Plectranthias takasei

materials_examined

Holotype: KPM – NI 21068, 40 mm SL. Type locality: Japan, Honshu, Sagami Bay, east of Izu Peninsula, Izu Oceanic Park, depth 52 meters. Illustrations: Gill et al., 2016, figs. 1 – 5. D: X, 15. A: III, 7. P: 13. C: 17 (9 + 8). V: 26 (10 + 16). S: 3. GR: 15 or 16 (4 + 11 or 12). LL: 26 to 28. CP: 12.

Annotated checklist of anthiadine fishes (Percoidei: Serranidae)

description

Description. (Data given first for holotype, followed where different by data for paratype in parentheses.) Dorsal rays X, 15, all segmented rays branched; anal rays III, 7, all segmented rays branched; pectoral rays 13 / 13, all rays unbranched; pelvic fin I, 5, all segmented rays branched; upper procurrent caudal-fin rays 4; lower procurrent caudal-fin rays 4; principal caudal-fin rays 9 + 8; branched caudal fin rays? + 7 (8 + 7); total caudal-fin rays 25; lateral line complete with 28 tubed scales on the left side, and 20 tubed scales followed by a pitted scale and 7 tubed scales on the right side (23 tubed scales followed by a pitted scale, 3 tubed scales then a pitted scale on the left side; scales damaged on right side); scales above lateral line to origin of dorsal fin 2 / 2; scales above lateral line to base of middle dorsal spine 3 / 2 (2 /?); scales below lateral line to origin of anal fin 9 / 9 (9 /?); diagonal rows of scales on cheek 5; predorsal scales 18 (17), extending to just short of posterior nostrils; circumpeduncular scales 12; gill rakers 4 + 12, the upper 3 and lower 5 rudiments (4 + 11, the upper 3 and lower 5 rudiments); pseudobranchial filaments 11 (10); br

Plectranthias takasei, new species of anthiadine fish from southern Japan (Teleostei: Serranidae)

diagnosis

Diagnosis. The following combination of characters distinguishes P. hinomaru from congeners: dorsal rays X, 15; no fleshy flaps on dorsal-fin spines; pectoral rays 13, all unbranched; branched caudal-fin rays 8 + 7; lateral line scales 28 (including intermittent and terminal pitted scales); circumpeduncular scales 12; fourth dorsal-fin spine longest; and preopercle without antrorse spines or serrations ventrally, with 2 – 3 weak serrations or crenulations posteriorly.

Plectranthias takasei, new species of anthiadine fish from southern Japan (Teleostei: Serranidae)

discussion

Remarks. Placement of the new species in Plectranthias should be regarded as provisional. The generic classification of the Anthiadinae is unsatisfactory, with few genera cladistically diagnosed by synapomorphies. The two largest genera, Plectranthias and the Indo-Pacific genus Pseudanthias Bleeker (1871) are particularly problematic. Not only is neither genus defined on the basis of synapomorphies, but both show considerable variation in characters that have been used to diagnose other anthiadine genera. For example, Plectranthias varies in the number of supraneural bones, degree of squamation on the head, presence or absence of antrorse spines on the ventral edge of the preopercle, number of lateral-line scales, and number of branched caudal-fin rays. It is likely that further studies will result in the reassignment of some species to new genera or to nominal genera placed in the synonymy of Plectranthias by Randall (1980).

Plectranthias takasei, new species of anthiadine fish from southern Japan (Teleostei: Serranidae)