Janakius Borovec & Skuhrovec, 2019

Borovec, Roman & Skuhrovec, Jiří, 2019, Two new genera of Trachyphloeini with a key to the genera of small terricolous South African Trachyphloeini and Embrithini (Coleoptera: Curculionidae: Entiminae), Zootaxa 4695 (5), pp. 451-476 : 458-461

Janakius Borovec & Skuhrovec , gen. nov.

( Figs 4 A–I, 5A–E)

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Type species: Janakius sylvaticus Borovec & Skuhrovec , sp. nov., by present designation.

Diagnosis. Small Trachyphloeini , less than 2.4 mm, epifrons separated from head by wide and deep furrow, furrow dorsally ellipse-shaped, at middle about as wide as diameter of eyes; epistome large, V-shaped, slenderer than apical part of epifrons; protibiae short and robust with mucro and two slightly shorter premucros directed inside; meso- and metatibiae with apical surface glabrous, shiny, with two equally long distinct mucros; metatibiae without corbels; abdominal ventrite 2 in middle longer than very short ventrites 3 and 4 combined; suture between ventrites 1 and 2 sinuose; tegmen with two short and weakly sclerotised parameres far from each other; sternite VIII in females with moderately long, slender apodeme, terminating just inside of plate; plate umbrella-shaped, weakly sclerotised.

Description ( Figs 4 A–I, 5A–E). Length 1.9–2.4 mm. Body dark brownish ( Fig. 5A ), basal part of scapes, funicles with clubs and anterior part of tibiae reddish brown, tarsi reddish. Body densely covered by dense, appressed scales, completely covering integument, regularly covering dorsal and except ventral part of head also ventral part of body, scapes, femora and tibiae; gena glabrous; subgena with conspicuous dense slender transverse squamose stripe at base and lateral parts, forming U-shaped pattern. Clubs densely finely setose. Scale-like setae on body well visible, moderately long, subspatulate, semiappressed, forming on elytra one regular dense row; antennae and legs with short semiappressed to semierect slender setae, weakly prominent beyond the outline. Colour pattern of body dark brownish, elytra irregularly sparsely scattered by short transverse spots from yellowish brown scales, pronotum with two lateral longitudinal yellowish-brown stripes, rostrum dorsally yellowish brown.

Rostrum short and wide ( Figs 5B ), robust, 1.4–1.5 × as wide as long, with distinctly and regularly rounded sides, at base about as wide as at apex; in lateral view vaulted, when covered by scales in the same flat level as head ( Fig. 5C ). Epifrons moderately wide, widest at base, weakly tapered anteriad with slightly convex sides, at base slightly narrower than distance between anterior margins of eyes, weakly longitudinally depressed, separated indistinctly from head by narrow transverse sulcus. When scraped, epifrons separated from head by strange, wide and extremely deep furrow, dorsally in shape of pointed ellipse, at middle about as wide as diameter of eyes ( Fig. 4B ), laterally reaching quarter of rostrum height, touching anterior border of eyes ( Fig. 4C ); anterior and posterior border of furrow distinctly arched, laterally pointed to moderately sharp tips, directed against themselves. Dorsal surface of epifrons flat with moderately wide longitudinal median stria, faintly matt, rough, with very small, fine punctures and short longitudinal striae, borders at posterior half weakly swollen. Frons glabrous with only several very small, rounded scales, faintly matt, with 3–4 pairs of long stout setae. Epistome large, distinct, V-shaped, posteriorly carinate, asquamose, weakly slenderer than apical part of epifrons, posteriad reaching anterior border of scrobes. Antennal scrobes dorsally well visible, crescent-shaped in anterior two thirds; laterally furrow-shaped, glabrous, well-edged, weakly curved and visible enlarged posteriad, with dorsal border parallel with dorsal border of epifrons and ventral border directed to middle of eyes, separated from eyes by slender squamose stripe. Head wide and flat, without tubercles above eyes; when scraped rough, moderately matt, densely finely longitudinally striate; laterally behind eyes glabrous, below eyes with sparse, very small rounded scales; ventrally gena glabrous ( Fig. 4D ), with weak micro-sculpture, shallowly finely and densely punctured; subgena posteriorly with slender and very dense stripe of small scales, with anterior two thirds glabrous, shiny, finely and sparsely punctate. Eyes moderately large, weakly vaulted and weakly prominent beyond the outline of head, laterally subcircular, placed in dorsal part of head. Mandibles trisetose, small, asquamose. Submentum with pair of long slender setae and group of very small, short and fine setae at anterior border.

