Mimogonellus Fagel, 1955

Sapieja, Mateusz & Jałoszyński, Paweł, 2024, Taxonomic study on Afrotropical Osoriinae (Coleoptera: Staphylinidae). Status of Mimogonellus Fagel and Madegassosorius Scheerpeltz, Zootaxa 5415 (3), pp. 436-450 : 441-445

Genus Mimogonellus Fagel, 1955

Mimogonellus Fagel, 1955: 26 .

Type species: Mimogonus leleupi Cameron, 1952 (original designation).

Revised diagnosis. Frons and vertex together transverse; head with postocular region exposed; clypeus trapezoidal with straight anterior margin; labrum symmetrical and subrectangular, strongly transverse; antennae moniliform, with subglobose antennomeres 4–10; maxillary palp 4 subconical, slightly narrowing posterad in short sub-basal region; pronotum inversely subtrapezoidal or subcordiform; notosternal sutures lacking (indistinct and superficial impressions or ridges may be present between prosternum and hypomera); tarsi 5-5-5; elytra without lateral rows of punctures; posterior margin of tergite X modified in both sexes, bearing one to several teeth on each side; aedeagus with parameres.

Redescription. Body of both sexes ( Figs 1–2 ) elongate and slender, weakly flattened; pigmentation brown; dorsum sparsely setose; body length in most species 3–8 mm.

Head ( Figs 1, 2 , 4 , 8 ) broadest at eyes, trapezoidal, distinctly smaller than prothorax. Postocular (occipital) region nearly parallel-sided and largely exposed; vertex and frons confluent and together transverse; supraantennal tubercles weakly elevated; clypeus trapezoidal, sparsely setose, with lateral margins straight and converging anterad, anterior clypeal margin straight on entire length. Compound eyes ( Fig. 8 ; ce) projecting laterally, distant from antennal and mandibular insertions. Foramen magnum (not shown) about as wide as 2/3 of head width; gular plate (not shown) vestigial, subtriangular and not exposed in intact specimens; genae ( Fig. 8 ; gn) covered with scale-like microsculpture, strongly expanded mesally and separated along midline by single longitudinal suture presumably derived from connected hypostomal sutures ( Fig. 8 ;?hs; see Discussion).

Labrum (not shown) subrectangular, with inconspicuous sparse dorsal setae. Mandibles ( Fig. 12 ; md) subtriangular, dorsally convex and ventrally concave, moderately to strongly curved, each with at least one preapical mesal tooth. Each maxilla ( Fig. 12 ) with subtriangular and strongly transverse cardo ( Fig. 12 ; cd) bearing several setae, triangular basistipes ( Fig. 12 ; bst) with two to three setae, mediostipes in studied specimens hidden under lateral portion of mentum; elongate palpifer ( Fig. 12 ; ppf) with large mesal region exposed in ventral view projecting anteriorly and with ventral elongate impression, palpifer bearing two to three long ventral subapical and several lateral (outer) subapical setae; and stout maxillary palp composed of nearly annular palpomere 1 ( Fig. 12 ; mxp1), clavate and weakly elongate palpomere 2 ( Fig. 12 ; mxp2), palpomere 3 ( Fig. 12 ; mxp3) transverse and in ventral view subtriangular, broadening distally, palpomere 4 ( Fig. 12 ; mxp4) longer than 2 and 3 combined, nearly subconical, slightly broadening distally in basal third or less, then strongly narrowing toward blunt apex, in ventral view palpomere 4 slightly asymmetrical, with outer margin slightly sinuate and inner convex. Each palpomere with a few long setae. Labium with sub-rectangular and strongly transverse submentum ( Figs 8 , 12 ; sm) hypostomal sutures lacking; mentum ( Fig. 12 ; mn) subtrapezoidal, with posterior region with subparallel lateral margins shorter than anterior region with sides converging anteriad, and with transverse anterior margin, mental setae numerous (in studied species over 10) and only partly symmetrically distributed; prelabium in intact specimens largely covered by mentum, except for ligula ( Fig. 12 ; lg), which is strongly projecting and strongly rounded anteriorly and bearing a pair of long lateral submedian setae directed anteriorly, trimerous labial palps minute, shorter than mentum. Labial palpomere 1 ( Fig. 12 ; lp1) subcylindrical and elongate, palpomere 2 ( Fig. 12 ; lp2) much shorter than 1 and similar in width or slightly wider, subcylindrical, palpomere 3 ( Fig. 12 ; lp3) fusiform with blunt apex, longer than palpomere 1. Setae present only on palpomeres 1 and 2, in studied species 1–2 subapical setae on each.

Antennae ( Fig. 6 ) moniliform, indistinctly broadening distally, composed of 11 antennomeres, of which scape, pedicel and first flagellomere elongate, 4–10 subglobose, and 11 elongate with a blunt or pointed apex. All antennomeres sparsely setose.

