Ewoma, Hlaváč & Baňař & Fokam, 2023

Hlaváč, Peter, Baňař, Petr & Fokam, Eric Bertrand, 2023, Pselaphinae of the Cameroon Volcanic Line. Part 3. A new genus of Goniacerini (Coleoptera: Staphylinidae: Goniaceritae) from Mount Cameroon, Zootaxa 5323 (2), pp. 255-267 : 258-262

Ewoma gen. nov.

Figs 1–17

Type species. Ewoma longiscapa sp. nov.

Etymology. The genus is named after our good friend and the excellent field assistant Francis Luma Ewome ( Cameroon, Bokwango), who is the collector of the type series and the manager of all our field expeditions on Mount Cameroon. The gender is feminine.

Diagnosis. Head with step-wise elevated rostrum, lacking frontal fovea, with asetose small dorsal tentorial pits located in deep, triangular impression, ventrally lacking median gular carina; maxillary palpi short, less than half as long as head, slender, palpomere 1 minute; palpomere 2 pedunculate at base, curved, gradually thickening distad, about twice as long as wide at distal part; palpomere 3 short, sub-quadrate; palpomere 4 elongate, over 2.5 times as long as palpomere 3, nearly cylindrical, widest in mid length, gradually tapering distad to truncate apex, apical sensory appendage short, stout, with truncate apex. Antennae composed of 11 antennomeres, club not delimited, scape cylindrical, very long, almost ten times as long as wide, about as long as length of antennomeres 2–9 combined; antennomeres 2–9 elongate, 10 transverse, 11 over twice as long as 10. Pronotum slightly wider than long, lacking median and lateral antebasal foveae, lacking longitudinal and antebasal sulcus, surface of pronotal disc with rough, wrinkled structure, step-wise elevated over lateral parts and prolonged by median lobe, with lateral median foveae located in half of pronotal length on lateral, not elevated parts. Elytra distinctly longer than pronotum and about as long as abdomen, with two basal foveae, discal striae almost reaching posterior elytral margin, with wide entire sutural striae. First visible (IV) tergite clearly longest, about twice as long as second (V), first three visible paratergites well–developed, second visible sternite (III) with pair of basolateral foveae, third to fifth visible sternites (V–VII) with two pairs of basolateral foveae. Aedeagus slightly asymmetrical, median lobe slightly longer than wide; endophallus with left-oriented, slender, at apex pointed sclerite and dense bunch of spines; with circular diaphragm; parameres, short, invisible from dorsal view.

Description. Body ( Fig. 1 ) elongate, robust, convex, mat, elytra moderately shining; bicoloured, body dark brown with lighter reddish–brown elytra, maxillary palpi, antennae and legs about same colour as body; except elytral disc and disc of first visible tergite (IV) densely covered by golden setae.

Head sub-hexagonal, slightly less than 1.5 times as long as wide, rostrum narrow, with long, golden setae on its anterior part. Temples slightly rounded, convergent to posterior margin of head, clearly more than twice longer than eyes; vertex and frons confluent, flat; dorsal tentorial pits (= vertexal foveae of Chandler (2001)) setose, punctiform, situated in deep lateral impression in half of length of temples; frontal fovea absent; antennae located under rostrum in antennal openings which are prolonged to reach dorsal tentorial pits by deep, triangular impression; eyes convex, protruding anterad. Neck region retracted into prothorax, subcylindrical, with well–defined gular plate laterally not demarcated by gular sutures, lacking median gular carina; posterior tentorial pits confluent, forming isosceles triangular impression reaching almost half length of head, equal sides of triangle with long dense setae.

Antennae ( Fig. 2 ) composed of eleven antennomeres, slender; antennal insertions narrowly separated. Scape cylindrical, very long, almost ten times as long as wide, about as long as length of antennomeres 2–9 combined; pedicel asymmetrical, with shape of irregular rectangle, inner margin shorter than outer one, from all antennomeres shortest, antennomere 3 slightly longer than pedicel; antennomeres 3–9 elongate, 10 transverse, 11 over twice as long as 10 and 1.7 times as long as wide; antennal club not delimited.

Labium ( Fig. 3 ) with slightly transverse mentum ( Fig. 3 ; mn) which is widest close to anterior margin, from here slightly convergent posteriad, posterior corners strongly expanded to lateral, subtriangular protrusions; ligula ( Fig. 3 ; lig) bilobed, each lobe with conspicuously long seta; labial palpi ( Fig. 3 ; lp) bimerous, palpomere 1 ( Fig. 3 ; lp1) short, palpomere 2 ( Fig. 3 ; lp2) strongly elongate and weakly clavate, with two conspicuously long apical setae.

Labrum ( Fig. 6 ) strongly transverse, about five times as wide as long, with lateral margin slightly rounded, antero-lateral margin bearing bunch of long setae, anterior margin straight, strongly dentate.

