Scarabaeolus (Scarabaeolus)
Creators: name: Zidek, Jiri
name: Pokorný, Svatopluk
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Trilobita
Corynexochida
Styginidae
Scarabaeolus

description: Review of the Subgenus Scarabaeolus
The list below shows the species deemed by us to belong in the subgenus Scarabaeolus, their type repositories, who first included them, and figures at the end of this paper. Bth = Balthasar, DD = Davis and Deschodt/Deschodt and Davis (in Deschodt et al. 2015); [1] and [2] = numbers of mesotibial spurs; * = on permanent loan to TMSA. Full names of all authors appear in the following Species Accounts.
anderseni Wth. [2] BMNH Deschodt et al. 2015 Fig. 72
andreaei zur Str. [1] SAMC Deschodt et al. 2015
bohemani Har. [1] MNHN Deschodt et al. 2015 Fig. 43–46
canaliculatus Fm. [2] MNHN Ferreira 1972 Fig. 73, 92–93
carniphilus DD [2] TMSA Deschodt et al. 2015
clanceyi Fer. [1] DMSA Ferreira 1972 Fig. 65, 103
cunene sp. n. [2] TMSA this paper Fig. 33–38
damarensis Js. [2] MNHN Ferreira 1972 Fig. 75, 95
ermienae DD [1] TMSA Deschodt et al. 2015
flavicornis (Boh.) [2] NHRS Ferreira 1972 Fig. 5–8
fragilis sp. n. [1] TMSA this paper Fig. 25–28
fritschi Har. [2] MNHN? Deschodt et al. 2015 Fig. 74, 87, 94 funebris (Boh.) [1] NHRS this paper Fig. 63, 102
gilleti Js. [2] ISNB Ferreira 1972 Fig. 76, 96
gracai Fer. [2] MHNM* Ferreira 1972 Fig. 78
inoportunus Fer. [2] TMSA Ferreira 1972 Fig. 82, 104
inquisitus Pér. [2] SAMC Ferreira 1972
intricatus (Fab.) [2] ZMUC Ferreira 1972 Fig. 81, 100
karrooensis zur Str. [1] NHMB Deschodt et al. 2015 Fig. 66, 90
knobeli Fer. [1] TMSA Ferreira 1972 Fig. 21–24
kochi Fer. [2] TMSA Ferreira 1972 Fig. 79, 98
krugeri sp. n. [2] TMSA this paper Fig. 1–4
kwiluensis Js. [2] MRAC Barbero et al. 1998 Fig. 77, 97
laevifrons Fm. [2] MNHN Ferreira 1972 Fig. 84, 91
lizleri sp. n. [2] TMSA this paper Fig. 9–12
lucidulus (Boh.) [2] NHRS Ferreira 1972 Fig. 83, 101
megaparvulus DD [2] TMSA Deschodt et al. 2015 Fig. 59–62
namibensis sp. n. [2] TMSA this paper Fig. 17–20
niemandi DD [2] TMSA Deschodt et al. 2015
nitidus DD [1] TMSA Deschodt et al. 2015
obsoletepunctatus Bth [1] NMPC Deschodt et al. 2015 Fig. 67–68
orientalis sp. n. [1] TMSA this paper Fig. 47–50
pabulator Pér. [2] SAMC Ferreira 1972 Fig. 80, 99
palemo Oliv. [1] MNHN Barbero et al. 1998 Fig. 69–70, 88
parvulus (Boh.) [1] NHRS Ferreira 1972 Fig. 64, 89
planipennis DD [1] TMSA Deschodt et al. 2015
rubripennis (Boh.) [2] NHRS Ferreira 1972 Fig. 13–16 rugosipennis sp. n. [2] TMSA this paper Fig. 29–32
similis sp. n. [1] TMSA this paper Fig. 55–58 soutpansbergensis DD [1] TMSA Deschodt et al. 2015
werneri sp. n. [1] BMNH this paper Fig. 39–42
Other species have been included in Scarabaeolus by Ferreira (1968b, 1972) [S. ebenus (Klug, 1855), S. suri (Hausmann, 1807)], Barbero et al. (1998) [S. interstitialis (Boheman, 1857), S. rugosus (Hausmann, 1807), S. rusticus (Boheman, 1857)] and Mostert and Holm (1982) [S. scholtzi Mostert and Holm, 1982, S. silenus (Gray, 1832)], however none of them conforms to the subgeneric definition noted in the Introduc- tion. Deschodt et al. (2015) included S. scholtzi on the presence of the second mesotibial spur, but noted that according to Forgie et al. (2005) this species consistently falls outside of their “ Scarabaeolus clades”. Scarabaeus scholtzi is a relatively large (about 20 mm) Pachysoma -like apterous scarab whose second mesotibial spur is slender and nearly half as long as the principal spur (as in Sceliages), quite unlike the minuscule and rather stubby structure in Scarabaeolus. Besides that, it is a structure present in other scarabaeine tribes as well (e.g. the Gymnopleurini), and thus an adaptation that arose more than once. As such it can be useful for utilitarian sorting of species, but not for determining relationships. We therefore do not include S. scholtzi in the subgenus.