Pronotum ( Fig. 4 ) inversely subtrapezoidal or subcordiform, with sinuate or convex lateral margins; anterior corners variously distinct, posterior corners nearly right or obtuse-angled; base of pronotum lacking pits, but in some species with various impressions. Lateral pronotal carinae ( Fig. 9 ; pc) sharp or diffuse, complete or nearly complete, in some species indistinct near pronotal base. Hypomeron ( Fig. 9 ; hy) weakly impressed, fused with prosternum, but in some species variously distinctly demarcated by superficial vestiges of sutures, ‘false notosternal sutures’ ( Figs 14–16 ; fnss), developed as barely discernible longitudinal impressions visible only at certain angles ( Figs 14–16 , 17–24 ), or accompanied mesally by weakly elavated ridge, posteriorly confluent with hypomeral ridge ( Figs 21–24 ; hyr) [see Discussion]. Postcoxal hypomeral lobe subtriangular, mesally reaching nearly middle of procoxa.

Prosternum ( Fig. 9 ) with basisternal (e.g., precoxal) region ( Fig. 9 ; bst) strongly transverse, weakly convex and with anterior margin forming broad subtriangular median expansion covering gular plate. Prosternal process ( Fig. 9 ; pstp) strongly elongate, triangular with pointed apex reaching beyond middle of procoxae. Prosternum with variously distinct transverse groove or step-wise line just in front of procoxal rests. Procoxal fissures ( Fig. 9 ; pcf) open and trochantins ( Fig. 9 ; tn) exposed.

Mesoscutellar shield ( Fig. 27 ; mss) exposed between elytral bases, triangular.

Mesoventrite ( Fig. 25 ; v 2 ) transverse and largely asetose, with lateral margins indistinctly converging anterad, anterior margin weakly emarginate, prepectus massive, anteromedian impressions functioning as procoxal rests shallow and broadly separated at middle. Anterior margins of mesocoxal rests carinate. Mesoventral intermesocoxal process ( Fig. 25 ; msvp) elongate subtriangular with narrowly rounded or nearly pointed apex, not elevated or with weakly elevated median longitudinal ridge, process reaching middle length of mesocoxae, where its tip is narrowly separated from anterior metaventral process.

Metaventrite( Fig.25 ; v 3 )subrectangular and setose, with lateral margins nearly parallel-sided or weakly diverging posteriorly, at the level of anterior margins of metacoxae strongly converging posteriorly. Anterior metaventral process ( Fig. 25 ; amtvp) elongate subtriangular with blunt apex reaching middle of mesocoxae. Posterior margins of mesocoxal rests carinate. Posterior margin of metaventrite strongly biarcuate, with lateral regions projecting posteriorly much farther than metaventral intermetacoxal process ( Fig. 25 ; mtvp), which is broadly subtrapezoidal with shallow posteromedian emargination and not separating metacoxae. Metanepisterium ( Fig. 25 ; aest3) visible in ventral view; metepimeron ( Fig. 25 ; epm3) in intact specimens exposed only in its posteriormost region, exposed portion subtriangular.

Elytra ( Fig. 25 ) together subrectangular; anterior elytral margin demarcated from articulating lobe by transverse impression; humeral calli weakly elevated; lateral elytral margins almost parallel and straight or weakly rounded; posterior margin of each elytron truncate, together transverse, weakly convex or weakly concave. Inner lateral margin of each elytron distinctly emarginate, with adsutural sulcus.

Legs ( Figs 1, 2 , 9 , 25 , 29–31 ) short and moderately slender. Procoxae ( Fig. 9 ; cx1) elongate, with proximal region resting in prococal rest broader than distal region and demarcated by transverse ventral ridge (visible in Fig. 15 ); mesocoxae ( Fig. 25 ) oval; metacoxae ( Fig. 25 ) about as long as broad, each with transverse and asetose proximal region and slightly elongate and setose distal region. All trochanters ( Fig. 9 ; tr1, 14) small, subtriangular. Femora clavate, strongly compressed, with dorsal surface concave and ventral convex; profemur ( Fig. 9 ; fm1) in both sexes with distinct profemoral denticle on dorsal anterior edge ( Fig. 9 ). Tibiae thickened distally (protibiae more so than meso- and metatibiae); protibia in most species with longitudinal row of spine-like setae on outer margin ( Fig. 29 ), but in some species spines lacking, inner margin of protibiae with longitudinal row of dense and thin setae (presumably antennal cleaning device), mesotibiae and metatibiae longer than protibiae and slenderer, with or without outer longitudinal row of spines. Tarsi short, all pentamerous.

