Smicronyx crassithorax Haran, 2018

Haran, Julien, 2018, A review of the genus Smicronyx Schoenherr (Coleoptera, Curculionidae, Curculioninae) in tropical Africa, Zootaxa 4508 (2), pp. 267-287 : 272-273

Smicronyx crassithorax Haran sp. n.

Figs 1D , 3D , 5D

Material examined. Holotype ♂: ‘ Holotype [Red label]’ ‘195662. Mali. Kéniéroba , 70kmSW Bamako. 12°06’N 8°20’W. vi–vii.2014. V. Kravchenko (SMNHTAU) . Paratypes. Data as for holotype, 195664 (1♀, SMNHTAU); Data as for holotype, 195661 (1♀, MNHN). Other material. Tanganyika [ Tanzania], Ukiriguru , 14.x.1960, IAD Robertson, C. procera (1♂, BMNH) .

Description. Body length 2.3–2.5 mm. Colour. Body integument entirely reddish, antennae, rostrum, prothorax, suture of elytra and tarsi usually darker, integument clearly visible through vestiture; vestiture of elytra consisting of recumbent scales, rounded or twice as long as wide, whitish, forming more or less distinct transverse patches, and series of pale brown semi–erect elongate scales on each interstria; vestiture of prothorax consisting of whitish recumbent elongate scales oriented toward the median line, scales denser and thicker on sides and at base.

Head. Rostrum shorter than head capsule plus prothorax, almost straight, slightly longer and more downcurved in ♀ than in ♂, densely covered by scales and punctate between base and antennal insertion; antennas inserted near apical 1/3 (♀) or near apical ¼ (♂); transverse furrow at base of rostrum shiny; head capsule almost glabrous dorsally, with slight cover of scales, denser near transverse furrow; eyes flat, contiguous on ventral side; antennae dark reddish, scape bisinuate at base, moderately clavate at apex, segment 1 elongate, as long as 2+3, 4–5 quadrate, 6–7 wider than long. Prothorax. Wider than long (w/l ratio: 1.11), widest near middle, almost as wide as elytra at base, sides subparallel in basal two-thirds, narrowed at apex; integument greatly punctuate, distance between punctures less than diameter of punctures, integument between punctures smooth and shiny. Elytra. Sides subparallel in basal two-thirds, rounded in apical third, widest near middle (w/l ratio: 0.64); humeri raised; striae narrow, interstriae flat, wide and reticulate, apex of interstria 5 with moderate declivital callosity, followed by depression; scutellum small but visible, squamose. Abdomen. Underside mostly covered with non-overlapping whitish scales. Legs. Reddish, covered with whitish semi–erect elongate scales; femora greatly clavate, unarmed; tibiae straight, slightly bisinuate near middle. Genitalia. Penis moderately elongate (w/l ratio: 0.56), sides subparallel in basal half, converging towards apex in apical half, apex bilobate, curvature in lateral view stronger near apex ( Fig. 5D ).

Life history. Host plant unknown; the specimens were collected by sweeping vegetation, in June–July. Given the known biology of neighbouring species, the recording of 2 specimens on Calotropis procera (Apocynaceae) seems accidental.

Distribution. Mali, Tanzania.

Discussion. Smicronyx crassithorax belongs to the S. remaudierei species group (see discussion on S. remaudierei ). Within this species group, it can be distinguished from S. remaudierei and S. bisignatus by the absence of a distinct ventral tooth on the femora, and from S. adjamati by its much wider prothorax. It can be distinguished from S. zambianus by its reddish integuments and its elongate elytra of w/l ratio: 0.64 (black integuments and w/l ratio: 0.70 in S. zambianus ). The two examined individuals from Tanzania exhibited a distinctly larger overall body size and penis than those from Mali. The number of specimens available for this study was too limited to explore the stability of these characters in this population.

Name derivation. Smicronyx crassithorax is named in reference to the particularly large dimensions of its prothorax.

Figures

FIGURE 1. Habitus of species of Smicronyx from tropical Africa (Part 1). A. Smicronyx bisignatus Hoffmann, holotype ♂. B. S. remaudierei Hoffmann, holotype ♂. C. S. adjamati, sp. n., holotype ♂. D. S. crassithorax sp. n., paratype ♀. E. S. zambianus sp. n. holotype ♂. F. S. syriacus Faust, specimen from Israel (♂). G. S. gossypii Marshall, holotype ♂. H. S. albosquamosus Wollaston, specimen from Israel (♂). I. S. pauperculus Wollaston, specimen from Tanzania (♂). J. S. rufus sp. n., holotype ♂. K. S. zonatus sp. n., holotype ♂. L. S. kenyanus sp. n., holotype ♂. Scale bars (A to L): 1 mm.

FIGURE 3. Head and prothorax in lateral view of species of Smicronyx from tropical Africa (Part 1). A. Smicronyx bisignatus Hoffmann, holotype ♂. B. S. remaudierei Hoffmann, holotype ♂. C. S. adjamati, sp. n., holotype ♂. D. S. crassithorax sp. n., paratype ♀. E. S. zambianus sp. n. holotype ♂. F. S. syriacus Faust, specimen from Israel (♂). G. S. gossypii Marshall, holotype ♂. H. S. albosquamosus Wollaston, specimen from Israel (♂).

FIGURE 5. Penis of Smicronyx from tropical Africa, in dorsal (left) and lateral (right) view. A. Smicronyx bisignatus Hoffmann, holotype ♂. B. S. remaudierei Hoffmann, holotype ♂. C. S. adjamati, sp. n., holotype ♂. D. S. crassithorax sp. n., paratype ♀. E. S. zambianus sp. n. holotype ♂. F. S. syriacus Faust, specimen from Israel (♂). G. S. gossypii Marshall, holotype ♂. H. S. albosquamosus Wollaston, specimen from Israel (♂). I. S. pauperculus Wollaston, specimen from Tanzania (♂). J. S. rufus sp. n., holotype ♂. K. S. zonatus sp. n., holotype ♂. L. S. kenyanus sp. n., holotype ♂. M. S. namibicus sp. n., holotype ♂. N. S. kiboanus Voss, paratype ♂. O. S. guineanus Voss, specimen from Senegal (♂). P. S. buchnerae sp. n., holotype ♂. Scale bars (A to N): 100 µm.