Escarabaeus remii Davis and Deschodt, 2016

Deschodt, Christian M., Davis, Adrian L. V. & Scholtz, Clarke H., 2016, Three new species, a synonymy and taxonomic notes on southern African members of the dung beetle genera Scarabaeus s. str. Linnaeus, 1758 and Escarabaeus Zídek & Pokorný, 2011 (Scarabaeidae: Scarabaeinae), Journal of Natural History 51 (5 - 6), pp. 299-316 : 310-314

publication ID	https://doi.org/ 10.1080/00222933.2016.1261949
publication LSID	lsid:zoobank.org:pub:CEC29F9E-2B2B-4568-8AE2-4CC65F79EC96
persistent identifier	https://treatment.plazi.org/id/03B7AE4B-FFC0-BC55-FEC1-FB19601EF925
treatment provided by	Carolina
scientific name	Escarabaeus remii Davis and Deschodt
status	sp. nov.

Treatment

Escarabaeus remii Davis and Deschodt View in CoL sp. nov.

( Figure 1 View Figure 1 , 2 View Figure 2 and 7 View Figure 7 )

Specimens examined Holotype: ♂ Botswana, Okavango, Thamalakane riv., P. Reavell, XII.1973. ( TMSA) Paratypes: two ♀ Tau Lodge Botswana ., S20.42679° E24.52141°, 20 . xii .2003 Light, C. Deschodt &L . Niemand. ( UPSA) , one ♂ spec and ten spec unsexed same as holotype, ( TMSA), one ♂ spec and one spec unsexed, Namibia; Rundu Distr ., 17 km E Rundu 1059 m, 17.[°] 51[’] S – 19.[°] 54[’] E, 14.3.2006;E-Y:3722, light trap, leg Ruth Müller ( TMSA), one spec unsexed, Botswana, Kasane, groundtraps, 1 – 19.9.85; Beyleveld ( TMSA), one spec unsexed, Kwandu River , WestCaprivi, SE 1723 Cd, 14-XI-1979, C . H. Scholtz COLS2073 ( SANC), one spec unsexed, 20 km N MAUN, BOTSWANA, SE 1923, Dc, 16-I- 1978, Holm, Jacobs, Kirsten, Scholtz, COLS23072 ( SANC), one spec unsexed BOTSWANA, Makgadikgadi Pans, Res, Khumaga, 20.[°] 26[’]S 24.[°]35[’]E, 04 .xii .1980, P. Reavell , COLS23074 ( SANC), one spec unsexed, BOTSWANA, Sepupa, SE 18 22 Ca 5 – 6 .I .1985, University of Pretoria , Dept . Entomology Tour ’ 85, COLS22492 ( SANC), one spec unsexed, MAUN . Botswana, (16kms N) 18.I.78, Grey sand, Open, Mopane Woodland, C (Bait), H . H. Aschenborn , COLS08770 ( SANC) .

Etymology: This species is named in honour of Remi the only son of CD.

Description: Large beetle, black.

Body size of holotype: Head capsule length 5.4 mm, combined length of pronotum and elytra over midline 15.3 mm, widest width over elytra 12.1 mm, height 8.0 mm.

Head: Surface anteriorly rugose, without granulation. Rugosity changes to punctures posterioriad. No projection on dorsal or ventral surface of clypeus. Clypeal teeth slightly upturned with anterior half of teeth smooth. Notch between innermost clypeal teeth rounded; notch between first and second clypeal teeth right angled. Vertex slightly convex. Antennae tan brown.

Pronotum: Punctate with punctures far apart, extending to margins. Setae in punctures very short and only seen under at least 60x magnification. Surfaces between punctures with microgranules. Single row of punctures on posterior margin.

Protibia: Inside margin smooth with dark long setae evenly spaced. Outside margin with four teeth in distal three quarters, proximal tooth smallest. Fine serrations all along inside margin and between teeth.

Elytra: Ribbed. Shagreened on interstriae. Striae clearly discernible with the naked eye. Margin between striae and interstriae well defined. Interstriae without setae.

Sterna: Median longitudinal groove over meta- and mesosternum, deepening to form a fovea on each of the sterna. Mesosternum with long thin setae. Mesosternum sloping at about 45 degrees anteriorly. Metasternum smooth.

Pygidium: Shagreened with small irregular punctures far apart.

Aedeagus: See Figure 2 View Figure 2 (E). Although very similar to that of Escarabaeus satyrus Boheman, 1860 ( Figure 2 View Figure 2 (F)), it is generally more slender and the spike is broader.

