Soteriscus laouensis sp. nov.

(Figures 21 and 22)

Material examined

Holotype: ♂, St. 16, along road margin under stones, leg. S. Taiti, 28 April 2004 (MZUF 9509) . Paratypes: 1 ♂♂, 35 ♀♀, same data as holotype (MZUF 9509) .

Description

Maximum length: ♂, 13 mm; ♀, 16 mm. Body enlarged, outline as in Figure 21A. Colour: male brown-grey with the usual yellowish muscle spots; female light brown with a marbled pattern, two darker spots per side on the anterior part of pereonites; antennae uniformly grey; pereopods pale with numerous dark spots; pleopodal exopods dark. Back smooth with some scattered short triangular scalesetae (Figure 21B); a distinct sulcus marginalis on lateral margins of pereon epimera with numerous gland pores along its whole length (Figure 21G); numerous gland pores scattered on the whole dorsal surface of the body; noduli laterales clearly visible, inserted more or less at the same distance from the lateral margin of the pereonites, b/c and d/c co-ordinates as in Figure 21C. Cephalon (Figure 21D–F) with no suprantennal line, frontal line straight; very small lateral lobes bent downwards and not protruding frontwards; eye with about 26 ommatidia. Pereonites 1–3 with posterior margin regularly convex; pereonite 4 with posterior margin straight; pereonites 5–6 with posterior corners pointing backwards, pereonite 7 with acute posterior corners and slightly sinuous posterior margin at sides. Pleonites 3–5 with well-developed falciform posterior points (Figure 21H). Telson triangular with distinctly concave sides (Figure 21H). Antennule (Figure 21I) with first article longer than second and third; third article with a short triangular point and a tuft of elongated aesthetascs at apex. Antenna (Figure 21J) reaching back posterior margin of pereonite 3; fifth article of peduncle almost as long as flagellum; first flagellar article about 1.5 longer than second. Buccal pieces as in the preceding species. Pleopodal exopods 1 and 2 with monospiracular covered lungs. Uropod (Figure 21K) with a triangular depression on protopodal outer margin; exopod about twice as long as endopod; endopod proximally inserted.

Male: Carpus and distal part of merus of pereopod 1 (Figure 22A), pereopod 2 and, to a lesser extent, pereopod 3 with a brush of pointed setae. Pereopod 7 (Figure 22B) ischium with slightly convex sternal margin and a longitudinal depression and a setose area on rostral surface; merus elongated, without peculiar structures. Pleopod 1 (Figure 22C) exopod with long medial lobe almost three times as long as wide, with some short setae along its margin and a broadly rounded apex; endopod with distal part with almost parallel sides and a tuft of short setae at apex. Pleopod 2 (Figure 22D) endopod distinctly longer than exopod. Pleopod 3–5 exopods as in Figure 22E–G.

Etymology

The species is named after the Oued Laou basin, where the specimens were collected.

Remarks

In having the male pleopod 1 exopod with a long medial lobe S. laouensis is similar to S. gaditanus, S. fuscovariegatus and S. gibbosus sp. nov. It is readily distinguishable from S. gaditanus in having the male pleopod 1 exopod with broadly rounded instead of triangular apical part and shorter uropodal exopods; from S. fuscovariegatus in the less protruding lateral lobes of cephalon (see Figure 3A in Vandel 1956b) and comparatively longer and thinner uropods; and from S. gibbosus in lacking the hump on the male pereopod 7 merus and distinctly thinner medial lobe of the male pleopod 1 exopod.