Nesotanais rugula Bamber, Bird & Angsupanich, 2003

Kakui, Keiichi, Kajihara, Hiroshi & Mawatari, Shunsuke, 2010, A new species of Nesotanais (Crustacea, Tanaidacea) from Japan, with a key to species and a note on male chelipeds, ZooKeys 33 (33), pp. 1-17 : 11-13

Nesotanais rugula Bamber, Bird & Angsupanich, 2003

Fig. 9 A–D

Suplemented description of male chelipeds (allotype, NHM 2001.6687). Basis with broad articulation with cephalothorax via sclerite, as long as wide, with one outer simple seta. Merus subtriangular, with one ventral simple seta and one ventrodistal small process. Carpus hexagonal, 1.16 times as long as wide, with one short dorsodistal and two ventral simple setae, one ventroinner and one ventral processes, and longitudinal

parallel series of cuticular ridges in outer region ( Fig. 9A ). Chela longer than carpus, twisted about 90-degrees with dactylus situated inwards. Propodal palm with nine short and one long inner simple setae at dactylus insertion, and longitudinal parallel series of cuticular ridges in inner region ( Fig. 9B ). Fixed finger with one dorsoproximal, three dorsosubdistal, and two ventrosubdistal simple setae, and one inner subdistal process ( Fig. 9C ) curving ventrally at a position just proximal to the ventrosubdistal setae; tip rounded, not bifid (right cheliped was broken, lacking its tip distal to the three dorsosubdistal setae). Flange long, 1.09 times as long as wide, with rectangular end, bearing inner crenulations. Dactylus slightly longer than fixed finger, gradually curving ventrally, with one ventromedial simple seta; three spiniform setae, and one small proximal triangular, one medial toothed, and one small subdistal rounded processes on cutting surface ( Fig. 9D ), and longitudinal parallel series of cuticular ridges in inner region (left cheliped was broken, lacking its tip distal to the toothed process).

Remarks. The original description of the male cheliped of Nesotanais rugula was based on the right cheliped. However, our observation revealed that both chelipeds of this species were apparently broken at different places, i.e., the left one lacks the tip of the dactylus, and the other lacks the tip of the fixed finger. Therefore, the original description is supplemented with respect to the following characters. The distal shape of the fixed finger being rounded (bifid according to Bamber et al. 2003), the number and shape of the processes on the dactylus being one small proximal triangular, one medial toothed, and one small subdistal rounded processes (one rounded op. cit.). Although the serial ridges on the inner surface of the propodal palm were illustrated by Bamber et al. (2003: fig. 20C), no statement on this structure was given in the original description.

Figures

Figure 9. Nesotanais rugula Bamber, Bird & Angsupanich, 2003. Allotype, male (NHM 2001.6687). A right cheliped, outer view B same, inner view C left cheliped, anterodorsal view of chela D right cheliped, anterodorsal view (slightly different angle from C). Scale bars equal 0.1 mm.