Limnebius nanostillus, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 164-166

Limnebius nanostillus , new species

Figs. 149 (habitus), 159 (aedeagus), 297 (map)

Type Material. Holotype (male): Antsiranana, Ankarana, camp, waterhole at Andrafiabe cave entrance, elev. 50 m, 12° 57' S, 49° 8' E, 1 xi–30 xii 2004, M. Balke (MD 021) ( ZSMC) . Paratypes (45): Same data as holotype (19 ZSMC) ; Antananarivo, 18.8704S 47.6708E Analamanga, Anjomara mountain next to Ambato- lampikely village, RN2, hygropetric rock, elev. 1470 m, 18° 52' S, 47° 40' E, 24 xi 2014, J. Bergsten, R. Bukontaite, J.H. Randriamihaja, T. Ranarilalatiana & S. Holmgren ( MAD14-79 ) (1 NHRS) ; Antsiranana, Antsaba, Antsaba River, elev. 400 m, 13° 39' S, 48° 45' E, 1 xi–30 xii 2004, M. Balke (MD 014) (2 ZSMC); Montagne d'Ambre, Foret d' Ambre, elev. 545 m, 13° 34' S, 49° 10' E, 1 xi–30 xii 2004, M. Balke & M. Monaghan (MD 010) (20 ZSMC); Same data, " MNCN AI-549 DNA specimen" (1 MNCN) ; Fianarantsoa, Isalo NP: Namaza R. hygropetric beside the river, P41H, 12.v.2006, elev. 781 m, 22° 32' S, 45° 22' E, Bergsten et al. (1 BMNH) ; Mahajanga, Boeny: Ankarafantsika NP. S 16.25300 E 0 46.73444, 71 m. a.o. 30 XI 2009 Field # MAD09-12 , elev. 71 m, 16° 15' S, 46° 44' E, 30 xi 2009, J. Bergsten, N. Jönsson, T.Ranarilalatiana, HJ. Randriamihaja ( MAD09-12 ) (2 NHRS).

Differential Diagnosis. Habitus as in Fig. 149; the smallest Limnebius known from Madagascar, ca. 0.77 mm long. A teardrop-shaped species, very convex and broad at the shoulders. The pronotum is bicolored, lighter brown in the posterior angles and continuing along the basal 1/3, grading gradually to darker on the disc (this is more distinctive on some specimens). The aedeagus ( Fig. 159) is relatively stout, arcuate or angled in lateral view; the main piece has a raised ridge, and the gonopore is located immediately below the setose apical area.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 0.77/0.44; head width 0.31; pronotum 0.19/0.44; elytra 0.52/0.44; approximate height, lateral view 0.29. Dorsum brown to piceous, pronotum lighter brown in basal 1/3 and in posterior lateral angles, disc darker. Body form distinctively drop-shaped. Pronotum with disc strongly shining, non-microreticulate, very sparsely finely punctulate, each puncture with very short adpressed seta; area posterior to eye (side view) with slightly larger punctures, each puncture with adpressed seta, longer than setae on disc. Elytra non-microreticulate, with punctures and setae similar to those on pronotum.

Males with first three pro- and mesotarsal segments slightly enlarged, with adhesive setae. Labroclypeal suture arcuate in frontal view in both sexes. Labrum simple, similar in sexes. Lateral angle of elytral apices more widely rounded and apices more truncate in males than in females, sutural angle more acute in females.

Etymology. Named in reference to the very small size and teardrop-shaped body.