Abdomen ( Figs 1 , 41 ) nearly cylindrical, tergum and sternum fused together without marked suture in exposed segments III–VII. Sternite VIII ( Fig. 35 ) subtriangular in both sexes, bearing small denticles on lateral margins in males and in some species also in females; tergite IX ( Fig. 36 ; tIX) medially divided and each hemitergite narrowing posteriorly in both sexes; sternite IX in males (not shown; illustrated in Yin & Steiner (2017)) strongly elongate and broadening posteriorly, with rounded posterior margin; tergite X ( Fig. 36 ; tX) modified, bearing from one to several variably shaped lateral teeth in both sexes.

Aedeagus ( Figs 43–46 ) elongate, distal portion of median lobe curved towards parameral side. Parameres symmetrical or nearly so, with apical setae.

Distribution. Nominal species occur in Africa, Madagascar, Laos, and Japan; Fagel (1955) mentioned undescribed species from Sumatra and New Guinea. During the present study, specimens from Australia and Thailand were also seen.

Figures

FIGURES 1–3. Dorsal habitus of Mimogonellus leleupi (Cameron), lectotype male (1) and paralectotype female (2); Mimogonellus keiseri (Scheerpeltz), comb. n., paratype male (3).

FIGURES 4–7. Mimogonellus leleupi (Cameron), lectotype male (4, 6); and Mimogonellus keiseri (Scheerpeltz), comb. n., paratype male (5, 7). Head and pronotum in dorsal view (4, 5), right antenna in dorsal view (6, 7).

FIGURES 8–11. Mimogonellus leleupi (Cameron), lectotype male (8, 9) and Mimogonellus keiseri (Scheerpeltz), comb. n., paratype male (10, 11). Head (8, 10) and prothorax (9, 11) in ventral view.Abbreviations:bst, basisternal region of prosternum; ce, compound eyes; cx1, procoxa; fm1, profemur; fnss, ‘false notosternal suture’; hr, hypostomal ridge; hy, hypomeron; pc, pronotal carina; pcf, procoxal fissure; pstp, prosternal process; sm, submentum; tn, trochantin; tr1, protrochanter;?hs, presumably fused hypostomal sutures. Arrowheads indicate profemoral denticles.

FIGURES 12–13. Mimogonellus leleupi (Cameron), lectotype male (12) and Mimogonellus keiseri (Scheerpeltz), comb. n., paratype male (13); mouthparts in ventral view.Abbreviations: bst, basistipes; cd, cardo; lg, ligula; lp1–3, labial palpomere 1–3; md, mandible; mn, mentum; mxp1–4, maxillary palpomere 1–4; ppf, palpifer; sm, submentum.

FIGURES 14–16. Mimogonellus leleupi (Cameron). Prothorax of lectotype male (14), paralectotype male (15, horizontally flipped to facilitate comparisons) and paralectotype female (16). Abbreviations: fnss, ‘false notosternal suture’.

FIGURES 17–24. Mimogonellus leleupi (Cameron). Hypomeral region of prothorax in ventral view at different angles. Lectotype male (17–20), paralectotype male (21–24, horizontally flipped to facilitate comparisons). Abbreviations: fnss, ‘false notosternal suture’; hyr, hypomeral ridge.

FIGURES 27–34. Mimogonellus leleupi (Cameron), lectotype male (27, 29, 30, 31) and Mimogonellus keiseri (Scheerpeltz), comb. n. paratype male (28, 32, 33, 34). Elytra in dorsal view (27, 28); protibia (29, 32), mesotibia (30, 33), and metatibia (31, 34) in ventral vies. Abbreviations: mss, mesoscutellar shield. Arrowheads indicate adsutural sulcus.

FIGURES 25–26. Mimogonellus leleupi (Cameron), lectotype male (25) and Mimogonellus keiseri (Scheerpeltz), comb. n., paratype male (26). Pterothorax in ventral view. Abbreviations: aest3, metanepisternum; amtvp, anterior metaventral process; el, elytra; epm3, metepimeron; msvp, mesoventral intermesocoxal process; mtvp, metaventral intermetacoxal process; pcr, procoxal rest; pp, prepectus; v2–3, ventrite 2–3.

FIGURES 35–42. Mimogonellus leleupi (Cameron), lectotype male (35, 36, 41), Mm. leleupi (Cameron), paralectotype female (39, 40), and Mimogonellus keiseri (Scheerpeltz), comb. n., paratype male (37, 38, 42). Male sternite VIII (35, 37); male tergite VIII, IX and X (36, 38); female tergite IX and X (39); female sternite VIII (40); distal portion of abdomen in right lateral view, upside down (41, 42). Abbreviations: s, sternite; t, tergite.

FIGURES 43–50. Mimogonellus leleupi (Cameron), lectotype male (43–46), and Mimogonellus keiseri (Scheerpeltz), comb. n., paratype male (47–50). Aedeagus in ventral (43, 45, 47, 49) and lateral (44, 46, 48, 50) views.