Tychius gracilitubus ( Bajtenov, 1977 )

Jiang, Chunyan, Caldara, Roberto & Zhang, Runzhi, 2020, The genus Tychius Germar (Coleoptera: Curculionidae: Curculioninae) in China, with description of three new species, Zootaxa 4856 (1), pp. 1-62 : 36-37

33. Tychius gracilitubus ( Bajtenov, 1977)

( Figures 109–112, 231–234, 301–302, 337, 349, 361, 394, 429, 455, 482)

Lepidotychius gracilitubus Bajtenov, 1977: 162 . Caldara, 1986: 187 ( Tychius ).

Material examined. CHINA: Shaanxi: Yulin Dingbian (1400 m), 1-VI-1987 (2); same data, 29-VII-1987 (3); Yulin Dingbian (1300 m), 30-VII-1986 (1); Jingbian, Jinjisha reservoir (37°37’N; 108°28’E, 1346m), Hedysarum fruticosum var. mongolicum , leg Chunyan Jiang, Xiaoliang Yang (3); Chengchuan (37°53’N; 108°1’E, 1360 m), Hedysarum fruticosum var. mongolicum , 21-V-2019, leg Chunyan Jiang, Xiaoliang Yang (4).

Redescription. Length 1.90–2.20 mm ( Fig. 109–112). Dorsal integument completely hidden by very dense, overlapped, broad, rounded to oval, yellowish scales, irregularly arranged on elytral interstriae. Rostrum ( Fig. 231– 234) in lateral view strongly curved in both sexes, especially in female (Rl/Rw 5.20–5.30 in male, 7.50–7.60 in female; Rl/Pl 0.80–0.91 in male, 1.10–1.27 in female). Eyes flat. Pronotum (Pw/Pl 1.10–1.22) with subrectilinear sides in basal half. Elytra rectangular (Ew/Pw 1.25–1.37; El/Ew 1.50–1.61), elongate. Femora ( Fig. 301–302) unarmed, tibiae ( Fig. 337) without sexual characters. Third tarsomere moderately wider than second tarsomere ( Fig. 349). Claws ( Fig. 361) with small medial teeth, a little less long than half of claw, fastened to claw in basal half. Male genitalia: body of penis ( Fig. 394) moderately wide and with sides slightly convergent in basal 1/3, then distinctly narrowed and parallel sided to apex, with subacute tip in dorsal view ( Fig. 429), with apex in lateral view upturned, twice longer than apodeme. Female genitalia: spermatheca ( Fig. 455) with long parallel-sided ramus, at right angle to cornu, short thin collum placed not at same plane of cornu as usually but at 90°, robust nodulus, cornu gradually narrowing to apex; spiculum ventrale ( Fig. 482) with arms slightly spaced and convergent in basal half, then joined to apex.

Remarks and comparative notes. This species is closely related to T. hedysaricus , from which it differs by the more curved rostrum in lateral view (especially in the female) and the more narrowed apical part of the penis in dorsal view. These same characters allow us to distinguish this species from all the others of the group. In three specimens of T. gracilitubus we did not find the apodemes of the penis ( Fig. 393) (see Discussion).

Biology. Recently some specimens were collected on Hedysarum fruticosum var. mongolicum . We also examined one specimen labeled as collected on Nitraria tangutorum Bobr. ( Nitrariaceae ); however, we believe this association to be incidental.

Distribution. This species was previously known only from Mongolia. New record from China (SHA).