Mentophilonthus triseriatus ( Bernhauer, 1928 )

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 : 152-153

Mentophilonthus triseriatus ( Bernhauer, 1928)

( Figs. 103–110 )

Philonthus (Philonthus) triseriatus Bernhauer, 1928: 112 .

Mentophilonthus triseriatus: LEVASSEUR (1966: 208) .

Type locality. Democratic Republic of the Congo, Mongende.

Type material examined. HOLOTYPE: ♁, ‘ Congo Belge, Mongende , 19.iv.1921, Schouteden, Chicago NHMus, M. Bernhauer Collection // Type, Philonthus triseriatus Bernhauer [ochre oblong label, handwritten]’ ( FMNH) . PARATYPES: 5 spec., ‘Mongende, 21.iv.1921, Schouteden, Chicago NHMus, M. Bernhauer collection’ [ochre oblong paratype label, handwritten] ( FMNH).

Additional material examined. DEMOCRATIC REPUBLIC OF THE CONGO: 1 spec., ‘Congo ex Belge, Libenge, 29.4.1948, R. Cremer - M. Neuman’ ( LHPC) ; 1 spec., ‘Edouard Vitshumbi, 10.ii.1954, J. Verbeke – KEA’ ( IRSB) ; 2 spec., ‘ Massif Ruwenzori , marais Kivaita, près Ibatama 1780 m, CONGO (Congo Belge), P.N.A., 14.xii.1956, P. Vanschuythbroeck, VS 850’ ( LHPC) .

Redescription. Body length 11.5 mm, length of fore body (to end of elytra), 5.5 mm.

Colouration. Head black, antennal sockets and clypeus along anterior margin very narrowly reddish-yellow, clypeus brown-yellow, mandibles, elytra and abdomen black-brown, pronotum brown-black, elytral suture, epipleura and posterior margin of elytra narrowly brown-yellow, posterior margin of first five visible tergites and paratergites narrowly yellow-brown, palpi and first three antennomeres brown-yellow, remaining antennomeres dark brown, legs yellowbrown, tarsomeres 3–5 of all tarsi somewhat paler.

Head short, oval, wider than long (ratio 30: 26). Posterior angles each with two long dark bristles. Eyes flat, occupying almost entire side of head (ratio 15.5: 6). Anterior margin of each eye with one coarse puncture bearing long yellow-brown bristle, posterior margin of each eye with three coarse punctures. Surface with fine, very dense 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 shorter than antennomere 2. Relative lengths of antennomeres: 1 = 11; 2 = 5; 3 = 5.5; 4 = 4; 5–7 =: 4; 8 –9 = 3.5; 10 = 3; 11 = 4.5.

Pronotum somewhat longer than wide (ratio 43: 40), distinctly narrowed anteriad, posterior angles entirely rounded. Each dorsal row with two coarse punctures. Each sublateral row with one puncture. Microsculpture similar to that on head.

Scutellum sparsely and finely punctate, posterior fourth impunctate. Punctures smaller than eye-facets, separated mostly by 2 puncture diameters in transverse direction. Transverse microsculpture much finer than that on head and pronotum.

Elytra combined wider than long (ratio 56: 53), slightly widened posteriad, very finely and sparsely punctate. Punctures slightly smaller than eye-facets, separated by distance slightly larger than a puncture diameter in transverse direction. Longitudinal row of five coarse punctures situated at midwidth of each elytron. Surface without microsculpture, with many microscopic dots. Setation brown-yellow.

Legs. Metatibia as long as metatarsus, all tibiae with several long brown bristles of unequal length. Metatarsomere 1 longer than metatarsomere 5. Relative lengths of metatarsomeres: 1 = 9; 2 = 5; 3 = 4; 4 = 3; 5 = 8.

Abdomen slightly narrowed from tergite V posteriad. First four visible tergites with two basal lines, elevated area between basal lines impunctate. Punctation at base of all visible tergites slightly finer and slightly denser than that on elytra, gradually becoming finer and sparser towards posterior margin of each tergite, surface without microsculpture. Lateral margins of each tergite with several brown bristles.

Male. Protarsomeres 1–3 markedly dilated, sub-bilobed, covered with modified pale setae ventrally, protarsomere 4 much less dilated, triangular. Sternite VIII ( Fig. 107 ), sternite IX ( Fig. 108 ), aedeagus ( Figs. 103–106 ).

Female. First three protarsomeres much less dilated than those in male, protarsomere 4 small, only protarsomeres 1–3 bearing modified pale setae ventrally. Tergite X ( Fig. 109 ), gonocoxites of female genital segment ( Fig. 110 ).

Differential diagnosis. Mentophilonthus triseriatus is very similar to M. struthio sp. nov., from which it may be distinguished by the shorter antennae, coarse punctation of the scutellum and darker body colouration. Mentophilonthus triseriatus may be distinguished from M. equus sp. nov. by longer eyes, wider head and sparser punctation of the scutellum, and it differs from both M. struthio sp. nov. and M. equus sp. nov. by the shape of the aedeagus.

Bionomics. Unknown.

Distribution. Democratic Republic of the Congo (this paper); Republic of the Congo, Rwanda ( HERMAN 2001).

Figures

Figs. 95-106. 95–102 – Mentophilonthus struthio sp. nov.: 95–99 – aedeagus (95 – ventral view, 96 – lateral view, 97 – ventral view, without paramere, 98 – underside of paramere with sensory peg setae, 99 – lateral view, without paramere); 100 – apical portion of male sternite VIII, ventral view; 101 – female tergite X, dorsal view; 102 – gonocoxites of female genital segment. 103–106 – Mentophilonthus triseriatus (Bernhauer, 1928): 103–106 – aedeagus (103 – ventral view, 104 – lateral view, 105 – ventral view, without paramere, 106 – underside of paramere, with sensory peg setae).

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.