Congomostes hintelmanni Ballerio, Gill & Grebennikov

Ballerio, Alberto, Gill, Bruce D. & Grebennikov, Vasily V., 2011, Illustrated overview and identification key to Cameroonian Ceratocanthinae beetles (Coleoptera: Scarabaeoidea: Hybosoridae) with description of four new species, Zootaxa 2892, pp. 1-24 : 12-16

Congomostes hintelmanni Ballerio, Gill & Grebennikov , n. sp.

( Figs. 9–11 )

Material. Holotype, male: Cameroon S.-West Prov., Mt. Kupé at Nyasoso, N04°49.153’ E009°42.453’, 19– 21.V.2006, 1550m, V. Grebennikov leg. ( CNCI) [distended specimen glued on card, dissected, genitalia mounted in DMHF resin on separate card, same pin]. Paratypes: 3 specimens: 1 male, same data as holotype but 19–22.V.2006, B.D. Gill leg. ( BDGC), 1 male, Cameroon S.-West Prov., Bakingili, N04°03.35’ E009°03.823’’, 24–26.V. 2006, 250m, B.D. Gill leg. ( BDGC), and 1 male [dissected] Cameroon S.-West Prov., Bakingili, N04°03.35’ E009°03.823’, 24–26.V. 2006, 250m, V. Grebennikov leg. ( ABCB).

Description. HL: 2.60 mm; HW: 2.50 mm; PL: 2.28 mm; PW: 4.23 mm; EL: 4.02 mm; EW: 4.07 mm. Large, flightless Ceratocanthinae ; body convex, uniformly black; sternum, antennae, and tarsi reddish brown; short, fine pale yellow pubescence on pronotum visible at medium magnification (45x).

Head subpentagonal, wider than long (W/L ratio = 1.7), distinctly narrower than pronotum; apex of head obtusely triangular, outer margin not serrate; genae triangular, distinctly protruding outwards, genal suture visible; genal canthus short, not reaching the occipital area of head; dorsal ocular area medium sized; interocular distance about ten times the maximum width of dorsal ocular area. Head convex; convexity consisting of a slightly raised tubercle on frontal portion and a semicircular, slightly raised process connecting the dorsal ocular areas; dorsal head surface punctation made of dense, deeply impressed, ocellate punctures; puncture distance less than their diameter; clypeopleuron short, subrectangular, unevenly sculptured, with surface distinctly punctured.

Pronotum (W/L ratio = 1.8), approximately as wide as elytra, fore edge slightly bisinuate, margined; fore angles subtruncate; sides of pronotum broadly and irregularly rounded, margin not visible in dorsal view, well developed and thick in lateral view; base with margin strongly beaded, visible in dorsal view, posterior median swelling slightly protruding backwards; pronotal sculpturing in the hind median swelling being slightly raised basally; entire pronotal surface strongly punctate with mixed, medium sized, horseshoe shaped punctures with a pore in the middle and simply ocellate punctures; puncture distance less than their diameter, less impressed than the punctures on head.

Scutellum about as wide as long, apex sharp and acute, with distal third narrow and depressed; each side being slightly curved inward, sides of base notched by articular process of elytron; apical portion of mesepisternum not visible from above, surface smooth, with few deep, small punctures, separated by a distance greater than their diameter.

Elytra about as wide as long (W/L ratio = 1.01), convex, maximum width and convexity near middle; apical third re-entering at apex, i.e. apical declivity reflexed in under body and not visible from above; elytra fused together; each elytron covered by four strongly elevated, sharp carinae; carinae symmetrical; first carina parallel and next to elytral suture, starting near base and reaching elytral apex; second carina almost parallel to the first, starting just after the first and ending before the apical portion of elytra; third carina starting near base and is immediately interrupted for about of its length, then continues/resumes until reaching the apical portion of elytra; fourth carina starting near humeral area, is interrupted for about 1/5 of its length and then starts again, reaching the apical portion of elytra. Vertical surface of carinae smooth; humeral callus indistinct; pseudoepipleura indistinct (elytra almost regularly rounded in transverse section); marginal elytral area narrow, enlarged outward near proximal third; inferior sutural stria replaced by a deep furrow, partly concealed by the epipleuron; striated articular area narrow, consisting of only three striae and visible only laterally; entire elytral surface punctured, punctation consisting of medium sized, mixed, horseshoe shaped punctures with a pore in the middle and simply ocellate punctures; punctures larger than those on pronotum, dense, separated by a distance less than their diameter, deeply impressed, although less impressed than the punctures on pronotum. Wings completely absent.

