Microplinthus arunensis 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 : 23-25

Microplinthus arunensis Meregalli n. sp.

http://zoobank.org/ urn:lsid:zoobank.org:act:59A10A76-8380-4E87-A2BF-E78C1982BAE8

Fig. 10

Material examined: Holotype ♀: “ NEPAL Khandbari / Distr. Forest S Man- / singma [27°30’N 87°20’E] 2200 m 11.iv. / 84 Smetana & Löbl // H. & A. Howden / Collection” ( CMNC) . Paratypes: “ NEPAL. Khand- / bari District // For, above Ahale [27°27’N 87°11’E] / 2400 m 25.III.82 / A. & Z. Smetana // H. & A. Howden / Collection” 2♀ (1♀ CMNC, 1♀ MER) .

Diagnostic description. Length 4.0 mm; body ovate, dark reddish-brownish, integument glossy on rostrum, almost matt on pronotum and elytra, shallowly reticulate. Vestiture composed of sparse setae, on rostrum and pronotum small, short, on elytra more broadly spatulate, curved onto tegument. Rostrum relatively slender, moderately broadened apicad, in lateral view dorsum curved, more in basal part, very slightly more thickened basad, junction with head slightly sinuate, on dorsal view sides very slightly and linearly convergent, dorsum lacking distinctly delimited longitudinal lines, with dense elongate punctures irregularly aligned longitudinally. Antennal scape moderately thickened from basal half; funicle antennomeres 1 and 2 short, 1 subglobose, 2 conical, slightly longer than wide, 3–7 short, transverse, club oval. Eye oval, with about 30 ommatidia. Pronotum as long as wide, sides slightly and regularly curved, apical margin in lateral view almost straight, not prominent above head; dorsum with median keel sharp from basal third to apex, surface very densely punctured, margins of punctures distinctly more raised externally, generally with a seta inserted on a microscopic pit at the most external point. Elytra ovate, convex, odd intervals 3 to 7 with raised elongate tubercles, suture and interval 2 with raised granules, striae as wide as intervals, with round punctures, intervals between punctures almost as long as punctures. Femur slender, scarcely thickened medially, inner tooth almost indistinct, sharply narrowed at articulation with tibia, surface densely punctured and with narrow setae; tibia slender, deeply rugose, external apical margin long oblique. Claws with small inner teeth. Ventrites strongly curvilinear narrowed from ventrite 2, surface of ventrites 1 and 2 densely punctured, ventrite 5 transverse, punctured. Female sternum VIII subrectangular, apodeme absent, arms not joined, branches slender, arms slender, moderately divergent, plate longer than wide, with sclerotization stronger towards apical part.

Variation. The specimens examined are very similar, the paratypes differ in the smaller tubercles on interval 3 and the rostrum slightly less curved. Body length varies between 4.0 and 4.5 mm.

Differential remarks. The species that live in the proximity are M. khandbariensis , M. koshianus and M. sherpa . The first species lacks the raised tubercles on the elytral intervals and has the female sternum VIII with short arms; M. koshianus has the rostrum thick, strongly curved and the pronotum strongly prominent above head; M. sherpa has the pronotum very deeply and irregularly sculptured, with the anterior margin distinctly curved above the head, female sternum VIII with very long and arcuate arms forming a continuous, X-shaped curve with branches.

Origin of the name. This name derives from the type locality in the Arun river valley.

Distribution. Eastern Nepal. Found in the mountains on the east of the Arun river valley, in Khandbari district ( Fig. 29 ).

Figures

FIGURE 10. Microplinthus arunensis, Holotype ♀. Body (A, B); rostrum (F, G); antenna (D); pronotum (E); elytra (C); femur (K); apex of foretibia (J); claws (I); ventrites (L); female sternum VIII (H). 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..