Revision of the southern African genus Frankenbergerius Balthasar with description of new taxa (Coleoptera: Scarabaeidae: Scarabaeinae)

The southern African genus Frankenbergerius Balthasar is revised. Two new species, F. opacus sp. n. and F. nitidus sp. n. (South Africa, Western Cape), and one new subspecies, F. armatus tuberculatus ssp. n. (South Africa, Mpumalanga), are described. F. imitativus (Péringuey) is considered a junior synonym of F. forcipatus (Harold). A key to the species and notes on biology are given.


Introduction
Southern Africa has a rich Scarabaeinae fauna with many groups retaining ancient Gondwanaland affiliations and relict distribution on the subcontinent (Halffter and Matthews 1966;Cambefort 1991;Davis 1997). In the Scarabaeinae, two ''old'' Gondwanaland tribes are recognized, the Canthonini and the Dichotomiini (Cambefort 1991), however the latter is probably polyphyletic (Génier 1996;Montreuil 1998). The major deterrent to phylogenetic, biogeographic, ecological studies of the group is the lack of taxonomic data. While the African taxa of Canthonini are relatively well known (Howden and Scholtz 1987;Howden 1987a, 1987b;Davis et al. 1999), many of the nominal genera currently placed in the Dichotomiini are still in need of taxonomic treatment. One of these poorly known groups is the genus Frankenbergerius Balthasar which was long considered a junior synonym of Coptorhina Hope.

Diagnosis
Males with less-developed clypeal processes and females of some species of Frankenbergerius, especially F. barratti (Waterhouse) with smooth elytra, are similar to species of Coptorhina. The two genera can immediately be distinguished, however, by the shape of the metepisternon. That of Frankenbergerius is triangular, widest in its anterior part, with slightly convex epipleural margin (Figure 1), while Coptorhina's is somewhat rectangular, widest in its hind part, with secondary suture and very convex epipleural margin ( Figure 2). Elytra of Frankenbergerius are not fused along sutural margins, as opposed to Coptorhina, and have complex sculpture in most species. The two genera differ strongly in secondary sexual characters. In Coptorhina, sexual dimorphism is very weak; males differ from females in having the last abdominal sternite slightly convex. In Frankenbergerius, sexes can easily be separated by the shape of the spur of the anterior tibiae, which is simple, acute in females and bifurcated in males. Males of some species also differ from females in having curious horn-like clypeal processes. However, the size of these horns, similar to other head processes in different groups of scarab beetles, is subject to much variation among individuals.

Description
Small to medium-sized beetles (length 4.5-16 mm, width 3.1-16 mm). Colour monotonous black to dark brown, sometimes anterior part of clypeus, legs or elytra slightly paler. Head and pronotum densely punctate and pubescent (except for F. barratti), in some species most of pronotum rugose. Each puncture, except for those of elytral striae, bears a short yellowish seta. Setae sometimes abraded on disc of pronotum and head.
Clypeus deeply sinuate in middle, angulate to dentate at sides in females and with more or less developed horns in males of most species. In some species anterior angles of clypeus with short carina directed proximally. Genae rectangular to rounded. Frontoclypeal suture interrupted on disc. Eyes small, the dorsal part slit-shaped, ventral part sub-rectangular. Distance between eye and gula approximately two times the width of eye in ventral view. Gula with longitudinal groove.
Pronotum more or less parallel-sided, wider than long. Anterior margin and base not bordered in most species; lateral margins bordered.
Elytra not fused, with humeral umbones, sinuate laterally near base. Elytral intervals flat to convex in apical part, with tubercles in most species. Scutellum not visible from above. Wings fully developed.
Anterior tibiae have three outer teeth with smaller intermediate teeth between (except for F. nanus, F. opacus sp. n., and F. nitidus sp. n.). Outer margins of middle and posterior tibiae without transverse keels, serrate.
Pygidium punctate on disc, bordered; with small longitudinal keel in F. opacus sp. n. Parameres symmetrical, their apices strongly to feebly sclerotized, without setae. Armature of internal sac of aedeagus is similar in most species.
The immature stages are unknown.

