Epistomius colonnellii, Borovec & Skuhrovec, 2017

Borovec, Roman & Skuhrovec, Jiří, 2017, Epistomius, a new genus of African forest litter Trachyphloeini, with descriptions of seven new species (Coleoptera: Curculionidae: Entiminae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 57 (2), pp. 645-676 : 658-660

Epistomius colonnellii sp. nov.

( Figs 1A–C , 2A–C , 3B , 6A–G )

Type locality. South Africa, Eastern Cape, Mbotyi Forest, 31°27′S, 29°44′E.

Type material. HOLOTYPE: ♂, ‘ South Africa, Eastern Cape, Mbotyi Forest , 31°27′S, 29°44′E, 1.–3.xii.2006, forest litter, sifting, J. Janák lgt.’ ( TMSA) . PARATYPES: 28 ♂ ♀, the same data as holotype ( JJRC, JSPC, NMPC, RBSC) ; 14 ♂♂, ‘ South Africa, Eastern Cape, Grahamstown, Alicedale, Blaukranz (forest), 15.XI.2006, G. Osella lgt .’; 12 ♂ ♀, ‘ South Africa, Eastern Cape, Port St. Johns (foresta), 10.XI.2006, G. Osella lgt .’; 203 ♂ ♀, ‘ South Africa, Eastern Cape, 5 km S-E di Port St. Johns (foresta costiera), S 31°36′58″ E 29°34′61″, 8.XI.2006, G. Osella leg. ( GOVI); 14 ♂ ♀, ‘ South Africa: E [Eastern] Cape, Port St. Johns – second plage, 31.38.66 S, 29.31.25 E, 8/ 9.XI.2006, E. Colonnelli [lgt.]’; 14 ♂ ♀, ‘ South Africa, E [Eastern] Cape, 5 km E Port St. Johns, 31°36′58″ S, 29°34′61″ E, 8/ 9.XI.2006, E. Colonnelli [lgt.] ’; 11 ♂ ♀, ‘RSA [ South Africa]: Eastern Cape (Transkei), Mbotyi Coast and Forest , 29.XI.-3. XII.2003, leg. W.Schawaller’ ( SMNS) ; 2 ♂ ♀, ‘RSA (E) [ South Africa, East], E [Eastern] Cape, Silaka Nat. Res. (top) nr. Port St. Johns , 31.6518 S / 29.4999 E, 13.11. 2013, 150 m, sifted litter, leg. M. Wanat’ ( MNHW) ; 48 ♂ ♀, ‘ South Africa, Eastern Cape, Silaka NR, Port St. John env., 31°39.0′ S 29°30.3′ E, 14.i.2016, J. Janák lgt.’ ( JJRC, RBSC) . Additional material examined. 28 ♂ ♀, ‘ South Africa, Eastern Cape, Cwebe NR, 32°13.6′ S 28°53.8′ E, 17.–18. ii.2014, J. Janák lgt.’ ( JJRC, RBSC).

Description ( Figs 1A–C , 2A–C , 6A–G ). Body length 1.88–2.56 mm, holotype 2.29 mm. Body dark brownish to blackish, scape and funicle reddish brown, apical quarter of tibiae and tarsi yellowish red. Elytra with sparse appressed scales of irregular shape, 4 across width of one interval, subsquared or subtriangular, finely longitudinally striate, in some scales with short fine fringes on one edge of scale; distance between two scales about as long as half diameter of one scale. Pronotum and head with rostrum with dense subrounded scales, with fine fan-shaped striae, creating short, fine and dense fringes on almost half of circumference, scales leaving only short spaces between them. Appressed scales on scape, femora and tibiae identical to pronotal ones, only slightly smaller. Perpendicularly erect elytral setae conspicuous, on posterior declivity distinctly longer than on disc, here longer than width of interval, slender, lancet-shaped, regularly sharply tapered apicad, finely longitudinally striate, creating one regular row on each interval, distance between two setae on posterior declivity slightly shorter than length of one seta. Setae on pronotum and head with rostrum somewhat shorter than setae on anterior part of elytra, perpendicularly erect, slender, subparallel-sided, setae on interocular space twice as long as the others. Scape, femora and tibiae with short, long-oval, semiappressed setae, densely irregularly scattered, hardly visible, not prominent from outline. Body vestiture light brownish with partly visible integumental colour, elytra with slender greyish V-shaped transverse stria on posterior declivity; pronotum with three slender longitudinal greyish striae; erect setae light brownish.

