Ceratothoa usacarangis (Avdeev, 1979)

Martin, Melissa B., Bruce, Niel L. & Nowak, Barbara F., 2015, Review of the fish-parasitic genus Ceratothoa Dana, 1852 (Crustacea: Isopoda: Cymothoidae) from Australia, with description of two new species, Zootaxa 3963 (3), pp. 251-294 : 283

Ceratothoa usacarangis (Avdeev, 1979)

Meinertia usacarangis Avdeev, 1979a: 51 , pl. 3–4.

Ceratothoa usacarangis .—Beumer, Ashburn, Burbury, Jetté & Latham, 1983: 31.— Trilles, 1994: 129.— Hine, Jones & Diggles, 2000: 79.— Bruce, Lew Ton & Poore, 2002: 173.

Type and type locality. The holotype (AGK 75042) and paratypes (AIC 75043-047, AIC 75048-050) are held at the Russian Pacific Federal Fisheries Research Institute, Vladivostok ( Avdeev 1979a). Collected from the Australia-New Zealand region, from different host (see host remarks).

Remarks. Ceratothoa usacarangis has an ovoid body, widest at pereonite 5; cephalon slightly immersed in pereonite 1, anterior margin subtriangular; pereonite 1 with small antero-lateral projections; pleonites 2–5 are slightly longer than pereonite 7; pereopod 7 basis with large carinae and an expanded ischium; uropods the same length as the pleotelson; and a wider than long pleotelson.

Ceratothoa usacarangis is similar to C. banksii in the ovoid body shape, subtriangular cephalon anterior margin, stout and short antennula and antenna, pleonites 2–5 slightly longer than pereonite 7, and pleotelson wider than long. Ceratothoa usacarangis is identified by the concave posterior margin of the pleotelson, expanded ischium and basis of pereopod 7 and distal margin of exopod 1 convex. The species has been reported on three host fish from the family Carangidae .

Avdeev (1979a) described Ceratothoa usacarangis as having the anterolateral margins of pereonite 1 similar to that of C. collaris , the difference being the anterolateral margins of pereonite 1 are smaller than those of C. collaris , reaching one-third the length of the cephalon. The posterolateral margin of pereonite 7 is deeply arched, and the uropods protrude from the rear edge of the pleotelson ( Avdeev 1979a).

The holotype and paratypes were not found in the TINRO collection, and we were unable therefore to borrow them. Avdeev (1979a) gave a detailed description with figures of both the male and female in Russian. To date, this species has only been recorded from the Australia – New Zealand region.

Distribution. Australia (Great Australian Bight; Gulf of Carpentaria and north-west coast of Australia) ( Avdeev 1979a).

Hosts. Reported from Pseudocaranx dentex (Bloch & Schneider, 1801) (previously Usacaranx georgianus ) (see Avdeev 1979a; Hine et al. 2000), Selaroides leptolepis (Cuvier, 1833) or Atule mate (Cuvier, 1833) (previously Alepes mate ) (see Avdeev 1979a).