Microplinthus helambuensis 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 : 36-38

Microplinthus helambuensis Meregalli n. sp.

http://zoobank.org/ urn:lsid:zoobank.org:act:A862FC6D-740D-49AB-8028-AFF5B946A3A0

Fig. 18

Material examined. Holotype ♂: “ Zw. Mulkharka u. / Tare-Pati [Mulkharka: 28°08’N 85°22’E; Thare Pati, 28°02’N 85°29’E] / [back] Pa 153 // Zentral-Nepal / Sept.–Okt. 1971 / lg. H. Franz ” ( NHMW) . Paratype: same data as the holotype, 1 ♂ ( MER) .

Diagnostic description. Length 3.13 mm. Body slender, integument rather glossy, dark brownish. Vestiture composed of few setae, shorter than one interval width, moderately broadened, scattered on elytral surface. Rostrum short, stout, dorsal sides linear, subparallel, dorsum at antennal insertion almost as wide as at base, in lateral view moderately curved, main curvature at midlength; sculpture on dorsum formed by large punctures, aligned in 4 rows composed of about 8 punctures from base to smooth apical plate, longitudinal lines irregular, partly interrupted by punctures, apical plate smooth, glossy, in median part extended behind antennal insertion. Antennal scape thickened from apical quarter, with a few thick setae prominent forwards; funicle antennomere 1 short and thick, 2 subconical, short, barely as long as wide, 3–7 transverse, club oval. Eye oval, with at most 30 ommatidia. Pronotum slightly longer than wide, sides weakly curvilinear, barely more convergent anteriad, maximum width at midlength; apex almost straight in lateral view, ocular lobes barely differentiated; dorsum densely punctured, punctures large, isolated, deeply and regularly impressed, with 8–10 punctures aligned from base to apex, interspaces between punctures linear, partly reticulate near base, weakly convex; median line distinct from basal third and extended almost to apex. Elytra slender, long oblong, barely larger than pronotum, sides very feebly curvilinear, maximum width at midlength, odd intervals linear, moderately convex, lacking raised humps or tubercles, striae deeply impressed, wider than intervals, with deeply impressed large punctures. Femur slender, scarcely swelled, with a small sharp inner tooth; tibia strongly rugose, with dense suberect setae, inner margin slightly sinuate, denticulate, apex long obliquely cut. Tarsomere 3 short, slightly asymmetrical, lobes not prominent; claws simple. Ventrites 1 and 2 moderately narrowed, 3–5 at base of same width, 5 regularly rounded, 1 and 2 very sparsely punctured, 5 rough near apex. Penis weakly and regularly curved, flattened in anterior part, maximum width in basal part, sides slightly sinuate anteriad, lamella moderately prominent, apex rounded.

Variation. The paratype is 3.26 mm long and has the elytral intervals less raised.

Differential remarks. The species that live in the same area are M. ganesha and M. gupta . The former has matt integument, elytra with distinctly curved sides and numerous raised setae and pronotum densely and irregularly punctured; the latter has elytra with oblong humps. Microplinthus helambuensis is morphologically quite similar to M. jaegeri . This species differs in the pronotum lacking a clearly differentiated median line, the striae deeply impressed, the penis with sinuate, narrow apex. Microplinthus helambuensis appears to be closely related to M. godawaricus . This species mainly differs in the elytra with shortly oval spatulate setae, not longer than wide, and the pronotum with smaller punctures, with about 12–13 irregularly impressed punctures from apex to base in the central part near the poorly developed, irregular median line (about 8 regularly impressed punctures in M. helambuensis ).

Origin of the name. This species name derives from the type locality in Helambu Himal.

Distribution. Central Nepal, north of Kathmandu ( Fig. 29 ).

Figures

FIGURE 18. Microplinthus helambuensis, Holotype ♂. Body (A, B); rostrum (F, G); antenna (C); pronotum (E); elytra (D); femur and foretibia (J); apex of foretibia (L); tarsus (K); claws (N); ventrites (M); penis (H, I). 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..