Revision of the genus Delopleurus Boheman (Coleoptera: Scarabaeidae: Scarabaeinae) with description of new species from Africa

The genus Delopleurus Erichson, 1847, is revised. Five new species are described from Africa: Delopleurus naviauxi sp. nov., Delopleurus krikkeni sp. nov., Delopleurus darrenmanni sp. nov., Delopleurus fossatus sp. nov. and Delopleurus pubescens sp. nov. One new synonymy is established (Delopleurus parvus (Sharp, 1875) = Delopleurus cardoni Paulian, 1934, syn. nov.). Lectotype of Delopleurus pullus Boheman, 1857, is designated. Delopleurus janssensi Frey, 1963, is transferred to the genus Metacatharsius Paulian, 1939. A key to the Delopleurus species and locality maps are given. http://zoobank.org/urn:lsid:zoobank.org:pub:67AE5CC5-9C9C-4872-A2B6-68C3BA82C44A


Introduction
This paper is the last in a series of taxonomic revisions of the peculiar scarabaeine 'dung beetles' of the Sarophorus group of genera (Sarophorus Erichson, Frankenbergerius Balthasar, Coptorhina Hope, and Delopleurus Erichson). This group was first recognized by Erichson (1847) who noted the sinuate epipleura (strongly in Coptorhina Hope and Delopleurus Erichson and not so strongly in Sarophorus Erichson) and correspondingly widened metepisterna. Later the status and position of Frankenbergerius Balthasar within the group was validated (Frolov and Scholtz 2005) and other characters shared by the members of the group were found (Frolov 2002;Frolov andScholtz 2003, 2005;Frolov et al. 2008).
Delopleurus comprises superficially similar, small-sized, dark brown to black, strongly convex beetles distributed in Africa south of the Sahara and in southern Asia. The genus is commonly classed as dung beetles; however, there is no evidence of its association with dung. Available data suggest that the beetles are associated with higher fungi similar to the related genus Coptorhina, members of which are obligate feeders on basidiomycetes . Delopleurus is also peculiar in having a disjunctive range including most of the Afrotropical Region and Indian Peninsula. Distribution of the other genera of Sarophorus group is limited to the Afrotropical region.

Delopleurus Erichson 1847
Type species: D. pullus Boheman 1857. Delopleurus was established by Erichson (1847) for 'one small south African species, which differs from Coptorhina in narrower hind legs'. Ten years later Boheman (1857) gave the name to this species, D. pullus, and so fixed the type species of the genus. Sharp (1876) described Coptorhina parva from northern India. Arrow (1931) moved C.parva to Delopleurus and described the second species from India, D.striatus. Paulian (1934) described the third species from India, D. cardoni. Janssens (1939) described the second species from Africa, D. gilleti, and gave a diagnostic key to all species known by then. Frey (1963) described D. janssensi from Ethiopia. Except for this primary taxonomic literature, members of the genus were listed in the catalogues and monographs (Péringuey 1901;Gillet 1911;Balthasar 1963;Ferreira 1972;Král and Löbl 2006;Davis et al. 2008) but few additional data were given.