Diagnostic characters
The most important diagnostic character of Frankenbergerius species is the sculpture of the dorsal surface of the body and especially the elytra. The shape of the parameres is speciesspecific but in some individuals the character may be ambiguous. The shape of the clypeus in males is distinctive for some species (except for F. nanus, F. opacus sp. n., and F. nitidus sp. n.) in which clypeal processes are strongly developed.

Biology
Little is known of Frankenbergerius biology although inferences can be made from information recorded with museum specimens. The beetles have been collected most frequently in dense vegetation in association with litter and decomposing plant matter. Several records imply a close association with mushrooms. As opposed to Coptorhina, which has been studied in more detail and is known to be an obligatory basidial mushroom eater (Tribe 1976), Frankenbergerius presumably retained a more ancestral life style with no strict preference to mushrooms but rather to any rotten plant matter. The largest series of the beetles (F. armatus, 31 specimens) was collected in Silaka Forest Reserve (Eastern Cape Province) in rotten Cussonia fruit.
Frankenbergerius specimens have been collected by means of pitfall traps baited with different types of bait (banana, meat, and faeces) but this does not necessarily imply that the specimens were attracted to the baits. Very long trap exposures (up to 68 days) suggest that the beetles might be captured occasionally along with other litter dwellers. The only indication that Frankenbergerius specimens might be attracted to dung is one specimen of the rare species F. nanus collected near Darling (Western Cape Province) in a pitfall trap with fresh cattle dung which was exposed for 24 h. However, in some 15 months of trapping in the area (10 traps on three occasions per month), this was the only Frankenbergerius specimen recorded, so this was probably a chance trapping (A. Davis, personal communication). No specimens have been collected in dung pads, nor are there direct indications that specimens are attracted to carrion.
Mycetophagy has been hypothesized to be the ancestral feeding type of the Scarabaeinae, with a change to dung in most taxa evolving much later (Scholtz and Chown 1995). However, feeding on the higher fungi, the mushrooms, is more likely to be a later change from humus or dung to a more nutritious substance. In the lineage to which the genus Frankenbergerius belongs, the genera Coptorhina and Delopleurus, the obligatory mushroom eaters, represent the most derived taxa with the greatest number of apomorphies, while the genus Sarophorus Erichson, which feeds on dung, humus, and carrion, largely retained plesiomorphic character states (Frolov and Scholtz, 2003).
Nesting behaviour of Frankenbergerius has not been studied but it can be assumed that it is similar to related taxa. Coptorhina specimens have been observed feeding on mushrooms with two types of fruit-body. In the case of ''puff-ball'' mushrooms the adults burrow into the fruit-body, detach pieces and drag them into their burrows. In ''parasol'' mushrooms, the beetles climb the stalk and detach pieces of the gills, which they then drag into their burrows. Brood balls are constructed from the macerated pieces, eggs are laid and the balls coated with soil. Because males of some species of Frankenbergerius have long clypeal horns, they are probably unable to burrow into a fresh mushroom or detach pieces of it and probably do not take part in brood ball construction. Field observations are needed to clarify the genus' nesting behaviour.
Frankenbergerius specimens are apparently not attracted to light and are presumably day-fliers.

Diagnosis
This species can easily be separated by its large size (8.5-16 mm) and almost smooth upper side of body. Males usually have long and slender clypeal horns ( Figure 30).
Head. Clypeus of males with two long, acute horns curved upwards; horns 1-0.5 times the length of the head (Figures 30, 31). In females, clypeus with protruding anterior angles separated by deep sinuation (Figure 32). Genae right-angled, finely bordered. Genal sutures distinct. Lateral margin of clypeus distinctly sinuate near genal suture in males but without sinuation in females. Frontal suture obsolete. Head densely punctate except for disc which is smooth and slightly convex. Eyes small, almost completely divided by canthus, dorsal parts slit-shaped.
Pronotum. Pronotum with subparallel sides, two times wider than long. Anterior margin sinuate medially, anterior angles slightly sinuate laterally. Disc smooth, anterior and lateral parts densely punctate (puncture separated by one to two puncture diameters). Elytra. Striae distinct, punctate (punctures separated by three to four puncture diameters). Intervals slightly convex, smooth, without tubercles.
Underside. Pygidium with deep border, its disc densely punctate. Abdominal and thoracic sternites coarsely punctate except for disc of metasternum.
Legs. Anterior tibiae with smaller teeth between major outer teeth in most specimens. Intermediate teeth can be obsolete in older individuals. Spur of anterior tibia bifurcated in males and simple, acute in females.
Variability. Shape and length of clypeal processes in males vary (Figures 30,31) otherwise variation among examined specimens is very slight. Females differ from males in not having bifurcated spur of anterior tibiae and in the shape of the clypeus ( Figure 32).

