Microplinthus letheensis 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 : 30-33

Microplinthus letheensis Meregalli n. sp.

http://zoobank.org/ urn:lsid:zoobank.org:act:4FA51F06-863E-400C-A783-4F3C3A27043F

Fig. 15

Material examined: Holotype ♀: “Kali-Gandakhi Tal / zw. Lete u. Tukche [=Tukuche; Lethe: 28°36’N 83°38’E; Tukuche: 28°44’N 83°37’E] / [back] Pa 132 u. 133 // Zentral-Nepal / Sept.–Okt. 1971 / lg. H. Franz ” ( NHMW) . Paratype: “Kali-Gandakhi Tal / Lete / [back] Pa 118 // Zentral-Nepal / Sept.–Okt. 1971 / lg. H. Franz ”, 1 ♀ ( MER) .

Diagnostic description. Length 4.60 mm. Body oblong, integument almost matt, reticulate, dark brownish. Vestiture composed of very few short setae, on elytra vestiture composed of smaller short narrow setae and few broad, spatulate setae, adherent to integument or scarcely raised on declivity. Rostrum strong, dorsal sides distinctly broadened at base, linearly moderately convergent apicad, in lateral view regularly curved, junction with head continuing curvature of rostrum; dorsal sculpture regular, composed of large punctures regularly impressed, interspaces narrow, raised, longitudinal lines slightly zig-zag-shaped around the punctures; apex smooth from behind antennal insertion in median part, from antennal insertion towards sides. Antennal scape slender, sharply thickened at apex; antennomere 1 shortly globose, 2 conical, less than twice as long as wide, 3–6 globose, 7 distinctly larger; club oval. Eye large, oblong, with about 40 ommatidia. Pronotum slightly longer than wide, sides sublinearly weakly broadened from base to apical third, shortly constricted apicad; median keel narrow, weakly raised, extended from basal third to apical quarter; dorsum with small punctures regularly impressed, well separated from each other, interspaces usually almost as wide as punctures, weakly convex. Elytra oblong, intervals flat, with oblong humps, slightly more evident on declivity; striae composed of round punctures, very regularly impressed, evenly spaced, interspaces between punctures as high as intervals. Femur robust, thickened medially, with a narrow median convexity not tooth-like, very scarcely narrowed before articulation with tibia; tibia short, scarcely sinuate internally, apex rounded, not obliquely extended along outer side of tibia. Tarsomere 3 asymmetrical, inner lobe distinctly smaller; claws simple. Ventrites with sides almost linearly convergent from 2 to 5, 1 and 2 with sparse small round punctures rather regularly impressed and spaced, 3–4 smooth, 5 subtrapezoidal, punctured. Female sternum VIII lacking an apodeme, arms narrowed only near branches, moderately divergent, straight, branches narrow, slender, feebly curved upwards, lamina subquadrate, densely sclerotized.

Variation. The female paratype is slightly smaller (length 4.39 mm) and has higher elytral tubercles.

Differential remarks. Microplinthus letheensis is sympatric with M. franzi . This species has claws with inner teeth, then it differs by the elytra oval, with curvilinear sides, the pronotum with punctures irregularly impressed, and the short ventrites. Microplinthus kaligandaki and M. parbatensis live further to the south. Both species have erect setae on the elytral intervals (recumbent on integument in M. letheensis ), the latter has appendiculate claws, integument reddish, pronotum with dense, reticulate punctuation and the elytra lacking raised tubercles.

Origin of the name. This name derives from the type locality in the village of Lethe.

Distribution. Western Nepal, in the upper part of the Kaligandakhi valley ( Fig. 29 ).

Figures

FIGURE 15. Microplinthus letheensis, Holotype ♀. Body (A, B); rostrum (F, G); antenna (C); pronotum (E); elytra (D); femur and foretibia (I); apex of foretibia (L); tarsus (M); claws (J); ventrites (H); female sternum VIII (K). Bar: 2 mm.

FIGURE 29. Distribution map of some species of Microplinthus. Map data: Google Earth, Maxar Technologies, used according to Google Earth Terms of Service..