Diagnosis
Delopleurus and closely related Coptorhina share somewhat rectangular metepisternum, widest in its hind part, very convex epipleural margin ( Figure 1A), and other taxonomic characters of the Sarophorus group of genera . From Coptorhina it can easily be separated by quadridentate clypeus and smaller body size (3.5-6.1 mm in Delopleurus and 8.0-20.0 mm in Coptorhina).
Clypeus distinctly quadridentate in most species. Two medial teeth are almost always acute, lateral ones are acute to right-angled. In some species, lateral clypeal teeth are almost not separated from the lateral margin ( Figure 7A, D). Head without carinae on disc, and lacking horns or tubercles. Small carina present near inner margin of eye. Genae right-angled, indistinctly separated from clypeus. Frontoclypeal and genal suturae almost indistinct. Eyes small, their dorsal parts small, slit-shaped in some species, ventral parts larger, sub-rectangular. Distance between eye and gula approximately twice the width of eye in ventral view. Gula with longitudinal groove ( Figure 9F). Dorsal surface of clypeus rugose in most species, frons densely punctate to rugose.
Pronotum more or less trapezoidal, about two times wider than long. Anterior and lateral margins with distinct border, base with or without border. Pronotum is not excavated, without horns or ridges but with fine short longitudinal groove basally along the midline.
Elytra trapezoidal, as wide as long, shiny to opaque, with deep sinuation on lateral margins receiving convex metepisternum ( Figure 1A). Striae fine but distinct, punctate; striae 1-7 reach base of elytron, stria 8 reaches the sinuation but not the base; striae 9-10 are very close to epipleura and mostly inseparable from each other except apically. Elytral intervals flat to convex, with minute punctation. Elytra fused along suture. Scutellum not visible from above. Wings well developed and feature a number of characters that Delopleurus share with species of the Sarophorus group of genera : brown colour except for very basal part, reduced anal area (veins J and AP 3+4 are absent), CuA widened apically along the wing margin, RA 4 does not reach the wing margin and becomes wide and indistinct apically.
Anterior tibiae have three outer teeth. Margin basad of third tooth feebly or not serrate. Spur of anterior tibia more or less bifurcated in males and apically acute to rounded and curved inwards in females. In one species (D. naviauxi sp. nov.), anterior tibia with one small acute tooth between first outer tooth and spur ( Figure 1D). Outer margins of middle and posterior tibiae without transverse carinae, serrate. Tarsi of all legs well developed, shorter than tibiae. Claws about half the length of fifth tarsal segment.
Pygidium about twice as wide as long, its sculpture is species-specific and, in some species, differs strongly from that in the other scarabaeine taxa. In some Delopleurus species basal and apical borders are relatively narrow and the disc occupies most of pygidium ( Figure 2E). In others, however, the borders are much wider and the disc is almost slit-shaped ( Figure 2B). Sculpture of pygidium is sex-dependent in some species.

Sexual dimorphism
Males can be easily separated from females by having more or less bifurcated spurs of anterior tibiae ( Figure 1B, C). Some species differ strongly in the sculpture of the pygidium.

Diagnostic characters
Unlike other scarabaeines, Delopleurus species can be best separated by the sculpture of the pygidium. Although shape of the parameres and internal sac armature shows some species specific features, they are not considered reliable diagnostic characters. However, availability of the other characters, especially that of the pygidium, makes dissection unnecessary in routine identification.

Distribution
Delopleurus has a disjunctive range covering most of the Afrotropical Region and Indian Peninsula. The ranges of species are rather limited (except for D. gilleti Janssens) although this may be a result of undersampling. Two regional faunas, Afrotropical and Indian, share no common species, which may indicate that they have long developed in isolation. The genus range disjunction can be best explained by the contraction of a previously very large range since the late Neogene. It is possible that in the late Miocene, when huge regions of Africa and Eurasia, including the territories of the present-day Sahara and Mediterranean, were covered by the African-type savannas, Delopleurus was widely distributed in the Eurasia. No palaeontological data exist on the past occurrence of Delopleurus in Europe and extratropical Asia, but considering very low taphonomic potential of these soil dwellers, discovery of any fossil Delopleurus seems highly improbable.