Distribution
This rare species is known from a few localities in South Africa and Lesotho ( Figure 43).

Diagnosis
This species can be distinguished by elytral interval 8 with a long carina occupying twothirds of the length of the elytron and by its small body size.

Description
Black to dark brown, shiny beetle ( Figure 39). Body length of males 4.6-7.2 mm, width 2.5-3.2 mm, of females 4-7.3 mm and 2.4-3.9 mm. Dorsal surface with minute setae which may be abraded on most surfaces.
Head. Clypeus with two horn-like processes; processes slightly longer in males (Figures 41,42). Genae obtuse, finely bordered. Genal sutures distinct. Lateral margin of clypeus with deep sinuation near genal suture. Frontal suture obsolete medially. Dorsal surface of horn-like processes granular, rest of head densely punctate except for middle area of clypeus which is smooth. Eyes small, almost completely divided by canthus, their dorsal parts slit-shaped. Pronotum. Pronotum narrower in anterior part, 1.6 times wider than long. Anterior margin not sinuate medially, or with minute unclear sinuation. Lateral margins and anterior angles finely bordered, anterior margin and base not bordered. Surface coarsely punctate with more or less elongated punctures.
Elytra. Striae distinct, punctate (punctures separated by three to four puncture diameters). Intervals indistinctly punctate on disc, with elongated tubercles. Interval 8 with long carina occupying two-thirds of elytron.
Underside. Pygidium with deep border, its disc densely punctate. Abdominal and thoracic sternites coarsely punctate except for disc of metasternum.
Legs. Anterior tibiae with smaller teeth between major outer teeth in most specimens. Spur of anterior tibia bifurcated in males and simple, acute in females.
Variability. Except for body size, the specimens examined show very little variation. Females differ from males in not having bifurcated spur of anterior tibiae and clypeus with somewhat shorter processes with smaller sinuation between (Figures 41, 42).

Distribution
This species is known from a number of localities in Limpopo, Mpumalanga, and KwaZulu-Natal provinces.

Diagnosis
This species is similar to F. armatus but can be separated from it by having elytral intervals 1-4 smooth or with only traces of tubercles. It also differs in the shape of the parameres ( Figure 37).
Head. Clypeus with two horn-like processes; processes sometimes longer in males (Figures 33-36). Genae obtuse, finely bordered. Genal sutures distinct. Lateral margin of clypeus slightly sinuate near genal suture or without sinuation. Frontal suture obsolete medially. Dorsal surface of horn-like processes granular, other part of head densely punctate except for middle area of clypeus which is smooth. Eyes small, almost completely divided by canthus, their dorsal parts slit-shaped.
Pronotum. Pronotum narrower in anterior part, 1.8 times wider than length. Anterior margin not sinuate medially, or with minute unclear sinuation. Lateral margins and anterior angles finely bordered, anterior margin and base not bordered. Punctures separated by a puncture diameter on disc, becoming denser and somewhat elongated laterally.
Elytra. Striae distinct, punctate (punctures separated by three to four puncture diameters). Intervals 1 and 2 without tubercles; intervals 3-7 with small tubercles; interval 8 with long keel interrupted at middle of elytron; interval 9 with smaller keel situated in the middle of elytron.
Underside. Pygidium with deep border, its disc densely punctate. Abdominal and thoracic sternites coarsely punctate except for disc of meso-and metasternum.
Legs. Anterior tibiae with smaller teeth between major outer teeth in most specimens. Spur of anterior tibia bifurcated in males and simple, acute in females.
Variability. Except for body size there is some variation in the length of the clypeal processes in males (Figures 33-35). Females can be separated by acute, not bifurcated spur of anterior tibiae and in most cases by shorter clypeal processes ( Figure 36).

Distribution
This species is known from a few distant localities in Magaliesberg (Northwest Province), southern Drakensberg and Ciskei (Eastern Cape Province) ( Figure 43).

