Afrus, Janák, Jiří & Bordoni, Arnaldo, 2015

Janák, Jiří & Bordoni, Arnaldo, 2015, Revision of the genus Thyreocephalus and description of Afrus gen. nov. of Africa south of the Sahara (Coleoptera: Staphylinidae: Staphylininae), Zootaxa 4038 (1), pp. 1-94 : 6-7

Afrus gen. nov.

Type species: Thyreocephalus spegazzinii Bernhauer, 1915

Description. Form elongate, stout, of medium size (6.5–10 mm).

Head variably punctate, punctures not forming semi-impressed rows of coalescent grooves, frontal grooves short or moderately long, ocular grooves inconspicuous or absent ( Figs. 3, 5 ). Anterior margin of frons between antennal insertions extended into short and very wide, apically sligthly rounded process, limited at each side by rounded emargination, and slightly impressed dorsally. Eyes small, head with large impression behind the eyes, temples longer than length of eyes seen from above, evenly rounded, laterally with evident subelliptical groove ( Figs. 4, 7 ). Antennae geniculate, moderately short, antennal insertions separated from each other by distance about equal to distance separating each insertion from anteromedian margin of eye ( Figs. 3, 5 ), first segment long, thickened towards apex, equal in length to at least the four following segments combined, second segment shorter than third, distal segments more or less transverse ( Figs. 1, 2 ). Labrum completely chitinised, short, transverse, lobate apically, with long and strong apical setae ( Figs. 10 , 17 ). Mandible stout, lateral furrow reduced to vague impression at base ( Figs. 3–5, 7 ). Maxillary palpi moderately long, segment 3 shorter than segment 2, segment 4 longer and somewhat narrower than segment 3, subacute apically ( Fig. 5 ). Labial palpi moderately long, last segment distinctly longer than segment 2. Mentum short, transverse, pentagonal. Ligula divided. Gula very short, gular sutures contiguous.

Pronotum without dorsal rows of punctures, with one big puncture (without seta) close to anterior angles ( Figs. 1–3, 5 ); antersternal plate with a suture (similar as in Fig. 26 ); both superior and inferior line of pronotal hypomera strongly developed, superior line turning downwards well before middle, joining or almost joining inferior line next to front margin of procoxae and continuing onto front margin of pronotum ( Fig. 6 ). Prosternum elevated medioposteriorly (similar as in Fig. 26 ), without posteromedian carina, intercoxal process protruding, triangular; epimera present. Mesosternum very short, transverse, widely separating middle coxae. Metasternum very long.

Elytra overlapping at suture ( Figs. 1, 2 ). Legs moderately long; protarsi simple (not dilated) in either sex, first four segments gradually becoming shorter, last segment about as long as three preceding segments combined; protibiae with numerous strong spines on outer margin; mesotibiae strongly spinose, with only apical ctenidium; first segment of mesotarsus and metatarsus about equally long as second, last segment about as long as preceding three segments combined; metatibiae spinose on outer margin, with only apical ctenidium ( Fig. 15 ).

Abdomen ( Fig. 1, 2 ) ‘Staphylininae-shaped’ with fourth or fifth segment broadest. Tergite 7 with complete membranous palisade fringe at its posterior margin ( Figs. 1, 2 ).

Male. Tergite and sternite 8 of male simple, not modified. Tergite 10 of male genital segment rather narrowly exposed between sclerites of tergite 9, strongly narrowed proximally ( Figs. 11 , 18 ), sclerites of tergite 9 contiguous mediobasally. Sternite 9 of male genital segment asymmetrical ( Figs. 12 , 19 ), located centrally. Aedeagus with basal bulbus subovoid, short median lobe, symmetrical parameres and inner sac with shape of variably long and wide ribbon with scales of different size ( Figs. 13 , 20 ).

Female. Genital segment with sternite proportionally short and two supplementary sclerites that cover its proximal part ( Figs. 14 , 21 ).

Differential diagnosis. This genus differs from other genera of Xantholinini that lack dorsal rows of punctures on the pronotum in combination of the following characters:

1) superior line turning downwards well before middle, joining or almost joining inferior line next to front margin of procoxae and continuing onto front margin of pronotum ( Fig. 6 )

2) head with large impression behind the eyes, lateral part of temple with evident subelliptical groove ( Figs. 3– 5, 7 )

3) metatibia with only apical ctenidium which extends onto inner margin backwards to about middle ( Fig. 15 ).

The sister group of Afrus gen. nov. could be Thyreocephalus , which is supported by the following two characters: superior line turning downwards well before middle, joining or almost joining inferior line next to front margin of procoxae and continuing onto front margin of pronotum ( Fig. 6 ) and metatibia with only apical ctenidium which extends onto inner margin backwards to about middle ( Fig. 15 ), but this genus differs from Afrus by the absence of a subelliptical groove on the lateral parts of the temple and the presence of a subapical ctenidium ( Figs. 27, 28 ). The two hitherto known species of Afrus are also smaller (6.5–10 mm) than Thyreocephalus species from Africa south of the Sahara (body length 10–35 mm).

Figures

FIGURES 3 – 7. 3, 4, Afrus collarti (Cameron); 5 – 7, Afrus spegazzinii (Bernhauer). 3, 5, head and anterior part of pronotum (iop—internal ocular puncture, pop—posterior ocular punctures); 4, 7, lateral part of head (SG—subelliptical groove); 6, lateral part of ventral side of pronotum (SL—superior line, IL—inferior line). Scale 0.5 mm.

FIGURES 1 – 2. 1, Afrus collarti (Cameron); 2, Afrus spegazzinii (Bernhauer). Scale 1 mm.

FIGURES 9 – 15. Afrus spegazzinii (Bernhauer); 9, head and pronotum; 10, labrum; 11, male tergite 10; 12, male sternite 9; 13, aedeagus; 14, female genital segment (fp—fused pleurites, s—sternite, ss—supplementary sclerites); 15, metatibia (ac—apical ctenidium).

FIGURES 16 – 21. Afrus collarti (Cameron); 16, head and pronotum; 17, labrum; 18, male tergite 10; 19, male sternite 9; 20, aedeagus; 21 female genital segment.

FIGURES 24 – 28. 24, Thyreocephalus brunneiventris (Tottenham); 25, 27, T. alluaudi (Fauvel); 26, T. interocularis (Eppelsheim); 28, T. ferox (Harold); 24, 25, head and anterior part of pronotum; 26, ventral side of pronotum (ap—antesternal plate, pr—prosternum, ip—intercoxal process, SL—superior line, IL—inferior line); 27, 28, metatibia (ac—apical ctenidium, sac—subapical ctenidium). Scale 0.5 mm.