Siolicaris sioli

Siolicaris sioli (Noodt, 1963a)

(Figs. 1–2)

Synonymy. Parastenocaris sioli Noodt — Noodt (1963a), Rouch (1986), Ranga Reddy (2001).

Parastenocaris siolii Noodt; incorrect spelling— Jakobi (1972), Löffler (1981), Dussart (1984), Rouch (1986), Dussart & Defaye (1990), Reid (1998).

Siolicaris siolii (Noodt), incorrect spelling— Corgosinho et al. (2008).

Siolicaris sioli (Noodt) —Corgosinho et al. (2010).

Material examined. Noodt’s collection: Parastenocaris sioli, syntype (Case 2, slide 17), 2 ♂ dissected and mounted on a single slide; Parastenocaris sioli, paratype (Case 2, slide 15), 1 ♂ dissected and mounted on a single slide.

Type locality. Coastal groundwater of the Amazon River at Santarém-PA (Brazil).

Description. Male. Body size of 330 µm (after Noodt 1963a). Telson smooth, anal operculum smooth and slightly concave; anal sinus bordered by fine spinules (Fig. 1A and Noodt 1963a, p. 132, fig. 64). Furca (Figs. 1A) with 7 setae; setae I–III proximally inserted, anterior to seta VII; seta II reduced; seta IV subdistal, inserting dorsally, on outer margin of furca; seta V inserting on the distal margin of furca; seta VI shorter than seta V, inserting beneath it; seta VII approximately of the same size as seta VI, socketed at basis and inserted dorsally, close to inner margin of furca.

A1 (Fig. 1B–F) haplocer, 8-segmented and prehensile, 7 th segment without a distal inner apophysis; armature beginning with proximal segment: 0/6/4/1/5+Ae/2 [1 hyaline spine (dotted structure) and 1 setae]/2 [1 hyaline spine (dotted structure) and 1 distal seta]/9+Ae; distal segment with distal hyaline margin.

A2 (Fig. 2A) with allobasis; abexopodal margin ornamented with 2 spinules; 1-segmented exp with 1 seta, and 1-segmented enp bearing 7 setae.

Md (Fig. 1G) coxal gnathobasis bearing 1 seta and 1-segmented palp with 2 setae.

Mx1 (Fig. 1H) praecoxal arthrite with 5 elements (1 dorsal surface seta, 3 claw-like pinnate spines and 1 slender seta), coxa and basis not observed.

Mx2 (Fig. 1I) basis with 2 endites, proximal endite with 1 seta, distal endite with 2 slender setae and 1 pinnate spine, proximal endopodal segment drawn into a claw, distal endopodal segment with 2 setae.

Mxp (Fig. 1I–J) subchelate, composed of syncoxa, basis, 1-segmented endopod fused to the claw-like apical seta.

P1 (Fig. 2G) coxa bare; basis with small outer seta. Exp 3-segmented, exp-1 with outer spine, exp-2 unarmed, exp-3 with 2 outer spines and 2 geniculate setae of different lengths; enp 2-segmented, slightly longer than exp, enp-1 as long as the combined length of first 2 exopod segments, enp-2 with 1 apical outer spine and 1 apical geniculate seta.

P2 (Fig. 2B) coxa bare; basis without outer seta, with outer pore and row of spinules on the outer margin; exp 3-segmented, exp-1 with long outer spine and hyaline frill on distal inner corner; exp-2 without armature and with distal row of long spinules; exp-3 with 3 setae, hyaline frill on distal inner corner and row of long spinules on outer distal corner; enp 1-segmented, cylindrical, shorter than exp-1, with 2 spinules on outer margin and distal seta.

P3 (Fig. 2C–D) coxa bare; basis rectangular, longer than broad, with row of strong spinules on outer margin, below the insertion of outer seta, and pore; exp with 3 outer spinules, apophysis short, robust, 1-segmented, with rounded tip and strongly bent inwards while in rest position; thumb strong, much longer than apophysis, with pointed tip and roundish distal hyaline membrane, enp reduced to tiny seta.

P4 (Fig. 2E) coxa with 2 long and strong spinules on anterior margin; basis trapezoidal, with an outer seta and pore; exp 3-segmented, exp-1 with outer spine and hyaline frill on distal inner corner; exp-2 unarmed and with distal row of long spinules; exp-3 with 2 setae and hyaline frill on distal inner corner; enp completely absent.

P5 (Fig. 2F) trapezoidal, without inner process, with inner row of small spinules and 3 setae, all distally inserted; both limbs close to each other, connected by short, triangular intercoxal sclerite.

P6 as an irregular plate with lateral triangular projections.

Female. Unknown.