Paramaja gibba (Alcock, 1895)

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 : 36-38

Paramaja gibba (Alcock, 1895)

( Figure 13B )

Material examined. M07, Stn. 37, 243m, ♀ ov. 50.2× 58.4mm (IEO-CD-MZ07/1916); M07, Stn. 78, 300m, ♂ 50.2× 59.6mm (IEO-CD-MZ07/1912); M08, Stn. 25, 265m, ♂ 46.8× 53.4mm (IEO-CD-MZ08/1781), 16S ( MZ 424956 ) , COI ( MZ 434802 ) ; M08, Stn. 67, 378m, ♀ 49.1× 52mm (IEO-CD-MZ08/1820), 16S ( MZ 424957 ) , COI ( MZ 434803 ) ; M09, Stn. 60, 304m, ♂ 61.4× 69mm (IEO-CD-MZ09/1800), 16S ( MZ 424958 ) , COI ( MZ 434804 ) .

Habitat and distribution. Majidae is constantly under review. In 2015, Ng and Richer de Forges described seven new genera to separate the species that were included within Maja Lamarck, 1801 until that moment. In this study Maja gibba was replaced in Paramaja , a genus described by Kubo in 1936. Paramaja gibba is close to Paramaja kominatoensis Kubo , a commonly mistaken and misidentified species. Paramaja gibba is distributed from the IWP, Madagascar ( Mozambique Channel), India, Thailand to Western Australia ( Ng & Richer de Forges 2015), and Japan ( Sakai 1976), at 230–600m depth.

Results and remarks. These specimens agree well with the descriptions and figures of Ng & Richer de Forges (2015): “ in adults, pseudorostral horns dorso-ventrally flattened; carapace dorsal surface relatively less swollen, with numerous small and large distinct tubercles and granules which are never swollen”. The five studied specimens were collected during the M07, M08 and M09 surveys, at depths from 243 to 378m. These are the first record of P. gibba off Mozambique. Subsequently, in April 2009, two specimens were collected during the MB-exp ( GBIF.org 2021, unpublished record).

Colouration observed. The specimens were bright orange with darker sunken areas and clearest lateral areas; legs were bone-colour although they seem to be brown due to fouling attached to them, as they were very hairy. Chelipeds were pale orange, with white finger tips. After preservation, both in ethanol and formalin, carapace and chelipeds turned to pale bone colour, while legs keep the brown-like colour due to the fouling.

DNA barcodes. There are not 16S and COI sequences available for this species on any public database. The three sequences obtained for 16S represent three different haplotypes, differing in one and two mutations, and they are the first 16S sequences for this species. One of these haplotypes belonging to the female IEO-CD-MZ09/1820 matches 100% with a 16S sequence ( GQ 153568 ) of P. kominatoensis (as Maja kominatoensis ), obtained by Sotelo et al. (2009) from one specimen from Philippines. Similarly, in the case of COI, the three specimens present three different haplotypes, two of them differ only in one position, and another one that vary in three and four mutations.The COI sequence of the male IEO-CD-MZ09/1800 also matches 100% with two sequences ( MG 029415 , KX757758 ) of two specimens of P. kominatoensis (as Maja kominatoensis ) from India uploaded to Genbank by Deepak et al. (unpublished), and 99% with the COI sequence ( GQ 153558 ) of P. kominatoensis (as Maja kominatoensis ) from Philippines ( Sotelo et al. 2009). These data from 16S and COI barcodes put into question the validity of both species as separate taxa and support the suggestion by Griffin & Tranter (1986) that they may be synonymous. Therefore, a review of these two species ( P. gibba and P. kominatoensis ), including more specimens and more molecular data (also nuclear genes), is needed to clarify their taxonomic relationships and distributions.

Figures

FIGURE 13. A, Platymaia turbynei, ♂ IEO-CD-MZ07/1924; B, Paramaja gibba, ♀ IEO-CD-MZ08/1820; C, Sakaija africana ♀ IEO-CD-MZ08/1784; D, Pleistacantha ori, ♀ IEO-CD-MZ08/12545; E, Parathranites ori, ♀ IEO-CD-MZ08/1767; F, Paratranites granosus, ♀ IEO-CD-Mz08/1785; G, Parathranites orientalis, ♀ IEO-CD-MZ07/1909 (preserved). Scale bars: 1cm.