Remark
C. forcipata was unknown to Péringuey when he described C. imitativa and his later record of the former species (Péringuey 1908, p 627) is based on its original description. Examination of the type specimens of the two nominal species shows no noticeable differences in the punctuation of the pronotum nor sculpture of the elytra, contrary to the characters given in the keys by Janssens (1939, p 32) and Ferreira (1954, p 8, 9).

Diagnosis
This species is most similar to F. forcipatus but can be separated by its smaller size, by having elytral intervals 2-4 with more distinct tubercles and by the parameres narrower in lateral view (Figures 23, 24).

Polymorphism
In the examined material, there are two distinct forms of males: one with clypeal horns curved upwards and slightly backwards (Figures 14, 22) with somewhat truncate apices, and another form with acute horns curved upwards but not backwards (Figures 17, 21). An additional, although minor difference, is the less tuberculate elytra in the first form (Figures 25, 26). The form with truncate apices of clypeal horns was collected in the Eastern Cape and KwaZulu-Natal provinces and the other one in Mpumalanga and Northern Province (Figure 27). The distinctness of the form with acute clypeal horns from ''typical'' F. armatus was apparently recognized by M. Ferreira; one such specimen in the TMSA bears the label ''Type " Pseudocoptorhina armata var. tuberculata nov. M.G. Ferreira 1954''. However, the name was not published.
Because of the allopatric distribution and distinct morphological differences between males with well-developed horns we treat these two forms as subspecies. The absence of noticeable differences in paramere shape and ambiguous differences in elytral sculpture (characters that are normally distinctive for other Frankenbergerius species) prevent us from assigning them specific rank. However, if further research shows reproductive isolation or sympatric distribution, their rank should be reconsidered.

Remark
Harold (1871, p 112) described C. granulifera from Port Natal [Durban]. Later he transferred E. armatus to Coptorhina and wrote that C. granulifera belongs to this species (Harold 1872, p 205). We did not have the opportunity to examine the type of C. granulifera, however, the collection locality suggests that it is the nominotypical subspecies of F. armatus, to which the type of C. granulifera belongs.

Description
Male (Figure 22). Dorsal surface of pronotum, elytra and head with small yellowish setae. Most of setae may be abraded; in most specimens setae absent on disc of head and pronotum.
Head. Clypeus in some individuals with horns curved upwards and slightly backwards ( Figure 14) with somewhat truncate apices. Genae obtuse, finely bordered. Genal sutures visible as fine lines. Lateral margin of clypeus not, or very feebly, sinuate near genal suture. Frontal suture broadly interrupted at middle. Area behind genae slightly concave, coarsely punctate with big adjoining punctures, with distinct margins. Genae and anterior part of clypeus densely punctate; margins of punctures indistinct. Very anterior part of clypeus with sculpture nearly rugose. Disc of head with minute, feebly visible punctuation. Inner (dorsal) surface of clypeal horns finely granular, outer (ventral) surface smooth. Anterior margin of clypeus flattened, deeply sinuate at middle, slightly rugose.
Pronotum. Anterior angles rounded. Lateral margins with fine border, hind and anterior angles and anterior margin with wider border. Border of anterior margin widened and sinuate at middle. Base not bordered. Hind angles obtuse. Dorsal surface densely and coarsely punctate; punctures separated by 0.2-0.3 times their diameters on disc, becoming denser laterally.
Elytra. Striae fine on disc becoming slightly wider and deeper apically, shiny, punctate (punctures separated by three to four puncture diameters). Intervals flat on disc, feebly convex in apical part, smooth to slightly shagreened and punctate (punctures separated by 1.5 to two puncture diameters). Intervals 2-7 with longitudinal tubercles, less developed than those in F. armatus tuberculatus. Interval 8 with long keel interrupted at middle of elytron. Interval 9 with smaller keel situated at about middle of elytron. Keels, especially hind part of keel on interval 8, serrate in most individuals.
Underside. Pygidium with deep border, its disc densely punctate. Abdominal and thoracic sternites coarsely punctate except for disc of meso-and metasternum.
Legs. Anterior tibiae with smaller teeth between major outer teeth in most specimens. Spur of anterior tibia bifurcated in males and simple, acute in females.
Variability. Body length of males 4.6-8.2 mm, width 3.5-5.2 mm, of females 6.2-8.3 mm and 3.9-5.0 mm. Colour of body from black to dark brown. Length of clypeal processes varies, some males have shorter clypeal processes ( Figure 15). Females can be separated by acute, not bifurcated spur of anterior tibiae and, in some cases, by shorter clypeal processes ( Figure 16).