Biology
Little information is available about the biology of Delopleurus and the immature stages of the genus are unknown. In Ivory Coast, a few specimens of D. gilleti were collected on mushrooms of Termitomyces cf. schimperi along with more numerous Coptorhina nitidipennis Boheman (Yves Cambefort, pers. comm.). In Namibia (Caprivi, Darren Mann, pers. comm.), beetles of D. darrenmanni sp. nov. were collected in mushrooms (Termitomyces sp.) on and around termite mounds, also in association with Coptorhina (C. nitidipennis and C.angolensis Arrow). There were apparently Coptorhina burrows under the fungal umbrella or a few centimetres away. No smaller burrows of Delopleurus were seen however. It is possible that Delopleurus can use mushroom pieces buried by Coptorhina.
Delopleurus beetles have never been found in or under dung pads, and they have never been collected by pitfalls baited with dung or carrion [Philippe Walter collected a few specimens in traps baited with fish (Yves Cambefort, pers. comm.) but these were most probably chance captures].
Available data suggest that Delopleurus are specialist feeders of agaric mushrooms (Agaricales). They seem to be associated with the termitophilous genus Termitomyces, a widespread fungal genus with large fruit bodies. In the case of Delopleurus and Coptorhina, feeding on mushrooms can be a secondary adaptation from the putatively generalist saprophagy of their ancestors. Feeding on mushrooms as an adaptation to arid biotopes in beetles was hypothesized by Striganova (1980).
All Delopleurus specimens examined have well developed wings and apparently are good fliers. But no specimens have been collected at light, according to the labels and data from collectors. This, along with small eyes (typical for all members of the Sarophorus group genera), suggests that the beetles have diurnal flight activity.    2. Fore tibia with small acute tooth near apical spur ( Figure 1D). Pygidium with slitshaped pubescent disc ( Figure

Diagnosis
This species can be separated from other Delopleurus species by having deep transverse fossa on the pygidium and by the fore tibia with a small acute tooth near apical spur.
Pronotum trapezoidal, about two times wider than long. Anterior and lateral margins bordered, base without border. Pronotum relatively densely punctate on disc (punctures separated by one to two puncture diameters), punctation becoming denser laterally.
Elytra trapezoidal, as wide as long, shiny. Stria distinct, with punctures larger than striae. Elytral intervals slightly convex on disc, with minute punctation.
Anterior tibiae with three outer teeth and a small acute tooth between first outer tooth and apical spur ( Figure 1D).
Paratype. female, slightly larger than the holotype (6.0 mm). The specimen has malformed or worn, reduced anterior tibiae without outer teeth and tarsi, and reduced clypeal teeth. It also differs from the holotype in having less shiny dorsal side.
Male unknown.

Distribution
The species is known from two localities in Northern Acacia-Commiphora bushlands and thickets ecoregion in East Africa ( Figure 2C).

Etymology
The species is named after Roger Naviaux, a French collector.

Remarks
Yves Cambefort (MNHN) examined the Delopleurus specimen from Maji ya Chumvi in the 1980s and noted that it was distinct from other described species of this genus. However, he did not describe it at that time. In the course of the revision of the genus, I examined the specimen from Makuyu which is housed in the BMNH. After comparison of the two specimens we concluded that they are conspecific and belong to a new species described above.

Diagnosis
Males of this species can be separated from other Delopleurus species by the disc of pygidium being rugose, somewhat granulate and pubescent with sparse brown setae ( Figure 2E). Such a sculpture is similar to that of females of D. pullus ( Figure 3E) but it is not rugose in the latter.
Pronotum more or less trapezoidal, about two times wider than long. All margins with distinct border. Disc and base punctate with punctures separated by two to three puncture diameters, sides and especially anterior angles more densely punctate.
Elytra trapezoidal, as wide as long, somewhat opaque. Stria deep, with punctures slightly larger than striae width. Elytral intervals slightly convex (more distinctly on disc).
Anterior tibiae with three outer teeth, without a small acute tooth between first outer tooth and apical spur.
Pygidium with relatively slender borders and convex disc. Basal border slender and almost parallel-sided except in the middle. Apical border about twice as thick in the middle as the basal border, becoming more slender laterally. Disc with irregular, rugose and granulate sculpture, pubescent with short yellowish setae ( Figure 2E).
Parameres with a small protuberance ventroapically (visible in lateral view, Figure 2F).
Female unknown.

Distribution
The species is known from a few localities in the Congolese forest-savanna and Miombo woodlands ( Figure 2G).

Etymology
The species name is a Latin word denoting the peculiar sculpture of the pygidium.  Péringuey 1901;Ferreira 1972;Gillet 1911;Janssens 1939.

