Bolboceratex posticatus (Boheman)

Gussmann S. M. & Scholtz, C. H., 2000, Systematic revision of endemic southern African genera of Bolboceratinae (Coleoptera: Scarabaeoidea: Bolboceratidae), Journal of Natural History 34, pp. 1045-1123 : 1114-1117

Bolboceratex posticatus (Boheman)

(®gures 24a±e, 26e, f, 28j±l, 32a, 35)

Bolboceras posticatum Boheman, 1860: 114 ; PeÂringuey 1901: 489 (Redescr., Transl.); Boucomont 1902: 5; 1912: 12; Paulian 1941: 35.

Bolboceratex posticatus (Boheman) : Krikken 1984: 33.

Bolboceras petulans Kolbe, 1907: 30 ; PeÂringuey 1908: 645 (Descr., Transl.); Boucomont 1912: 12; Paulian 1941: 35 (syn. of Bolboceras posticatum ).

Description

Body length. 9.2±14.7 mm.

Colour. Light to dark brown.

Head. Dorsal surface asetose. Outer margin of mandible (®gure 26e) distinctly sinuate and anteriorly strongly curved inward. Labrum (®gure 26e) asetose; declivous in anterior third and posterior two-thirds, transverse carina obsolete to feebly developed; anterior margin feebly to moderately sinuate. Clypeus (®gure 26e) sloping upward posteriorly to apex of feebly developed or obsolete transverse anterior carina; lateral carina anteriorly feebly developed or mostly obsolete but raised and distinct above antennal insertion, continuing posteriorly from there in a slightly arcuate line to almost posterior end of frons, but often obsolete adjacent to eyecanthus; antero-lateral angle of genae sharply raised; with posterior transverse bituberculate carina, carina laterally terminating with tubercles, not joining lateral clypeal carina. Frons more or less ¯at. Antennal club with glabrous area of basal segment two-thirds of exposed surface.

Pronotum (®gure 32a). With Y-shaped concavity occupying anterior median two-thirds of pronotum; concavity rather shallow and strongly narrowed to posterior end, sides steepest at posterior end; posteriorly with distinctly impressed midline opening up into concavity but not reaching posterior pronotal margin; posteromedially adjacent to narrowing concavity usually with short, thin transverse groove above a rounded, sparsely punctured swelling; concavity with small punctures at posterior end and on sides, more and more interspersed with large, partly conūent shallow punctures at anterior part; disc with ®ne punctures, increasingly interspersed with large, shallow, often conūent punctures laterally; concavity at its widest point narrower than frons between eyes; lateral margin feebly crenulate.

Scutellum (®gure 26f). Basal width about 1.6Ölength; with large, shallow, partly conūent punctures, at base interspersed with a few smaller punctures.

Elytron. Striae moderately impressed, their punctures separated by three to four puncture diameters (®gure 26f); intervals with double punctation (approximately three to four ®ne and 10±12 minute punctures between two striae).

Metasternum. As in generic description but length of longitudinal suture variable, either reaching meso-metasternal suture (®gure 24a) or not reaching it (®gure 24d).

Legs. Protibia six-dentate. Metatibia in lateral view distinctly broadening towards apex; with subapical carina unlobed; with knoblike projections spread randomly over surface above subapical carina. Metatarsus with two subapical setae on tarsomere 2, with one subapical seta on tarsomere 3.

Male genitalia (®gure 28j±l). Median apparatus of aedeagus with a pair of long projections (arrows ®gure 28j)

Distribution (®gure 35). The distribution range of Bolboceratex posticatus stretches in a band from eastern Namibia through Botswana into the northern parts of South Africa and as far as the coast in southern MocËambique.

Type material examined. LECTOTYPE, Bolboceras petulans Kolbe :`petulans n.sp. ’ [handwriting Kolbe]/`Damara bis Ngami See, Fleck S.’/`posticatu m Boh.’ [unknown handwriting] /`50 ’ (ZMHB); LECTOTYPE m, Bolboceras inchoatum PeÂringuey :`Delagoa B. [25.58S 32.35E], J.a [illegible] Coster, i.90’/` Bolboceras inchoatus typ. m 97’ [handwriting PeÂringuey]/`Type SAM/Ent 5091’ [red label] (SAMC).