The following synonymies have been proposed in the subgenus; their authorships are detailed below in the Species Accounts:
S. xavieri Ferreira, 1968 = S. andreaei zur Strassen, 1963
S. cicatricosus (Boheman, 1857), n. praeocc. = S. bohemani Harold, 1868
S. reichei Waterhouse, 1890 = S. canaliculatus Fairmaire, 1888
S. azureus Ferreira, 1952 = S. damarensis Janssens, 1940
S. vansoni Ferreira, 1958 = S. lucidulus (Boheman, 1860)
S. bohemani Harold, 1868 = S. palemo Olivier, 1789
S. morbillosus Fabricius, 1792 = S. palemo Olivier, 1789
Deschodt et al. (2015) re-validated S. reichei, which is not accepted here because it is based on a photo of a S. canaliculatus syntype that either due to encrustation or low resolution shows no detail of elytral sculpture and judged by elevation and evenness of the ribbing could as well be identified as S. fritschi. The S. reichei holotype (Fig. 85) is an empty shell with a gaping hole in place of the metasternal process, leg joints freely moveable and the left antennal club missing, but otherwise the structure is well preserved. Zur Strassen (1967) examined the types of S. reichei and S. canaliculatus, followed Gillet (1911) and subsequent authors in synonymizing S. reichei, and characterized S. canaliculatus as having the elytra striated and intervals elevated but not distinctly ribbed. This (but not the smooth pronotal sagittal line, whose extent and elevation are quite variable) distinguishes S. canaliculatus (Fig. 73) from S. fritschi (Fig. 74), and in this regard the holotype of S. reichei (Fig. 86) matches perfectly all specimens of S. canaliculatus that we have seen. In S. fritschi (Fig. 87), on the other hand, elevation of intervals does not diminish laterally but remains more-or-less equal, the coarse punctures in their keels bear short yellowish setae, and the sharply demarcated, finely punctate striae are much wider. The parameres of these two species are identical (Fig. 93, 94) and the elytral sculpture differs in degree of development rather than in form, so in terms of population biology it could even be claimed that S. canaliculatus is only a variety of S. fritschi. However, in absence of a thorough analysis we keep the taxa separate and only point out the close similarity.
The S. bohemani = S. palemo synonymy was proposed by Janssens (1940), rejected by zur Strassen (1967), and proposed again by Deschodt et al. (2015). We maintain both species as valid the great similarity in habitus notwithstanding, because in our opinion they can usually be separated by their aedeagi (Fig. 45–46 vs. 88 and zur Strassen 1967: fig. 8 vs. 9). An exception is a series of 11 TMSA specimens, seven from Limpopo (Fig. 51–54) and four from Northern Cape provinces, which remind of S. bohemani in having grayish antennal clubs (see also Deschodt et al. 2015: fig. 5) but aedeagi more resembling S. palemo, with the paramere tips dorsally rounded and ventrally produced into short beaks, as in the typical western S. palemo (Fig. 88). We find naming this series premature, call it S. cf. bohemani / palemo, and theorize that it could be a transitional population in an area where the two species meet. As pointed out by Deschodt et al. (2015: 524), the question of validity/synonymy of these two taxa would best be resolved by molecular techniques.
