoides aphrodite . However, their radiographs of the holotype and a paratype (their figures 1 and 2) indicate this count is in error, and that the species agrees with other species of Tosanoides Kamohara, 1953 in having 10+16 vertebrae. We record a count of 10+17 from two additional anthiadines, one of four examined specimens of P. longimanus , and the holotype and only known specimen of P. grahami n. sp. Justification for classifying P. grahami in Plectranthias rather than Hypoplectrodes , Epinephelides or Othos is given under Remarks for P. grahami .

We here recognise 22 species of Plectranthias from Australian waters: P. sp. 1 from a large seamount north of Middleton Reef and Norfolk Rise, Tasman Sea; P. alleni from off southwest Western Australia; P. azumanus ( Jordan & Richardson 1910) from off southwest Western Australia; P. bennetti from Holmes Reef, Coral Sea; P. cruentus from Lord Howe Island and possibly from off Stradbroke Island, Queensland; P. ferrugineus n. sp. from the North West Shelf; P. fourmanoiri from Christmas Island and Holmes Reef, Coral Sea; P. grahami n. sp. from off central New South Wales, Tasman Sea; P. inermis from Christmas Island; P. japonicus from the North West Shelf and Arafura Sea; P. kamii Randall, 1980 from Christmas Island, east of the Murray Islands, Coral Sea, and Lord Howe Island; P. lasti from the North West Shelf and off Marion Reef, Queensland; P. longimanus from the Timor Sea, Great Barrier Reef, Coral Sea and southern Queensland; P. maculicauda from southeastern Australia; P. megalophthalmus from northeast of the Whitsunday Islands, Queensland; P. mcgroutheri n. sp. from the North West Shelf; P. melanesius Randall, 1980 from southeastern Queensland and a seamount north of Middleton Reef; P. moretonensis n. sp. from off Stradbroke Island, Queensland; P. nanus from the Cocos (Keeling) Islands, Christmas Island, the Great Barrier Reef and Coral Sea; P. retrofasciatus Fourmanoir & Randall, 1979 from the Great Barrier Reef; P. robertsi from off the Queensland coast, Coral Sea; and P. winniensis from the Great Barrier Reef and Coral Sea. Four of the species represent new records for Australia: P. azumanus , P. kamii , P. megalophthalmus and P. melanesius . Previous records of P. megalophthalmus from the North West Shelf are based on misidentified specimens of P. lasti . Records of P. wheeleri from the North West Shelf are here identified as P. mcgroutheri n. sp. A record of P. yamakawai Yoshino from Christmas Island is based on a misidentified specimen of P. kamii . Plectranthias retrofasciatus was previously recorded from the Great Barrier Reef as P. pallidus , here shown to be a junior synonym. Video-based records of P. kelloggi from the Great Barrier Reef appear to be based also on P. retrofasciatus .

Key to Australian species of Plectranthias

1 Predorsal scales not extending anteriorly beyond supratemporal commissure (to vertical above preopercle)...... P. cruentus

- Predorsal scales reaching anteriorly to at least vertical through posterior edge of eye................................ 2

2 No teeth on palatine; colour in preservative pale with four brown bars, and four prominent dark grey to black spots, one over mid-dorsal fin, one at end of dorsal fin, one at end of anal fin, and one mid-ventrally on abdomen in front of anus.................................................................................................. P. fourmanoiri

- Palatine teeth present; coloration not as above............................................................... 3

3 Two or three large antrorse serrations on lower edge of preopercle.............................................. 4

- Serrations, if present on lower edge of preopercle neither enlarged nor antrorse................................... 13

4 Third dorsal spine longest.............................................................................. 5

- Fourth, fifth or sixth dorsal spine longest................................................................... 8

5 Pectoral fin with 14 rays................................................................ P. mcgroutheri n. sp.

- Pectoral fin with 13 rays................................................................................ 6

6 Lateral line with 32–38 tubed scales................................................................. P. kamii

- Lateral line with 27–30 tubed scales...................................................................... 7

7 Pectoral rays all unbranched; 6 branched rays in lower lobe of caudal fin; predorsal scales reach mid-interorbital space, at vertical through posterior edge of pupil........................................................ P. moretonensis n. sp.

- Pectoral rays mostly branched; 7 branched rays in lower lobe of caudal fin; predorsal scales reach posterior nostrils or farther forward................................................................................. P. retrofasciatus

8 Pectoral rays 16–18.......................................................................... P. winniensis

- Pectoral rays 12–15................................................................................... 9

9 Lateral line complete, with 27–30 tubed scales; predorsal formula 0/0+0/2/1+1; hypurals 1–2 autogenous ( Figure 5A ).... 10

- Lateral line incomplete, with 10–21 tubed scales; predorsal formula 0/0/2/1+1; hypurals 1–2 undifferentiated ( Figure 5B )... .................................................................................................. 12

10 Three antrorse serrations on lower edge of preopercle................................................. P. bennetti

- Two antrorse serrations on lower edge of preopercle......................................................... 11

11 Basal cteni present on at least some anterior lateral-line scales; circumpeduncular scales 12..................... P. sp. 1

- Basal cteni absent; circumpeduncular scales 14–16............................................ P. ferrugineus n. sp.

