Euclosiana exquisita (Galil, 2003)

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 : 27

Euclosiana exquisita (Galil, 2003)

( Figure 8G )

Material examined. M08, Stn. 18, 217m, ♀ 26.9× 28.4mm (IEO-CD-MZ08/1757), 16S ( MZ 424941 ), COI ( MZ 434787 ) .

Habitat and distribution. According to Galil (2003b), Euclosiana exquisita is known only from the typelocation, Madagascar, at 185–314m depth.

Results and remarks. Only one female was collected in M08 at 217m depth. This specimen agrees well with the descriptions and figures by Galil (2003b). E. exquisita has not been reported in the area before and therefore our specimen is the first record of the species in Mozambican waters. After the MOZAMBIQUE surveys, some specimens were collected in the MB-exp in 2009 ( MNHN Collection).

Colouration observed. Carapace and chelipeds were reddish brown, with three bright orange circles on each gastric region, being the median circle the largest. The anterior third of carapace is coarsely pitted. There were two very pale and poorly marked circles on the cardiac region, and a couple of faint lines on the middle of the intestinal region that remain after preservation, none of them described by Galil (2003b). The granules of the chelipeds were white, and the legs with orange and white bands. The ventral side was white. After preservation in ethanol, the carapace and chelipeds turned to brown, and the circles and legs to bone colour.

DNA barcodes. There are not 16S sequences available for this species in Genbank, being this the first one. There is only one COI sequence deposited in BOLD ( MDECA 222-10), corresponding to one specimen identified as Leucosia sp. by Chan, that was collected in Mozambique by the MB-exp in 2009 (date collection: 2009-04-09), and deposited at the MNHN ( MNHN-IU 200812661). The COI sequence of the female IEO-CD-MZ08/1757 fits 99.68% with the BOLD sequence (differing in two mutations). Therefore, the specimen MNHN-IU200812661 identified as Leucosia sp. must be considered to be Euclosiana exquisita .

In Genbank there are sequences of 16S and COI for Euclosiana crosnieri , E. scitula , and E. unidentata , deposited by Shi et al. (2020). The distances with Euclosiana exquisita are the expected for congeneric species: 16S (98%, five mutations) and COI (94%, 35 mutations). However, the high divergence of E. crosnieri and E. scitula respect to E. unidentata (16S, 96.8%, 12 mutations - including three gaps - and COI, 87%, 86 mutations) suggests an intergeneric distance. It must be pointed out that E. crosnieri and E. scitula could be synonyms, as they present exactly the same 16S and COI sequences.

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.