Maxilla ( Fig. 4 ) with large, semicircular cardo ( Fig. 4 ; cd); basistipes ( Fig. 4 ; bst) triangular, elongate; mediostipes ( Fig. 4 ; mst) subtriangular, much shorter than basistipes, with long distal setae; palpifer ( Fig. 4 ; plp) elongate, with long distal seta; lacinia ( Fig. 4 ; lac) shorter than galea ( Fig. 4 ; gal), both with dense, long setae along distal and mesal margin. Maxillary palpi ( Fig. 4 ) short, less than half as long as head, slender, palpomere 1 minute, elongate, about twice as long as wide; palpomere 2 pedunculate at base, curved, gradually thickening distad, about twice as long as wide at distal part; palpomere 3 subquadrate, as wide as 2 but much shorter; palpomere 4 elongate, about twice as long as wide, over 2.5 times as long as palpomere 3, slightly longer than 2, with straight, oblique base, nearly cylindrical, widest in mid length, gradually tapering distad to truncate apex, apical sensory appendage ( Fig. 4 ; sa) short with truncate apex.

Mandibles ( Fig. 5 ) subrectangular, with large, long, sharp apical tooth and five triangular, rounded pointed mesal pre–apical teeth, first minuscule, middle largest, lacking setae.

Pronotum ( Fig. 7 ) indistinctly wider than long, with slightly convergent lateral margins, lacking median and lateral antebasal foveae; lacking longitudinal and antebasal sulcus; surface of pronotal disc with rough, wrinkled structure, step-wise elevated over lateral parts and prolonged by median lobe ( Fig. 7 ; ml), with lateral median foveae ( Fig. 7 ; lmf) located in half of pronotal length on lateral, not elevated parts; anterior corners rounded, posterior corners marked obtuse-angled.

Prosternum ( Fig. 8 ) fused with hypomera ( Fig. 8 ; hy); basisternal region ( Fig. 8 ; bst) shorter than coxal region, with three pairs of large, well-separated foveae, first largely separated pair located in antero-lateral corner ( Fig. 8 ; alfp), second, also largely separated pair of foveae located antero-lateral margin of procoxal cavity ( Fig. 8 ; lpf), third, closely separated pair of foveae located on antero-lateral margin of prosternal process ( Fig. 8 ; mpf); prosternal process ( Fig. 8 ; psp) triangular, pointed, not separating procoxae. Hypomera divided by complete hypomeral ridges ( Fig. 8 ; hyr) into wide, elongate inner region ( Fig. 8 ; ihy) and broad outer region ( Fig. 8 ; ohy), latter with shallow hypomeral groove ( Fig. 8 ; hyg).

Mesonotum ( Fig. 9 ) with microreticulate mesoscutum ( Fig. 9 ; sc2) and smooth mesoscutellum ( Fig. 9 ; scl2) fused together to form triangular scutellar shield pointed at apex and exposed between elytral bases as small but clearly discernible structure.

Mesoventrite ( Figs 12–13 ) clearly demarcated from metaventrite, with massive prepectus ( Fig. 12 ; pp), anteromedian asetose, reticulated transverse impression functioning as procoxal rest ( Fig. 13 ; pcr), with pair of setose, cylindrical fovaea located close to postero-lateral margin of procoxal rest ( Figs 12–13 ; lmvf). Mesoventral ridge ( Fig. 12 ; mvr) distinct, step-wise, reaching anterior margin of mesocoxae, demarcating median region from lateral areas, both sparsely setose. Mesocoxae narrowly separated by truncate mesoventral process ( Fig. 12 ; msvp) with apex reaching middle of mesocoxae, meeting anterior truncate tip of anterior metaventral process ( Fig. 12 ; amtvp), both processes flat.

Metaventrite ( Figs 12–13 ) transverse, about twice as long as mesoventrite; posterior margins of mesocoxal rests carinate; with pair of setose foveae located in antero-lateral side of metaventrite ( Figs 12–13 ; lmcf) and with single setose fovea in middle of anterior metaventral process ( Figs 12–13 ; mmvf); posterior metaventral process ( Fig. 13 ; pmtvp) broad and long, with two parallel protrusions, posterior margin slightly convex.

Metanotum ( Fig. 11 ) transverse, with very long alacristae ( Fig. 11 ; alc) with their posterior ends extending beyond posterior metascutellar margin as minute subtriangular projections; metascutum ( Fig. 11 ; sc3) posteriorly not demarcated from vestigial metascutellum; metapostnotum ( Fig. 11 ; pn3) arcuate, short, and broad, with broadly rounded posterior margin.

Elytra ( Fig. 10 ) sub-rectangular, distinctly longer than pronotum and about as long as abdomen, with two basal foveae ( Fig. 10 ; bef), discal striae ( Fig. 10 ; ds) almost reaching posterior elytral margin, with wide entire sutural striae ( Fig. 10 ; ss). Hind wings developed.