Distribution
The subspecies is distributed is Eastern Cape and KwaZulu-Natal provinces up to 29uS in the north (Figure 27).

Type material examined
Lectotype ( In the original description, Boheman (1857, p 200) did not designate the holotype nor did he indicate the number of specimens examined. However, the size range provided (length 7.5-8.0 mm, width 5.0-5.2 mm) suggests that a few specimens were studied. The five specimens collected by Wahlberg fit these measurements well and might have all been examined by Boheman. One of these specimens bears a label ''typus'', but it has lessdeveloped clypeal horns (and its left horn is broken) to class it unequivocally as the subspecies armatus. The locality label ''Caffraria'' suggests that this specimen could have been collected in the natural habitat of either of the two subspecies. To ensure stability of the nomenclature, another male specimen which has the explicit features of F. armatus armatus is here designated as the lectotype.
( 24,26,27) Diagnosis This subspecies differs from the nominotypical one chiefly by the shape of the clypeal horns in males: the horns curve upwards, with acute apices (Figures 17, 21).
Legs. Anterior tibiae with smaller teeth between major outer teeth in most specimens. Spur of anterior tibia bifurcated in males and simple, acute in females.
Aedeagus. Similar to F. armatus armatus (Figure 17). Paratypes: body length of males 7.0-11.0 mm, width 4.1-5.2 mm, of females 6.3-8.6 mm and 4.0-5.1 mm. Colour of body from black to dark brown. In most specimens, disc of head and pronotum without setae. Length of clypeal horns varies in males (Figures 18, 19). Females can be separated by acute, not bifurcated spur of anterior tibiae and by shorter clypeal processes in some cases ( Figure 20).

Distribution
This subspecies is distributed is Mpumalanga and Limpopo provinces. The southernmost known locality is Wakkerstroom in southern Mpumalanga (Figure 27). Aedeagus. Parameres with widely rounded apices ( Figure 12).

Type material
Paratypes: body length varies in males from 5.8 mm to 7.1 mm, width from 4.0 mm to 3.6 mm, in females 7.5-6.1 mm and 4.6-3.9 mm, otherwise variation among specimens is very weak.

Diagnosis
This species is similar to F. opacus sp. n. and F. nitidus sp. n. but can be separated from them by having distinct transverse convexity on the last abdominal sternite. From the former it can also be separated by the pronotum having a flat base, and from the latter by matt elytral intervals.
Head. Clypeus with anterior angles dentiform with deep sinuation between. Genae rounded, finely bordered. Genal sutures visible as fine lines. Lateral margins of clypeus very feebly sinuate near genal suture. Frontal suture indistinct. Genae and anterior part of clypeus densely punctate, almost rugose. Disc of head with minute, feebly visible punctures.
Pronotum. Anterior angles rounded. Lateral and anterior margins bordered, base not bordered. Border of anterior margin widened at middle, without sinuation. Hind angles rounded. Dorsal surface densely and coarsely punctate; punctures separated by 0.2-0.3 times their diameters on disc, becoming denser laterally. Base not concave (Figure 3).
Elytra. Striae distinct, punctate (punctures as wide as striae, separated by three to four puncture diameters); striae 9 and 10 very close, with deeper and larger punctures. Intervals matt, impunctate, with elongated tubercles.
Legs. Anterior legs with three outer teeth without smaller teeth between. Spur of anterior tibia bifurcated in males and simple, acute in females.
Variability. Except for body size variation indicated above, the specimens examined are very similar.

Distribution
This species is known from a few localities in the vicinity of Cape Town ( Figure 43).

Diagnosis
This species is similar to F. nanus and F. opacus sp. n. but can be separated from the former by having the last abdominal sternite flat, without a transverse convexity, and by shiny elytral intervals with rounded to elongated tubercles. From F. opacus n. sp. it differs in having the base of the pronotum flat, very close elytral striae 9 and 10, and pygidium without longitudinal keel in basal part.