Mentophilonthus tristichus ( Cameron, 1929 ) 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 : 154-155

Mentophilonthus tristichus ( Cameron, 1929) comb. nov.

( Figs. 111–113 )

Philonthus (Philonthus) tristichus Cameron, 1929: 62 .

Type locality. Democratic Republic of the Congo, Haut Uele, Mauda: Dika.

Type material examined. PARATYPES: 1 ♁, 1 spec., ‘ Congo, 2.III.1925, Haut-Uele: Mauda, Dr. Schouteden, M. Cameron Bequest, B.M. 1955–147 // Paratype, Philonthus tristichus Cameron det. [white oblong label, handwritten]’ ( BMNH).

Redescription. Body length 6.4 mm, length of fore body (to end of elytra) 3.2 mm.

Colouration. Head black, pronotum brown-black, elytra black-brown, suture narrowly brown-yellow, abdomen and antennae black, antennomere 1, base of antennomere 2 and legs yellow-brown, inner side of all tibiae and tarsi infuscate, maxillary and labial palpi dark brown.

Head orbicular, as long as wide, eyes slightly longer than temples (ratio 13: 11). Anterior margin of each eye with one puncture. Temporal area with several coarse punctures. Surface with very dense and fine microsculpture consisting of transverse and oblique waves.

Antennae reaching posterior fourth of pronotum when reclined. Antennomere 1 as long as antennomeres 2–3 combined, antennomere 11 as long as antennomere 3. Relative lengths of antennomeres: 1 = 11; 2 = 5; 3 = 6; 4–9 = 4; 10 = 3.5; 11 = 6.

Pronotum longer than wide (ratio 46: 41), narrowed anteriad, posterior angles entirely rounded. Each dorsal row with two punctures. Each sublateral row with one puncture. Surface shiny, with very fine microsculpture consisting of transverse and oblique waves.

Scutellum with very fine and sparse punctation and microsculpture, setation dark.

Elytra combined wider than long (ratio 55: 52), surface with scattered larger punctures intermixed with many miscroscopic dots. Longitudinal row of three coarser punctures situated at midwidth of each elytron. Surface shiny, without microsculpture.

Legs. Metatibia as long as metatarsus. Metatarsomere 1 longer than metatarsomeres 2–3 combined. Relative lengths of metatarsomeres: 1 = 10; 2 = 5; 3 = 4; 4–5 = 3.

Abdomen slightly narrowed posteriad. First four visible tergites with two basal lines, elevated area between basal lines very sparsely punctate. Punctation of visible tergites much coarser than that on elytra, punctures as large as eye-facets, separated mostly by a puncture diameter in transverse direction. Surface with fine microsculpture consisting of transverse and oblique waves, shiny. Lateral margins of all tergites with long black bristles.

Male. Protarsomeres 1–3 strongly dilated, sub-bilobed, covered with modified pale setae ventrally, protarsomere 4 considerably narrower than preceding ones. Sternite VIII ( Fig. 112 ), sternite IX ( Fig. 113 ). Aedeagus as in Fig. 111 (genitalia of the paratype with only paramere preserved, median lobe missing).

Female. Unknown.

Differential diagnosis. Mentophilonthus tristichus may be distinguished from the most similar M. seriatipennis by the paler maxillary and labial palpi and different punctation of the elytra; it differs from M. crocuta sp. nov. by the longer and more rounded head, longer pronotum and elytra, darker elytra and denser and coarser punctation of the elytra and abdomen; from M. hystrix sp. nov. it differs by the shorter and darker elytra and narrower head. It differs from all above species by the shape of the aedeagus.

Bionomics. Unknown.

Distribution. Democratic Republic of the Congo.

Figures

Figs. 107–113. 107–110 – Mentophilonthus triseriatus (Bernhauer, 1928): 107 – apical portion of male sternite VIII, ventral view; 108 – male sternite IX, ventral view; 109 – female tergite X, dorsal view; 110 – gonocoxite of female genital segment. 111–113 – Mentophilonthus tristichus (Cameron, 1929): 111 – undersite of paramere with sensory peg setae; 112 – apical portion of male sternite VIII, ventral view; 113 – male sternite IX, ventral view.