Bolboceratex rhodesianu

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 : 1117-1118

Bolboceratex rhodesianu s (Petrovitz)

(®gures 24a±e, 26g, h, 28j±l, 32b, 35)

Bolboceras rhodesianum Petrovitz, 1973: 335 , ®gures 1, 2.

Bolboceratex rhodesianus (Petrovitz) : Krikken 1984: 33.

Description

Body length. 10.4±13.8 mm.

Colour. Light- to mid-brown, but elytra often black in apical half or sometimes completely black except for mid-brown humeral umbone and elytral margins.

Head. Dorsal surface asetose. Outer margin of mandible (®gure 26g) distinctly sinuate and anteriorly strongly curved inward. Labrum (®gure 26g) asetose; declivous in anterior third and posterior two-thirds, transverse carina obsolete; anterior margin feebly to moderately sinuate. Clypeus (®gure 26g) sloping upward posteriorly to apex of feebly developed or obsolete transverse anterior carina; lateral carina feebly developed or obsolete anteriorly but raised and distinct above antennal insertion, continuing from there posteriorly in a straight and then arcuate line to almost posterior end of frons; antero-lateral angle of genae sharply raised; with posterior transverse monotuberculate carina, carina on each side of single tubercle curving backward and often but not always joining lateral raised carina above antennal insertion (®gure 26g). Frons more or less ¯at, with a medio-lateral swelling each in posterior part. Antennal club with glabrous area of basal segment two-thirds of exposed surface.

Pronotum (®gure 32b). With large Y-shaped concavity occupying anterior median two-thirds of pronotum; concavity 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; postero-medially 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, increasingly interspersed with large, partly conūent shallow punctures in 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 26h). Basal width about 1.64Ölength; with some ®ne punctures and with large, shallow, partly conūent punctures particularly in the middle.

Elytron. Striae moderately impressed, their punctures separated by three to four puncture diameters (®gure 26h); 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- or sometimes ®ve-dentate. Metatibia in lateral view distinctly broadening towards apex; with subapical carina unlobed; with knoblike projections spread randomly over surface above subapical carina.. Metatarsus lacking subapical setae on tarsomeres 2±4.

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

Distribution (®gure 35). The limited number of specimens originates from northern South Africa and Zimbabwe.

Type material examined. HOLOTYPE: l` Matopo Mts. , Matabele Ld., S. Rhodesia, Typus’ [black print on red label]/`Bolbocera s rhodesianum nov. Petrovitz’ [black print on red label] ( NHMG).

Additional material examined (23 specimens). South Africa: 7x, 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) ; 1x, same data but: 15.i.1978 ( TMSA) ; 5x, 1m, Tvl., Nylsvley, Nylstroom Distr. , 24.39S 28.42E, 18.ii.1980, E. Grei, light trap ( SANC) ; 1x, Tvl., Nylsvley, Nylstroom Distr. , 24.39S 28.42E, iii.1978, G. Ferreira ( SANC) . Zimbabwe: 1x, No. 21, Harare [17.50S 31.02E], Masvingo Rd, S. Rhodesia ( NMBZ, NMZ9428 ) ; 1x, No. 242, Harare, S. Rhodesia, ii± iv.1965 ( NMBZ, NMZ9429 ) ; 2x, 2mm, S. Rhodesia, Salisbury [Harare], D. Dodds ( SAMC) ; 1, l Salisbury , Mashonaland, 1910-195, J. H. Darling ( BMNH) ; 1, l1x, S. Rhodesia, Syringa [20.30S 28.00E], [19]08, R. Williams ( SAMC) .

Comments. The single clypeal tubercle easily distinguishes Bolboceratex rhodesianus from the other congeneric species that all possess a distinctly bituberculate transverse carina on the clypeus. Bolboceratex rhodesianus and its closest relative Bolboceratex posticatus share very similar external morphology and an identical aedeagus (®gure 28j±l). Besides the consistent diOEerence in clypeal armature (single tubercle versus bituberculate carina), only the often dark elytral coloration of Bolboceratex rhodesianus can be used as an additional, but not very reliable character for identi®cation. The holotype of Bolboceratex rhodesianus is one of the few specimens of uniform brown colour.