Alpheus formosus Gibbes, 1850

Alpheus formosus Gibbes, 1850 View in CoL

Zoea I Carapace length: 0.42 ± 0.04 mm (n = 10 larvae)

Cephalothorax ( Fig. 1A, 1B View FIGURE 1 ): rostrum absent; pterygostomian spine present; eyes sessile.

Antennule ( Fig. 1C View FIGURE 1 ): peduncle 3-segmented; endopod as a plumose seta; exopod with 4 terminal aesthetascs (2 spatulate, one of them being more robust) and 1 terminal plumose seta.

Antenna ( Fig. 1D View FIGURE 1 ): peduncle 2-segmented with 1 medial distal spiniform projection near the endopod; endopod with 1 terminal plumose seta and 1 medial distal spiniform projection; exopod (scaphocerite) 8-segmented with 11 plumose setae (2, 1, 2, 1, 1, 1, 1, 2), distal segment with 1 simple seta.

Mandible: palp absent.

Maxillule ( Fig. 1E View FIGURE 1 ): coxa with 6 (1 medial simple, 3 terminal simple, one larger in proximal region, 1 terminal serrulate plumose, 1 lateral simple) setae; base with 2 spiniform projections and 1 lateral simple seta; endopod with 1 terminal plumoserrulate and 1 lateral simple setae; exopod absent.

Maxilla ( Fig. 1F View FIGURE 1 ): coxa with 2 medial simple setae; base bilobed, each lobe with 5 medial simple setae (distal seta longer); endopod with 1 medial proximal simple and 2 terminal long (1 simple and 1 plumose) setae, with microtrichia; exopod (scaphognathite) with 5 plumose setae, without microtrichia.

First maxilliped ( Fig. 1G View FIGURE 1 ): coxa with 1 medial distal simple seta; base with 7 medial simple setae arranged 2+2+2+1; endopod 2-segmented with 1 medial distal simple seta, 5 [4 simple (1 medial + 3 terminal) and 1 terminal serrulate] setae; exopod 4-segmented with 0, 0, 2, 2 terminal natatory plumose setae plus 1 lateral distal simple seta on second segment.

Second maxilliped ( Fig. 1H View FIGURE 1 ): coxa without setae; base with 4 medial simple setae arranged 1+1+1+1; endopod 4-segmented with 1 medial distal simple, 0, 1 medial distal serrulate, 5 (1 medial simple, 3 lateral simple and 1 terminal serrulate) setae; exopod 4-segmented with 0, 1, 2, 2 terminal natatory plumose setae plus 1 terminal simple seta on second segment.

Third maxilliped ( Fig. 1I View FIGURE 1 ): coxa with 1 medial distal simple seta; base with 2 medial simple setae arranged 1+1; endopod 5-segmented with 0, 1 medial, 0, 3 (2 lateral proximal and 1 medial distal), 3 (2 medial proximal and 1 terminal) simple setae; exopod 5-segmented with 0, 0, 2, 2, 2 terminal natatory plumose setae plus 1 medial simple seta on second segment.

Pereopod ( Fig. 1J View FIGURE 1 ): first as a biramous bud.

Pleon ( Fig. 1A, 1K View FIGURE 1 ,): with 5 somites, presence of simple dorsal setae on the somites ( Figs. 1L View FIGURE 1 , 3B, 3C View FIGURE 3 ); lateral spines absent; pleopods absent; anal spine present ( Fig. 1M View FIGURE 1 ).

Telson ( Fig. 1M View FIGURE 1 ): triangular, with 7+7 (5 inners plumose, 2 outers plumose laterally) setae, 4 inner setae with shorter setules in the proximal region, inner pair shorter; 6 inner pairs with a row of denticles in the distal margin, 4 innermost pairs with marginal spines ( Fig. 3G, 3H View FIGURE 3 ).