Diagnosis
This species is most similar to D. gilleti but can be separated from it in having the pygidium with relatively larger disc punctate with smaller and sparser punctures in males and granulate and pubescent in females, and in having relatively sparsely punctate disc of pronotum.
Male ( Figure 3A). Clypeus quadridentate, two medial teeth acute, lateral ones rightangled to acute-angled. Clypeus rugose in anterior part and laterally, frons densely punctate (punctures separated by less than a puncture diameter). Pronotum more or less trapezoidal, about two times wider than long. Anterior and lateral margins bordered, base not bordered. Surface relatively sparsely punctate on disc (punctures separated by two to three puncture diameters) and denser laterally.
Elytra trapezoidal, as wide as long, shiny. Stria relatively deep, with punctures slightly larger than striae width. Elytral intervals feebly convex to almost flat, with minute punctation.
Anterior tibiae with three outer teeth, without a small acute tooth between first outer tooth and apical spur.
Pygidium with relatively slender borders and convex disc. Basal border slender and almost parallel-sided except in the middle. Apical border about twice as thick in the middle as the basal border, becoming more slender laterally. Disc glabrous, punctate with punctures separated by one to two puncture diameters ( Figure 3B).
Parameres with a small protrusion ventroapically (visible in lateral view, Figure 3C).
Female ( Figure 3D) can be separated from male in having acute, not bifurcated spurs of anterior tibiae and disc of pygidium with small granules and setae ( Figure 3E).

Distribution
The species is widely distributed in the northern part of Southern Africa ( Figure 3F).

Diagnosis
This species can be separated from other Delopleurus species by the sculpture of its pygidium. Males have punctate, glabrous, narrow disc of pygidium which is almost as long as apical and basal border in the middle ( Figure 4B). Females have characteristic slit-shaped disc with a transverse carina in the middle ( Figure 4E).
Pronotum more or less trapezoidal, about two times wider than long. Anterior and lateral margins distinctly bordered, base feebly bordered. Surface relatively sparsely punctate on disc (punctures separated by two to three puncture diameters) and denser laterally.
Elytra trapezoidal, as wide as long, shiny. Stria relatively deep, with punctures slightly larger than striae width. Elytral intervals feebly convex, with minute punctation.
Anterior tibiae with three outer teeth, without a small acute tooth between first outer tooth and apical spur. Anterior tibial spur bifurcated apically.
Pygidium with relatively thick borders and convex disc. Apical border almost as long as disc in the middle. Disc glabrous, punctate with punctures separated by two to four puncture diameters ( Figure 4B).
Female can be separated from male in having acute, not bifurcated spurs of anterior tibiae and in sculpture of pygidium, which has very wide borders and very narrow disc with transverse keel ( Figure 4E).

Distribution
The species is known from three localities in a relatively small area between the Zambezi and Okavango rivers in Zambezian woodland region ( Figure 4F).

Etymology
The species is named after Darren Mann (OUMNH), who collected the type series. Delopleurus gilleti Janssens ( Figure 5A-F)

Diagnosis
This species is most similar to male D. pullus but can be separated from it in having the pygidium with smaller disc which is punctate with bigger punctures (Figure 5B, E) and in having relatively densely punctate disc of pronotum ( Figure 5A, D). This species does not show sexual dimorphism in the sculpture of the pygidium.
Male ( Figure 5A). Clypeus quadridentate, medial teeth acute, lateral ones acuteangled. Clypeal margin laterad of lateral teeth somewhat angulate so clypeus looks hexadentate. Clypeal surface rugose in anterior part and laterally, frons densely punctate (punctures separated by less than puncture diameters). Pronotum about two times wider than long. Anterior and lateral margins distinctly bordered, base not bordered. Pronotum densely almost uniformly punctate with punctures separated by less than a puncture diameter.
Elytra trapezoidal, as wide as long, shiny. Stria relatively deep, with punctures slightly larger than striae width. Elytral intervals convex, with minute punctuation.
Anterior tibiae with three outer teeth, without a small acute tooth between first outer tooth and apical spur. Anterior tibial spur bifurcated apically.
Pygidium with relatively narrow borders and feebly convex disc. Disc glabrous, coarsely punctate with punctures separated by about one puncture diameter ( Figure 5B).
Parameres in lateral view somewhat abruptly truncate, with distinct processes ( Figure 5C).
Female ( Figure 5D) can be separated from male in having acute, not bifurcated spurs of anterior tibiae. Sculpture of pygidium is similar to that of male ( Figure 5E).

