Cnestus nitidipennis (Schedl, 1951)

Smith, Sarah M., Beaver, Roger A. & Cognato, Anthony I., 2020, A monograph of the Xyleborini (Coleoptera, Curculionidae, Scolytinae) of the Indochinese Peninsula (except Malaysia) and China, ZooKeys 983, pp. 1-442 : 1

Cnestus nitidipennis (Schedl, 1951) Fig. 33E, F, K

Xyleborus nitidipennis Schedl, 1951a: 88.

Cnestus nitidipennis (Schedl): Kalshoven 1959b: 165.

Type material.

Holotype (NHMW).

New records.

China: Hainan, Jianfengling Mt., 600 m, 26.iii.1984, Shimei Song (NMNH, 1). Sichuan, Leibo, 19.iv.1964, ex Carpinus (NMNH, 1). S Yunnan, Xishuangbanna, 20 km NW Jinghong, vic. Man Dian (NNNR), 22°07.80'N, 100°40.05'E, 730 m, 8.vii.2008, A. Weigel (NKME, 1); as previous except: 23 km NW Jinghong, vic. Na Ban village (NNNR), 22°10'N, 100°39'E, 700-1000 m, v-vii.2009, L. Meng (RABC, 1); as previous except: 37 km NW Jinghong, vic. Guo Men Shan, 22°14.48'N, 100°36.22'E, 1080 m, forest, 28.vi.2008, L. Meng (NKME, 1). Vietnam: Lao Cai, Hoang Lien N.P., 22.35, 103.77, 1500-2000 m, 20.v.2019, VN185, S.M. Smith, A.I. Cognato, ex 1-2 cm branch (MSUC, 1).

Diagnosis.

2.8-3.2 mm long (mean = 3.0 mm; n = 4); 2.14-2.28 × as long as wide. This species is distinguished by the uniquely emarginate epistomal margin; enlarged mandibles (in lateral view protruding forward at 90° to the plane of the frons, dorsoventrally deeper than normal; in anterior view, with an upwardly directed, smooth, rounded process on the dorsal side); absence of a mesonotal mycangial tuft on the pronotal base; pronotum from dorsal view type 6; pronotum apex strongly produced, extending to a process with numerous serrations; body glabrous, strongly shiny; declivity strongly rounded; protibiae very slender with three large, narrow denticles on outer margin; antennal club type 1, with no sutures visible on the posterior face; and 3-segmented antennal funicle.

This species is very similar to C. protensus and is distinguished by the smaller size, pronotal base with punctures clearly finer, sparser, surface smooth, shiny, pronotum appearing narrow, sides of pronotum parallel for approximately 2/3 total length.

Similar species.

Cnestus protensus .

Distribution.

China* (Fujian, Hainan, Sichuan, Yunnan), India (Arunachal Pradesh*, Sikkim), Indonesia (Java), Taiwan, Thailand, Vietnam.

Host plants.

Likely polyphagous. Recorded from Eupatorium ( Asteraceae ) ( Kalshoven 1959b) and Carpinus ( Betulaceae ).

Remarks.

Both C. nitidipennis and C. protensus possess unique morphology among Cnestus species including the pronotal apex very strongly produced, very slender protibia, enlarged mandibles and absence of a mycangial tuft. These morphological characters are convergent with Neotropical genera such as Sampsonius Eggers, 1935 ( Xyleborini ) and Amphicranus Erichson, 1836 ( Corthylini ) ( Wood 2007) which are inquilines. Further investigation of their behavior is necessary to determine if these species are also inquilines.

Figures

Figure 33. Dorsal, lateral and declivital view of Cnestus improcerus, 2.7 - 3.3 mm (A, B, I), C. mutilatus, 3.6 - 3.8 mm (C, D, J), C. nitidipennis, 2.8 - 3.2 mm (E, F, K), and C. protensus, 3.3 - 5.4 mm (G, H, L).