Samadinia, Ng & Richer de Forges, 2013

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 : 29-33

Samadinia g alathea (Griffin & Tranter, 1986)

( Figures 9C , 11 )

Material examined. M09, Stn. 8, 648m, ♂ 15.5× 16.7mm (IEO-CD-MZ09/1802-1), 16S ( MZ 424947 ) , COI ( MZ 434792 ) ; ♀ ov. 9.5× 11.5mm (IEO-CD-MZ09/1802-2), 16S ( MZ 424948 ) , COI ( MZ 434792 ) .

Habitat and distribution. Samadinia galathea was described by Griffin & Tranter (1986) as Rochinia galathea , from a male collected off Natal ( South Africa) in 1951. This was the only existing record and thus, its distribution was limited to the topotypical locality, off Natal between 535 and 610m depth (Griffin & Tranter 1986).

Results and remarks. Our specimens agree well with the descriptions and figures of Griffin & Tranter (1986) and Richer de Forges & Ng (2013). Two individuals, one male and one ovigerous female were collected at the same station at 648m, in March 2009 ( MZ09 ). This is the first record of S. galathea in waters of Mozambique, the second record worldwide and it extends the maximum depth reported for this species up to the 648m. In addition, it is the first time that a female of this species is recorded, allowing the description of the female morphology, that differs somewhat to the described morphology of males. In the female, the mesogastric region is very inflated, “hump”- type, and the hepatic lobes are flattened and directed upwards (see Figure 11 ) while they curve backwards in the case of the male. The female was ovigerous, indicating that March was within the spawning season of this species in the area.

Colouration observed. The carapace was white, with some pinkish areas. The hepatic lobes and intestinal area were dark orange, the chelipeds orange and the ambulatory legs white with pinkish merus.

DNA barcodes. There are not 16S sequences available for this species or close relatives in Genbank. These equal 16S sequences of the male and female specimens are the first ones and confirm that the two specimens, despite their clear morphological differences, belong to the same species. There is one COI sequence deposited in BOLD ( MDECA 051-10), corresponding to one specimen identified by Chan as Rochinia sp. , collected in Mozambique by the MB-exp in 2009 (date collection: 2009-04-09) and deposited at the MNHN ( MNHN _IU200810334), that fits 100% with the two equal COI sequences of the male and female of S. galathea . There is also a second COI sequence deposited in BOLD ( MDECA 724-10) corresponding to one specimen identified by Chan as Epialtidae sp. and collected in Madagascar, that fits 99.39% (four mutations) with S. galathea , this being the distance expected at intraspecific level in a COI sequence. Therefore, both specimens, Rochinia sp. and Epialtidae sp., would correspond to S. galathea .

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.

FIGURE 11. Samadinia galathea, A, B, ♂ IEO-CD-MZ09/1802-1; C, D, ♀ IEO-CD-MZ09/1802-2 (Scale bars: 1cm); E; Samadinia galathea, female, IEO-CD-MZ09/1902-2, ventral view of orbits; F, carapace, lateral view; G, right cheliped, merus and carpus; H, right chela; I, pleon; J, carapace, dorsal view (Scale bars: 0.5cm).