Distribution
The species is widely distributed in the savannas both south and north from the equator ( Figure 5F). Frolov, sp. nov. ( Figure 6A-D)

Diagnosis
This species can be easily separated from other Delopleurus species by sparsely punctate to impunctate disc and base of pronotum. Its pygidium is similar to that of D. fossatus sp. nov. but differs in having convex basal border distinctly widened medially ( Figure 6B). From D. fossatus sp. nov. it also differs in having larger eyes (in dorsal view).
Pronotum about two times wider than long. Anterior and lateral margins distinctly bordered, base feebly bordered laterally. Disc and base of pronotum impunctate, sides relatively densely punctate.
Anterior tibiae with three outer teeth, without a small acute tooth between first outer tooth and apical spur. Anterior tibial spur bifurcated apically.
Pygidium with relatively strongly convex disc separate by deep circular fossa from border. The apical border wider medially and somewhat tapering laterally; apical border somewhat tuberculate in the middle ( Figure 6B).
Parameres in lateral view with small processes ( Figure 6C).
Paratype, male. Differs from the holotype in being slightly larger (length 4.8 mm) and having only anteromedial part of pronotal disc impunctate.
Female unknown.

Distribution
The locality where the holotype was collected is uncertain (Adrian Davis, pers. comm.). In 1896, 'Samburu' might refer to a large area to the northwest of Mount Kenya and to the south of Lake Turkana, that was occupied by the Samburu people. But it might also be the railway station (3°46ʹ S, 39°16ʺ E) on the railroad Mombasa-Nairobi. This latter locality is some 100 km east-northeast of the locality where the paratype was collected, Mkomazi Game Reserve ( Figure 6D).

Etymology
The species is named after Jan Krikken (Naturalis, Leiden).

Remarks
Two new species are described in this work from the Eastern Arc Region, D. krikkeni sp. nov. and D. naviauxi sp. nov. The former species is known from two males and the latter from two females only. I believe that these specimens are not conspecific because the male specimens lack a characteristic small tooth apicad of the first major outer tooth on the anterior tibae, which is found in the D. naviauxi holotype. Sexdependent modifications of the legs are common in the Scarabaeinae but found in the males only. I think that this additional tibial tooth is sex-independent and should be present in the males of D. naviauxi sp. nov.

Diagnosis
This species is similar to D. krikkeni in having pygidium with deep circular fossa, but can be separated from it by having basal border of pygidium not or indistinctly widened medially, punctate disc of pronotum and smaller, slit-shaped dorsal parts of eyes.
Pronotum about two times wider than long. Anterior and lateral margins distinctly bordered, base feebly bordered. Pronotum densely punctate (punctures separated by one to two puncture diameters on disc, becoming denser laterally).
Anterior tibiae with three outer teeth, without a small acute tooth between first outer tooth and apical spur. Anterior tibial spur bifurcated apically.
Pygidium with strongly convex disc separated by deep circular fossa from borders. Apical and basal borders about the same thickness, not significantly thicker in the middle. Disc glabrous and coarsely punctate ( Figure 7B).
Parameres with small processes in lateral view ( Figure 7C). Female can be separated from male in having acute, not bifurcated spurs of anterior tibiae. Sculpture of pygidium is similar to that of male but the pygidium is one-eighth to one-ninth shorter ( Figure 7E).
Paratypes. Body length varies from 4.5 mm to 5.5 mm, otherwise the paratypes are similar to the holotype.

