Cryptoxyleborus mawdsleyi, Beaver & Hulcr, 2008

Beaver, Roger A. & Hulcr, Jiri, 2008, A Review of the Ambrosia Beetle Genus Cryptoxyleborus Schedl (Coleoptera: Curculionidae: Scolytinae), The Coleopterists Bulletin 62 (1), pp. 133-153 : 133-153

Key to Females of Species of Cryptoxyleborus

1. Each elytron with a mycangial pit visible close to scutellum opening on dorsal surface. Eyes large extending onto frons...................................... 2

– Elytra either with mycangial pit(s) opening onto basal declivital slope of elytra, or without evident mycangial pits. Eyes variable..................... 6

2. Elytra excavate from basal third, margins of excavation raised in apical half and with a row of backwardly pointing teeth, including a larger pair of teeth directed obliquely towards midline at about two-thirds of elytral length. 4.1 mm long........................................... C. mawdsleyi new species

– Elytra not excavate, convexly rounded on disc and declivity................ 3

3. Apex of elytron truncate, when viewed from behind, forming a small, approximately oval, impunctate, flattened facet. Anterior margin of pronotum not produced anteriorly, with two slightly larger marginal asperities in the middle. Mycangial pits subtriangular in shape. 1.9–2.3 mm long............................................................ C. barbieri Schedl

– Apex of elytron not truncate, without an apical, impunctate facet. Anterior margin of pronotum produced or not. Mycangial pits subcircular, oval or triangular......................................................................... 4

4. Anterior margin of pronotum slightly produced forwards medially, with two larger asperities on the projection. Mycangial pits triangular or oval....... 5

– Anterior margin of pronotum usually evenly rounded, sometimes slightly produced medially, with a row of several small, subequal asperities. Mycangial pits subcircular. 2.0– 2.4 mm long............ C. subnaevus Schedl 5. Elytra tapering in apical one-third only. Body length 2.5–3.0 mm............................................................................. C. naevus Schedl

– Elytra tapering in apical two-thirds. Body length 2.0– 2.1 mm ........................................................................... C. cuneatus new species

6. Eyes large, extending well onto frons, coarsely facetted. Interstriae 2 with uniseriate, acute, slightly hooked tubercles, usually present on at least posterior part of disc and declivity, but confined to apex of declivity in oxyurus ........................................................................... 7

– Eyes of moderate size, not extending far onto frons, more finely facetted. Interstriae without hooked tubercles.......................................... 12

7. Elytral disc with a transverse, saddle–like depression in the basal half, and a subapical tooth at the suture. Interstriae 2 with strong hooked tubercles from basal third........................................................................ 8

– Elytral disc without a transverse depression, or a subapical tooth at the suture. Interstriae with weak hooked tubercles, usually beginning only at or behind middle of elytra.......................................................... 9

8. Elytral disc with striae 1 deeply impressed in transverse depression. Sides of elytra subparallel in basal three quarters, then strongly incurved to apex. Tubercles on elytral declivity strong. 4.8 mm long......... C. major Browne

– Elytral disc with striae 1 not deeply impressed. Sides of elytra subparallel in basal two thirds, then gradually tapering to apex. Tubercles on elytral declivity less strong. 3.6–4.5 mm long....................... C. eggersi Schedl

9. Mycangia in elytral bases open by four pores. Hooked tubercles on interstriae 2 start behind middle of elytron. Interstriae 1 and 2 not ending in apical spines or teeth............................................ C. quadriporus Beaver

– Mycangia in elytral bases opening by a transverse slit. Hooked tubercles either starting before middle of elytron, or confined to apex. Elytral apices with spines or teeth............................................................. 10

10. Body length 4.0– 4.2 mm. Elytral disc glabrous, interstriae on declivity with a few scattered, rather coarse, semierect hairs. Hooked tubercles on interstriae 2 confined to elytral apex. Elytral apices separately acuminate, separated by a small V–shaped emargination................................ C. oxyurus Schedl

– Body length less than 3.5 mm. Both striae and interstriae with well–developed vestiture of fine, appressed and erect hairs. Hooked tubercles on interstriae 2 begin in anterior half of elytra. Elytra with a pointed or truncate tooth at the apex of interstriae 2, without a clear emargination.......................... 11

11. Body length 3.1–3.2 mm. Elytral vestiture irregularly biseriate on interstriae 2–4 of disc. Elytra with a truncate or pointed tooth at the apex of interstriae 2.......................................................... C. turbineus (Sampson)

– Body length 2.3–2.4 mm. Elytral vestiture uniseriate on all interstriae of disc, except at base of elytra. Elytra with a pointed tooth at the apex of interstriae 2......................................................... C. stenographus (Schedl)

12. Antennal club flattened with apical part of anterior face of first segment convex, and second segment well–developed, corneous (types 3,4; Fig. 4 ). 13

– Antennal club obliquely truncate, with apical portion of anterior face of first segment concave, second segment weakly developed, rarely corneous (types 1, 2; Fig. 4 )......................................................................... 16

13. Elytral interstriae reticulate–punctate, the shallow punctures very densely placed at the base, the punctures confused on the disc. 2.5–2.6 mm long.................................................................. C. confusus Browne

Figures

Fig. 4. Formalized types of antennal club found in Xyleborina. After Hulcr et al. (2007a). Upper row - 5 basic types; second row - variations of the types 1–3; third row - posterior face of the club of types 1 and 2; fourth row - lateral view of types 1–3.