Bolbaoeer coriaceus, (Petrovitz)

Gussmann, S. M. V. & Scholtz, C. H., 2001, Systematic revision of the Afrotropical genus BolbaOEer Vulcano, Martinez and Pereira (Coleoptera: Scarabaeoidea: Bolboceratidae: Bolboceratinae), with descriptions of eight new species, Journal of Natural History 35 (7), pp. 1013-1084 : 1046-1049

BolbaOEer coriaceus (Petrovitz)

(®gures 3k±n, 12a, c±g, 13a±f, 14)

Bolboceras coriaceum Petrovitz, 1969: 311 , ®gure 1.

BolbaOEer coriaceum (Petrovitz) : Nikolajev, 1982: 37, ®gures 11, 18; Krikken, 1984: 39.

Description male

Body length 15.6±20.1 mm (12 specimens). Colour light brown to dark brown. Outer margin of mandibl e distinctly sinuate. Clypeus with bituberculate, feebly arcuate or feebly bisinuate transverse posterior carina; position of tubercles variable, from in line with antennal insertions to in line with clypeo-frontal transition; length of posterior carina variable, from slightly shorter to longer than anterior carina. Frons feebly concave behind posterior clypeal carina. Antennal club with glabrous area of basal segment about one-half of exposed surface. Pronotum with anterior margin medially feebly raised, in dorsal view arcuate and not projecting over head; with four protrusions (®gure 3k±m): in major males outer horns distinctly longer and more strongly inward curved than inner horns, the latter ones sometimes reduced to feeble swellings (®gure 3k); in minor males all four horns much reduced in size, little curved, more or less equal in length and more approximated (®gure 3l, m); surface with large, densely spaced and often conūent punctures; punctures decreasing in density and size and also interspersed with some ®ne punctures often in between and always on pronotal protrusions. Scutellum with surface coarsely punctate. Elytron with strial punctures separated by four to ®ve and a half puncture diameters; intervals with approximately ®ve to six punctures between two striae. Protibia ®ve-dentate. Protibial spur about as long as ®fth tarsomere, apex shaped as in ®gure 12a. Metatrochanter postero-medially with distinct angle as in ®gure 12c, d; setation as in ®gure 12c (northern populations) or as in ®gure 12d (southern populations). Metafemur in ventral view in posterior third with line of densely spaced moderately long and long setae; otherwise with fairly dense, moderately long and long setation over entire surface but with very dense short and moderately long setation in basal area and along basal third of posterior margin. Metatibia in lateral view with subapical carina feebly bilobed or with one distinct lateral lobe only; with unmodi®ed spurs. Underside with posterior margin of sternite 5 laterally with convex curvature, medially triangularly emarginate (®gure 12g); posterior margin of sternite 6 with three arcuate emarginations (®gure 12g); pygidium unmodi®ed (®gure 12f). Genitalia with aedeagus as in ®gure 13a±c (northern populations) and 13d±f (southern populations); aedeagus strongly curved in lateral view; genital capsule apically with moderately long setation.

Description female

Body length 17.2±20.3 mm (15 specimens). Colour as in male. Outer margin of female mandible feebly sinuate. Frons with strongly raised bituberculate, transverse carina; position carina variable, from slightly anterior to to in line with posterolateral genal angle; carina straight and slightly shorter than anterior clypeal carina. Antennal club as in male. Pronotum with anterior margin as in male; with transverse, feebly carinate swelling at median portion of disc; carina in frontal view medially straight, rarely very feebly depressed, and laterally arcuate (®gure 3n); swelling with very few ®ne punctures, interspersed with large punctures; with large, mostly conūent punctures anterior, lateral and posterior to carinate swelling. Scutellum and elytron as in male. Protibia as in male. Protibial spur slightly longer than ®fth tarsomere, acuminate. Metatrochanter postero-medially with distinct angle and setation as in ®gure 12e. Metafemur in ventral view in posterior third with line of densely spaced moderately long and long setae; in basal area and anterior third with fairly dense long setation; in posterior third with fairly dense but moderately long setation; remaining median area with sparse setation. Metatibia as in male. Underside with posterior margin of sternite 4 with distinct bisinuate curvature; sternite 5 unmodi®ed; apex of sternite 6 unmodi®ed, i.e. rounded; pygidium unmodi®ed.

Distribution (®gure 14). The species was collected in the southeastern D.R.C., in Rwanda, Kenya, Tanzania and Zambia.

Type material examined. HOLOTYPE l[diss.]:`Holotypus’ [printed on pink label’ /`Coll. Mus. Tervuren, Katanga: Kipopo (E’ville) [Lubumbashi, 11.40S 27.28E], 16.xii.1961, Don R. MareÂchal’ /`K 1154’ /`Holotypus’ [printed on red label] /` Bolboceras coriaceum n.sp. Petrovitz’ [printed on red label] ( MRAC); 3 PARATYPES: 1 l[diss.],`Coll. Mus. Congo, Ruanda: Terr. Shangugu, Dendezi [not traced], 1600m, 5.iv.1953, P. Basilewsky’ ( MRAC); 2 ll,` MuseÂe du Congo, Elisabethville [Lubumbashi], 1935, Dr. Richard’ ( NHMG) .

