Xylosandrus geduensis 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 : 5-8

Xylosandrus geduensis Smith & Beaver sp. nov.

( Figs 9‒12 )

http://zoobank.org/ urn:lsid:zoobank.org:act:845C6E48-F4B5-47B0-8AAC-244459B1C562

Type material. Holotype, female: Bhutan, Gedu, 6.viii.[19]85, X. Padgham coll., ex Trewia nudiflora CIE A 17491, NHMUK014591825 ( NHML).

Diagnosis. 2.1 mm long (n = 1); 2.33 × as long as wide. This species is distinguished by the small size; declivity obliquely truncate, abruptly separated from disc; posterolateral margins of elytra carinate to interstriae 7; declivital face with 5 punctate striae; declivital interstriae with densely uniseriate denticles; pronotum from dorsal view rounded (type 1) and lateral view basic (type 0), pronotal summit at midpoint, basal 1/2 smooth, shining, sparsely minutely punctate; sparse mycangial tuft on the pronotal base; and outer margin of protibia armed with 5 large socketed denticles.

Description (female). 2.1 mm long (n = 1); 2.33 × as long as wide. Head, pronotum and elytral disc light redbrown, declivity dark red-brown, antennae and legs light brown. Head: epistoma entire, transverse, with a row of hair-like setae. Frons weakly convex to upper level of eyes; median carina present; surface shagreened, sparsely punctate, punctures, large, shallow, alutaceous, sparsely setose, setae erect, hair-like. Eyes very shallowly emarginate just above antennal insertion, upper part smaller than lower part. Submentum broad, triangular, deeply impressed. Antennal scape regularly thick, approximately as long as club. Pedicel as wide as scape, shorter than funicle. Funicle 4-segmented, segment 1 as long as pedicel. Club 1.1 × taller than broad, subcircular, obliquely truncate, type 1; segment 1 corneous, encircling anterior face, margin costate. Pronotum: 1.11 × as long as wide. In dorsal view rounded, type 1, sides parallel in basal 1/2, rounded anteriorly; anterior margin with a row of six serrations. In lateral view basic, type 0, disc flat, summit at midpoint. Anterior slope with densely spaced, moderate asperities, becoming lower and more strongly transverse towards summit, bearing long, fine, erect hair-like setae, some longer hair-like setae at anterior and lateral margins. Disc shining, alutaceous with sparse, fine punctures, glabrous. Lateral margins obliquely costate. Base transverse, posterior angles broadly rounded. Mycangial tuft present along basal margin, tuft broad, sparse, laterally extending to striae 3. Elytra: 1.22 × as long as wide, 1.1 × as long as pronotum. Scutellum moderately sized, linguiform, flush with elytra, flat, shining. Elytral base transverse, edge oblique, humeral angles rounded, parallel-sided in basal 2/3, then broadly rounded to apex. Striae punctate, not impressed. Disc occupying basal half of elytra, shining, interstriae punctate, moderately setose, setae semi-erect, hair-like. Declivity sharply distinct from disc, 5 striae visible, strial punctures larger, deeper than those of disc; interstriae with densely uniseriate denticles, denticles small, spaced 2-4 diameters of a denticle, with erect hair-like setae, as long as the distance between suture and striae 2. Apex emarginate, margins acutely carinate. Posterolateral margin carinate to interstriae 7. Legs: procoxae widely separated; prosternal coxal piece flat, inconspicuous. Protibiae slender, broadest at apical 1/4; posterior face smooth; outer margin of apical 1/2 with 5 large socketed denticles, their length much longer than basal width; apical mucro prominent, strongly incurved. Meso- and metatibiae flattened, outer margins evenly rounded with 10 and 12, small similarly sized socketed denticles, their length no longer than basal width, respectively.

Distribution. Bhutan.

Host plants. Mallotus (= Trewia ) nudiflorus ( Euphorbiaceae )

Etymology. In reference to the type locality, Gedu. Latinized adjective.

Remarks. This species is very similar to the Indomalayan species Xylosandrus derupteterminatus (Schedl) . It can be separated by the following combination of characters ( X. geduensis given first): elongate form, 2.33 × as long as wide vs stout 1.82–2.0 × as long as wide ( Smith et al. 2020); outer margin of protibia with 5 denticles vs 4 denticles; more gradual declivital slope, declivity occupying 1/2 of elytra vs. 2/5 of elytra; and interstrial setae shorter, as long as the distance between suture and striae 2 vs. longer, as long as the distance between the suture and striae 3.

Figures

FIGURES 9‒12. Xylosandrus geduensis holotype, 2.1 mm. Dorsal, lateral, posterior oblique and anterior views.