Portunus gibbesii, (Stimpson, 1859)

Mantelatto, Fernando L., Pantaleão, João A. F., Cuesta, José A., Fransozo, Adilson & Felder, Darryl L., 2018, The first zoeal stage morphology of Achelous spinimanus (Latreille), A. gibbesii (Stimpson), and Portunus sayi (Gibbes) (Decapoda, Brachyura) provides support for molecular phylogeny, Zootaxa 4378 (1), pp. 71-84 : 76-77

Achelous gibbesii ( Stimpson, 1859)

( Figs. 3a, b ; 4a, b; 5a, c; 6a)

Description of zoea I. Dimensions: CL: 0.34 ± 0.0 2 mm; CW: 0.29 ± 0.1 mm; DL: 0.30 ± 0.0 3 mm; RL: 0.16 ± 0.0 1 mm; RDL: 0.88 ± 0.0 4 mm; DS/RS: 1.88 ± 0.25 (n = 10).

Cephalothorax ( Figs. 3a, b ): dorsal spine long, curved distally backward and without setae. Rostral spine long, slightly longer than antennal protopod. Lateral spines well developed. One pair of posterodorsal simple setae present, anterodorsal setae absent; lateroventral margins with seven denticles, without setae. Eyes sessile.

Antennule ( Figs. 4a ): uniramous, smooth. Primary flagellum with two long terminal aesthetascs and two simple setae; accessory flagellum absent.

Antenna ( Figs. 4b ): uniramous, protopod well developed, long, reaching tip of cephalothorax rostral spine, with two rows of 12–14 spines along most of protopod length except base, increasing in size toward tip, in midpart a group of five small spinules. Endopod absent. Exopod unsegmented, approximately one-fourth (1/4) of protopod length, with two unequal terminal simple setae, longest one slightly shorter than exopod length.

Mandibles (not illustrated): incisor, molar process developed. Palp absent.

Maxillule ( Fig. 5a ): coxal endite with one simple, five plumodenticulate setae. Basial endite with two cuspidate, three plumodenticulate setae, microtrichia on proximal margin. Endopod 2-segmented, proximal segment without setae; distal segment with six (two medial, two subterminal, one terminal sparsely plumodenticulate, one terminal simple) setae. Exopod and epipod setae absent.

Maxilla ( Fig. 5c ): Coxal endite bilobed, with three plumose setae on both lobes, distal lobe with one terminal small spine. Basial endite bilobed, with four plumodenticulate setae on both lobes, proximal lobe with one terminal small spine. Unsegmented endopod bilobed, with two (one small simple, one long sparsely plumodenticulate) setae on proximal lobe, four (one long sparsely plumodenticulate, three short simple) setae on distal lobe. Exopod (scaphognathite) margin with four plumose setae and long distal process. Microtrichia on both proximal and distal margins of coxal endite, basial endite, endopod and distal process of the scaphognathite.

First maxilliped (not illustrated): coxa without setae. Basis with ten simple setae arranged 2+2+3+3. Endopod 5-segmented with two (sparsely plumose), two (sparsely plumose), zero, two (one sparsely plumose, one sparsely plumodenticulate), five (one subterminal simple, four terminal plumodenticulate) setae, respectively. Exopod 2- segmented, distal segment with four long terminal plumose natatory setae.

Second maxilliped (not illustrated): coxa without setae. Basis with four simple setae arranged 1+1+1+1. Endopod 3-segmented, with one sparsely plumose, one sparsely plumose, five (three simple, one serrulate, one long sparsely plumose) setae, respectively. Exopod 2-segmented, distal segment with four long terminal plumose natatory setae.

Third maxilliped: absent.

Pereiopods: absent.

Pleon (not illustrated): five pleonites present. Pleonite 1 without setae, pleonites 2–5 with one pair of posterodorsal simple setae. Pleonites 2, 3 with one pair of dorsolateral processes. Pleonites 3–5 with long, acute posterolateral processes. Pleopods absent.

Telson ( Fig. 6a ): furcated. Furcae distally spinulated, with one pair of well-developed lateral spines, one pair of small lateral spines just below the long ones, and one pair of dorsal spines; inner margin with three pairs of serrulate setae.

Figures

FIGURE 3. Cephalothorax, lateral view. a. Achelous gibbesii (Stimpson, 1859); b. Portunus sayi (Gibbes, 1850). Magnification of lateroventral margin.c. A. gibbesii; d. P.sayi. (Scale bar: a, c = 0.1 mm; b, d = 0.05 mm)

FIGURE 4. Antennule. a. Achelous gibbesii (Stimpson, 1859); c. Portunus sayi (Gibbes, 1850). Antenna. b. A. gibbesii; d. P. sayi. (Scale bar:0.05 mm)

FIGURE 5. Maxillule. a. Achelous gibbesii (Stimpson, 1859); b. Portunus sayi (Gibbes, 1850). Maxilla. c. A. gibbesii; d. P. sayi. (Scale bar:0.05 mm)

FIGURE6. Telson furcae, detail of spinulation.a. Achelous gibbesii (Stimpson, 1859); b. Portunus sayi (Gibbes, 1850) (Scale bar:0.02 mm)