Antennae with ten antennomeres; scape long and strongly securiform, ending with a cuspidate structure directed forward; funicle short; club with three relatively short antennomeres, setose. Labial palpi (including palpiger) ( Fig. 11 E) made of four palpomeres; second palpomere short and narrow; third palpomere expanded and about as long as the fourth; fourth elongate, egg-shaped; labium covered by long setae. Maxillae ( Fig. 11 F) with galea and lacinia membranous, fringed with dense and long, fine setae ( Fig. 11 G); labrum subrectangular, not sinuate at middle, entire surface covered by coarse, deep, simple punctures; epipharynx as in Fig. 11 H; mandibles strongly developed and well visible beyond labrum, with acutely pointed, short apex ( Figs. 11 A–D).

Procoxae subcontiguous; protrochanter small and narrow, with a small patch of long setae at tip; profemora smooth; protibiae with outer edge serrate with two strong teeth at apex, apical spur slender, strongly curved downwards. Protarsus attached near apical third on lateroventral surface of tibia, with basal tarsomere about as long as the following three combined; following three tarsomeres short and subequal; fifth slightly longer, bearing two small, regularly curved claws; tarsomeres, excluding ultimate, with tufts of short setae on ventral surface. Mesosternum short, deeply furrowed by striae; mesocoxae and metacoxae almost adjacent to each other; mesotrochanters and metatrochanters narrow; mesofemora with slight emargination at distal third of hind edge; mesotibiae slender (W/L ratio = 0.18), bearing two apical spurs near inner apical angle, the inner one bent inwards at a right angle; mesotarsi longer than apical edge, first tarsomere shorter than following three together; each mesotarsomere, except for the last, bearing a tuft of short setae on ventral surface; metafemora slightly enlarged at proximal third, then distinctly emarginate; metatibiae triangularly shaped, slightly enlarged apically; apex of tibiae with two short, straight apical spurs; metatarsi with first tarsomere about as long as the following three, tufts of short setae as in mesotarsi; mesotarsi and metatarsi inserted at inner apical angle of tibiae.

Male genitalia: aedeagus ( Fig. 10 A, C) with parameres relatively long, proximally curved downwards; temones present, basal piece slightly twisted, about two times as long as parameres; internal sac lacking any sclerite or pseudosclerite. Genital segment strongly sclerotized, triangular, with a short manubrium ( Fig. 10 B).

Secondary sexual dimorphism: although the female is unknown, it is very likely that the inner apical spur of male mesotibiae bent inwards at a right angle is a sexually dimorphic character, similar to what occurs with many other Ceratocanthine genera ( Ballerio 2006b).

Diagnosis. Congomostes hintelmanni can be easily distinguished from the other representatives of the genus by the distinctive appearance of the elytra (with strong, sharp carinae) and lack of wings, by the shape of aedeagus, by the shape of protibiae (which lack the extended apical outer teeth being replaced by short transverse teeth) and by the shape of metatibia (which lacks an expanded apical truncation).

Etymology. Patronymic, to commemorate the late Robert J. H. Hintelmann of Munich, Germany (see also the Acknowledgements section).

Remarks. The genus Congomostes Paulian, 1968 , besides the new species here described, includes two other species: Congomostes janssensi (Basilewsky, 1955) and Congomostes baloghi Paulian, 1968 , both known from the Democratic Republic of the Congo (formerly Zaire). Paulian (1977) suggested that they could be considered the same species. Actually they are very similar, but the scarcity of available material does not allow us to take a final decision on the status to attribute to Congomostes baloghi . The genus is characterized by the large size and black colour of its species and by the shape of the cephalic capsule and its appendages, with short genal canthus and antennal scape strongly securiform. However both the previously described species are volant and their overall appearance strongly diverges from that of C. hintelmanni . We assign the new species to Congomostes mainly because of the morphology of the head, namely the overall shape of the cephalic capsule, the shape of genal canthus, the morphology of mouthparts and the strongly securiform scape of the antennae. The generic assignment should be regarded as tentative, since the new species differs strongly from the other two by the morphology of the legs, which is normally unmodified in most Ceratocanthine genera. The strong differences in elytral architecture could be connected to the flightlessness of the new species.

Figures

FIGURE 9. Congomostes hintelmanni n. sp., habitus. A—distended specimen, dorsal, B – D—rolled up specimen, ventral (B), dorsal (C), lateral (D).

FIGURE 10. Congomostes hintelmanni n. sp., A, C—parameres, dorsal view (A) and lateral (C), B—genital segment. Scale bar: 0.4 mm (A, C), 0.7 mm (B).

FIGURE 11. Congomostes hintelmanni n. sp., mouthparts. A – D—mandibles, dorsal (A, B) and ventral (C, D), E—labium, F—maxilla, G—details of galea brush, H—epipharynx.