Variability: Some size variation is observed (smallest and largest specimens in type series: head capsule length 5.0 – 6.5 mm, combined length of pronotum and elytra over midline 14.7 – 18.9 mm, widest width over elytra 11.2 – 14.2 mm, height 7.1 – 9.2 mm.). The ribbing in some specimens is not as clear.

Diagnosis: This new species keys out to E. satyrus in Zur Strassen, 1967. The elytra are however strongly ribbed. The punctures on the pronotum are also much further apart.

Distribution: This species has a distribution following the Okavango and Zambezi River floodplains of north western Botswana, extending northwards into the Caprivi Strip of Namibia and possibly into southern Angola and Zambia.

New synonymy

Scarabaeus basuto zur Strassen, 1962: 350 View in CoL

Scarabaeus natalensis zur Strassen, 1962: 352 View in CoL syn. n.

Zur Strassen (1962) used various characters for separating S. basuto View in CoL and S. natalensis View in CoL . These comprised the depth of the elytral striae, the size of the punctures on the striae and interstriae, the granulation of the elytra, the sculpture of the basal margin on the prothorax (see Figure 8 View Figure 8 ), and the shape of the aedeagi. During data basing, a larger number of specimens was available to be studied than in the 1960 ’ s. These individuals showed a mosaic of the characteristics cited by zur Strassen ( Table 1). In the table, we note that one character form a cline (sculpture of posterior lateral margin of prothoracic disc) and that three instances of individual variation occur at end points on the cline but are considered as only intraspecific variation. We, thus, formally synonymise Scarabaeus natalensis Zur Strassen, 1962 View in CoL ; syn. n. with Scarabaeus basuto, 1962 View in CoL . Scarabaeus basuto, 1962 View in CoL is selected as the senior synonym under the Principle of the First Reviser (Article 24.2, ICZN, 1999).

Species requiring further investigation

Relationships and validity of Scarabaeus convexus ( Hausmann, 1807) , Scarabaeus spretus Zur Strassen, 1962 and Scarabaeus rusticus ( Boheman, 1857) require further investigation. They are currently considered as close relatives showing combined distributions from the southwest Cape along the southeast seaboard to uplands and highlands of northeast South Africa, where, S. convexus is found on cool moist highlands and

their characters.

S. rusticus on drier warmer uplands. However, there may be some discrepancy between distribution pattern and type localities for S. convexus and S. spretus , which are distributed primarily on southwest winter rainfall uplands and the southern seaboard of South Africa.

Scarabaeus spretus View in CoL was described from Table Mountain Zur Strassen (1967), and although the type locality of S. convexus View in CoL is not cited, it may be assumed to also be from the Western Cape as it was described by Hausmann (1807) together with Scarabaeus suri View in CoL , Scarabaeus rugosus View in CoL , Onthophagus giraffa View in CoL and Onthophagus minutus View in CoL , which are all southwest or southern Cape endemics. However, the species that is currently identified as Scarabaeus convexus View in CoL has a South African distribution that lies well to the east and northeast of the likely type locality. The type material that Hausmann used for the description of this species is in Europe and could not be traced. Therefore, it is currently not possible to resolve questions on the relationships between the type of S. convexus View in CoL , northeast populations identified as S. convexus View in CoL , and those of S. spretus View in CoL .

The possibility that Scarabaeus spretus View in CoL is a synonym of Scarabaeus convexus View in CoL , and that the inland species is undescribed, requires investigation. However, pending further morphological or molecular study we have made no recommendations for changes to the alpha taxonomy. At present, Zur Strassen (1967) separates S. spretus View in CoL by the presence of small punctures on the base of the pronotum that are absent in S. convexus View in CoL and S. rusticus View in CoL , a species that was described from ‘ Caffraria ’ ( Boheman 1857). Scarabaeus rusticus View in CoL is separated by the yellow antennae and irregular size of the inside front tibial teeth compared to the dark antennae and regular size of small teeth on the inside margin of the front tibiae in S. convexus View in CoL ( zur Strassen, 1967).

Relationships and validity of Scarabaeus ebenus Klug, 1855 ; and Scarabaeus interstitialis Boheman, 1857 ; have also been investigated. Clines from larger to smaller-bodied and denser to sparser punctation occur from the northern edge of the Highveld grasslands to lowland savannah. However, it is currently considered that smaller-bodied, more sparsely punctate inland savannah populations may be separated from eastern lowland and east coastal populations on the basis of larger ( S. interstitialis ) versus very small punctures ( S. ebenus ). Further investigation is justified.