Streptocranus petilus, Smith & Beaver & Cognato, 2020

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

Streptocranus petilus sp. nov. Fig. 76

Type material.

Holotype, female, China: Yunnan, Jinghong, 24.i.2018, Shengchang Lai, ex Hevea brasiliensis (IZAS).

Diagnosis.

2.3 mm long (n = 1); 3.83 × as long as wide. This species is distinguished by its small size; elytra with sides nearly parallel from base to apex; declivital interstriae 1 and 3 with two or three granules; and elytral distal projection short, subquadrate, strongly carinate.

Similar species.

Streptocranus bicolor , S. fragilis , S. mirabilis .

Description

(female). 2.3 mm long (n = 1); 3.83 × as long as wide. Body light to dark brown. Legs and antennae light brown. Head: Missing. Pronotum: 1.48 × as long as wide. In dorsal view conspicuously elongate and quadrate frontally, type c, sides tapering from summit to base; anterior margin without serrations. In lateral view conspicuously elongate and hooded frontally, type a, summit on apical 1/5. Anterior slope steep with densely spaced small asperities, becoming lower and more strongly transverse towards summit. Disc shiny, glabrous, with sparse, fine punctures. Lateral margins concave above procoxae. Base transverse, posterior angles narrowly rounded. Elytra: 2.28 × as long as wide, 1.5 × as long as pronotum. Scutellum small, triangular, flush with elytra, flat, shiny. Elytral base transverse, edge oblique, humeral angles rounded, nearly parallel-sided along entire length, apex emarginate, each elytron with a short, subquadrate, strongly carinate distal projection that is shorter than the depth of the emargination. Disc shiny; striae irregularly seriate, not impressed, with moderately sized, shallow punctures separated by 1-3 diameters of a puncture, glabrous; interstriae flat, impunctate, glabrous. Declivity short, occupying apical 1/4, gradually rounded, shiny; striae flat, punctures as large as those of disc; interstriae laterally diverging from base to apex, interstriae 1 and 3 with two or three granules, each granule with a moderately long, erect hair. Posterolateral margin rounded. Legs: procoxae contiguous; prosternal coxal piece short, inconspicuous. Protibiae slender with evenly rounded outer edge, broadest at apical 1/3; posterior face smooth; apical 1/3 of outer margin with four large socketed denticles, their length longer than basal width. Meso- and metatibiae flattened; outer margin obliquely triangular with four and five large socketed denticles, respectively.

Distribution.

China (Yunnan).

Etymology.

L. petilus = slender. In reference its general habitus. An adjective.

Host plants.

This species is only known from Hevea brasiliensis ( Euphorbiaceae ).

Remarks.

The head of the holotype was destroyed during fungal culturing and could not be examined.

Figures

Figure 76. Dorsal, lateral and declivital view of Streptocranus petilus holotype, 2.3 mm (A-C).