Additional material examined (23 specimens). D.R.C.: 1, Katanga, Elisabethville , March 1912, Colonel et Major Seligmann ( ISNB) ; 2mm, 18 miles SW of Elizabethville [ca 12.51S 27.04E, on the Zambian side of the border!], 1928, Dr H.S. Evans ( BMNH) . Kenya: 1, Kikuyu, Muguga [01.11S 36.39E], 1 December 1952, H.-J. Bredo ( ISNB) . Tanzania: 1 l[diss.], Tanganyika [Tanzania], Chunya District, Chunya [08.32S 33.25E], 2650 ft., 12 February 1947, G. Swynnerton, B.M. 1947-360. ( BMNH) ; 1m, same data but: 9 February 1947 ( BMNH) ; 1, Uheheland, Kidugala [Mission, 09.07S 34.32E] ( ZMHB) ; 1 l[diss.], Tanganyika Territory, Ngalia’s [not traced], 4 December 1925, N.C.E. Miller, Mwanza, Tabora Rd ( TMSA) ; 1m, W. Shore of L. Manyara [ca 03.32S 35.45E], Feb. ± May 1935, B. Cooper, B.M. 1935-418. ( BMNH) ; 1, 2mm, near Babati [04.12S 35.45E], 3 / 6 December 1997, Werner and Lizler ( RMCI) ; 1m, (Iringa), Ma ®nga [08.08S 35.21E], 1 / 15 January 1994, G. Curletti ( RMCI) ; 1m, near Mikumi [Mikumi town, 07.22S 37.00E], Morogoro, 14 December 1997, Werner and Lizler ( RMCI) ; 2mm, D.O. Afrika, Nyembe [not traced]± Bulungwa [04.03S 32.15.E], 1914, Hammerstein S. ( RMCI) . Zambia: 1 l[diss.], Kasompe [12.35S 27.54E], February 1982, A. Joubert ( COCS) ; 1 l[diss.], Serenje Dist. [13.00S 30.30E], about 4500 ft, 23± 26 December 1907 ( BMNH) ; 1m, Kashitu [Riv., 13.46S 28.58E], N. of Broken Hill, February 1915, H.C. Dollman ( BMNH) ; 1m, same data but: 23 March 1915 ( BMNH) ; 1m, same data but: 2 January 1915 ( TMSA) Untraced /vague: 1, Brit. C. Afr., Ubemba, 1900, R. P. Guilleme ( MNHN) ; 1m, Nyassa ( MNHN) .

Comments. All the females from the type series, i.e. the allotype and 12 paratypes, were incorrectly associated with the male holotype of B. coriaceus . They are clearly females of B. princeps and are listed under the latter. This leaves only one con®rmed association of one male and two females that were collected together and are housed in RMCI. The remaining 13 females listed under`Additional material examined’ were collected unassociated. Correct male / female associations could be established for B. dudleyi and B. abditus (see below). The females of the latter species share one character state that was not found in any of the other females of the B. coriaceus species-group: the apex of the pygidium is feebly arcuately emarginate or truncate (not illustrated) instead of evenly rounded. Both sexes of the B. coriaceus speciesgroup are recognized and at the same time distinguished from congeneric species by the distinct postero-median angle of the metatrochanter. The angle is, however, always less pronounced in females compared to males. The question remains whether the 13 independently collected females, in total or in part, indeed belong to B. coriaceus or to B. dudleyi . Locality data of B. dudleyi and male B. coriaceus indicate that the former species occurs, besides in Malawi, also possibly in the southern D.R.C. while B. coriaceus occurs from Zambia northeastward, suggesting a partially sympatric distribution. We can therefore only assume that the individually collected females, at least those from localities in Tanzania and Kenya, are more likely to be associated with B. coriaceus than with B. dudleyi . Having compared character states of these females and the two positively identi®ed B. coriaceus females with the females of B. dudleyi , we came to the following conclusions: no diOEerences could be detected in external morphology other than a very slight diOEerence in the posteromedian angle of the metatrochanter. The angle seems more pronounced in B. dudleyi females but weaker in the other females (compare ®gure 12j with 12e). But since the scarcity of material makes it impossible to determine the true boundaries of the distribution ranges and to examine the full scale of intraspeci®c variation of the above character state, the assignment of the 13 unassociated females to B. coriaceus has to be treated with caution and a question mark is added on the determination labels.

Character states that separate males of B. coriaceus from males of its closest relatives, B. dudleyi and B. abditus , are discussed under the latter. Male B. coriaceus can be distinguished from males of the other congeneric species by the following combination of character states: metatrochanter postero-medially with distinct angle (®gure 12c, d) versus evenly rounded (®gure 12b); apically modi®ed shape of the protibial spur (®gure 12a); species-speci®c modi®cations on sternites 5 and 6, unmodi®ed pygidium; and large aedeagus, strongly curved in lateral view (®gure 13c, f), with distinctly modi®ed parameres (®gure 13a, b, d, e). BolbaOEer coriaceus is the only species found within the genus that shows a distinct variation in the shape of the parameres. In the one extreme case, a male collected in Zambia, the apex of the paramere is relatively broad and convexly rounded on both sides (®gure 13a, b) while it is concavely shaped on the interior side (®gure 13d, e) in the other extreme case, the male paratype from Rwanda. Although not illustrated, various intermediate forms, with the interior margin much less arcuate exist but no particular geographical gradient could be determined. Since the other external morphological character states, apart from the usual diOEerences in pronotal armature between major and minor males, are stable, we are convinced that all the males belong to B. coriaceus and do not represent a diOEerent species.