Taxonomic history

Xyleborus distinguendus Eggers, 1930: 205.

Cyclorhipidion distinguendum (Eggers): Maiti and Saha 2004: 105.

Synonyms

Xyleborus fukiensis Eggers, 1941b: 225. Smith et al. 2020b: 186.

Xyleborus ganshoensis Murayama, 1952: 16. Smith et al. 2020b: 186.

Diagnosis

2.5−3.11 mm long (mean = 2.78 mm; n = 15); 2.6−3.0 times as long as wide. This species is distinguished by the short, steep declivity that is approximately 25% of total elytral length, armed with large tubercles on interstriae 1 and 3, interstriae 2 always unarmed; posterolateral margins rounded; and declivital interstriae 1 setae in 3 confused rows and interstriae 2 setae in 2 confused rows. 

May be confused with

This species is a part of a challenging species group consisting of Cyclorhipidion bodoanum, C. inarmatum, C. pelliculosum, C. tenuigraphum, and C. xeniolum. They can be most readily separated using Smith et al. (2020b) table 1:

species

declivital interstriae 1 setae

declivital interstriae 2 setae

lateral profile of declivity

declivital interstriae 2 granulate

 total length (mm)

xeniolum

uniseriate

uniseriate

obliquely truncate

unarmed

1.65−1.8

bodoanum

uniseriate

uniseriate

steeply rounded

unarmed

1.7−2.2

inarmatum

2 rows, confused

uniseriate

steeply rounded

unarmed

2.8−3.0

tenuigraphum

2 rows, confused

2 rows, confused

steeply rounded

often on apical third

2.7−3.0

pelliculosum

3 rows, confused

uniseriate

steeply rounded

unarmed

3.2−3.5

distinguendum

3 rows, confused

2 rows, confused

steeply rounded

unarmed

2.5−3.1

Distribution

China (Beijing, Fujian, Hong Kong, Jiangxi, Yunnan), India (Uttarakhand), Japan, Nepal, South Korea, Taiwan, Thailand, Vietnam. Recently established in the United States (Hoebeke et al. 2018) and France (Dodelin 2018) as C. fukiense.

Host plants

recorded from Castanea, Cyclobalanopsis, Lithocarpus, and Quercus (Fagaceae), and probably with a close association with Fagaceae (Beaver et al. 2014)

DNA data

Sequences available for COI and CAD.

COI: MN199576MN199577MN619886MN619887MN199578MN619888MN619889MN619890

CAD: MN620171; MN620172MN620173;  MN620174MN199595MN199593MN199594