Abdomen ( Figs 1 , 14–15 ) with first visible (IV) tergite clearly longest, over 1.6 times as long as second (V); all visible tergites lacking transverse mediobasal fovea, discal carinae and basolateral foveae. First three visible paratergites well-developed. First visible sternite (III) densely setose, second visible sternite (IV) longer than third visible sternite (V), with pair of basolateral foveae ( Fig. 14 ; blf), third to fifth visible sternites (V–VII) with two pairs of basolateral foveae ( Fig. 14 ; blf).

Legs long, slender, simple, lacking any modification like spines or teeth, all femora slightly clavate, tarsi lacking internal distal projections.

Aedeagus ( Figs 16–17 ) slightly asymmetrical, median lobe slightly longer than wide; endophallus with left-oriented, slender, at apex pointed sclerite and dense bunch of spines; with circular diaphragm; parameres, short, invisible from dorsal view.

Sexual dimorphism. Not apparent.

Remarks. Ewoma gen. nov. can be placed in the group of following genera of Afrotropical Goniacerini : Basilewskydiella Leleup and Leleupites Jeannel (both known by one species from The Democratic Republic of Congo), Ogmocerus Raffray (eight species widely distributed in the sub-Saharan Africa) and Vadonites Jeannel (one species from Cameroon). Genera of this group are defined by the following combination of characters ( Leleup 1978): 1) clypeus dorsally invisible, rounded; 2) antennae composed from eleven antennomeres; 3) epipleura lacking foveae and striae; 4) each elytron with two basal foveae; 5) legs long, slender, simple, lacking any modification like spines or teeth, all femora slightly clavate; 6) second tarsommere of protarsi lacking any distal inner protrusion. From these genera Ewoma can be separated as follows:

- from Basilewskydiella Leleup, 1978 by simple structure of surface of elytra and abdomen and by antennae with all antennomeres in males simple;

- from Leleupites Jeannel, 1950 by lacking median antebasal fovea and by antennae with all antennomeres in males simple;

- from Ogmocerus Raffray, 1882 by head with temples strongly convergent posteriad; by antennae with all antennomeres simple in males; by pronotal disc with wrinkled structure; by lacking median antebasal pronotal fovea and by first visible (IV) tergite clearly longest, over 1.6 times as long as second (V).

- from Vadonites Jeannel, 1953 by pronotum lacking antebasal sulcus and median antebasal fovea and by antennae with all antennomeres in males simple.

Figures

FIGURES 1–3. Ewoma longiscapa gen. et sp. nov. 1, dorsal habitus; 2, left antenna; 3, labium. Lettering: gal, galea; lig, ligula; lp1, labial palpomere 1; lp2, labial palpomere 2; mn, mentum.

FIGURES 4–6. Ewoma longiscapa gen. et sp. nov. 4, maxilla; 5, mandible; 6, labrum. Lettering: bst, basistipes; cd, cardo; gal, galea; lac, lacinia; mst, mediostipes; mxp1, maxillary palpomere 1; mxp2, maxillary palpomere 2; mxp3, maxillary palpomere 3; mxp4, maxillary palpomere 4; plp, palpifer; sa, sensory appendage.

FIGURES 7–10. Ewoma longiscapa gen. et sp. nov. 7, pronotum; 8, prosternum; 9, mesonotum; 10, left elytron. Lettering: alpf, antero-lateral prosternal fovea; bef, basal elytral fovea; bst, basisternal region; ds, discal stria; hy, hypomere; hyg, hypomeral groove; hyr, hypomeral ridge; ihy, inner region of hypomere; lmf, lateral median fovea; lpf, lateral prosternal fovea; ml, median lobe; mpf, medial prosternal fovea; ohy, outer region of hypomere; pcxc, procoxal cavity; psp, prosternal process; ss, sutural stria; sc2, mesoscutum; scl2, mesoscutellum.

FIGURES 11–13. Ewoma longiscapa gen. et sp. nov. 11, metanotum; 12–13 meso- and metaventrite. 12, photographed in Euparal; 13, the same photographed dry-mounted. Lettering: alc, alcarista; amtvp, anterior metaventral process; lmcf, lateral mesocoxal fovea; lmvf, lateral mesoventral foveae; mmvf, median metaventral fovea; mvr, mesoventral ridge; msvp, mesoventral process; pcr, procoxal rest; pmtvp, posterior metaventral process; pn3, metapostnotum; pp, prepectus; sc3, metascutum.

FIGURES 14–17. Ewoma longiscapa gen. et sp. nov. 14–15, abdomen, ventral, 14, photographed in Euparal; 15, the same photographed dry-mounted; 16, aedeagus, dorsal view; 17, aedeagus, lateral view. Lettering: blf—basolateral fovea.