Sitophilus linearis (Herbst, 1795)

Legalov, Andrei A., Vasilenko, Dmitry V. & Perkovsky, Evgeny E., 2023, First record of Sitophilus linearis (Herbst, 1795) (Coleoptera: Curculionidae) from East African copal, Ecologica Montenegrina 65, pp. 6-12 : 7-10

Sitophilus linearis (Herbst, 1795)

( Figs 1-2 )

Material: 1 ex., NHMD 189748 with old label “ Curculionidae fra Kopal ingen Data” [ Curculionidae from сopal without data]. Sample is an old piece of light-yellow copal in the shape of a rectangular prism ( Fig. 3 ) with dimensions of 16x7.3x 6.7 mm .

Description. Body brownish, subglabrous. Head nearly conical. Rostrum subcylindrical, nearly straight, 0.7 times as long as pronotum, about 4.9 times as long as wide at apex, about 4.2 times as long as wide in middle, about 3.3 times as long as wide at base, finely punctate, without carinae, with gentle and not subbulbose subbasal expansion. Eyes large, finely faceted, not protruding from contour of head. Temples longer than eye. Antennal scrobes contiguous to eye. Antennae short, inserted subbasally, reaching pronotum. First antennomere elongate-conical, weakly curved, about 4.4 times as long as wide at apex, reaching eyes. Funicle 6-segmented. Second-third antennomeres long-conical. Second antennomere about 1.6 times as long as wide at apex, 0.2 times as long as and 0.6 times as narrow as first antennomere. Third antennomere 1.5 times as long as wide at apex, slightly shorter and equal in width to antennomere. Fourthsixth antennomeres wide-conical. Fourth antennomere 0.8 times as long as wide at apex, about 0.6 times as long as and slightly wider than third antennomere. Fifth antennomere equal to fourth antennomere. Sixth antennomere about 0.7 times as long as wide at apex, subequal in length and about 1.3 times as wide as fifth antennomere. Antennal club compact, not truncate, about 1.4 times as long as wide in middle. Pronotum nearly bell-shaped, about 1.8 times as long as wide at apex, about 1.3 times as long as wide in middle and about 1.4 times as long as at base. Disk slightly flattened, densely punctate. Distances between punctations smaller than their diameter. Sides nearly straight. Scutellum semi-oval, equal in length and width. Elytra suboval, about 1.8 times as long as pronotum, about 1.7 times as long as wide at base, about 1.3 times as long as wide in middle, about 2.1 times as long as wide at apical fourth. Humeri weakly smoothed. Elytral striae regular and distinct, with large rounded punctation. Interstriae weakly convex, slightly narrower, or 1.0-2.0 times as wide as striae, lacking erect scales. Precoxal portion of prosternum quite long, about 1.2 times as long as procoxal cavity. Postcoxal portion of prosternum shorter, about 0.5 times as long as precoxal portion and about 0.t times as long as procoxal cavity. Procoxal cavities separated. Metaventrite weakly convex, finely punctate, 2.6 times as long as metacoxal cavity. Metepisternum about 5.4 times as long as wide in middle. Abdomen convex, finely punctate. First and second ventrites fused, subequal in length. Suture between first and second ventrites distinct. First ventrite about 0.6 times as long as metacoxal cavity. Third and fourth ventrites subequal in length. Third ventrite 0.8 times as long as second ventrite. Fifth ventrite about 3.7 times as long as fourth ventrite. Procoxae large, spherical. Femora weakly thickened, lacking teeth, punctate. Pro- and metafemora 3.0 times as long as maximum width. Tibiae nearly straight, attached to femora without brackets, with large uncus. Protibiae with large mucro. Protibia 4.3 times as long as wide at apex. Metatibia about 4.4 times as long as wide at apex. Tarsi long. First and second tarsomeres conical. Third tarsomere distinctly bilobed. Fifth tarsomere elongate. Tarsal claws free, divergent. Protarsi: first tarsomere 1.8 times as long as wide at apex; second tarsomere 1.1 times as long as wide at apex, about 0.7 times as long as and about 1.2 times as wide as first tarsomere; third tarsomere slightly longer than wide at apex, 1.4 times as long as and 1.5 times as wide as second tarsomere; fifth tarsomere about 5.1 times as long as wide at apex, 1.8 times as long as and about 0.4 times as wide as third tarsomere. Metatarsi: first tarsomere about 1.8 times as long as wide at apex; second tarsomere about 1.1 times as long as wide at apex, about 0.8 times as long as and about 1.2 times as wide as first tarsomere; third tarsomere equal in length and width at apex, 1.2 times as long as and about 1.4 times as wide as second tarsomere; fifth tarsomere 5.5 times as long as wide at apex, about 1.8 times as long as and about 0.3 times as wide as third tarsomere. Total body length (without rostrum) 4.1 mm. Length of rostrum 0.9 mm.

Remarks. The specimen belongs to the subfamily Dryophthorinae based on the geniculate antennae inserted at base with a compact antennal club, and a funicle with six antennomeres. Separated procoxal cavities, exposed metepisternum, free tarsal claws and tibiae attached to femora without brackets indicate placement in the tribe Litosomini . The specimen is placed in the subtribe Sitophilina because of bilobed third tarsomere and distinct suture between first and second ventrites. Antennae inserted before eye make it possible to assign the species to the genus Sitophilus . It is Sitophilus linearis because it has rostrum with gentle and not subbulbose subbasal expansion, antennal scrobes contiguous to eye and elytral interstriae lacking erect scales.

Figures

Figure 1. Sitophilus linearis, habitus, East African copal: a – ventro-lateral view, right; b – lateral view, left; c – dorsal view.

Figure 2. Sitophilus linearis, East African copal: a – rostrum, head and prosternum, ventral view; b – metaventrite and abdomen, ventral view.

Figure 3. Copal piece.