Pseudanthias paralourgus, Gill & Pogonoski & Johnson & Tea, 2021

Gill, Anthony C., Pogonoski, John J., Johnson, Jeffrey W. & Tea, Yi-Kai, 2021, Three new species ofAustralian anthiadine fishes, with comments on the monophyly of Pseudanthias Bleeker (Teleostei: Serranidae), Zootaxa 4996 (1), pp. 49-82 : 53-61

Pseudanthias paralourgus n. sp.

Figures 2–3 ; Tables 1–3

Common name: Purple-tip Anthias urn:lsid:zoobank.org:act:01FBB14E-A7FD-45EA-9E8A-6E52A3478F5C

Holotype. QM I.38668, 134.0 mm SL, Australia, Queensland, off Cape Moreton , 27°03′S, 153°33′E, 110–114 m, trawl, S. McCulloch, 10 Feb 2010 ( Fig. 2A ) (COI: GenBank MZ 170044 ).

Paratypes (n = 4). QM I.10148, 2: 110.0–120.0 mm SL, Australia, Queensland, 27 miles north of Cape Moreton , 26°35′S, 153°28′E, 119 m, trawl, F. Wallace, 7 Apr 1970 ; QM I.38969, 2: 98.7–105.3 mm SL, Australia, Queensland, east of Coolum , 26°32′S, 153°36′E, 115 m, trawl, Queensland Fisheries Service, 19 Oct 2010 .

Diagnosis. The following combination of characters distinguishes P. paralourgus from other anthiadines: dorsal rays X,16; pectoral rays 18–20; lateral-line scales 40–44; greatest body depth 35.9–38.3% SL (2.6–2.8 in SL); predorsal formula 0/0+0/1+1; no auxiliary scales on body; third dorsal spine longest; caudal fin lunate with filamentous extensions; males with pink mostly horizontal vermiculate lines on the ventral and posterior body and distal tips of caudal fin broadly pink-purple.

Description. Frequency distributions for selected meristic characters are provided in Table 2. Dorsal rays X,16, all segmented rays branched; anal rays III,7, all segmented rays branched; pectoral rays 19/19 (18–20), all rays branched except upper 2/1 (2/2) rays (lower ray unbranched bilaterally in one paratype and unilaterally in one paratype); pelvic rays I,5, all segmented rays branched; principal caudal rays 9+8; branched caudal rays 7+6; upper procurrent caudal rays 9 (8–10); lower procurrent caudal rays 10 (9–10); total caudal rays 36 (34–36); lateral-line scales 43/43 (40–44), with additional tubed scale on caudal-fin base (absent in paratypes); scales above lateral line to origin of dorsal fin 6/? (6–7); scales above lateral line to base of fifth dorsal spine 5/4 (4–6); scales below lateral line to origin of anal fin 19/19 (19–21); circumpeduncular scales 26 (27–28); gill rakers 11+26 (10–12+26–27=36– 39); branchiostegal rays 7; pseudobranch filaments at least 17, with lower part of pseudobranch damaged (19–21).

Morphometric values are presented in Table 3.

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Vertebrae 10+16; supraneurals 3; predorsal formula 0/0+0/2/1+1; main shaft (proximal component) of first dorsal pterygiophore perpendicular to body axis; dorsal pterygiophores in interneural spaces 9–13 1/1/1+1/1+1/1 (1/1/1+1/1+1/1, 1/1/1+1/1+1/1+1, or 1/1/1+1/1/1+1); terminal dorsal pterygiophore in interneural space 18 (18–19); no trisegmental pterygiophores associated with dorsal fin; proximal tip of first anal pterygiophore near distal tip of haemal spine on first caudal vertebra; terminal anal pterygiophore in interhaemal space 5; no trisegmental pterygiophores associated with anal fin; ribs present on vertebrae 3 through 10; epineurals present on vertebrae 1 through 12; paired parapophyses present on first caudal vertebra; 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; ( Fig. 2B ).

Dorsal-fin origin slightly in front of vertical through posterior edge of operculum; third dorsal spine longest; distal tips of dorsal spines with fleshy tabs, best developed on third spine; dorsal fin not incised before first segmented ray; soft dorsal fin pointed, 13 th ray longest; second or third anal spine longest, second spine stoutest; anal fin pointed, with third segmented ray elongate, sometimes filamentous; caudal fin lunate with filamentous tips; pectoral bluntly pointed, reaching just part vertical through anal origin; second pelvic ray longest, with filamentous tip reaching well beyond anal origin.

