Ceratothoa Dana, 1852

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 : 253-254

Genus Ceratothoa Dana, 1852

Ceratothoa Dana, 1852: 203 ; 1853: 747.— Miers, 1876b: 104 –105.—Schioedte & Meinert, 1883: 322.— Richardson, 1905: 233.— Bowman, 1978: 217 –218.— Brusca, 1981: 177.— Bruce & Bowman, 1989: 1.— Horton, 2000: 1041.— Martin, Bruce & Nowak, 2013: 396 .— Hadfield, Bruce & Smit, 2014a: 3 .

Codonophilus Haswell, 1881: 471 ; 1882: 283.— Hale, 1926: 201, 223.

Rhexana Schioedte & Meinert, 1883: 289 .

Cteatessa Schioedte & Meinert, 1883: 296 .

Meinertia Stebbing, 1893: 354 ; 1900: 642; 1910: 103.— Richardson, 1905: 236.— Menzies, 1962: 116.— Schultz, 1969: 156.

Rhexanella Stebbing, 1911: 179 .

Not Ceratothoa: Dana, 1853: 747 .— Richardson, 1905: 236.— Schultz, 1969: 155.— Kussakin, 1979: 287 [= Glossobius Schioedte & Meinert, 1883 ].

Diagnosis. Bruce & Bowman (1989) provided a provisional diagnosis; a detailed diagnosis was provided by Hadfield et al. (2014a).

Type species. Dana (1852) included Cymothoa gaudichaudii Milne Edwards, 1840 (type locality Coquimbo, Chile) and Cymothoa parallela Otto, 1828 (type locality “ Oran ” [ Algeria] see Horton (2000; neotype designation) as the only two species for genus Ceratothoa . The ICZN Code (Art 68.2) recognizes a “ type species by original designation” if the nominal species is explicitly designated by the author. Dana (1852) under the Act (69.1.1) did not state or indicate the type species or equivalent and therefore the type species can only be designated by a later author as a subsequent designation.

The female syntype for Ceratothoa gaudichaudii is very damaged and incomplete while the male syntype (MNHN-Is315) remains intact ( Trilles 1973b; Hadfield et al. 2014a). Within the Cymothoidae , both generic and species diagnoses are dependent on adult female characters, therefore designating C. gaudichaudii (based on the male syntype) as the type species is not the best action. Additionally the validity of this species is questionable and we briefly discuss its current status under the section species inquirenda (p. 39).

The type specimen of Ceratothoa parallela is no longer extant ( Bruce & Bowman 1989; Horton 2000) and a neotype (MNHN-Is415) was designated by Horton (2000) with brief description, distribution and host preference for the species. Bruce & Bowman (1989) and Hadfield et al. (2014a) provided a detailed genus diagnosis and the defining characters of the genus are now well understood.

Here we designate Cymothoa parallela Otto, 1828 as type species for the genus to ensure the long-term stability of the genus.

Remarks. Ceratothoa can be identified by the contiguous antennal bases, antennula more stout than antenna; pereonite 1 longest, body widest at pereonite 4 or 5; and the pereopods have a large carinae on basis (Martin et al. 2013; Hadfield et al. 2014a).

Other related buccal-attaching genera can be distinguished from Ceratothoa by the following characteristics: Cinusa Schioedte & Meinert, 1884 : anteriorly widest at pereonite 3–4; slender antennae with close-set and almost contiguous bases ( Hadfield et al. 2010); Glossobius Schioedte & Meinert, 1883 : pereopod 3 dactylus twice as long as pereopod 2 dactylus, pereonite 1 anterolateral margins minute or projecting forward ( Bruce & Bowman 1989); Lobothorax Bleeker, 1857 : strongly developed lobes on pereonite 1 anterolateral margins, which extend past the cephalon ( Yu & Bruce 2006); Cymothoa Fabricius, 1793 : widely separated and not expanded basal articles of the antennula (Martin et al. 2013); and Smenispa Özdikem, 2009 : co-linear pereon and pleon, and pleopods 3–5 with large folds ( Martin et al. 2014a).