Grapsus fourmanoiri, CROSNIER, 1965

Flores, Augusto A. V., Paula, José & Dray, Tiago, 2003, First zoeal stages of grapsoid crabs (Crustacea: Brachyura) from the East African coast, Zoological Journal of the Linnean Society 137 (3), pp. 355-383 : 357-360

GRAPSUS FOURMANOIRI CROSNIER, 1965 (FIGS 1,2)

Dimensions: TT 0.90 mm ± 0.02, CW 0.52 mm ± 0.07, CL 0.50 mm ± 0.01.

Carapace ( Fig. 1a ): dorsal spine short and straight; rostral spine anteriorly directed; lateral spines absent; a pair of postero-dorsal setae present; setae absent from ventral carapace margin; eyes sessile.

Antennule ( Fig. 1b ): uniramous, endopod absent; exopod unsegmented bearing 3 unequal terminal aesthetascs and 2 unequal terminal setae.

Antenna ( Figs 1a,c ): shorter than rostral spine; protopodal process with 2 rows of spines of increasing size 1 Setation of the exopod (number of simple setae + number of large terminal setae); 2 with two teeth; 3 with an additional setalike protuberance.

References of original descriptions: Pereyra Lago (1993b) ( Chiromantes eulimene ); Pereyra Lago (1993a) ( Perisesarma guttatum ); Pereyra Lago (1989) ( Neosarmatium meinerti ); Pereyra Lago (1987) ( Parasesarma catenata ); Baba et al. (1984) and Mia & Shokita (1996) ( Helice leachi ).

towards the tip; endopod absent; exopod reduced to a small bud with a terminal simple seta.

Maxillule ( Fig. 2f ): epipod seta absent; coxal endite with 6 (3 sparsely plumose, 2 plumodenticulate and 1 simple) setae; basial endite with 5 (1 subterminal, plumodenticulate; 4 stout, terminal plumodenticulate) setae and 2 acute teeth present; endopod 2-segmented, proximal segment with 1 (plumodenticulate) seta; distal segment with 5 (1 subterminal, plumodenticulate + 4 distal, plumodenticulate) setae; exopod seta absent.

Maxilla ( Fig. 2g ): coxal endite bilobed bearing 4 (sparsely plumose) + 5 (sparsely plumose) setae, basial endite bilobed with 5 (4 sparsely plumose, 1 plumodenticulate) setae + 4 (2 sparsely plumose, 2 plumodenticulate) setae; endopod bilobed with 2 (1 plumodenticulate, 1 sparsely plumose) setae + 2 (sparsely plumose) setae; scaphognathite (exopod) margin with 4 plumose setae and 1 long distal stout process.

First maxilliped ( Fig. 2h ): basis with 8 setae (arranged 2 sparsely plumose; 1 sparsely plumose, 1 simple; 2 simple; 2 simple); endopod 5-segmented with 1 (sparsely plumose), 2 (simple), 1 (sparsely plumose), 2 (plumodenticulate), 5 (1 subterminal simple + 4 terminal plumodenticulate) setae; exopod unsegmented with 4 terminal plumose natatory setae.

Second maxilliped ( Fig. 2i ): basis with 4 setae (arranged 1 sparsely plumose, 1 sparsely plumose, 1 sparsely plumose, 1 simple); endopod 3-segmented with 0, 1 (denticulate), 5 (1 subterminal denticulate + 1 terminal simple, 3 terminal sparsely plumose) setae; exopod unsegmented with 4 terminal plumose natatory setae.

Third maxilliped: absent

Pereiopods: absent

Abdomen ( Figs 1a,d ): 5 somites; somite 2 with a pair of dorsolateral processes directed anteriorly; somites 3–5 with 1 pair of dorsolateral processes directed ventrally; postero-lateral processes in all somites, small in somite 1, acute in somite 2, and more developed, bearing distinct lobes in somites 3–5; a pair of median postero-dorsal setae in somites 2–5; maximum abdomen width at somite 4.

Telson ( Figs 1d,e ): with 2 postero-lateral pairs of spines, the posterior one smaller; dorsal median spine absent; small denticles distributed in scattered patches, but completely covering intermediate regions of forks; forks small, slightly divergent; posterior margin with 3 pairs of stout setae spinulated as shown in Fig. 1 (e).

Figures

Figure 1. Grapsus fourmanoiri Crosnier. First zoeal stage: (a) lateral view; (b) antennule; (c) antenna; (d) dorsal view of abdomen; (e) detail of telson. Scale bars represent 0.2 (a), 0.05 (b, c and e) and 0.1 mm (d).

Figure 2. Grapsus fourmanoiri Crosnier. First zoeal stage: (f) maxillule; (g) maxilla; (h) first maxilliped; (i) second maxilliped. Scale bars represent 0.05 mm.