Anuretes plectorhynchi Yamaguti, 1936

Boxshall, Geoff, 2018, The sea lice (Copepoda: Caligidae) of Moreton Bay (Queensland, Australia), with descriptions of thirteen new species, Zootaxa 4398 (1), pp. 1-172 : 26

Anuretes plectorhynchi Yamaguti, 1936

( Fig. 9 )

Material examined. 1♀, 3♂♂ from Diagramma labiosum MacLeay, 1883 (TC16955), 10 January 2016; 1♀, 1♂ QM Reg. No. W53047; 2♂♂ NHMUK Reg. Nos 2017.190–191.

Site on host. Unknown (in body wash).

Differential diagnosis. Cephalothorax dorsoventrally flattened with well-developed marginal membranes; about 1.17 times longer than wide; thoracic zone extending posteriorly to completely conceal short fourth pedigerous somite in dorsal view ( Fig. 9A ). Frontal plates lacking lunules. Genital complex broadest anteriorly, with convex lateral and posterior margins resulting in a semicircular outline in dorsal view; about 1.8 times wider than long; genital complex and abdomen less than 20% of length of cephalothorax; abdomen reduced, largely incorporated into genital complex; bearing paired caudal rami posteroventrally ( Fig. 9B ). Antenna ( Fig. 9C ) with acute posteriorly-directed process on proximal segment. Post-antennal process curved; associated papillae unisensillate. Tine of maxillule long and straight; post-oral process short, hook-like ( Fig. 9C ). Maxillary whip simple (not bifid). Sternal furca ( Fig. 9D ) with slightly-divergent tines. Pair of well-developed, hook-like processes present on ventral cephalothoracic surface posterior to intercoxal sclerite of leg 1 ( Fig. 9D ). Distal exopodal segment of leg 1 with 3 plumose setae on posterior margin; distal spines 2 and 3 each with accessory process; seta 4 offset, originating on ventral surface of segment, just longer than spine 1. Leg 2 with outer spine on first exopodal segment straight and elongate, lying obliquely across surface of ramus and extending almost to distal tip of ramus ( Fig. 9E ); outer spine on segment 2 similar in shape but smaller; proximal outer spine of segment 3 smaller than distal; distal outer spine with lateral membrane around tip. Leg 3 ( Fig. 9F ) with 2-segmented exopod; bearing large straight spine on proximal segment and 8 setal elements on compound distal segment: endopod 2-segmented; first segment unarmed, compound distal segment with 6 setae. Leg 4 uniramous, 3-segmented; exopodal segments with I; III spines. Leg 5 comprising outer protopodal seta isolated on surface of genital complex and well-defined exopodal lobe bearing 3 plumose setae and rudimentary spine ( Fig. 9B ). Body length of adult female 1.28 mm. Mean body length of adult male 0.82 mm, range 0.78 to 0.86 mm (based on 3 specimens).

Remarks. Yamaguti (1936) described A. plectorhynchi based on three females collected from Diagramma pictum (as Plectorhynchus pictus ) caught in the “Pacific”, presumably close to Japan (from the title of the paper). The species recorded as A. plectorhynchi by Prabha & Pillai (1986) from Indian waters was clearly not conspecific with Yamaguti’s type material, and was recognized as a distinct species by Ho & Lin (2000) and renamed A. similis Ho & Lin, 2000 . Anuretes plectorhynchi was recently reported from the Philippines on Platax orbicularis (Forsskål, 1775) ( Venmathi Maran et al., 2016). This is the first record from Australian waters.

Figures

FIGURE 9. Anuretes plectorhynchi Yamaguti, 1936, female. A, habitus, dorsal; B, genital complex and abdomen, ventral; C, antenna, post-antennal process, maxillule and post-oral process, drawn in situ; D, sternal furca, interpodal bar of leg 1 and ventral processes; E,exopod of leg 2;F,exopod and endopod of leg 3, ventral view drawn in situ. Scalebars:0.5 mm on A, 200 µm on B, 100 µm on C–E, 50 µm on F.