Pachygrapsus minutus, A. MILNE EDWARDS, 1837

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 : 368

PACHYGRAPSUS MINUTUS A. MILNE EDWARDS, 1837

(FIGS 9,10)

Dimensions: TT 0.62 mm ± 0.01, CW 0.29 mm ± 0.02, CL 0.43 mm ± 0.01.

Carapace ( Fig. 9a ): with a distinct postero-dorsal protuberance; dorsal spine short and straight; rostral spine straight and larger than dorsal spine; lateral spines absent; a pair of dorsal setae present; eyes sessile.

Antennule ( Fig. 9b ): uniramous, endopod absent; exopod unsegmented bearing 3 unequal terminal aesthetascs and 1 terminal seta.

Antenna ( Figs 9a,c ): slightly shorter than rostral spine; protopodal process with scattered spines of increasing size towards the tip; endopod absent; exopod very reduced bearing a terminal simple seta.

Maxillule ( Fig. 10f ): epipod seta absent; coxal endite with 6 (sparsely plumose) setae; basial endite with 5 (1 subterminal, plumodenticulate; 3 stout, terminal plumodenticulate; 1 stout, terminal denticulate) seta; 1 acute tooth present in distal margin; endopod 2-segmented, proximal segment with 1 (sparsely plumose) seta, distal segment with 5 (1 subterminal, sparsely plumose + 4 terminal plumodenticulate) setae; exopod seta absent.

Maxilla ( Fig. 10g ): coxal endite bilobed bearing 5 (sparsely plumose) + 4 (sparsely plumose) setae, basial endite bilobed with 5 (sparsely plumose) + 4 (sparsely plumose) setae; endopod bilobed with 2 (sparsely plumose) + 2 (sparsely plumose) setae; scaphognathite (exopod) margin with 4 plumose setae and 1 long distal stout process.

First maxilliped ( Fig. 10h ): basis with 8 setae (arranged 2 simple; 2 simple; 2 simple; 2 simple); endopod 5-segmented with 1 (simple), 2 (simple), 1 (simple), 2 (1 simple, 1 plumodenticulate), 5 (1 subterminal simple + 4 terminal plumodenticulate) setae; exopod unsegmented with 4 terminal plumose natatory setae.

Second maxilliped ( Fig. 10i ): basis with 4 setae (arranged 1 sparsely plumose, 1 sparsely plumose, 1 simple, 1 simple); endopod 3-segmented with 0, 1 (simple), 5 (1 subterminal denticulate + 1 subterminal simple, 1 terminal simple, 2 terminal sparsely plumose)

setae; exopod unsegmented with 4 terminal plumose natatory setae.

Third maxilliped: absent

Pereiopods: absent

Abdomen ( Figs 9a,d ): 5 somites; somite 2 with 1 pair of dorsolateral processes directed anteriorly, somites 3–4 with 1 pair of dorsolateral processes directed ventrally; postero-lateral processes in all somites, small in somite 1, and increasingly conspicuous, bearing distinct lobes in somites 2–5; a pair of median postero-dorsal setae in somites 2–5; maximum abdomen width at somite 4.

Telson ( Figs 9d,e ): with 2 postero-lateral pairs of spines, the posterior one larger; dorsal median spine absent; small setae distributed in scattered patches, almost covering forks except the tips; forks small, slightly divergent; posterior margin with 3 pairs of stout setae spinulated as shown in Fig. 9 (e).

Figures

Figure 9. Pachygrapsus minutus Crosnier. First zoeal stage: (a) lateral view; (b) antennule; (c) antenna; (d) dorsal view of abdomen; (e) detail of telson. Scale bars as in Figure 1.

Figure 10. Pachygrapsus minutus Crosnier. First zoeal stage: (f) maxillule; (g) maxilla; (h) first maxilliped; (i) second maxilliped. Scale bars as in Figure 2.