The S. morbillosus = S. palemo synonymy can be accepted only partially and conditionally, for west African specimens that have been dissected. We examined the ZMUC types (5 ST) of S. morbillosus (Fig. 70–71) but could not dissect them, and we have no knowledge of the MNHN types of S. palemo. In this regard, we had to rely on zur Strassen’s (1967) work and his subsequent identifications of S. palemo, but they unfortunately did not answer the question of identity of this species because his drawings of S. palemo aedeagus (zur Strassen 1967: fig. 8) do not match aedeagi that we extracted from two TMSA specimens identified by him (in 1993) as S. palemo and described in this paper as S. (Scarabaeolus) orientalis sp. n. (Fig. 47–50). The aedeagus figured by zur Strassen in 1967 came from a Senegal speci- men that, although not identified as such in his paper, probably is one of the syntypes (see Olivier 1789: 187–188); it has a paramere with a large, triangular ventral tooth, whereas the aedeagi extracted by us from Transvaal specimens (Frm: Rhenosterpoort, leg. L. Schulze) have only a minute, easily overlooked ventral denticle (Fig. 50). The difference is too great to be considered intraspecific, and since Olivier’s (1789) syntypes of S. palemo came from two locations as far apart as Senegal and the Cape of Good Hope, we suspect that his type series consists of two species. Fabricius’ syntypes of S. morbillosus are from “ Guinea ” (actually Ghana, see Moretto and Génier (2015: 4)), and due to a closer proximity to Senegal thus more likely correspond to the Senegal syntype of S. palemo. Conversely, the S. palemo syntype (s) from the Cape of Good Hope are more likely to correspond to S. orientalis sp. n. from Transvaal, whose aedeagus does not quite match but is very close to S. cunene sp. n. (Fig. 37–38) S. lizleri sp. n. (Fig. 11–12), S. rubripennis (Boheman) (Fig. 15–16) and S. planipennis Davis and Deschodt (Deschodt et al. 2015: fig. 6E). Only dissection of the Cape of Good Hope type(s) can show whether our assumption is correct, as external inspection alone is likely to be inconclusive.
One feature of S. morbillosus worth mentioning is the presence of orangish pads at the proximal ends of the profemora (Fig. 71). Since they are located on the dorsal side this observation is purely accidental, made possible only by the preparation style of Fabrician specimens (Fig. 70). Whether it does have any taxonomic significance is unknown to us, as due to a small number of specimens, most of them borrowed, we could not reposition or detach front legs for clear observation of the femora.
In dorsal view, the parameres of Scarabaeolus appear symmetrical because the ventral tooth does not extend far enough laterally to show. The asymmetry of the parameres becomes obvious only in ventral view, except for S. nitidus where in dorsal view the tip of the right paramere curves inward and overlaps the tip of the left paramere (in S. bohemani and S. palemo this is apparent only in ventral view). Apart from this exception the dorsal symmetry is consistent throughout the subgenus and accounts for a relatively high degree of similarity, with species-level differences in slenderness/stockiness of the parameres and in their tips, which may be truncate, inflated, bent laterally, dorso-ventrally slanted or ventrally produced into short beaks. Dorsal symmetry is common in the nominotypical subgenus as well, but usually the parameres are symmetrical also in ventral view, which is not the case in Scarabaeolus. The ventral asymmetry is thus added to the subgeneric characterization noted in the Introduction.
Scarabaeus obsoletepunctatus Balthasar (Fig. 67–68) is based on a somewhat worn and faded female that lacks both antennal clubs, has only one mesotibial spur, and resembles S. bohemani (Fig. 43–44). However, our examination shows it to be a valid species, because in contrast to S. bohemani it has denticles at bases of three rather than just two proximal protibial teeth, lacks a striola of punctures along the pronotal base, and the medial lobe of the base extends entirely over the scutellum. It bears a typed label “Benguella”, which regardless of whether it means vicinity of the city or the province at large is roughly 300 km north of the Namibia border. We are aware only of the holotype. Deschodt et al. (2015: 521) list also northwestern Namibia in their key, but do not provide concrete records.
We examined 17 specimens (15 GWPC, 1 NMPC, 1 BMNH) from “ Namibia, 60/ 80 km N of Aus, 9–10. XI.2006, Werner & Smrž leg.” that do not differ in any regard from S. (Scarabaeolus) megaparvulus Davis and Deschodt, except that contrary to the original description all the specimens have two mesotibial spurs. We therefore list that species as having two spurs and suggest that the type material be re-examined.
A species hitherto not included in the subgenus is S. funebris (Boheman), which its describer compared to S. morbillosus Fabricius. We find the comparison fitting and see nothing in the distribution and morphology of S. funebris (Fig. 63, 102) to prevent its inclusion in Scarabaeolus. Its inclusion is supported also by the aedeagus, which, except for being slenderer, closely resembles those of S. similis sp. n. (Fig. 57–58) and S. kochi Ferreira (Fig. 98).
description: Published as part of Zidek, Jiri & Pokorný, Svatopluk, 2018, New species of the Scarabaeus subgenus Scarabaeolus Balthasar, with a review of the subgenus (Scarabaeidae: Scarabaeinae: Scarabaeini), pp. 1-35 in Insecta Mundi 611 on pages 11-14, DOI: 10.5281/zenodo.3726987