Antennae ( Fig. 5A ) moderately short and robust. Scapes short and robust, 3.9–4.1 × as long as wide, 1.2 × as long as funicle, weakly curved at midlength, apical half regularly and gradually enlarged apicad, at apex equally wide as clubs. Funicles 7–segmented, with segment 1 enlarged and longer than segments 2 and 3 combined; segments 3–7 short, transverse; clubs with segment 1 largest.

Pronotum ( Fig. 5A ) 1.4–1.5 × as wide as long with regularly rounded sides, weakly more tapered anteriad than posteriad, behind anterior border weakly constricted. Disc regularly vaulted, without furrow or depressions; base regularly arched. Anterior border laterally straight, weakly obliquely directed posteriad. Procoxal cavities contiguous, placed in the middle of pronotum; procoxae subglobular. Scutellum not visible.

Elytra ( Fig. 5A ) oval, 1.2–1.3 × as long as wide, with regularly rounded sides, apically broadly rounded, with regularly rounded shoulders; base arched; posthumelar calli weakly developed, visible only in dorsolateral view; 10-striae, striae moderately wide, punctured; intervals equally wide and almost flat; in lateral view posterior declivity distinctly overhanging apex. Mesocoxae semiglobular, narrowly separate, mesosternal process narrower than fifth of diameter of mesocoxa, not reaching posterior margin of metacoxae. Metacoxae shortly transverse, separated by almost twice their width.

Femora unarmed, medially weakly inflated and flattened. Tibiae short and robust; protibiae ( Fig. 5E ) 4–4.4 × as long as wide, with lateral edge straight and inner edge double sinuose, apex obliquely subtruncated, at inner portion elongated anteriad and enlarged inside, apically armed with 5–6 sparse, slender yellowish spines of unequal length with the longest spine at the middle, not reaching just inner angle and with mucro and two slightly shorter premucros at inner part, curved and directed inside. Meso- and metatibiae with apical surface suboval, asquamose and shiny, laterally armed with fringe of fine, bristle-shaped yellowish long spines and inside with two equally long distinct mucros; metatibiae without corbels. Tarsi long and moderately slender; segment 1 long and slender; segment 2 wider than long; segment 3 bilobed and distinctly wider than previous segments; onychium equally long as segment 3. Claws fused at basal half, then divorced.

Abdominal ventrites ( Figs 4A, E ) subtriangular, as long as wide to 1.1 × as long as wide; ventrite 1 in middle slightly shorter than ventrites 2–4 combined, distinctly longer than ventrite 2, behind metacoxa about as long as ventrite 2, in males slightly shallowly depressed, in females slightly vaulted; ventrite 2 in middle longer than very short ventrites 3 and 4 combined; ventrite 5 large, in males obtuse apically, in females subtriangular apically. Suture between ventrites 1 and 2 sinuose, narrow and fine; other sutures straight, wide and deep. Ventrites ( Fig. 4E ) densely squamose, appressed scales completely covering integument and with short, semiappressed, densely irregularly scattered slender setae.

Sexual dimorphism. Externally not apparent except for slight differences in shape of ventrites 1 and 5.

Male genitalia. Penis ( Fig. 5D ) short and well sclerotised, temones well sclerotised, 1.9–2.1 × as long as body of penis and 2.2–2.4 × as long as tegminal manubrium; endophallus short, inside with fine elongated sclerites. Tegmen ( Fig. 4F ) with slender ring with two very short and weakly sclerotised parameres far from each other, distance between them longer than length of one paramere. Tegminal manubrium 1.4 × as long as diameter of ring. Sternite IX moderately long and slender, anteriorly curved and tapered, posteriorly with fused basal arms, apical plate absent.

