Dumetoniscus graniticus Taiti & Checcucci, 2009

Taiti, Stefano & Checcucci, Ilaria, 2009, New species and records of terrestrial Isopoda (Crustacea, Oniscidea) from Socotra Island, Yemen, ZooKeys 31 (3), pp. 73-103 : 87-89

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

Figures

Figure 4. Dumetoniscus graniticus gen. n., sp. n. ♀ from Adho Dimelho: A Adult specimen, dorsal view B Dorsal scale-seta C Co-ordinates of noduli laterales D Cephalon, frontal view E Cephalon, dorsal view F Cephalon and pereionite 1, lateral view G Pereionite 7, pleon, telson and uropods H Antennule I Antenna.

Figure 5. Dumetoniscus graniticus gen. n., sp. n. ♀ from Adho Dimelho: A Right mandible B Left mandible C Maxillule D Maxilla E Maxilliped F Uropod, lateral view. ♁ from Adho Dimelho G Pereiopod 1.