Xyleborinus attenuatus

Taxonomic history

Xyleborus attenuatus Blandford, 1894b: 114.

Xyleborinus attenuatus (Blandford): Beaver and Liu, 2010: 30.

Synonyms

Xyleborus alni Niisima, 1909: 160. Knížek, 2011: 246.

Xyleborus canus Niisima, 1909: 161. Smith et al., 2018b: 397.

Diagnosis

2.6−2.9 mm long (mean = 2.78 mm; n = 5); 2.9−3.25 times as long as wide. This species is distinguished by the declivitaldeclivital:
pertaining to the elytral declivity
face with interstriaeinterstria:
longitudinal spaces along the elytra between the striae, which is not as<br /> impressed and bear smaller punctures.
2 armed by granulesgranule:
a small rounded protuberance, like grains of sand
at declivitaldeclivital:
pertaining to the elytral declivity
summit, unarmed on declivitaldeclivital:
pertaining to the elytral declivity
face; denticlesdenticle:
a small tooth, the sides of which are equal and the tip is above the middle of the base
of declivitaldeclivital:
pertaining to the elytral declivity
interstriae 3 larger than those of interstriaeinterstria:
longitudinal spaces along the elytra between the striae, which is not as<br /> impressed and bear smaller punctures.
1; denticlesdenticle:
a small tooth, the sides of which are equal and the tip is above the middle of the base
pointed, spine-like, slightly incurved; denticlesdenticle:
a small tooth, the sides of which are equal and the tip is above the middle of the base
on interstriaeinterstria:
longitudinal spaces along the elytra between the striae, which is not as<br /> impressed and bear smaller punctures.
5 large, sharply pointed, spine-like, curved slightly downwards; discaldiscal:
pertaining to the disc of either the pronotum or elytra
interstriae 1 and 2 unarmed; de­clivital interstriaeinterstria:
longitudinal spaces along the elytra between the striae, which is not as<br /> impressed and bear smaller punctures.
2 flattened; and large size.

This species is nearly identical to Xyleborinus thaiphami and can be distinguished by the declivitaldeclivital:
pertaining to the elytral declivity
interstriae 3 denticlesdenticle:
a small tooth, the sides of which are equal and the tip is above the middle of the base
that are incurved rather than acutely pointed and interstriaeinterstria:
longitudinal spaces along the elytra between the striae, which is not as<br /> impressed and bear smaller punctures.
5 denticlesdenticle:
a small tooth, the sides of which are equal and the tip is above the middle of the base
always down-curved.

May be confused with

Xyleborinus saxesenii, X. subgranulatus, X. subspinosus, and X. thaiphami

Distribution

China (Chongqing, Shaanxi), Japan, South Korea, Russia (Far East), Taiwan; introduced and established in Central and Northern Europe and North America (Knížek 1988, Hoebeke and Rabaglia 2007Hoebeke and Rabaglia 2007:
Hoebeke ER, Rabaglia RJ. 2007. First reported occurrence of Xyleborinus alni (Coleoptera: Curculionidae: Scolytinae) in the eastern United States, with notes on its recognition and tree hosts. Proceedings of the Entomological Society of Washington 109: 240-248., Gomez et al. 2018aGomez et al. 2018a:
Gomez DF, Rabaglia RJ, Fairbanks KEO, Hulcr J. 2018a. North American Xyleborini north of Mexico: a review and key to genera and species (Coleoptera, Curculionidae, Scolytinae). ZooKeys 768: 19-68. https://doi.org/10.3897/zookeys.768.24697)

Host plants

recorded from trees in the families Betulaceae, Fagaceae and Rosaceae (Beaver and Liu 2010Beaver and Liu 2010:
Beaver RA, Liu L-Y. 2010. An annotated synopsis of Taiwanese bark and ambrosia beetles, with new synonymy, new combinations and new records (Coleoptera: Curculionidae: Scolytinae). Zootaxa 2602: 1-47. https://doi.org/10.11646/zootaxa.2602.1.1) and Pinus (Pinaceae) (Smith et al. 2020bSmith et al. 2020b:
Smith SM, Beaver RA, and Cognato AI. 2020b. A monograph of the Xyleborini (Coleoptera, Curculionidae, Scolytinae) of the Indochinese Peninsula (except Malaysia) and China. ZooKeys 983: 1-442. https://doi.org/10.3897/zookeys.983.52630)

DNA data

Sequences available for COI and CAD.

COI: OP617790

CAD: OP607220