Mentophilonthus dilucidus ( Tottenham, 1962 ) Hromádka, 2009

Hromádka, Lubomír, 2009, Revision of the Afrotropical species of the genus Mentophilonthus (Coleoptera: Staphylinidae: Philonthina), Acta Entomologica Musei Nationalis Pragae (suppl.) 49 (1), pp. 119-160 : 130-131

Mentophilonthus dilucidus ( Tottenham, 1962) comb.nov.

( Figs. 29–33 )

Philonthus (Philonthus) dilucidus Tottenham, 1962: 154 .

Type locality. Nigeria, Ibadan.

Type material. HOLOTYPE: ♁, ‘ NIGERIA, Ibadan , 22.v.1936, V.F.Eastop, C.E. Tottenham collection, B.M.1974–587 // Holotype, Philonthus dilucidus Tottenham ,det.[white oblong label, handwritten]’ ( BMNH) . PARATYPE: ♁, ‘Nakiwogo, Entebbe, xi.1961, A.J. Haddowm, height 400 ft. [white oblong label, handwritten]’ ( BMNH).

Redescription. Body length: 8.5 mm, length of fore body (to end of elytra) 4.2 mm.

Colouration. Head black, pronotum black with brown shine, scutellum paler, elytra blackbrown with posterior angles and epipleura yellow-brown, abdomen black-brown, posterior margins of abdominal tergites and posterior half of each paratergite yellow-brown, maxillary and labial palpi brown, first three antennomeres yellow-brown, remaining antennomeres brown-yellow, legs with femora and tarsi yellow-brown, middle and posterior tibiae somewhat darker.

Head rounded, slightly wider than long (ratio 25: 22); posterior angles entirely obliterated, each with two long dark bristles. Eyes flat, about twice as long as temples (ratio 11.5: 5.5). Anterior margin of each eye with one setiferous puncture. Temporal area with several punctures. Dorsal surface shiny, with dense and fine microsculpture consisting of transverse and oblique waves.

Antennae reaching posterior third of pronotum when reclined. Antennomere 1 somewhat longer than antennomeres 2–3 combined, antennomere 11 about a half shorter than antennomere 1. Relative lengths of antennomeres: 1 = 9; 2 = 4; 3 = 4.5; 4–10 = 3.5; 11 = 4.5.

Pronotum about as long as wide, slightly narrowed anteriad. Posterior angles strongly rounded. Each dorsal row with one puncture situated in posterior third, each sublateral row with one puncture. Lateral margins each with one long, dark brown bristle in anterior half. Microsculpture similar to that on head.

Scutellum very finely and densely punctate, punctures smaller than eye-facets. Microsculpture very fine; setation long and dark.

Elytra combined wider than long (ratio 46: 39), slightly widened posteriad. Punctation very fine and relatively sparse, punctures as large as eye-facets, separated by two puncture diameters in transverse direction. Longitudinal row of four coarse punctures situated at about midwidth of each elytron. Surface without microsculpture; setation testaceous.

Legs. Metatibia as long as metatarsus. Metatarsomere 1 longer than metatarsomeres 2–3 combined. Relative lengths of metatarsomeres: 1 = 7.5; 2–4 = 3.5; 5 = 5.

Abdomen with base distinctly narrower than posterior width of elytra, gradually narrowed posteriad. First three visible tergites with two basal lines, elevated area between basal lines very finely and sparsely punctate. Punctation of visible tergites similar to that on elytra, separated mostly by two puncture diameters in transverse direction. Surface between punctures without microsculpture. Lateral margins of all tergites with several short bristles; shiny.

Male. Protarsomeres 1–3 markedly dilated and subbilobed, covered with modified pale setae ventrally, protarsomere 4 distinctly narrower than preceding ones, lacking modified setae ventrally. Aedeagus ( Figs. 29–33 ).

Female. Unknown.

Differential diagnosis. Mentophilonthus dilucidus is similar to M. struthio , from which it may be distinguished by the shorter antennae, narrower elytra, paler elytra and abdomen, and sparser punctation of the elytra and abdomen. It may be distinguished from M. curiosus by the coarser punctation of abdomen, and from both above species by the shape of the aedeagus.

Bionomics. Unknown.

Distribution. Nigeria.

Figures

Figs. 24–38. 24–28 – Mentophilonthus descarpentriesi Levasseur, 1965: 24–27 – aedeagus (24 – ventral view, 25 – lateral view, 26 - ventral view, without paramere, 27 – underside of paramere, with sensory peg setae); 28 – male sternite IX, ventral view. 29–33 – Mentophilonthus dilucidus (Tottenham, 1962): 29–33 – aedeagus (29 – ventral view, 30 – lateral view, 31 – ventral view, without paramere, 32 – underside of paramere, with sensory peg setae, 33 – lateral view without paramere). 34–38 – Mentophilonthus dilutior (Bernhauer, 1928): 34–37 – aedeagus (34 – ventral view, 35 – lateral view, 36 – ventral view, without paramere, 37 – underside of paramere with sensory peg setae); 38 – apical portion of male sternite VIII, ventral view.