Head ( Figs 1A , 6A–C ). Rostrum in males ( Fig. 6B ) distinctly tapered in basal half and enlarged in apical half, with concave sides and subparallel-sided in females ( Fig. 6C ), slightly tapered in basal half and indistinctly enlarged in apical half, rounded around scrobes, in males 1.15–1.17× as wide as long, at apex 1.01–1.07× as wide as at base; in females 1.27–1.33× as wide as long, at base 1.04–1.07× as wide as at apex. Epifrons with slender longitudinal median stria, when cleared of scales shiny, with moderately wide longitudinal median furrow along whole length, with two very slender longitudinal keels along whole length, weakly tapered basad and with several short, irregular longitudinal striae. Frons deepened, finely irregularly rough. Epistome in males wide, wider than epifrons at midlength, in females narrow, equally wide as epifrons at midlength. Head when cleared of scales with several fine and short longitudinal striae radiating from base of epifrons furrow, not reaching anterior border of pronotum. Eyes faintly prominent from outline of head.

Antennae ( Fig. 6A ). Antennal scape 6.0–6.1× as long as wide and 1.5× as long as funicle, club 1.1× as wide as scape at apex. Funicle segment I 1.9–2.0× as long as wide and 1.8–2.0× as long as segment II, which is 1.6–1.7× as long as wide; segments III–V 1.1–1.2× as wide as long; segment VI 1.1× as wide as long; segment VII isodiametric. Club 2.4–2.6× as long as wide.

Pronotum ( Fig. 6A ) in males 1.40–1.48×, in females 1.45–1.50× as wide as long, widest just behind midlength, with distinctly, regularly rounded sides, constricted behind anterior border. When cleared of scales regularly convex, shiny, sparsely irregularly coarsely punctured by large deep punctures, distance between them shorter than diameter of one puncture, anterior border reddish, bordered by transverse row of small punctures. Pronotum in lateral view almost flat, lowered behind anterior border.

Elytra ( Fig. 6A ) in males 1.15–1.18×, in females 1.17–1.22× as long as wide.

Legs ( Figs 6A, E ). Tarsomere II 1.3–1.4× as wide as long; tarsomere III 1.3× as wide as long and 1.4–1.5× as wide as tarsomere II; onychium 1.5× as long as tarsomere III.

Male genitalia ( Figs 3B , 6G ). Penis very short and wide, only slightly longer than wide, subparallel-sided with slightly rounded sides, apex obtuse, only slightly pointed.

Variability ( Figs 2A–C ). While material from Mbotyi Forest, Port St. Johns and Grahamstown has elytral setae perpendicularly erect and straight, on posterior disc longer than width of interval, slender, lancet-shaped and regularly sharply tapered apicad, material from the locality Cwebe has setae bent posteriad, as long as width of one interval, subspatulate, apically rounded. The material from Cwebe was not included in the type series to conserve the typical characters (see the variability chapter in Epistomius description).

Etymology. We are honoured to name the newly described species after our good friend, Enzo Colonnelli (Rome, Italy), an eminent specialist in weevils, mainly Ceutorhynchinae , who collected part of the type material.

Biology. All material was sifted from native forest litter.

Distribution. South Africa: Eastern Cape ( Fig. 4 ).

Differential diagnosis. The species is characterized by elytral setae on apical declivity semierect to erect, rostrum in males enlarged apicad, with epistome wider than epifrons. It is similar to E. janaki sp. nov., from which it can be distinguished by the following characters: elytral setae on posterior declivity long and slender, pointed, twice as long as conspicuous setae on basal half; tarsomere II 1.3–1.4× as wide as long; elytra in males longer, 1.15–1.18× as long as wide; and penis short, about as long as wide, at apex obtuse, tip not separated.

Figures

Fig. 1. Epistomius colonnellii sp. nov.A – rostrum without scales, dorsal view, B – abdominal ventrites; C – female sternite 8 and gonocoxites, dorsal view.

Fig. 2. Variability in elytral scales in three species.Epistomius colonnellii sp. nov.(A – lateral view, B, C – variability in dorsal view); Epistomius natalensis sp. nov. (D – lateral view, E, F – variability in dorsal view); Epistomius niger sp. nov. (G – lateral view, H, I – variability in dorsal view).

Fig. 3. Apex of penis.A – Epistomius bulirschi sp. nov.; B – Epistomius colonnellii sp. nov.; C – Epistomius janaki sp. nov.; D – Epistomius natalensis sp. nov.; E – Epistomius ngomiensis sp. nov.; F – Epistomius niger sp. nov.; G – Epistomius wanati sp. nov.

Fig. 6. Epistomius colonnellii sp. nov. A – habitus, dorsal view, holotype, male; B – rostrum, male, dorsal view; C – rostrum, female, dorsal view; D – rostrum, male, lateral view; E – protibia, male; F – spermatheca; G – aedeagus. Scale bars: 1 mm (A), 0.5 mm (G) and 0.2 mm (F).

Fig. 4. Distribution of Epistomius species in South Africa; Epistomius bulirschi sp. nov. (yellow circle); Epistomius colonnellii sp. nov. (brown circles); Epistomius janaki sp. nov. (violet circles); Epistomius natalensis sp. nov. (blue circles); Epistomius ngomiensis sp. nov. (red circles); Epistomius niger sp. nov. (green circles); and Epistomius wanati sp. nov. (orange circle).