Naxioides robillardi ( Miers, 1882 )

Muñoz, Isabel, García-Isarch, Eva & Cuesta, Jose A., 2021, Annotated and updated checklist of marine crabs (Decapoda: Brachyura) of Mozambique supported by morphological and molecular data from shelf and slope species of the “ MOZAMBIQUE ” surveys, Zootaxa 5056 (1), pp. 1-67 : 29

Naxioides robillardi ( Miers, 1882)

( Figure 9B )

Material examined. M07, Stn. 13, 620 m, ♀ 41.6× 51.8mm ( CW × PRL) (IEO-CD-MZ07/1892) , 16S ( MZ 424946 ) .

Habitat and distribution. Naxioides robillardi is distributed throughout the IWP: Gulf of Oman, East Africa ( Kenya, Somalia), Madagascar, Reunion Island, Mauritius, Solomon, Indonesia, Hong Kong, Philippines, Australia, Japan ( Poupin, 1995) and recently reported from Korea ( Lee et al. 2020). It inhabits hard bottoms between 30 and 260m ( Poupin 1995). Naxioides hirtus A. Milne-Edwards was the only species of Naxioides previously reported in Mozambican waters ( Barnard 1950; Kensley 1981).

Remarks. The keys and descriptions used for the identification of this specimen were Griffin & Tranter (1986a), Miers (1886) and Poupin (1995). Poupin (1995) distinguished two forms of this species: N. robillardi forma t ypica, and N. robillardi forma mammillata, our specimen being coincident with the first. It should be noted that we collected one single female specimen in M07, at 620m depth. The absence of other specimens and the fact that the only one was lacking the chelipeds, made not possible to confirm all the characteristics used for distinguishing both forms. The present specimen is the first record of N. robillardi in Mozambican waters, extending the maximum depth reported for this species up to 620m.

Colouration observed. The carapace was beige and it is covered in short dense yellowish-brown pubescence, with purplish-red spines, similar to that described by Miers (1882). Ambulatory legs were purplish-red, with subtle light and dark bands, almost imperceptible. After preservation in formalin the specimen acquired a homogeneous bone colour, without traces of the purplish-red colour, contrary to the permanence of violet areas in merus and carpus of the ambulatory legs described by Poupin (1995) after preservation in ethanol.

DNA barcodes. There are not 16S sequences available for this species in Genbank, this being the first one. There are three equal COI sequences in Genbank ( MT469872 , MT469873 , MT469874 ) obtained by Lee et al. (2020) from one specimen of N. robillardi from Korea. However , no COI sequence could be reared from the specimen IEO-CD-MZ07/1892 from MZ07 and therefore, comparison is not possible.

Figures

FIGURE 9. A, Oxypleurodon difficilis, ♂ IEO-CD-MZ08/1774; B, Naxioides robillardi, ♀ IEO-CD-MZ07/1892; C, Samadinia galathea, ♂ IEO-CD-MZ09/1802-1; D, Samadinia pulchra, ♂ IEO-CD-MZ07/1893; E,F, Cyrtomaia gaillardi, ♂ IEO-CD- MZ08/1788; G, Platymaia alcocki, ♂ IEO-CD-MZ08/1789. Scale bars: 1cm.