Epistomius niger, 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 : 669-671

Epistomius niger sp. nov.

( Figs 2G–I , 3F , 10A–G )

Type locality. South Africa, KwaZulu-Natal, Ongoye Forest Reserve, 28°50.6′S, 31°40.1–2′E.

Type material. HOLOTYPE: 1 ♂, ‘ South Africa, KwaZulu-Natal, Ongoye Forest Reserve , 28°50.6′ S 31°40.1-2′ E, 11.i.2016, Berlese extraction, leaf & log litter, sifting, J. Janák lgt.’ ( TMSA) . PARATYPES: 24 ♂ ♀, the same data as holotype ( JJRC, JSPC, NMPC, RBSC) ; 4 ♂ ♀, ‘RSA [ South Africa], KwaZulu-Natal, Ongoye Forest, Birders Lodge , 280 m, 2.-6.XII.2010, leg. D. Bartsch & J. Berg’ ( SMNS) ; 69 ♂ ♀, ‘ S. Afr. [ South Africa], KWZ Natal [KwaZulu-Natal], Ongoye Forest , 294 m, 4.- 5.12.2010, 28.50 S – 31.44 E, E-Y: 3890, sifting forest litter, leg. Ruth Müller’ ( TMSA) . Additional material examined. 14 ♂ ♀, ‘ South Africa, KwaZulu-Natal, Entumeni Nature Reserve, 28°53.2′ S 31°22.6′ E, 11.i.2016, J. Janák lgt.’ ( JJRC, RBSC).

Description ( Figs 2G–I , 10A–G ). Body length 1.71–2.31 mm, holotype 1.75 mm. Body blackish, basal two thirds on antennal scape, funicle and short apical part of tibiae reddish brown, tarsi yellowish brown. Elytra, pronotum and head with rostrum sparsely covered with appressed oval to drop-shaped scales, 3–4 across width of one interval, leaving between scales distance only slightly shorter than width of one scale. Appressed scales on femora and tibiae identical to elytral ones but smaller. Setae on basal half of elytra semiappressed, short, inconspicuous, on apical half erect, conspicuous, slender, widest at midlength, narrowly apically rounded, only slightly shorter than width of one interval, distance between two setae on posterior declivity more than twice as long as length of one seta. Setae on pronotum and head with rostrum subspatulate, short, about equal to those of basal half of elytra, semiappressed, hardly prominent in lateral view. Scape, femora and tibiae with short, long-oval semiappressed setae, hardly prominent from outline. Scales and setae light greyish brown.

Head ( Figs 10A–D ). Rostrum in males ( Fig. 10B ) extremelly enlarged in apical half, apical part distinctly prominent laterally, 1.15–1.19× as wide as long, at apex 1.17–1.19× as wide as at base and 0.9× as wide as head including eyes; in females ( Fig. 10C ) evenly weakly enlarged apicad with weakly concave sides, 1.06–1.08× as wide as long, at apex 1.04–1.08× as wide as at base, 0.8× as wide as head including eyes. Epifrons with weakly concave sides, when cleared of scales shiny, smooth, unpunctured, with deep and well developed longitudinal median stria reaching to middle of vertex and with two inconspicuous lateral longitudinal keels. Frons deepened, smooth. Epistome in males distinctly wider than width of epifrons at midlength, in females narrower, only slightly wider than epifrons at midlength. Head when cleared of scales shiny and smooth, with several very fine, almost indistinct longitudinal striae. Eyes convex, somewhat prominent from outline of head.

Antennae ( Fig. 10A ). Antennal scape 5.8–6.1× as long as wide and 1.5–1.6× as long as funicle, at apex 0.8× as wide as club. Funicle segment I 1.6–1.7× as long as wide and twice as long as segment II, which is 1.1–1.2× as long as wide; segments III–VI 1.3× as wide as long; segment VII 1.4–1.5× as wide as long. Club 1.6–1.7× as long as wide.

Pronotum ( Fig. 10A ) in males 1.43–1.49× as wide as long, in females 1.35–1.39× as wide as long, widest behind midlength, with rounded sides, more tapered anteriad than posteriad, constricted behind anterior margin. When cleared of scales regularly convex, shiny, densely coarsely punctured, with 6–7 punctures along the length, punctures large, distance of punctures shorter than their semidiameter. Pronotum in lateral view weakly convex, behind anterior border lowered.

Elytra ( Fig. 10A ) in males short, globular, 1.09–1.11× as long as wide, in females longer, oval, 1.16–1.19× as long as wide.

Legs ( Figs 10A, E ). Tarsomere II 1.6–1.7× as wide as long; tarsomere III 1.5× as wide as long and 1.3× as tarsomere II; onychium 1.9–2.1× as long as tarsomere III.

Male genitalia ( Figs 3F , 10G ). Penis short, weakly longer than wide, widest at base, slightly evenly tapered apicad, apex subtriangular; in lateral view weakly irregularly curved, equally wide, tapered only at apex, with slender lengthened tip.

Variability ( Figs 2G–I ). Typical population from Ongoye has elytral setae on apical declivity slender, widest at midlength, apically shortly rounded, slightly shorter than width of one interval, while population from Entumeni has the same setae lancet-shaped, narrower, sharply apically pointed, weakly longer than width of one interval. The material from Entumeni was not included in the type series to conserve the typical characters (see the variability chapter in Epistomius description).

Etymology. The blackish colour of antennae, legs and integument suggested the Latin name of this new species.

Biology. The type specimens were sifted from leaf litter in native broad-leaved forest.

Distribution. South Africa: KwaZulu-Natal ( Fig. 4 ).

Differential diagnosis. Epistomius niger sp. nov. is by conspicuously enlarged rostrum and globular elytra in males similar to E. bulirschi sp. nov., from which it can be easily distinguished by erect setae on posterior declivity, in males also by penis not enlarged in apical third and in females by rostrum weakly enlarged apicad with epistome wider than epifrons at midlength. In view of the variability of elytral erect setae it could be confused mainly with E. colonnellii sp. nov. as it has similar shape of setae and rostrum in males distinctly enlarged apicad, but it is distinguishable mainly by slenderer tibiae and tarsi with longer onychium, blackish antennal funicle and penis 1.6–1.7× as long as wide, tapered apicad with small tip, while E. colonnellii sp. nov. has penis shorter and wider, 1.3–1.4× as long as wide, parallelsided, apically obtuse.

Figures

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. 10. Epistomius niger 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).