Calappa africana J.C.Y. Lai & P.K.L. Ng, 2006

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 : 19

Calappa africana J.C.Y. Lai & P.K.L. Ng, 2006

( Figure 4C, D )

Material examined. M07, Stn. 37, 243m, ♂ 88.8× 65.1mm (IEO-CD-MZ07/1923); M08, Stn. 15, 283m, ♀ 88.8× 64.4mm (IEO-CD-MZ08/1815), 16S ( MZ 424923 ) , COI ( MZ 434769 ) ; M09, Stn. 4, 258m, ♀ 121.1× 82.6mm (IEO-CD-MZ09/1791), 16S ( MZ 424924 ) , COI ( MZ 434770 ) .

Habitat and distribution. This species was confused for many years with Calappa japonica Ortmann, 1892 , until it was described by Lai & Ng (2006) as a new species. Since then, C. japonica has been confined to the Pacific and Calappa africana to the Southeast African coast, South Africa, and Mozambique (58m) ( Barnard 1950, 1955; Kensley 1981), Kenia and Somalia (type locality, 70–80m) ( Lai & Ng 2006).

Results and remarks. To identify our specimens, we use the original description ( Lai & Ng 2006) and a posterior revision of C. africana together with C. japonica and C. exanthematosa Alcock & Anderson made by Ng et al. (2011). The three studied individuals were collected in the three surveys (M07, M08 and M09) at depths of 243, 283 and 258m, respectively. These specimens were initially identified as C. africana as they had many diagnosis characters similar to those of the original descriptions by Lay & Ng (2006), although other characters did not totally agree with them. It is the case for the second male pleopods (G2) (see Figures 6A, B ) which are more curved, distally crook-like, as described for C. japonica by Galil (1993) (see Figure 6D ) than “G2 subequal in length to G1, slender, curved, distal tip rounded” as described by for C. africana Lay & Ng (2006) (see Figure 6C ). Our records extend the depth range in Mozambican waters from 58 up to 283m.

Colouration observed. Lai & Ng (2006) described the colour of the freshly preserved paratipe of C. africana as follow: “… the dorsal surface of the carapace is beige to light brown in colour, speckled with salmon pink to light red mottles”. Barnard (1950) also described the colours of preserved specimens of C. japonica , which today must be referred to C. africana : “As preserved, pale with salmon pink mottling around the pustules and on hinder half of the carapace”. The colour of our preserved specimens agrees well with those descriptions. Photographs taken from two fresh specimens show the following live coloration pattern: the dorsal carapace surface, as well as the outer part of the chelae varies from brown-red to yellow. The female captured in M08 (IEO-CD-MZ08/1815) was more yellowish, while the male from M07 (IEO-CD-MZ07/1923) was more reddish (see Figures 4C,D ). In addition, the carapace has a dorsal pattern of large yellow spots surrounded by red, but without any reticulate pattern, which is typical of C. japonica (Ng et al. 2011) . The spots on the upper half of the carapace were marked, even with volume (as tubercles), while the ones in the lower half were much less pronounced and fading.

DNA barcodes. 16S and COI were obtained for two specimens, IEO-CD-MZ08/1815 and IEO-CD-MZ09/1791. The 16S sequences had no differences between them, and for COI two haplotypes differing only in one position were obtained. There are not sequences available for C. africana on any public database. However, the 16S sequences fit 99.44% (only differ in three positions) with an unpublished sequence of C. japonica ( MG 029426 ) obtained by Deepak et al. probably from an Indian specimen and fit 99.56% (only differ in two positions) with a shorter sequence (450 bp) of C. japonica from Japan obtained by Ewers-Saucedo et al. (2016). Respect to COI the two haplotypes differ in one or two mutations of another unpublished COI sequence ( KT 003706 ) of Calappa sp. (voucher CSP2) also obtained by Deepak et al. and probably also belonging to an Indian specimen. According to these data, probably the Calappa sp. is an individual of C. africana , a closer species to C. japonica as indicated by the low divergence in the 16S gene, and both species could be sympatric in Indian waters.

Figures

FIGURE 4. A, Lyreidus brevifrons, ♂ IEO-CD-MZ08/1771; B, Raninoides crosnieri, ♂ IEO-CD-MZ07/1910; C, Calappa africana, ♀ IEO-CD-MZ08/1815; D, C. africana, ♂ IEO-CD-MZ08/1797; E, Mursia africana, ♂, IEO-CD-MZ08/1797; F, Mursia aspera, ♂ IEO-CD-MZ07/1903 (preserved); G, Mursia flamma, ♀ IEO-CD-MZ07/1904; H, Mursia sp, ♂ IEO-CD- MZ09/1775. Scale bars: 1cm.

FIGURE 6. A and B, G2 Calappa africana IEO-CD-MZ07/1923; C, G2 Calappa africana (after Lay & Ng, 2006): D, G2 Calappa japonica (after Galil, 1993). Scale bars: 1mm.