Geograpsus crinipes Dana, 1851

Al-Haj, Ahmed E. & Al-Aidaroos, Ali M., 2014, Description of the first zoëal stage of Geograpsus crinipes (Dana, 1851) (Decapoda: Brachyura: Grapsidae) from the Red Sea, African Invertebrates 55 (1), pp. 19-19 : 20-23

Geograpsus crinipes Dana, 1851

Figs 1–3

First zoëa.

Size (mm): RDL=0.89 ± 0.01, CW=0.52 ± 0.02, CL=0.43 ±0.07, ABL= 0.84± 0.02.

Carapace ( Fig. 1A ): Globose. Dorsal spine short and without setae. Rostral spine straight, shorter than dorsal spine. Lateral spine reduced to minute spine. There is a pair of dorsolateral setae. Anterodorsal, posterior and ventral margins without setae. Eyes: sessile.

Antennule ( Fig. 1B ): Uniramous. Endopod absent. Exopod unsegmented, with 2 long and 1 shorter unequal terminal aesthetascs, and 1 simple seta.

Antenna ( Fig. 1C ): Well-developed protopod process, longer than rostral spine, with 2 rows of 7 spinules of increasing size distally towards the tip. Endopod absent. Exopod reduced to a small bud with a simple terminal seta.

Mandible: Palp absent.

Maxillule ( Fig. 2A ): Coxal endite with 5 plumodenticulate setae. Basal endite with 5 setae and 2 minute spines. Endopod 2-segmented, proximal segment with 1 distal seta; distal segment with 1 subterminal and 4 terminal setae. Exopod setae absent.

Maxilla ( Fig. 2B ): Coxal endite bilobed, with 5+4 setae. Basal endite bilobed, with 5+4 setae. Endopod bilobed, with 4 (2 subterminal + 2 terminal) setae. Exopod (scaphognathite) margin with 4 plumose setae and a setose posterior stout process.

First maxilliped ( Fig. 2C ): Coxa without setae. Basis with 8 setae arranged 2+2+2+2. Endopod 5-segmented, with 1, 2, 1, 2 and 5 (1 subterminal + 4 terminal) setae. Exopod 2-segmented, distal segment with 4 terminal plumose natatory setae.

Second maxilliped ( Fig. 2D ): Coxa without setae. Basis with 4 setae arranged 1+1+1+1. Endopod 3-segmented, with 0, 1 and 5 (2 subterminal, denticulate + 3 terminal) setae, respectively. Exopod 2-segmented, distal segment with 4 terminal natatory setae.

Third maxilliped: Absent.

Pereiopods: Absent.

Pleon ( Figs 3A, B ): Five somites, somite 2 with 1 pair of dorsolateral processes directed anteriorly. Somites 3–5 with 1 pair of dorsolateral processes directed ventrally, somites 2–5 with 1 pair of posterodorsal setae, also with posterolateral processes, these especially well-developed in somites 3–4. Pleopods absent.

Telson ( Figs 3A, B ): Forks short, slightly divergent; with a minute spine at base of each furcal arm, and lateral margins without spines. Posterior margin with 3 pairs of stout spinulate setae, medial setae shorter than the proximal ones; bt /fl> 1.

Figures

Fig.1. Geograpsus crinipes (Dana,1851), first zoëa:(A)lateral view of carapace;(B) antennule;(C) antenna.

Fig. 2. Geograpsus crinipes (Dana, 1851), first zoëa: (A) maxillule; (B) maxilla; (C) first maxilliped; (D) second maxilliped.

Fig. 3. Geograpsus crinipes (Dana, 1851), first zoëa: (A) lateral view and (B) dorsal view of abdomen and telson.