Scolytus aztecus Wood, 1967

Smith, Sarah M. & Cognato, Anthony I., 2014, A taxonomic monograph of Nearctic Scolytus Geoffroy (Coleoptera, Curculionidae, Scolytinae), ZooKeys 450, pp. 1-182 : 30-31

Taxon classification Animalia Coleoptera Curculionidae

Scolytus aztecus Wood, 1967 Fig. 26

Scolytus aztecus Wood, 1967: 120.

Diagnosis.

Scolytus aztecus are distinguished by the characteristics of the elytral apex with the apical margin produced between interstriae 1 and 2, deeply emarginated at interstriae 3, produced on interstriae 4 and deeply emarginated at stria 4.

Description (male).

5.0 mm long (mean = 5.0 mm; n = 2); 2.5 times as long as wide. Body dark red-brown to black, antennae light brown, legs light brown to dark red-brown. Pronotum typically darker than elytra.

Head. Epistoma broadly, deeply emarginated; epistomal process weakly developed, low; median area above mandibles bearing dense patch of long yellow hair-like setae. Frons appearing flattened when viewed laterally, slightly transversely impressed just above epistoma; surface moderately, coarsely longitudinally aciculate-punctate; aciculations converging at epistoma; punctures large, coarse and more dense medially above epistoma; surface moderately and uniformly covered by long, fine, yellow erect hair-like setae, setae longer than width of midpoint of eye. Antennal scape short, elongate; club flattened, almost subquadrate, setose with partial septum, two arcuate sutures visible.

Pronotum as long as wide; apical margin broadly rounded, area between eyes lined with scales; sides distinctly arcuate, strongly constricted near apex, forming a weak transverse impression near apical margin; surface smooth, shining, punctures on disc fine, shallow and moderately abundant, larger, more abundant laterally and on apical constriction; apical, anterolateral and lateral margins bearing moderately abundant, erect, yellow hair-like setae; base weakly bisinuate.

Elytra with sides sub-parallel on apical half, narrowing to rounded, serrate apex; apical margin of elytra produced between interstriae 1 and 2, deeply emarginated at interstria 3, produced on interstria 4 and deeply emarginated at stria 4; apical margin of elytral apices bearing large, coarse punctures; apex moderately emarginated at suture. Disc smooth, shining; interstriae bearing short, sparse yellow hair-like setae spaced by length of a setae or less; interstriae weakly impressed, more than twice width of striae, interstrial punctures uniseriate, smaller than those of striae; striae moderately impressed. Declivity bearing sparse, short, erect yellow setae. Metepimeron half-length of metanepisternum.

Venter. Apical margin of ventrite 1 weakly elevated above base of ventrite 2. Ventrite 2 nearly perpendicular to ventrite 1; surface rugose, coarsely, deeply punctate; covered with abundant erect setae that are greater than length of segment 3; surface convex; armed medially with laterally compressed spine with base extending from apical margin to ¾ of segment, apex rounded, shining, impunctate; lateral margins of ventrites 2-3 and ventrite 4 unarmed. Ventrite 5 carinate ridge closer to basal margin of segment; length of ventrite 5 greater than combined lengths of ventrites 3 and 4; setal patch and median depression absent.

Female.

4.6-5.9 mm long (mean = 5.23 mm; n = 4); 2.3-2.5 times as long as wide. Similar to male except epistoma feebly and broadly emarginated, epistomal process absent, frons convex when viewed laterally, weakly longitudinally aciculate, setae sparse, shorter, less than width of eye; frons weakly transversely impressed on lateral margins above epistoma and at vertex; median line on frons raised. Apical margin of elytra slightly produced between interstriae 1 and 2, emarginated at interstria 3, slightly produced on interstria 4 and emarginated at stria 4. Second ventrite unarmed.

Specimens examined.

11.

Type material.

Holotype Scolytus aztecus Wood: female, labeled "27 mi E. Morelia, Mich., VI-4-1965, Mexico, 8,000 ft, S.L. Wood, Abies religiosa " (USNM). Paratypes: MEXICO: Michoacán: 27 mi E. Morelia, 14.VI.1965, S.L. Wood, ex. Abies religiosa (USNM-3).

Non-type material.

MEXICO:DURANGO: Potreyo del Sauto y Cebadillas, 19.IV.[19]90, J. Tulio Mendez M., 935-A, ex. Pseudotsuga menziesii (THAC-4). Nuevo León: Santa Catarina, San Antonio de las Alazanas, 14.XII.2011, Gerardo Cuellar, ex. Pseudotsuga menziesii (MSUC-3).

Distribution.

MEXICO: Durango, Michoacán, Nuevo León (Fig. 27).

Hosts.

Abies religiosa (Kunth) Schltdl. & Cham. (sacred fir), Abies durangensis Martínez (Durango fir) and Pseudotsuga menziesii (Mirb.) Franco (Douglas fir). Abies species are likely the preferred host.

Biology.

Scolytus aztecus is an uncommon species and little is known regarding its biology. Scolytus aztecus colonizes both standing trees and felled trees ( Wood 1967; Cibrián Tovar et al. 1995). The treetops attacked by Scolytus aztecus exhibit red foliage. Scolytus aztecus has been collected feeding in the cambium of large Abies trees, although it has also been collected from Pseudotsuga . Because of limited host records, it is unknown whether the primary host is Abies or Pseudotsuga . Phylogenetic placement of the species suggests Abies (Fig. 4) because the species belongs to a clade of Abies feeding taxa. The adult gallery is transverse across the grain of the wood with a central nuptial chamber, similar in appearance to that of Scolytus ventralis (see Cibrián Tovar et al. 1995, fig 132). Larval mines are in the cambium and do not score the wood. Pupation occurs in the cambium ( Wood 1967; Cibrián Tovar et al. 1995).

Remarks.

This is the first description of a male for this species.