Additional material examined (35 specimens). Botswana: 1m, V.-L.Kal. Exp., Gemsbok Pan [ca 21.40S 21.25E], 23/4-5/5/30 ( TMSA) ; 1, l4x, Botswana (B3), 18 mls NE Kalkfontein [Tshootsha] [SE 21 21 Cc], 12± 13.iv.1972, Southern African Exp., B.M. 1972-1/at light ( BMNH) ; 2x, Botswana (B1), 42 mls W Kalkfontein [Tshootsha] [22.13S 20.15E], 11± 12.iv.1972, Southern African Exp. B.M. 1972-1/at light ( BMNH) ; 2x, Botswana (B7), Kuke Pan [20.59S 22.25E], 14.iv.1972, Southern African Exp. B.M. 1972-1/at light ( BMNH) . Namibia: 2x, D.S.W. Afrika, Windhoek ± Rehoboth, xii.96, Rehbock S. ( ZMHB) ; 1x, Windhoek, Farm Otjisewa [22.18S 16.57E] ( TMSA) ; 2x, Farm Portsmut 33 [23.09S 16.24E], Windhoek Distr. , 14± 24.iv.1972, Strydom & Jones ( TMSA) ; 1x, Gobabis [22.27S 18.58E] am schwarzen Nosob Flusse, Ende iii± iv.1902, Gentz S.G. ( ZMHB) ; 2x, Ike 346, Outjo, SE 19 16 Da , 10± 14.iii.1979, S. Louw, M-L. Penrith ( SMWN, H38329) ; 1x, SWA, Outjo, SE 19 16 Da , 10.iii.1979, V. B. Whitehead ( SAMC) . South Africa: 1m, N. Cape, Twee Rivieren Camp , Kalahari Gemsbok N.P., 26.28S 20.37E, 12± 15.iv.1989, C. H. Scholtz ( UPSA) ; 1x, Twee Rivieren, Kal. Gems. Park , 22.v.1972, L. & O. Prozesky ( TMSA) ; 1x, Pretoria [25.45S 28.12E], 3.x., A. J. T. Janse ( TMSA) ; 1, l 1m, O. F.S., Sophiasdal 280, Hoopstad, SE 27 25 Dc /d, 4.iii.1978, A.Strydom ( BMSA, No. 7412); 1x, Bothaville [27.22S 26.37E], A. Roberts ( TMSA) ; 1x, Etale, SE 17 15 Bd [not found on maps], 7.iv.1984, E. von Maltitz ( UPSA) ; 1m, S.Afr., Zululand, Missionrock for.h., 28.16S 32.29E, 9.xii.1975, E-Y: 965, at light, leg. EndroÈdy-Younga ( TMSA) ; 1, l Vaalwater, SE 24 28 Ab , 2.iii.1980, T. Vermeulen ( TMSA) ; 1, l same data but: ii.1980, P. du Plessis ( TMSA) ; 1x, same data but: 2.iii.1980, A. Groenewald ( UPSA) ; 3x, Nylsvley , Naboomspruit, SE 24 28 Da , 1100 m, Savanna Ecosystem Research Project, C.S.I.R., 4.iv.1975, trap, E. Holm, F. Kirsten, C. Scholtz ( TMSA) ; 1, l Tvl., Nylsvley, Nylstroom Distr. , 24.39S 28.42E, 18.ii.1980, E. Grei, light trap ( SANC) ; 1x, Schoemansdal, SE 28 29 Bb , iv.1978, Bruwer ( UPSA) ; 1, l unlabelled (TMSA).

Comments. Type material of Bolboceras posticatum Boheman could not be traced. The Natural History Museum Stockholm informed us that, although the respective type material is catalogued, no specimens could be found. It is suspected that the type material is either lost, illegally removed or misplaced in the collection. Fortunately the original description by Boheman (1860) mentions key characteristics of the species such as the clypeal and pronotal ornamentation that leave little doubt about the identity of the species. In addition, later identi®cations of specimens are mostly consistent.

The combination of a distinctly sinuate outline of the outer mandible and a bituberculate clypeal carina distinguishes Bolboceratex posticatus from most of the congeneric species. Only Bolboceratex jouberti spec. nov. shares both these character states with Bolboceratex posticatus . The former species, however, has a long transverse bituberculate clypeal carina with the tubercles widely spaced, a much more pronounced pronotal concavity with a pair of small tubercles (®gure 33a), an entire lateral pronotal margin and usually elytra darker than the rest of the body. DiOEerences between Bolboceratex posticatus and its closest relative Bolboceratex rhodesianus (Petrovitz) are discussed under the latter.