Ceratothoa arimae ( Nunomura, 2001 ) Nunomura, 2001

Martin, Melissa B., Bruce, Niel L. & Nowak, Barbara F., 2015, Review of the buccal-attaching fish parasite genus Glossobius Schioedte & Meinert, 1883 (Crustacea: Isopoda: Cymothoidae), Zootaxa 3973 (2), pp. 337-350 : 346-347

Ceratothoa arimae ( Nunomura, 2001) comb. nov.

Glossobius arimae Nunomura, 2001: 29 , figs. 1, 2.

Type and locality. The holotype ( TOYA Cr-12844), allotype ( TOYA Cr-12845) and paratypes ( TOYA Cr-12846– 12854) are held at the Toyama Science Museum, Japan. Type locality is Ohshima Bay, Tokyo Prefecture, from Labracoglossa argentiventris Peters, 1866 ( Nunomura 2001) .

Remarks. Examination of photographs kindly provided by Dr Yamauchi of G. arimae show that the species unambiguously belongs to, and is here transferred to the genus Ceratothoa . The species shows the following generic characters: pereonite 1 anterolateral margins broad and slightly produced; pleotelson narrower than pereonite 7, posterior margin rounded; and large carinae on basis of pereopods 4–7.

Ceratothoa arimae has only been reported from Labracoglossa argenteiventris Peters, 1866 of the family Kyphosidae , which occurs from central Honshu to Kyushu, Japan in the northwestern Pacific ( Froese & Pauly 2015). The only other reported Ceratothoa species using hosts from the family Kyphosidae is Ceratothoa banksii ( Leach, 1818) attaching to Girella tricuspidata (Quoy & Gaimard, 1824) in Australian waters ( Martin et al. 2015). Ceratothoa banksii differs from C. arimae in having a subparallel or subquadrate body shape; pereonites lightly coloured; the cuticle posterior margin of each pereonite is thickened and noticeably darker anteriorly; pereonites 1– 4 laterally straight; pleotelson posterior margin subtruncate, and anterior margin similar in width or wider than pereonite 7.

Ceratothoa arimae is most similar to Ceratothoa imbricata ( Fabricius, 1775) in the rhomboid-like body shape (pereonites 1–4 increasing in width and lateral margins straight; pereonites 5–7 decreasing in width, lateral margins convex) narrow or slightly broad anterolateral margins of pereonite 1, and pleotelson less narrow than pereonite 7. However, C. imbricata has the posterior part of the pereonites darker than anterior part, and has only been reported from host Trachurus sp. ( Carangidae ) ( Martin et al. 2015); whereas C. arimae has the posterior part of the pereonites lighter than the anterior region, and is reported from demersal host Labracoglossa argenteiventris (Kyphosidae) .