Nipponbathynella Schminke, 1973

Park, Jong-Geun & Cho, Joo-Lae, 2015, Redefinition of Nipponbathynella based on the four new species from East Asia (Crustacea: Bathynellacea: Parabathynellidae), Journal of Natural History 49 (37), pp. 2275-2307 : 2276-2277

Genus Nipponbathynella Schminke, 1973

Type species

Nipponbathynella miurai Ueno, 1952

Other species

Nipponbathynella uozumii Morimoto, 2002 , Nipponbathynella pectina Cho et al. 2008 , Nipponbathynella leesookyungae sp. nov., Nipponbathynella donggangensis sp. nov., Nipponbathynella wanjuensis sp. nov. and Nipponbathynella shigaensis sp. nov.

Amended generic diagnosis after Schminke (1973), Cho et al. (2008) and Schminke (2011)

Body elongated and cylindrical. Antennule six-segmented. Fifth antennular segment long with a medial group of setae on inner margin. Antenna two-segmented with three setae on distal segment. Labrum with dentate-free margin. Mandible with incisor process of three teeth, triangular proximal tooth, molar process of four stout spines and one-segmented palp. Maxilla four-segmented with setal formula of 2-4(5)-n-7. Thoracopods I–VII with one-segmented exopod of thoracopod I and two-segmented exopod of thoracopods II–VII. Female thoracopod VIII one-segmented, radicle-like process directing backwards. Male thoracopod VIII with massive protopod consisting of three lobes: frontal lobe, inner lobe bur-like or absent, dentate lobe being sometimes smooth; epipod present in form of either conical, elongated process or triangular tooth; basis approximately one-third size of protopod, with or without basal seta; endopod with two apical setae. Pleopod absent. Uropod with rod- or comb-shaped sympod carrying spines; most distal spine usually thicker and larger than others decreasing slightly in size distally; endopod drawn out as a spine, with two distal setae; exopod with one strong seta on inner margin, without basi-ventral seta. Pleotelson without seta. Anal operculum protruded. Furcal rami with numerous spines.

Remarks

We supplement the generic diagnosis proposed by Cho et al. (2008) based on the morphology of four new species: N. leesookyungae sp. nov., N. donggangensis sp. nov., N. wanjuensis sp. nov. and N. shigaensis sp. nov. The added novelties are the setal formula of the maxillule (2-4(5)-n-7 meaning variation in the number of setae occurring on third endite), the segmental feature of the exopod in thoracopods I–VII, details of the protopod and epipod on the male thoracopod VIII, features of spines on the uropodal sympod and the inner seta on the uropodal exopod. Such a seta is apparently absent in N. uozumii (see Morimoto 2002) and misinterpreted in the case of N. pectina (see Cho et al. 2008). Its position at two thirds height of the inner margin in N. leesookyungae and N. donggangensis evidently indicates that the uropodal exopod of N. pectina also carries a seta on the inner margin.