Graptodytes eremitus, Ribera, Ignacio & Faille, Arnaud, 2010

Ribera, Ignacio & Faille, Arnaud, 2010, A new microphthalmic stygobitic Graptodytes Seidlitz from Morocco, with a molecular phylogeny of the genus (Coleoptera, Dytiscidae), Zootaxa 2641, pp. 1-14 : 6-7

Graptodytes eremitus n.sp.

( Figs 1–6 , 9–11 )

Type locality. Cave Doussoulile, Tiqqi, SW Morocco (N 30°44,529’ W9°19,803’).

Type material. Holotype male, “ Morocco, Tiqqi 28.VII.2008 / cave Doussoulile N 30°44,529’ W9°19,803’ / leg J.M. Bichain, A. Faille, B. Junger & M. Perreau” plus holotype label. Specimen and DNA voucher number IBE-AF33, MNHN Wit Tamdoun expedition code WT-NP51. DNA aliquotes preserved in the DNA and tissue collections of the MNCN and IBE; voucher specimen, with aedeagus mounted in a transparent card, preserved in the MNHN.

Diagnosis. The morphology of the aedeagus clearly places the new species in the genus Graptodytes , despite the lack of longitudinal impressions in the pronotum. The large size (ca. 3 mm), parallel-sided shape, uniformly pale brown colour, small eyes and shape of the median lobe allow an easy separation of G. e re m i t u s n.sp. from all related species of the genus.

Description. Habitus as in Figs 1–4 . Length 3.05 mm, maximum width 1.30 mm. Body outline elongated, parallel-sided, flattened. Colour uniformly light brown, cuticle translucent ( Figs 3–4 ). Body surface with a very fine, hardly visible dense microreticulation.

Head very large, wide, regularly round, glabrous. Eyes reduced, flat; ommatidia well defined on periphery of eye but hardly distinguishable in central part; maximum diameter of approximately eight ommatidia and 1/ 4 of length of head (vs. 12–15 ommatidia and half length of head in species of the G. v a r i u s group) ( Figs 6–8 ). Eyes surrounded first by a smooth and flat area and then a ring of stronger punctures with some setae. Antennae long and slender.

Pronotum finely bordered; wider in anterior part, slightly wider than elytra; posterior part only slightly narrower than base of elytra. Angle between pronotum and elytra obtuse. Sides of pronotum with some very long, fine white setae. Surface with very sparse, stronger setiferous punctures with whitish short fine setae; with an irregular row of setiferous punctures on lateral, anterior and posterior margins. Submarginal lateral marks on pronotum almost imperceptible, forming very shallow depressions externally, although an internal mark is clearly visible by transparency ( Fig. 3 ).

Elytra elongated, parallel-sided, uniformly pale brown, with traces of irregular serial rows of setiferous punctures, inter-strial spaces slightly raised. Margins with rows of very long, fine whitish setae ( Fig. 5 ).

Legs long and slender, protarsal claws of male simple, without apparent modifications. Ventral side of anterior and middle femora with two rows of very robust setae. Tibia with long, whitish sensory setae.

Ventral surface covered with long, sparse fine setae (denser than on upper surface). Medial part of posterior margin of metacoxa deeply incised ( Fig. 4 ).

Aedeagus as in Figs 9–11 , apex of median lobe flat in lateral view, very slightly asymmetrical and with a medial emargination in ventral view; parameres as in Fig. 11 .

Habitat. The single known specimen was found in a small pool (a siphon) in the deep part of the Doussoulile cave (at ca. 70 meters below the level of the entrance). The pool was on rock with some fine sediment, with clear water, and the specimen was actively swimming. Other fauna collected in the same cave were Collembola, Oniscidae and Amphipoda (Crustacea), Acari, and some spiders and Coleoptera ( Antisphodrus sp., Porotachys bisulcatus Nicolay and trogloxene Staphylinidae ).

Etymology. The hermit Graptodytes , from the Latin eremita, and this from the Greek eremites, from eremos (desert), in reference to the loneliness of the single known specimen in the deep area of a cave in the (relative) vicinity of the Sahara desert.

Figures

FIGURES 1 – 2. Habitus of Graptodytes eremitus n. sp. (holotype, after DNA extraction, specimen mounted dry); 1, dorsal view (photo: J. Fresneda); 2, lateral view (photo: J. Gómez-Zurita).

FIGURES 3 – 5. Graptodytes eremitus n. sp. (holotype, previous to DNA extraction, submersed in ethanol); 3, dorsal view; 4, ventral view; 5, detail of the marginal setae of the elytra. Note the membranous wings, the genitalia and the longitudinal impressions at both sides of the pronotum, visible through the translucent cuticle (photos: I. Ribera).

FIGURES 6 – 8. Detail of the lateral view of the left eye of 6, G. e re m it us n. sp.; 7, G. atlantis; 8, G. ignotus (photos: J. Fresneda).

FIGURES 9 – 11. Genitalia of G. eremitus n. sp. (holotype); 9, median lobe, ventral view; 10, median lobe, lateral view; 11, right paramere (photos: J. Fresneda).