Mouth large and oblique, posterior margin of maxilla reaching almost to vertical through posterior edge of pupil; mouth terminal, lower jaw projecting slightly; premaxilla with an enlarged recurved canine anterolaterally, a band of small conical teeth about 4–5 rows wide at symphysis reducing to 2–3 rows on sides of jaw, with the outer row of teeth larger and slightly curved either inwards (on front part of jaws) or anteriorly (on middle and posterior part of jaws), and the inner few teeth nearest symphysis enlarged and caniniform, lying almost flat against roof of mouth; dentary with an enlarged recurved canine anterolaterally, with a band of small conical teeth about 4–5 rows wide at symphysis; sides of lower jaw with single row of slightly curved, conical teeth, with one or two teeth on middle of jaw greatly enlarged and caniniform; vomer with a triangular patch of small conical teeth, 3–4 rows wide in midline; palatine with a narrow band of small conical teeth, 3 rows wide at widest point; ectopterygoid, mesopterygoid and tongue edentate.

Opercle with 3 flat spines, middle spine longest, upper spine mostly concealed by scales; preopercle with 35/30 (24–31) fine serrations mostly on vertical portion, those largest near angle of preopercle and sometimes extending to posterior part of ventral portion; interopercle with 2/4 (0–5) variously developed serrations; subopercle with?/8 (3–5) variously developed serrations. Anterior nostril positioned at middle of snout, tubular with small flap on posterior rim, flap almost reaching posterior nostril when laid back; posterior nostril at mid-upper, anterior border of orbit, covered by thin, narrow membrane anteriorly, this sometimes with small flap. No papillae on posterior rim of orbit. Snout not hypertrophied with papillae at symphysis.

Scales ctenoid with peripheral cteni ( Roberts, 1993); lateral line broadly arched over pectoral fin, following body contour to caudal-fin base; head scaly, including mandible, maxilla, snout, and infraorbitals, no scales on lips; no auxiliary scales on body, a few auxiliary scales sometime present on head; low scaly sheath on soft dorsal and anal fins, with indistinct small scales present between segmented rays; caudal fin with scaly basal sheath, with small scales extending over much of fin, except for fin tips and posterior part of membranes of middle rays; pectoral fins with basal, wedge-shaped sheath of small scales, scales extending to just over half length of longest rays.

Colour of males in life (based on colour photo of freshly dead male holotype; Fig. 2A ): head and body orange, becoming yellow ventrally on body and pale yellow on head; a broad pink oblique band extending from behind eye and occiput to anterior body, edged ventrally by bright pink to silvery pink stripe extending from midposterior edge of eye to upper part of pectoral base; second bright pink to silvery pink stripe extending from first infraorbital to lower part of pectoral base; area between pink stripes orange-yellow; iris bright yellow, edged with bright pink to dark purple; broad pink band on head and body breaking into mostly horizontal vermiculate lines, which cover most of ventral and posterior body including caudal peduncle; spinous portion of dorsal fin bright yellow, anterior three spines mostly bright red to bright purple-pink distally, pink becoming confined to distal tips of more posterior spines; membrane between anterior spines each with a small purple-pink spot basally, these becoming elongate streaks on more posterior spines; anal fin and soft portion of dorsal fin bright yellow, narrowly bright pink distally, with variously sized bright pink spots or streaks along each ray; caudal fin bright yellow, bright pink-purple broadly on tips and narrowly on edges of fin lobes, the basal part of fin with bright pink spots and short streaks along each fin ray; pelvic fins pink? (not visible in colour photo); pectoral fins deep pink basally, the remainder of fins pinkish hyaline.

Colour of females in life: Not known.

Colour in preservative: Head and body tan, paler ventrally, two smallest specimens with grey-brown curved or crescent-shaped markings on each scale on upper body between lateral line and dorsal base and along upper part of caudal peduncle ( Fig. 2C ), larger specimens with no apparent markings; fins pale tan.

Habitat and distribution. Pseudanthias paralourgus is currently known only from off southeastern Queensland ( Fig. 3 ). However, given the similarity of the two species, it is likely that records of P. elongatus from the Chesterfield Islands and New Caledonia (Rivaton et al., 1990; Rivaton & Richer de Forges, 1990; Kulbicki et al., 1994; Fricke et al., 2011) are based on specimens of this species. It has been collected in trawls at depths ranging from 110– 119 m. Specimens of Tosana longipinnis n. sp. (see description below) were collected in the same trawls. The two species likely form mixed-species aggregations in the water column well above the bottom, feeding on plankton.

Comparisons. Analysis of mitochondrial COI sequence data retrieved Pseudanthias elongatus as its closest match, with an uncorrected p -distance of 1.9%. The next closest was P. pleurotaenia , with uncorrected p -distances to P. paralourgus and P. elongatus of 11.6% and 10.1%, respectively. Phylogenetic analyses inferred using mitochondrial COI support a monophyletic group comprising the three species ( Fig. 1 ), although other species not included in the analysis, such as P. bimaculatus ( Smith, 1955) , are likely to also be closely related (see below).

