Heisonyx fuscus, Borovec & Colonnelli & Osella, 2009

Borovec, Roman, Colonnelli, Enzo & Osella, Giuseppe, 2009, On the South African genus Heisonyx (Coleoptera: Curculionidae: Entiminae), Acta Entomologica Musei Nationalis Pragae 49 (2), pp. 841-860 : 850-851

Heisonyx fuscus sp. nov.

( Figs. 5 , 13 , 23 ) Type material. HOLOTYPE: J (BMNH), ‘Willowmore, Cape Colony, S. Brauns’. ALLOTYPE: ♀ (BMNH), ‘Uitenhage, Cape Colony, Oct. 1898, T. O’Neil’. PARATYPES: 3 JJ (BMNH), ‘Willowmore, Cape Colony, S. Brauns’.

Description. Body length: 1.8–2.1 mm, holotype 1.8 mm (males); 2.4 mm (female).

Integument black, tarsi, antennal funicle and club reddish-brown. Coloration of scales light brownish, pronotal disc with large dark brownish area, elytra with irregularly scattered small dark brownish spots ( Fig. 5 ). Recumbent elytral scales regularly rounded, weakly longitudinally striate, very dense, leaving only strial punctures visible. Lifted elytral scales short and wide, only somewhat longer and slightly narrower than recumbent ones, arranged in one dense inconspicuous row on each interval. Pronotum and head with similar double type of scales, lifted scales irregularly scattered. Femora, tibiae and antennal scapes densely covered by recumbent scales and slanted long and slender scale-like setae.

Rostrum 1.22–1.26 times as wide as long, feebly tapered anteriad with feebly rounded sides. Epifrons with straight sides, strongly narrowed anteriad, at base almost as wide as space between anterior edges of eyes, very shallowly depressed along midline, with very narrow and short longitudinal stria present only between antennal insertions and with another longitudinal stria running parallel with margin of epifrons and distally almost reaching the level of posterior border of eyes. Epifrons densely covered by recumbent scales, separated from head by very fine, hardly visible transversal V-shaped stria. Rostrum in lateral view convex. Antennal scrobes in dorsal view appearing on apical half of rostrum as narrow furrows, in lateral view feebly curved and feebly enlarged distally, with distinct borders, dorsal margin directed toward dorsal edge of eyes, lateral border directed toward middle of eyes. Eyes rather small, almost flat, hardly protruding from outline of head.

Antennae short and robust. Scape short, about as long as funicle, curved in midlength, in apical half gradually but strongly thickened towards apex. Funicle 5-segmented, funicular antennomere 1 conical, robust, 1.3–1.4 times as long as wide and 1.2–1.3 times as long as funicular antennomere 2, the latter 1.5 times as long as wide, funicular antennomeres 3 and 4 1.4 times as wide as long, funicular antennomere 5 1.5–1.6 times as wide as long, club narrower than scape at apex.

Pronotum 1.26–1.33 times as wide as long, widest behind middle, in anterior half strongly narrowed. Disc regularly convex, in some specimens with short and very narrow longitudinal stria on anterior half. Pronotum in lateral view feebly convex, in anterior third flat.

Elytra oval, 1.19–1.21 times as long as wide, widest in middle, with feebly obliquely subtruncated humeri, angulate and narrowing toward apex. Interval 1 near elytral base strongly narrowed, at apex enlarged and elevated, intervals 3 and 5 at apex feebly enlarged, interval 5 weakly elevated, other intervals almost flat. Striae very narrow, appearing as a row of fine punctures.

Tibiae short and robust, internal margin of protibia enlarged at apex, laterally rounded, with 6–7 short, dark brownish to blackish spines and with two short hook-shaped brownish spines at inner angle, sometimes barely visible through dense fringe of yellowish bristles on inner angles. Tarsi short, tarsomere 2 1.4–1.5 times as wide as long, tarsomere 3 1.4 times as wide as long and 1.3–1.4 times as wide as tarsomere 2, ungular tarsomere short, as long as tarsomere 3, claw reddish-brown.

Male genitalia. Aedeagus short with feebly rounded sides, at apex narrowed with large triangular concavity, so that apex looks bidentate ( Fig. 13 ).

Female genitalia. Spermatheca not examined. Ovipositor with short and wide, long-oval hemisternite, at apex obliquely subtruncated, with short, apically setose stylus ( Fig. 23 ).

Differential diagnosis. Heisonyx fuscus sp. nov., H. barclayi sp. nov. and H. danielssoni sp. nov. share the 5-segmented antennal funicle; the main distinguishing characters are given in the key below. Other characters allowing distinction of H. fuscus sp. nov. from the above two species are as follows: rostrum with very short longitudinal stria present only between antennal insertions (present along the whole length in H. barclayi sp. nov. and H. danielssoni sp. nov.), apex of aedeagus with triangular concavity (apex rounded and feebly angulate in H. barclayi sp. nov.), and apex of protibia rounded with 6–7 short spines (feebly lobed with three spines in H. danielssoni sp. nov.).

Etymology. The colour of the new species suggested its name, meaning dark in Latin.

Bionomics. Unknown.

Distribution. South Africa: Eastern Cape.

Figures

Figs. 4–7. Habitus. 4 – Heisonyx barclayi sp. nov., paratype; 5 – H. fuscus sp. nov., holotype; 6 – H. danielssoni sp. nov., holotype; 7 – H. hexarthrum sp. nov., holotype. Scale bar: 1 mm.

Figs. 10–15. Aedeagus. 10 – Heisonyx vitticollis Marshall, 1947, lectotype; 11 – H. barclayi sp. nov., paratype; 12 – H. danielssoni sp. nov., holotype; 13 – H. fuscus sp. nov., holotype; 14 – H. hexarthrum sp. nov., paratype; 15 – H. jelineki sp. nov., paratype. Scale bar: 0.3 mm.

Figs. 16–27. Protibia and female genitalia. 16–19 – Heisonyx vitticollis sp. nov., paralectotype: 16 – right protibia, 17 – ovipositor, 18 – spermatheca, 19 – sternum 8 in female; 20–21 – H. barclayi sp. nov.: 20 – ovipositor, 21 – spermatheca; 22 – H. danielssoni sp. nov., spermatheca; 23 – H. fuscus sp. nov., ovipositor; 24–25 – H. hexarthrum sp. nov.: 24 – ovipositor, 25 – spermatheca; 26–27 – H. jelineki sp. nov.: 26 – ovipositor, 27 – spermatheca. Scale bars: 0.25 mm (a – sternum 8; b – ovipositor and spermatheca; c – protibia).