Meridiobolbus Krikken, 1984

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 : 1081-1085

Meridiobolbus Krikken

(®gures 9a±e, 15a±f, 16a±i, 18a, b, 19, 20, 24e)

Meridiobolbus Krikken, 1984: 38 .

Type species: Bolboceras hebes PeÂringuey, 1908 , by original designation.

Description

Body length. 9.5±17.7 mm.

Colour. Light to dark brown.

Head. Dorsal surface asetose. Outer margin of mandible rounded and often anteriorly more strongly curved inward. Labrum declivous anteriad and posteriad from feebly developed, slightly arcuate, to obsolete transverse carina; anterior margin distinctly sinuate. Clypeus with feebly to strongly elevated transverse anterior carina; with well-de®ned, short diagonal, posteriorly steeply inclined carina, the latter connecting the antero-latera l marginal angle and the respective endpoint of the transverse anterior carina (e.g. ®gure 15c); with distinct lateral carina from endpoint of anterior carina extending to above antennal insertion, from there extending posteriorly in a slightly curved line past eye-canthus on frons, sometimes reaching posterior end of frons (e.g. ®gure 15c). Frons with strongly elevated bituberculate or trituberculate transverse carina positioned between eye-canthi or slightly posteriad to eye-canthus; antero-lateral angle of eye-canthus distinctly raised. Antennal club ovoid, slightly shorter than diameter of eye; glabrous area of basal segment more or less half of exposed surface.

Pronotum. With four protuberances, variably positioned (see species descriptions); with large and ®ne punctation; lateral margin entire.

Scutellum. Deltoid; basal width about 1.25±1.44Ölength; lateral margin medially abruptly curved (e.g. ®gure 15b); variably punctate (see species descriptions).

Elytron. Anterior margin not upturned; striae moderately to strongly impressed, their punctures small and separated by two to four puncture diameters; intervals ¯at, with single or double punctation (®ne and minute punctures); sutural stria terminating at scutellum in a straight line, second stria obsolete near scutellum, neither reaching scutellum nor elytral base.

Prosternum behind procoxae (®gure 9b, c). As in Namibiobolbus , i.e. with protruding median, longitudinal carina near base, sometimes with additional small tubercle at apex.

Metasternum (®gure 9a). As in Namibiobolbus , i.e. disc more or less ¯at, process medially depressed and with upturned, ridged lateral margins; with longitudinal, median suture reaching meso-metasternal suture; meso-metasternal suture present at the top of the steep, sloping anterior declivity.

Legs. Protibia of normal shape, non-dilated, ®ve- or rarely six-dentate. Protibial spur acuminate; elongate, longer than ®fth tarsomere. Protarsus with ®rst tarsomere shorter than ®fth tarsomere, about equally long as tarsomere 2, 3 or 4. Metafemur with punctation and setation of ventral side as in ®gure 9d or 24e. Metatibia in lateral view variable regarding shape and armature (see species descriptions). Metatarsus lacking subapical setae on tarsomeres 2±4.

Underside. With moderately dense and long setation.

Male genitalia. Compact aedeagal type with lobelike projections on parameres.

Distribution (®gures 19, 20). Eastern Namibia, Botswana, northern and central parts of South Africa, and Zimbabwe.

Comments. Of the six southern African genera, Meridiobolbus is the least well de®ned. It is closest to Namibiobolbus with which it shares a number of characters. The lack of strong sexual dimorphism, the pronotum of males with four versus three protrusions and the aedeagal type are, however, considered su cient to maintain Meridiobolbus as a separate genus.