Distribution
The species is known from Mlanje, Malawi ( Figure 7F) in the southern Rift Valley.

Etymology
The epithet is a Latin word denoting the sculpture of the pygidium.

Diagnosis
This species differs from the other Delopleurus species in having bilobate glabrous disc of pygidium with very thick borders similar in both sexes ( Figure 8B, E), and elytral striae with large punctures ( Figure 8A, D).
Male ( Figure 8A). Clypeus quadridentate, medial teeth acute, lateral ones rightangled. Clypeal surface rugose in anterior part and laterally, frons densely punctate (punctures separated by less than puncture diameter). Pronotum about two times wider than long. Anterior and lateral margins distinctly bordered, base not or feebly bordered laterally. Surface of pronotum densely punctate anterolaterally, sparsely punctate with smaller punctures basally and anteromedially.
Elytra trapezoidal, as wide as long, shiny. Stria fine, with punctures much larger than striae width. Elytral intervals slightly convex to almost flat, with minute punctuation.
Anterior tibiae with three outer teeth, without a small acute tooth between first outer tooth and apical spur. Anterior tibial spur bifurcated apically.
Female ( Figure 8D) can be separated from male in having acute, not bifurcated spurs of anterior tibiae. Sculpture of pygidium is similar to that of male ( Figure 8E).

Type material
Delopleurus parvusholotype, female with the labels 'Ind.

Distribution
The species is known from a few localities in the Indian Peninsulasoutheastern Deccan Plateau and Chota Nagpur Plateau. Locality map ( Figure 8F) suggests that it can be associated with transitional zones between moist and dry deciduous forest ecoregions. Paulian (1934) described Delopleurus cardoni from nine specimens from northern India ('Chota-Nagpore Nawatoli Palkot, R.P.Cardon VII-VIII.1897'). He separated D.cardoni from D.parvus on the basis of the punctate disk of pronotum in the former species and smooth in the latter. Comparison of the types of the both nominal species showed, however, that the both have relatively densely punctate disk of pronotum and do not differ significantly in other characters. The new synonymy is therefore established.

Delopleurus striatus Arrow 1931
Diagnosis This species (known from a single female) differs from other Delopleurus species in having characteristic granulate disc of pygidium ( Figure 9C).
Clypeus appear bidentate with two medial teeth acute ( Figure 9B). Clypeus rugose in anterior part and laterally, frons densely punctate (punctures separated by one to three puncture diameters).
Pronotum about two times wider than long. Anterior and lateral margins distinctly bordered, base bordered except in the middle. Pronotum densely punctate anterolaterally, sparsely punctate on the base and anterior part medially.
Elytra trapezoidal, as wide as long, shiny. Stria relatively deep, with punctures 1.5-2 times larger than striae width. Elytral intervals flat, with minute punctuation.
Anterior tibiae with three outer teeth, without a small acute tooth between first outer tooth and apical spur. Anterior tibial spur rounded apically.

Distribution
The species is known from the single locality in northern periphery of the Indo-Gangetic Plain ( Figure 9D).
Metacatharsius janssensi (Frey), comb. nov. ( Figure 9E) Delopleurus janssensi Frey, 1963 Delopleurus janssensi was described from two specimens from Warder, Somali region of Ethiopia. The holotype, female, has all the diagnostic characters of the genus Metacatharsius Paulian (large dorsal eye parts can be seen on the habitual photo, Figure 9E). The paratype is similar to and apparently conspecific with the holotype. In the original description, the author compared this species with D. pullus and D. gilleti but did not provide characters specific for the genus Delopleurus. However, the original description and locality data agree well with the type specimens. There is no doubt that Delopleurus janssensi was described from misidentified Metacatharsius specimens and the new generic combination is therefore established here. It is possible that M. janssensi is conspecific with another described species of the genus. There are up to 18 species of this genus known from adjacent Somalia (Ferreira 1972) and the genus is currently a subject of taxonomic revision (François Génier, pers. comm.). It is out of the scope of the present work to specify the taxonomic status of M. janssensi more exactly.