Microplinthus tamanus Meregalli, 2020

Meregalli, Massimo, 2020, Revision of the Nepalese genus Microplinthus Zherichin, 1987 (Coleoptera: Curculionidae: Molytinae), with description of 25 new species, Zootaxa 4794 (1), pp. 1-63 : 15

Microplinthus tamanus Meregalli n. sp.

http://zoobank.org/ urn:lsid:zoobank.org:act:D9E317B6-B285-4618-B7B0-0E6A6D964C51

Fig. 5

Material examined: Holotype ♂: “ NEPAL Prov. Janakpur / Distr. Dolakha, Rolwaling / Himal, upper Simigau [27°51’N 86°15’E] / village, 3300 m NN / 28.V.2000 / leg. J. Schmidt ” ( NMEG) . Paratype: same data as the holotype, 1♀ ( NMEG) .

Diagnostic description. Length 4.30 mm. Body oval-oblong, integument dark brownish, slightly glossy. Vestiture composed of sparse slender setae recumbent, almost appressed, to integument, and shorter setae inserted on elytral punctures. Rostrum slender, dorsal sides slightly enlarged basad, linearly converging to antennal insertion, in lateral view moderately and regularly curved; dorsum glossy, with small spaced punctures irregularly aligned on dorsum, longitudinal interspaces forming irregular lines, usually broader than punctures in dorso-lateral area in basal half, apical plate glossy, smooth, long extended before antennal insertion, particularly in median part, with scarce minute punctures bearing a small seta.Antenna slender, scape moderately thickened at apex; funicle antennomeres 1 and 2 conical, 1 twice as long as wide, 2 more slender, barely enlarged at apex, 3 times as long as wide, 3–6 globose, 7 larger; club shortly oval. Head very densely punctured, contrasting with the almost smooth vertex with fine punctures. Eye oblong, flat, with almost 50 ommatidia. Pronotum longer than wide, ratio length / width 1.15, base slightly prominent towards elytra, sides weakly and linearly broadened from base to apical third, more strongly convergent apicad; apical margin in lateral view straight, not prominent above head, ocular lobes almost indistinct; dorsum with a sharp median keel, continuous from base to apex, punctures very dense, interspaced of punctures linearly raised, particularly on external side, clearly angular, with a pore in the most external point bearing a hairlike seta. Elytra oblong, intervals flat with numerous oblong tubercles bearing tufts of setae; striae narrow, much narrower than intervals, with scarcely differentiated spaced punctures, interspaces often with a small glossy granule. Femur moderately thickened, with trace of inner tooth; tibia slender, weakly sinuate internally, apex truncated, lateral edge forming a 90° angle, with short fringe of setae on lateral part. Tarsomere 3 with elongated lobes, claws with strong inner teeth. Ventrites regularly narrowed, 1 and 2 densely punctured, interspaces of punctures broader than punctures on basal part of 1, punctures very dense near apex of 1, 3–5 glossy, smooth, unpunctured. Female sternum VIII with arms not joined, apodeme absent, arms straight, lamina strongly sclerotized, sclerotization broad and convergent, branches narrow and slightly curved upwards.

Variation. The female paratype is 3.81 mm long. It does not show any particular external differences from the holotype other than the usual secondary sexual characters in the ventrites.

Differential remarks. No other species were examined from the vicinity of the type locality. It differs from all other species with appendiculate claws and elytra with high tubercles by the elongate pronotum, 1.15x as long as wide, and the shallowly sculptured rostrum. Based on the phylogenetic analysis, the most closely related species appears to be M. messneri , which has larger elytra and more robust inner teeth on the tarsal claws.

Origin of the name. The species name derives from the Tama Koshi river ( Fig. 28 ).

Distribution. Central Nepal. Found on the mountains on the east banks of the Tama Koshi valley.

Figures

FIGURE 5. Microplinthus tamanus, Holotype ♀. Body (A, B); rostrum (G, H); antenna (D); pronotum (F); elytra (E); femur and foretibia (I); apex of foretibia (J); tarsus (C); claws (M); ventrites (L); female sternum VIII (K). Bar: 2 mm.

FIGURE 28. Distribution map of some species of Microplinthus. Map data: Google Earth, Maxar Technologies, used according to Google Earth Terms of Service.