Heisonyx hexarthrum Borovec & Colonnelli & Osella 2009, sp. nov.
Creators: name: Borovec, Roman
name: Colonnelli, Enzo
name: Osella, Giuseppe
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Curculionidae
Heisonyx
Heisonyx hexarthrum

description: Heisonyx hexarthrum sp. nov.   
(Figs. 7, 14, 24–25)  
 Type material. HOLOTYPE: J (BMNH), ‘ South Africa, Cape Province, Mossel Bay, 15.iii.-20.iv.1932, R. E. Turner’. ALLOTYPE: ♀ (BMNH), same data as holotype. PARATYPES: the same data as holotype, except of date: 3 spec. 15.iii.- 20.iv.1932; 17 spec. x.1933; 1 spec. 20.x.1938; 2 spec. 25.x.1938; 1 spec. 31.x.1938; 1 spec. 28.xi.1938; 5 spec. 7.xii.1938; 1 spec. 10.xii.1938; 10 spec. 11.xii.1938; 1 spec. 14.xii.1938; 1 spec. 26.i.1939; 7 spec. June 1921 (all BMNH, except of 3 spec. in ECRI, GOAI, RBSC).   
 Description. Body length: 1.9–2.1 mm, holotype 1.9 mm (males); 2.0– 2.3 mm (females).   
Integument black, legs and antennae sometimes brownish. Whole body except antennal club very densely covered by regularly rounded, very shallowly longitudinally striate scales. Coloration of scales whitish with conspicuous, wide, V-shaped yellowish-brown spot with narrow, dark brownish-edged patch on middle of inner five elytral intervals and two very narrow, irregular, V-shaped stripes, sometimes reduced to small spots, on apical part of elytra. Intervals 3 and 4 on basal part of elytra with longitudinal brownish stripe (Fig. 7). Pronotum with four wide longitudinal brownish stripes. Head with brownish spot behind interocular space. Elytra with slanted, sparse and inconspicuous, hair-like whitish scales, only a little longer and somewhat narrower than the diameter of one recumbent scale and arranged in a row on each interval. Head and pronotum with irregularly scattered semierect hair-like scales. Legs and antennae with slanted setae, longer than those on elytra.  
Rostrum 1.32–1.45 times as wide as long, very feebly tapered anteriad. Epifrons strongly narrowing anteriad, feebly depressed longitudinally along midline, with narrow median longitudinal stria parallel with border of epifrons and reaching posterior margin of eye. V-shaped stria at base of rostrum clearly visible. Rostrum in lateral view convex, separated from the rest of head by narrow transversal stria. Antennal scrobes in dorsal view clearly visible on anterior half of rostrum, in lateral view narrow, feebly curved, with dorsal margin directed towards dorsal edge of eye and ventral one towards middle of eye. Eyes large, moderately convex, protruding from outline of head.  
Antennae slender, scape straight, from apical half gradually enlarged toward apex. Funicle 6-segmented. Funicular antennomere 1 robust, conical, 1.1–1.2 times as long as wide, 1.3–1.4 times as long as funicular antennomere 2, the latter 1.3–1.4 times as long as wide, funicular antennomeres 3 and 4 isodiametric, funicular antennomere 5 1.1 times as wide as long, funicular antennomere 6 1.2–1.3 times as wide as long, club as wide as scape at apex.  
Pronotum wide, 1.42–1.53 times as wide as long, widest at posterior third, with arcuated sides, strongly narrowing toward anterior margin, without any sculpture on disc, feebly convex in lateral view, in anterior third flat.  
Elytra short-oval, wide, 1.19–1.26 times as wide as long, widest at midlength. Interval 1 at base narrowed, in apical third enlarged. Striae clearly visible, narrow, intervals almost flat.  
Tibiae slender, internal margin of protibia enlarged, laterally rounded, with row of 8–9 short and fine bristle-shaped brownish spines, sometimes obscured by several greyish setae, and with three hook-shaped blackish spines at internal angle. Tarsi short, tarsomere 2 1.4–1.5 times as wide as long, segment 3 1.4–1.5 times as wide as long and 1.3–1.4 times as wide as tarsomere 2, ungular tarsomere short, 0.7 times as long as tarsomere 3, claw black.  
Male genitalia.Aedeagus with regularly, feebly rounded sides, regularly narrowing apically, with obtusely rounded apex (Fig. 14).  
Female genitalia. Spermatheca C-shaped, with long and regularly curved cornu, large, wide and short ramus and small, grain-like nodulus (Fig. 25). Ovipositor with hemisternite well sclerotised, slender, pointed and curved laterally (Fig. 24).  
 Differential diagnosis. The 6-segmented antennal funicle and the contrasting whitish and brownish vestiture of fresh specimens make this new species easy to distinguish from all other known Heisonyx.   
 Etymology. The Greek noun hexarthrum, meaning 6-segmented, alludes to the fact that this is the only species known to have six funicular joints.   
 Bionomics. Unknown.   
 Distribution. South Africa: Western Cape.
description: Published as part of Borovec, Roman, Colonnelli, Enzo & Osella, Giuseppe, 2009, On the South African genus Heisonyx (Coleoptera: Curculionidae: Entiminae), pp. 841-860 in Acta Entomologica Musei Nationalis Pragae 49 (2) on pages 852-854, DOI: 10.5281/zenodo.5324996