Female genitalia. Gonocoxites ( Fig. 4H ) short and wide, evenly tapered apicad, at apex shortly obtuse, with very short, hardly visible styli with tuft of 3–4 fine setae. Sternite VIII ( Fig. 4G ) with moderately long, slender apodeme, 3.0–3.2 × as long as plate and terminating just inside of plate; plate weakly sclerotised, 1.5 × as wide as long, umbrella-shaped, with very slender apical margin with short setae and ill-defined basal margin. Spermatheca ( Fig. 4I ) large, crescentic, with slender cornu and large, elongated corpus, ramus and nodulus developed, small.

Derivation of name. The genus is named after collector of the majority of type material, friend and colleague Jiří Janák (Rtyně nad Bílinou, Czech Republic), an eminent specialist on Staphylinidae and Carabidae , who col- lected incredible numbers of soil associated Entiminae in South Africa and Madagascar and who tried to persuade the first author to change his interest from Carabidae to any other beetle family, in our common trip to Slovakia in 1977.

Biology. All known specimens were sifted from forest litter. Reproduction amphigonic.

Distribution. South Africa, Eastern Cape.

Included species. The genus is described as monotypic.

Remarks. The set of characters, distinguishing Janakius Borovec & Skuhrovec , gen. nov. from all other Trachyphloeini is as follows: rostrum when scraped separated from head by wide and extremely deep transverse sulcus, reaching laterally anterior border of eyes, dorsally with arched borders, pointed to moderately sharp tips at lateral borders; head and rostrum ventrally glabrous with only slender stripe of densely placed scales at posterior border of subgena; protibiae at apex mesally distinctly enlarged with mucro and two slightly shorter premucros, slender and curved inside; meso- and metatibiae with two equally long mucros; abdominal ventrites squamose with metaventral process distinctly wider than transverse diameter of metacoxa; ventrite 2 in middle distinctly longer than short ventrites 3 and 4 combined; suture between ventrites 1 and 2 sinuose; tegminal ring with two short and weakly sclerotised parameres, far from each other. Wide and deep transverse sulcus between rostrum and head, elongated to sharp tips, is exceptional in all South African Entiminae known to us.

Janakius Borovec & Skuhrovec , gen. nov. is different from all other South African Trachyphloeini with connate claws by wide, oval elytra, rostrum with regularly rounded sides, robust antennae and tibiae. By these characters, but mainly by protibiae with mucro and two premucros prominent mesally, the newly described genus is similar only to Heisonyx Marshall, 1947 (Embrithini) . It is easily distinguished from this genus mainly by two equally long connate claws, while Heisonyx has onychium with only one claw, but also by metatibiae lacking corbels ( Heisonyx has slender squamose metatibial corbels), head and rostrum separated by extremely deep and wide transverse sulcus ( Heisonyx has head and rostrum separated by very narrow and shallow sulcus), frons glabrous ( Heisonyx has frons squamose), epistome distinct, large, reaching anterior border of antennal scrobes ( Heisonyx has epistome small, sometimes hardly visible, not reaching anterior border of antennal scrobes).

Figures

FIGURE 4. Janakius sylvaticus sp. nov. A—habitus, ventral view, male; B—rostrum without scales, dorsal view, male; C— rostrum without scales, lateral view, male; D—head, ventral view, male; E—ventrites, female; F—tegmen, male; G—sternite VIII, female; H—gonocoxites; I—spermatheca. Scale bars: 0.5 mm (F, G), 0.25 mm (H, I).

FIGURE 5. Janakius sylvaticus sp. nov. A—habitus, dorsal view, male; B—rostrum, dorsal view, male; C—rostrum, lateral view, male; D—aedeagus; E—protibia, male. Scale bars: 1 mm (A), 0.5 mm (D).