Sarmatium crassum, DANA, 1851

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 : 373-378

SARMATIUM CRASSUM DANA, 1851 (FIGS 13,14)

Dimensions: TT 0.92 mm ± 0.04, CW 0.43 mm ± 0.04, CL 0.58 mm ± 0.02.

Carapace ( Fig. 13a ): dorsal spine slightly curved posteriorly; rostral spine straight, of similar size of dorsal spine; lateral spines absent; a pair of posterodorsal and a pair of antero-dorsal setae present; eyes sessile.

Antennule ( Fig. 13b ): uniramous, endopod absent; exopod unsegmented bearing 3 unequal terminal aesthetascs and 1 terminal seta.

Antenna ( Figs 13a,c ): of similar size than rostral spine; protopodal process with aligned spines of different size; endopod absent; exopod developed but considerably shorter than protopodal process, with 2 very reduced, 1 small and 1 stout, long-terminal setae.

Maxillule ( Fig. 14f ): epipod seta absent; coxal endite with 5 (denticulate) setae; basial endite with 5 (1 subterminal, denticulate; 4 stout, terminal denticulate) setae, 2 acute teeth also present; endopod 2- segmented, proximal segment with 1 (simple) seta, distal segment with 5 (1 subterminal, sparsely plumose + 4 distal, plumodenticulate) setae; exopod seta absent.

Maxilla ( Fig. 14g ): coxal endite bilobed bearing 5 (sparsely plumose) + 3 (sparsely plumose) setae, basial endite bilobed with 5 (plumodenticulate) + 4 (plumodenticulate) setae; endopod bilobed with 2 (unequal, plumodenticulate) + 3 (plumodenticulate) setae; scaphognathite (exopod) margin with 4 plumose setae and 1 long distal stout process.

First maxilliped ( Fig. 14h ): basis with 10 setae (arranged 2 simple; 2 simple; 3 simple; 3 simple); endopod 5-segmented with 2 (sparsely plumose), 2 (sparsely plumose), 1 (sparsely plumose), 2 (1 sparsely plumose, 1 plumodenticulate), 5 (1 subterminal sparsely plumose + 4 terminal plumodenticulate) setae; exopod unsegmented with 4 terminal plumose natatory setae.

Second maxilliped ( Fig. 14i ): basis with 4 setae arranged (1 simple, 1 simple, 1 simple, 1 simple); endopod 3-segmented with 0, 1 (plumodenticulate), 6 (1 subterminal, sparsely plumose + 1 subterminal, simple; 4 terminal simple) setae; exopod unsegmented with 4 terminal plumose natatory setae.

Third maxilliped: absent

Pereiopods: absent

Abdomen ( Figs 13a,d ): 5 somites; somite 2 with 1 pair of dorsolateral processes directed anteriorly, somite 3 with 1 pair of dorsolateral processes directed ventrally; postero-lateral processes in somites 2–5, round in somite 2, and increasingly acute in somites 3–5; a pair of median postero-dorsal setae in somites 2–5.

Telson ( Figs 13a,d,e ): lateral and dorsal medial spines absent; small setae arranged in a few patches in proximal fourth of forks, small spines bordering margins of forks, except for the proximal fourth and tip; forks large, curved dorsally and divergent; posterior margin with 3 pairs of stout setae spinulated.

SESARMA LEPTOSOMA HILGENDORF, 1869

(FIGS 15,16)

Dimensions: TT 0.63 mm ± 0.02, CW 0.44 mm ± 0.04, CL 0.42 mm ± 0.02.

Carapace ( Fig. 15a ): small spinules bordering ventral margins; dorsal spine strongly curved posteriorly; rostral spine straight, slightly shorter than dorsal spine; lateral spines absent; a pair of postero-dorsal and a pair of antero-dorsal setae present; eyes sessile.

Antennule ( Fig. 15b ): uniramous, endopod absent; exopod unsegmented bearing 3 terminal aesthetascs and 3 terminal setae of unequal size.

Antenna ( Figs 15a,c ): similar in size to rostral spine; protopodal process with 2 rows of spines of different size, smaller ones aligned in distal third of process, except the tips; endopod absent; exopod developed but shorter than protopodal process, with 3 very reduced, 1 small and 1 stout, long-terminal setae.

Maxillule ( Fig. 16f ): epipod seta absent; coxal endite with 6 (3 sparsely plumose, 3 plumodenticulate) setae; basial endite with 5 (1 subterminal, plumodenticulate; 4 stout, terminal plumodenticulate) setae, 2 acute teeth also present; endopod 2- segmented, proximal segment with 1 (simple) seta, distal segment with 5 (1 subterminal, simple + 4 distal, plumodenticulate) setae; exopod seta absent.

Maxilla ( Fig. 16g ): coxal endite bilobed bearing 5 (sparsely plumose) + 3 (sparsely plumose) setae, basial endite bilobed with 5 (2 sparsely plumose, 3 plumodenticulate) setae + 4 (3 sparsely plumose, 1 plumodenticulate) setae; endopod bilobed with 2 (unequal, sparsely plumose) + 3 (sparsely plumose) setae; scaphognathite (exopod) margin with 4 plumose setae and 1 long distal stout process.

First maxilliped ( Fig. 16h ): basis with 9 setae (arranged 2 simple; 2 simple; 3 simple; 2 simple); endopod 5-segmented with 2 (simple), 2 (1 simple, 1 sparsely plumose), 1 (simple), 2 (simple), 5 (1 subterminal simple + 1 terminal simple, 3 terminal plumodenticulate) setae; exopod unsegmented with 4 terminal plumose natatory setae.

Second maxilliped ( Fig. 16i ): basis with 4 setae (arranged 1 sparsely plumose, 1 simple, 1 simple, 1 simple) setae; endopod 3-segmented with 0, 1 (plumodenticulate), 6 (1 subterminal simple + 4 terminal simple, 1 terminal plumodenticulate) setae; exopod unsegmented with 4 terminal plumose natatory setae.

Third maxilliped: absent

Pereiopods: absent

Abdomen ( Figs 15a,d ): 5 somites; somite 2 with 1 pair of dorsolateral processes directed anteriorly, somite 3 with 1 pair of dorsolateral processes directed ventrally; postero-lateral processes from round to acute in somites 1–5; a pair of median postero-dorsal setae in somites 2–5.

Telson ( Figs 15d,e ): lateral and dorsal medial spines absent; small setae distributed in scattered patches, small spines in fork margins, except for the tips; forks large, slightly divergent; posterior margin with 3 pairs of stout setae, the median ones with proximal larger spinulae on external margin.

Figures

Figure 13. Sarmatium crassum Dana. 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 14. Sarmatium crassum Dana. First zoeal stage: (f) maxillule; (g) maxilla; (h) first maxilliped; (i) second maxilliped. Scale bars as in Figure 2.

Figure 15. Sesarma leptosoma Hilgendorf. 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 16. Sesarma leptosoma Hilgendorf. First zoeal stage: (f) maxillule; (g) maxilla; (h) first maxilliped; (i) second maxilliped. Scale bars as in Figure 2.