12 Pectoral rays 12–13; lateral line with 10–17 tubed scales; circumpeduncular scales 12; 2–6 conspicuous serrations on interopercle, 2–7 conspicuous serrations on subopercle ( Figure 3A ); greatest body depth 32.3–39.9 % SL; body depth at anal origin 27.1–32.0 % SL............................................................................ P. longimanus

- Pectoral rays usually 14–15, rarely 13; lateral line with 15–21 tubed scales; circumpeduncular scales 12–15, usually 14; 0–2 weak serrations on interopercle and subopercle ( Figure 3B ); greatest body depth 29.4–33.3 % SL; body depth at anal origin 24.6–27.2 % SL................................................................................ P. nanus

13 Predorsal scales not extending anteriorly beyond vertical through mid-pupil; pectoral rays 12–13; branched caudal rays 7+6............................................................................................. P. inermis

- Predorsal scales extending anteriorly to at least posterior nostrils; pectoral rays 14–18; branched caudal rays 8+7........ 14

14 Pectoral rays 18; lateral-line scales 41–42..................................................... P. grahami n. sp.

- Pectoral rays 14–17; lateral-line scales 28–37.............................................................. 15

15 No serrations on preopercle............................................................................ 16

- Preopercle distinctly serrated, at least posteriorly........................................................... 17

16 Segmented dorsal rays 14; scales below the lateral line to the anal origin 9–10................................. P. lasti

- Segmented dorsal rays 15; scales below the lateral line to the anal origin 12–13..................... P. megalophthalmus

17 Segmented dorsal rays 13–14, usually 14; in preservative, a short dark stripe in front of the eye, a faint dusky stripe from behind eye across upper side of body, and a faint small dusky spot at midbase of caudal fin (stripes and spot better developed in small specimens)..................................................................................... P. alleni

- Segmented dorsal rays 14–16, usually 15; coloration not as above.............................................. 18

18 Gill rakers 5–7+10–13=16–19; orbit diameter 9.8–11.9 % SL; tenth dorsal spine 3.4–6.2 % SL; bony interorbital width 3.5–4.2 % SL...................................................................................... P. japonicus

- Gill rakers 5–8+13–16=18–26; orbit diameter 11.4–15.4 % SL; tenth dorsal spine 4.4–12.1 % SL; bony interorbital width 4.2–7.1 % SL....................................................................................... 19

19. Pectoral rays 15–16, usually 16; total caudal rays 28–31, usually 28–29; predorsal formula 0/0/2/1+1; second segmented pelvic ray elongate and filamentous; third dorsal spine 10.2–12.9% SL; tenth dorsal spine 4.4–6.0 % SL; colour in preservative generally pale, with dusky grey markings on anterior few lateral-line scales................................... P. robertsi

- Pectoral rays 14–16 (rarely 14 or 16); total caudal rays 30–34; predorsal formula 0/0+0/2/1+1; second segmented pelvic ray not elongate; third dorsal spine 15.2–18.2 % SL; tenth dorsal spine 8.0–12.1 % SL; coloration not as above................ 20

20 Caudal peduncle with melanophores arranged in a large (larger than pupil) dark spot mid-laterally.......... P. maculicauda

- Caudal peduncle with melanophores arranged in a bar or saddle............................................... 21

21 Melanophores of caudal peduncle marking form a dorsal saddle, which extends ventrally to about 1–2 scale rows beneath lateral line.................................................................................... P. azumanus

- Melanophores of caudal peduncle marking form a bar, which extends ventrally to ventral margin of peduncle...................................................................................................... P. melanesius

Figures

FIGURE 3. Lower part of left cheek in ventrolateral view showing serrations on interopercle (IOP), preopercle (POP) and subopercle (SOP) in: A) Plectranthias longimanus, WAM P.28534-021, 22.8 mm SL (note that mouth is open); B) P. nanus, WAM P.28541-039, 24.3 mm SL. Dotted line shows junction between interopercle and subopercle; arrows indicate antrorse serrations on preopercle; scale bars = 2 mm. Illustrations by A.C. Gill.

FIGURE 5. Caudal skeletons of A) Plectranthias inermis, AMS I.45300-250, 28.0 mm SL, showing autogenous hypurals 1 and 2; B) P. longimanus, AMS I.22613-052, 20.3 mm SL, showing undifferentiated hypurals 1 and 2. Abbreviations: EP1–3, epurals 1–3; HSP, haemal spines; HYP1–5, hypurals 1 through 5; HYPAP, hypurapophysis; NSP, neural spines; PARHYP, parhypural; PU2–3, preural centrum 2 and 3; UR, uroneural. Cartilage shown in dark grey; arrows indicate outer principal caudal rays; scale bars = 1 mm. Illustrations by A.C. Gill.