Euwallacea alastos Smith, Beaver & Cognato, 2022

Smith, Sarah M., Beaver, Roger A., Pham, Thai Hong & Cognato, Anthony I., 2022, New species and new records of Xyleborini from the Oriental region, Japan and Papua New Guinea (Coleoptera: Curculionidae: Scolytinae), Zootaxa 5209 (1), pp. 1-33 : 16

Euwallacea alastos Smith, Beaver & Cognato sp. nov.

( Figs 49–52 )

http://zoobank.org/ urn:lsid:zoobank.org:act:5090DCC4-5358-461E-9DCD-59F2D7B1A55D

Type material. Holotype, female: JAPAN, G. Lewis, NHMUK014591822 (NHMUK).

Diagnosis. This species is distinguished by its stout form; declivital posterolateral margin costate and granulate; pronotum appearing subquadrate when viewed dorsally (type 3); protibiae outer margins obliquely triangular bearing five short obtuse denticles; declivital strial punctures approximately the same size on disc and declivity; declivity gradually rounded; and declivital surface opalescent.

This species is very similar to E. praevius ( Blandford, 1894) and can be distinguished by the following combination of characters ( E. alastos given first): stouter form, 2.56 vs 2.72–2.92 × as long as wide; stout elytra 1.44 vs 1.6–1.83 × as long as wide; declivital surface opalescent vs strongly shining; declivital interstriae minutely granulate vs distinctly denticulate.

Similar species. E. praevius , E. andamanensis ( Blandford, 1896) , Xyleborus aquilus Blandford, 1894

Description (female). 3.2 mm long (n = 1); 2.56 × as long as wide. Body ferruginous. Legs and antennae light brown. Head: epistoma entire, transverse, with a row of hair-like setae. Frons flattened to upper level of eyes; surface alutaceous sparsely, finely punctate, setose; punctures each a long, erect hair-like seta. Eyes deeply emarginate just above antennal insertion, upper part smaller than lower part. Antennal scape long and slender, longer than club. Pedicel as wide as scape, shorter than funicle. Funicle 4-segmented, segment 1 longer than pedicel. Club approximately circular, flat, type 3; segment 1 corneous, transverse on anterior face, occupying basal ~1/3; segment 2 narrow, soft; segments 1‒3 present on posterior face. Pronotum 1.12 × as long as wide. In dorsal view subquadrate with prominent anterolateral corners, type 3, sides weakly convex; anterior margin without serrations. In lateral view tall, type 2, disc flat, summit at midpoint. Anterior slope with densely spaced, broad asperities, becoming lower and more strongly transverse towards summit. Disc strongly shiny with sparse, minute punctures, some longer hairlike setae at margins. Lateral margins obliquely costate. Base transverse, posterior angles acutely rounded, almost quadrate. Scutellum small, linguiform, flush with elytra, flat, shiny. Elytra: 1.44 × as long as wide, 1.43 × as long as pronotum. Base transverse, edge oblique and unarmed by granules, humeral angles rounded, parallel-sided in basal 3/4, then angulate to apex. Disc convex, shiny, striae not impressed, with large, shallow punctures separated by less than one diameter of a puncture, glabrous; interstriae flat, very sparsely finely punctate, punctures half size of strial punctures, each with a long, erect seta (mostly abraded). Declivity occupying approximately half of elytra, gradual, face flat, opalescent; striae impressed, strial punctures as large as those of disc; interstriae impunctate, interstriae uniformly minutely granulate along the entire length. Posterolateral margin elevated, carinate and granulate to interstriae 7. Legs: procoxae contiguous. Protibiae obliquely triangular, posterior face smooth; apical 1/3 of outer margin with five moderate, spaced socketed denticles, their length as long as basal width. Mesotibiae flattened; outer margin evenly rounded with eight moderate socketed denticles.

Distribution. Japan.

Host plants. Unknown.

Etymology. G. alastos = unforgettable. The specimen resided at least 140 years in the NHMUK before its recognition as a new species and its description. Adjective applied as a noun in apposition.

Figures

FIGURES 49‒52. Euwallacea alastos holotype, 3.2 mm. Dorsal, lateral, posterior oblique and anterior views.