Scolytus rabaglii Smith and Cognato

Smith, Sarah M. & Cognato, Anthony I., 2013, A New Species of Scolytus Geoffroy, 1762 and Taxonomic Changes Regarding Neotropical Scolytini (Coleoptera: Curculionidae: Scolytinae), The Coleopterists Bulletin 67 (4), pp. 547-556 : 553-555

Scolytus rabaglii Smith and Cognato , new species

( Figs. 12–23 )

Type Material. Holotype,female, VENEZUELA: Táchira: 42km SE San Cristobal, 700m, 19.V.1974, H. & A. Howden ( DEBC) . Paratypes 18: VENEZUELA: Intercepted at Detroit, MI, 30. VI.1983, W. Waisanen, Detroit MI 003178, ex. in dunnage (MSUC-2, RJRC-2, USNM-14) .

Diagnosis. Scolytus rabaglii has distinctive morphology: both sexes are easily distinguished from other Neotropical Scolytus by the combination of lateral teeth on the apical margins of sternites 2–4 ( Figs. 16–17 , 22–23 ), the absence of a callus or bulla on sternite 5 ( Figs. 16–17 , 22–23 ), the convex and reticulate frons that is impressed just above the epistoma ( Figs. 14–15 , 20–21 ), the apical margin of sternite 2 armed with a long, latitudinally flattened and wide spine with the base extending from the basal margin to at least ¾ the length of the segment, anterior height equal to longitudinal basal width ( Figs. 12, 16–18, 22–23 ), by the minutely and obscurely punctured sternites 3–5 and by the dull and shagreened appearance of sternites 3–5 ( Figs. 16–18, 22–23 ).

Description (Male). ( Figs. 12–17 ). 3.0– 3.2 mm long (mean = 3.12 mm; n = 4); 2.13–2.46 times as long as wide. Head, pronotum, elytra, and abdominal venter dark red-brown; legs and antennae yellowbrown. Pronotum typically darker than elytra.

Epistoma entire; epistomal process absent; median area above mandibles bearing dense patch of long, yellow, hair-like setae. Frons appearing convex when viewed laterally; apical third of frons transversely impressed above epistoma; surface moderately and coarsely longitudinally rugose-reticulate and punctate to just dorsally of inner apices of eyes; reticulations converging at epistoma; punctures small, coarse; surface slightly and uniformly covered by long, fine, yellow, erect, hair-like setae, setae longer than half width of eye. Antennal scape short, elongate, less than length of first 4 funicular segments; club flattened, oblong, about twice as long as wide, densely setose; sutures not evident.

Pronotum about as long as wide; apical margin broadly rounded, area between eyes lined with scales; sides distinctly arcuate, strongly constricted near apex; basal half of pronotal surface smooth, shining, punctures on disc fine; apical half weakly strigose, punctures shallow and moderately abundant, larger, coarser and more abundant laterally and on apical constriction; apical and anterolateral margins bearing sparse, erect, yellow, hair-like setae; base weakly bisinuate.

Elytral bases weakly elevated from interstriae 1–6. Elytral sides sub-parallel on apical half, narrowing to quadrate and smooth apex; apical margin of elytral apices smooth, shining; apex entire. Disc smooth, shining; interstrial punctures weakly impressed, interstriae more than twice width of striae, interstrial punctures uniseriate, equal in size to those of striae; strial punctures weakly impressed, punctures bearing sparse, long, semi-erect, pale yellow, hair-like setae from base to apex. Metepimeron less than half length of metepisternum.

Apical margin of sternite 1 weakly elevated above base of sternite 2. Sternite 2 nearly perpendicular to sternite 1; surface smooth, shagreened, finely punctate with small, coarse punctures; face flattened; apical margin armed with long, latitudinally flattened and wide spine with base extending from basal margin to at least 3/4 length of segment, anterior height equal to longitudinal basal width, spine variable in shape but always long, flattened and apically hooked towards elytra; each lateral margin of sternites 2–4 armed with lateral tooth, lateral teeth progressively smaller from sternite 2 to 4. Sternite 5 with carinate ridge along apical margin of segment. Venter covered in moderately abundant, long erect, pale yellow setae.

Female. ( Figs. 18–23 ). 2.0–3.0 mm long (mean = 2.9 mm; n = 15); 2.1–2.5 times as long as wide. Similar to male except setae more abundant on frons, spine on segment 2 smaller, shorter, narrower and less strongly flattened with its base extending from apical margin to 1/2 length of segment, spine uniformly falx-shaped.

Distribution. Venezuela (Táchira).

Biology. Unknown. This species was intercepted in transit to Detroit , Michigan, USA on 30 June 1983 .

Etymology. The name rabaglii honors Robert Rabaglia’ s (USDA Forest Service) contribution to the knowledge of adventive bark beetles.

Notes. There is a large amount of variation observed in the shape of the median spine on male sternite 2. Of the four individuals examined, one has a median longitudinal carina instead of a spine, and the size of the spine is variable but is larger than those of the female.

Figures

Figs. 12–17. Scolytus rabaglii, male. 12) Lateral view; 13) Dorsal view; 14) Head, anterior view; 15) Head, anterior oblique view; 16) Venter, posterior view; 17) Venter, posterior oblique view.

Figs. 18–23. Scolytus rabaglii, female. 18) Lateral view; 19) Dorsal view; 20) Head, anterior view; 21) Head, anterior oblique view; 22) Venter, posterior view; 23) Venter, posterior oblique view.