Dumetoniscus graniticus Taiti & Checcucci, sp. n.

urn:lsid:zoobank.org:act: CB8FBB40-DB33-4B0E-9B9B-6B18A17206FA

Material examined. Socotra: 1 ♁ Holotype, Hagghier Mts, Adho Dimelho, 12°34'19.1"N 54°02'52.9"E, 1000 m, sifted leaf litter in bush, 22.I.2003, leg. S. Taiti, MZUF-9280 ; 5 ♁♁, 3 ♀♀, 1 juv. Paratypes, same data, MZUF-9280; 2 ♁♁, 5 ♀♀, Paratypes, same data, NHCY (MZUF) .

Diagnosis. A species of Dumetoniscus characterized by enlarged body shape (ca. twice as long as wide), cephalon with a triangular frontal medial lobe, triangular telson with straight sides, male pleopod 1 exopod triangular and endopod with apical part pointed and slightly bent outwards.

Description. Maximum length: ♁ 3.0 mm; ♀, 4.8 mm. Body enlarged (ca. 2 times longer than wide) (Fig. 4A). Colour brown with yellow spots; pereionites 5–7 with postero-lateral corners pale (reddish in vivo?); antennae, pleopods and uropods brown. Vertex of cephalon and dorsal side of pereion with some rounded shallow tubercles; posterior margins of pereionites 5–7 and of all pleonites granulated; dorsum with small T-shaped scale-setae (Fig. 4B); co-ordinates of noduli laterales as in Fig. 4C. Cephalon (Fig. 4 D–F) with frontal lateral lobes rounded and obliquely directed downwards, medial lobe triangular slightly protruding frontward compared with the lateral lobes; eyes very large, globose, with up to 16 ommatidia in the larger specimens. Pereionites with posterior margins straight. Pleonites 3–5 with falciform posterior points. Telson (Fig. 4G) triangular with straight sides, slightly surpassing posterior margin of uropo- dal protopods. Antennule (Fig. 4H) with third article about three times longer than second with a tuft of about seven aesthetascs and a small point at the apex. Antenna (Fig. 4I) with flagellum as long as fifth article of peduncle; second flagellar article ca. twice longer than first, bearing one and two aesthetascs. Mandibles (Fig. 5A,B) with molar penicil consisting of about six plumose setae. Maxillule (Fig. 5C) with inner branch bearing two elongated setose penicils and a distinct triangular posterior point. Maxilla (Fig. 5D) with outer lobe smaller than inner one, two strong setae between the two lobes. Maxilliped (Fig. 5E) and uropods (Fig. 5F) as in the generic diagnosis.

Male. Pereiopod 1 (Fig. 5G) carpus and merus with about five strong setae. Pereiopod 7 (Fig. 6A) ischium with straight sternal margin. Pleopod 1 (Fig. 6B) exopod triangular; endopod with distal part pointed and slightly bent outwards. Pleopod 2 (Fig. 6C) endopod longer than exopod. Pleopod 3–5 exopods as in Fig. 6 D-F.

Etymology. Latin graniticus = related to granite. The name refers to the granitic Hagghier Mts where the specimens were collected.

Family Platyarthridae