Euwallacea insolitus Smith & Beaver, 2022

Beaver, Roger A. & Smith, Sarah M., 2022, The bark and ambrosia beetles of Bhutan (Coleoptera: Curculionidae: Scolytinae and Platypodinae): a synopsis with three new species of Scolytinae, Zootaxa 5174 (1), pp. 1-24 : 5

Euwallacea insolitus Smith & Beaver sp. nov.

( Figs 5‒8 )

http://zoobank.org/ urn:lsid:zoobank.org:act:C268A443-EE7A-4892-BC62-BA81618D361A

Type material. Holotype, female: Bhutan, Gedu , TDRI, 6.viii.[19]85, A.J, D.E. Padgham coll., ex Acer sp. CIE A17491, NHMUK014591818 ( NHML).

Diagnosis. 2.9 mm long (n = 1); 2.42 × as long as wide. This species is distinguished by its pronotum conical in dorsal view (type 0); obliquely truncate antennal club with two sutures on the posterior face (type 2); elytra unarmed by tubercles and granules, and posterolateral margin rounded.

Similar species. Anisandrus Ferrari spp.

Description (female). 2.9 mm long (n = 1); 2.42 × as long as wide. Body dark brown. Legs and antennae brown. Head: epistoma entire, transverse, with a row of hair-like setae. Frons weakly convex to upper level of eyes; surface alutaceous, sparsely punctate, setose; punctures bearing a long, erect hair-like seta. Eyes shallowly emarginate just above antennal insertion, upper part smaller than lower part. Submentum broadly triangular, slightly impressed. Antennal scape regularly thick. Funicle 4-segmented. Club longer than wide, obliquely truncate, type 2; segment 1 corneous, transverse on anterior face, occupying basal half; segment 2 narrow, corneous; segments 1 and 2 present on posterior face. Pronotum: 0.92 × as long as wide. In dorsal view conical, type 0, sides convex, conical anteriorly; anterior margin without serrations. In lateral view tall, type 2, disc flat, summit at apical 2/5. Anterior slope with dense low, broad asperities, becoming lower and more strongly transverse towards summit. Disc shagreened with moderately dense, minute punctures, some longer hair-like setae at margins. Lateral margins obliquely costate. Base transverse, posterior angles acutely rounded. Elytra: 1.50 × as long as wide, 1.64 × as long as pronotum. Scutellum moderately sized, linguiform, shining, flush with elytra, flat. Elytral base transverse, edge oblique and unarmed by granules, humeral angles rounded, parallel-sided in basal 3/5, then broadly rounded to apex. Striae and interstriae flush, unarmed by tubercles or granules; interstriae opalescent. Disc flat, striae not impressed, with large, deep punctures separated by 1.5‒2 diameters of a puncture, setose; each puncture bearing a semi-erect hair-like seta, increasing in length towards declivity; interstriae flat, punctures subequal to strial punctures, each bearing an erect seta longer than the width of an interstria. Declivital slope very gradual, occupying approximately 1/3 of elytra, declivital face weakly convex; strial punctures very large, shallow, much larger and deeper than those of disc, setose, setae short, as long as strial punctures; interstriae sparsely, minutely punctate, setose, setae long, erect. Posterolateral margin rounded. Legs: protibiae distinctly triangular, broadest at apical 1/4; posterior face smooth; apical 1/2 of outer margin with 7 moderate socketed denticles, their length as long as basal width. Meso- and metatibiae flattened; outer margin evenly rounded with 8 moderate socketed denticles, respectively.

Distribution. Bhutan.

Host plants. Acer (Sapindaceae) .

Etymology. L. insolitus = unusual, strange. An adjective. In reference to the unusual combination of characters exhibited by this species (see remarks.)

Remarks. This is a rather unique Euwallacea species with an idiosyncratic combination of characters. Overall, the species is rather similar to Anisandrus species which often have a similar form with a conical type 0 pronotum, gradual elytral declivity, rounded posterolateral elytra margin, and unarmed interstriae. It can be readily distinguished from Anisandrus by the lack of a pronotal mycangial tuft and type 2 antennal club with two sutures on the posterior face.

Figures

FIGURES 5‒8. Euwallacea insolitus holotype, 2.9 mm. Dorsal, lateral, posterior oblique and anterior views.