Carcinoplax ischurodous ( Stebbing, 1923 )

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 : 25

Carcinoplax ischurodous ( Stebbing, 1923)

( Figure 8C )

Material examined. M07, Stn. 13, 620m, ♂ 36.5× 25mm (IEO-CD-MZ07/1918); M08, Stn. 39, 631m, ♂ 51.6× 33mm, ♂ 54.4× 33.7mm (IEO-CD-MZ08/1824), 16S ( MZ 424933 ) , COI ( MZ 434779 ) ; M09, Stn. 14, 608m, ♂ 39.5× 25.9mm (IEO-CD-MZ09/1768), 16S ( MZ 424934 ) , COI ( MZ 434780 ) .

Habitat and distribution. IWP, from South Africa ( Barnard 1950) to the southwestern Pacific Ocean ( Guinot & Richer de Forges 1980) at depths of 464–800m, being one of the few Carcinoplax species mainly distributed on the slope and not on the continental shelf ( Castro 2007). The morphology of C. ischurodous differs considerably from the rest of its congeneric species, this suggesting the possibility of belonging to a different genus ( Guinot 1989; Manning & Holthuis 1988).

Results and remarks. The three specimens, each one collected in one of the three surveys at depths between 608 and 631m, perfectly fit the descriptions and figures of Castro (2007). The species was reported in the latest checklist for the area ( Emmerson 2016c), but only from records off South Africa. Thus, this is the first record of C. ischurodous in Mozambican waters.Anyway, we are aware from GBIF.org (2021, unpublished record) of the existence of conserved specimens of C. ischurodous housed on the MNHN from the MB-exp (2009) (unpublished).

Colouration observed. Fresh specimens looked polished, with the carapace orange-brown with some white small spots, and the posterolateral margin lighter; the chelipeds were bright orange with some deep-orange patches on the merus; the fingers and the knob at the beginning of the fingers were bright white. The pereiopods were pale orange with unarmed and pinkish dactyls.

DNA barcodes. There are not sequences of this species on any public database. The two equal 16S sequences and the two COI sequences (two haplotypes) are the first ones for this species. The BLAST search results for 16S show a 94.01% similarity with Goneplax rhomboides ( JN591655 ) (27 mutations, including two gaps), and 93.79% with Carcinoplax surungensis ( FJ 943433 ) (36 mutations, including five gaps), and a longer distance respect to Carcinoplax longimanus (this study), 45 mutations, including four gaps. All these evidences support the possibility that C. ischurodous could belong to a different genus closer to Goneplax than to Carcinoplax .

Figures

FIGURE 8. A, Platepistoma guezei, ♀ IEO-CD-MOZ07/279; B, Dairoides margaritatus, ♀ IEO-CD-MZ07/1911 (preserved); C, Carcinoplax ischurodous, ♂ IEO-CD-MZ08/1824; D, Carcinoplax longimanus, ♂ IEO-CD-MZ08/1787; E, Carcinoplax longimanus, ♀ IEO-CD-MZ08/1851; F, Tanaoa pustulosus, ♀ IEO-CD-MZ08/1776; G, Euclosiana exquisita, ♀ IEO-CD- MZ08/1757. Scale bars: 1cm.