Pseudione Kossmann, 1881

Brito, Ayrton, Cardoso, Irene Azevedo & Boyko, Christopher B., 2018, A new species of Pseudione Kossmann, 1881 (Crustacea, Isopoda, Bopyridae) parasitizing the squat lobster Munida microphthalma A. Milne-Edwards, 1880 in the Southwestern Atlantic, Zootaxa 4377 (3), pp. 444-450 : 445

Pseudione Kossmann, 1881

Diagnosis (after An et al. 2015). Female: Body oval or pyriform; all segments distinct. Frontal lamina moderately developed. Coxal plates reduced; first oostegites with rounded posterolateral point. Six pleomeres, first five produced into moderately to greatly developed lateral plates; pleopods biramous, lanceolate; uropods usually uniramous, lanceolate.

Male: Body smoothly tapered anteriorly and posteriorly from midpoint (pleon occasionally abruptly wider or narrower than final pereomere); all body regions distinct. Pereopods subequal, anterior pereopods not markedly larger than others. Pleon 1/5 to 1/3 of total body length, of six pleomeres (specimens of some species with pleomeres variously fused and pleons proportionately shorter); pleopods uniramous, tuberculiform to flaplike; no uropods, posterior border of terminal pleomere slightly to greatly produced into posterolateral points.

Remarks. Species in Pseudione infest a diverse group of decapod hosts, including carideans, nephropids, thalassinoids, galatheoids, pagurids and lithodids ( Williams & Boyko 2012). The genus Pseudione Kossmann, 1881 , including 53 species prior to this study, is the largest genus in the subfamily but female are morphologically heterogeneous and the genus is paraphyletic ( Boyko 2004; Boyko et al. in press.). The above diagnosis reflects the current paraphyletic state of the genus pending a review and an initial effort towards separation of the species into monophyletic groupings (Boyko et al. in press; Williams & Boyko, in prep.).