Pseudanthias paralourgus and P. elongatus are very similar in morphometric and meristic values ( Tables 2–3). Principal component analyses of meristic and morphometric characters failed to distinguish the two species. However, although sample sizes are small for P. paralourgus , it possibly differs from P. elongatus in having slightly longer dorsal rays (longest dorsal ray 21.2–23.4 versus 17.1–21.3% SL). The two species can be further differentiated by live male coloration ( Figs. 2 , 4 ). Pseudanthias paralourgus differs from P. elongatus in having the spinous portion of the dorsal fin bright yellow with bright red to purple-pink fin spines and a bright purple-pink spot or streak behind the base of each spine (versus spinous portion of the dorsal fin bright yellow with similar purple-pink markings, but with a broad bright pink to purple stripe along the distal third of the fin); and the caudal fin bright yellow with pinkish red spots and streaks, and the posterior tips of the fin broadly bright pink-purple (versus caudal fin bright yellow to bright orange with bright pink to red or purple spots and streaks, sometimes with dorsal and ventral edges of fin tips yellow to orange or red).

The male live coloration of P. paralourgus is relatively distinctive, particularly the pink mostly horizontal vermiculate lines on the ventral and posterior body. Aside from P. elongatus , similar markings are found in P. pleurotaenia and P. bimaculatus . Pseudanthias paralourgus is readily distinguished from P. pleurotaenia in having fewer lateral-line scales (40–44 versus 44–50), usually one fewer segmented dorsal rays (16 versus 16–18, usually 17), usually one more pectoral ray (18–20 versus 17–19) and a different male live coloration. In life, male P. pleurotaenia have a large rectangular to square violet marking on the mid-side, although this is weakly developed in some populations, such as in the form from off Western Australia described as P. sheni by Randall & Allen (1989), which we consider a synonym of P. pleurotaenia following Kuiter (2004). Pseudanthias paralourgus is readily distinguished from P. bimaculatus in having a lunate caudal fin with filamentous extensions and caudal concavity of 21.5–32.4% SL (versus caudal fin emarginate, without filamentous extensions and a caudal concavity of 6–17% SL), and the third dorsal spine obviously elongate (versus second and third dorsal spines slightly elongate).

Remarks. Anthiadines that form mixed-species schools often exhibit similar coloration patterns so they can gain advantages associated with social mimicry ( Randall & McCosker, 1993, Randall, 2005). The small dusky crescent-shaped markings on the dorsal body of the two smallest paratypes of P. paralourgus is remarkably similar to markings found in Tosana species and is possibly associated with social mimicry of the more abundant T. longipinnis n. sp. (described below).

Etymology. The specific epithet means edged with purple ( Brown, 1956) and refers to the distinctive purpletipped caudal fin lobes. It is from the Greek para, beside or near, and halourgos. The latter literally means “from the sea,” and is taken here to refer to the purple dye obtained from certain marine molluscs ( Brøns & Dross-Krüpe, 2018).

Figures

FIGURE 1. Maximum-likelihood phylogeny of selected anthiadine serranids inferred using mitochondrial COI. Plectranthias flammeus was used as the outgroup. Support values at nodes denote likelihood bootstrap percentages. Nodes with bootstrap support values below 50 are not labelled. Coloured branches represent genera nested within Pseudanthias: Tosana (blue-green); Nemanthias (blue); Luzonichthys (purple); Tosanoides (orange); Odontanthias (pink); Serranocirrhitus (red).

FIGURE 2. A) Pseudanthias paralourgus n. sp.: A) QM I.38668, 134.0 mm SL, male holotype, freshly dead, off Cape Moreton, Queensland, Australia (photo by J.W. Johnson); B) QM I.38668, 134.0 mm SL, holotype, radiograph by A. Hay and S.E. Reader; C) QM I.38969, 98.7 mm SL paratype, preserved, east of Coolum, Queensland, Australia, showing grey-brown markings beneath the dorsal-fin base (photo by A.C. Gill).

FIGURE 3. Distribution records for Pseudanthias paralourgus n. sp. Type locality outlined in black.

FIGURE 4. Pseudanthias elongatus, freshly dead males from Japan:A) ZRC 60413, 109 mm SL, Okinawa (photo by S.K. Tea); B) KPM-NI 35704 (image KPM-NR 107565B), 94.6 mm SL and C) KPM-NI 40175 (image KPM-NR 109233B), 90.0 mm SL, both collected off Enoura, west of Sagami Bay, Honshu. (© Kanagawa Prefectural Museum; photos by H. Senou)