Garreta namalugens Davis & Deschodt, 2018

Davis, Adrian L. V. & Deschodt, Christian M., 2018, Two new species of Garreta Janssens, 1940 (Coleoptera: Scarabaeidae: Scarabaeinae) from Southern Africa, Zootaxa 4450 (2), pp. 242-248 : 243-246

Garreta namalugens Davis & Deschodt , new species

Figs 1–6

Description of holotype. Holotype ♂: 14.1 x 8.7 mm (length with head extended x maximum width). Habitus uniformly charcoal with dark blue or green undertone; undertone occasionally cupreous.

Head. Clypeus with four denticles; right angled gap between middle two denticles; outside denticles rounded; clypeal surface with irregular granules, which are close together but clearly separated from one another.

Pronotum. Pronotum surface very finely shagreened with small, discrete granules that are separated by more than one granule diameter. Sculpture-free longitudinal midline extends from the basal margin halfway up the disc of the pronotum.

Elytra. Elytral interstriae with similar surface sculpture to the pronotum, i.e. very finely shagreened with small granules that are separated by more than one granule diameter. Striae are narrow, unclear, shagreened and apunctate.

Anterior legs. Narrow and strongly curved inwards.

Aedeagus. Similar to other species of Garreta ( Fig. 3 ).

Sexual dimorphism. Inward curving front legs of male type material are narrower than those of females. Terminal spur of front legs acute in females and more blunt in males.

Variability. Very little size variation between the paratype specimens; colour varies from dark blue or green undertone to cupreous.

Etymology. The name is a combination of the specific name of its closest relative Garreta lugens and the Nama people of Namibia.

Type specimens examined. Holotype ♂: " NamibRand Nature Reserve, S 24.885184° E16.065035 °, 14.iii.2017, 1184m, Deschodt & Davis, Fresh Hyrax dung", in SANC. Paratypes: 18 spec. same as holotype, 10 in UPSA [9 kept in 99% Ethanol to allow for possible future molecular work], 5 in TMSA, 3 in SANC; 6 spec. " Spitzkoppe S21.829723° E15.181811°, 17-19.iii.2017, Deschodt & Davis ", 2 in UPSA, 2 in TMSA, 2 in SANC; 1 spec. " Losberg , NamibRand Nature Reserve , S25.073295° E16.048717°, 15.iii.2017 Deschodt & Davis , Hyrax dung midden", in UPSA; 1 spec. " NAMIBIA: KAOKOLAND, Otjihipa Mountains, base camp at 780 m, 17° 16.4'S 12° 28.8'E, 16-19.iii.2005 ’ E.Holm et al. ", in SANC .

Differential diagnosis. G. namalugens new species, shows slightly smaller body-size than Garreta australugens new species and Garreta lugens ; it also lacks the basal impressions on each side of the midline of the pronotum that are present in G. australugens new species and G. lugens .

Habitat and distribution. The holotype and two paratype specimens of Garreta australugens, new species were sampled using a composite bait of pig, cattle and elephant dung on finer-grained, gabbro-derived soils in dry, open woodland at the South African Wildlife College on the west border of the Kruger National Park (Davis et al. 2012). Further paratype specimens are known from lowland localities in dry areas of northeast South Africa and southeast Zimbabwe as well as moist areas of central Mozambique. Specimens cited as G. lugens from South Africa, Mozambique and Botswana (Moretto & Génier 2015) are probably also G. australugens new species, although reexamination is required to validate their identity.

The authors recorded Garreta namalugens new species, flying abundantly on March 13-15th 2017, circa two weeks after substantial rainfall in Namibrand Nature Reserve. Activity was observed throughout the day. Live individuals were seen flying into crevices between huge granite boulders at the edge of the Nubib Mountains, presumably, in search of fresh dung of the Rock Hyrax (Procavia capensis (Pallas, 1766 )). Bodies of dead individuals were excavated from silt under the accumulated dung in Hyrax middens. Although G. namalugens new species, was also attracted to pitfall traps baited with pig dung in the mountains, none was observed to fly into the adjacent sandy plains in order to feed on the dung of large herbivorous mammals, comprising either substantial, coarse-fibred, zebra droppings, or, dung pellets dropped by gemsbok or springbok. As regards species in the tribe Gymnopleurini, only Gymnopleurus andreaei Ferreira, 1954, and a few G. humanus Macleay, 1821, were observed on herbivore dung on the plains (ALVD and CMD, pers. observ.). So far, records for G. namalugens new species, have only been validated for west central Namibia with a single specimen from the Kaokoveld in northwest Namibia.

The three species comprising Garreta australugens new species, G. lugens and G. namalugens new species, appear to represent a radiation between, now, geographically isolated, mostly dry lowlands in southwest, southeast and northeast Africa. However, confirmation of close relationships needs to be made using a molecular systematic analysis.

Figures

FIGURE 1. Habitus of (A) Garreta australugens Davis & Deschodt, new species (holotype), (B) Garreta lugens (Fairmaire, 1891) and (C) Garreta namalugens Davis & Deschodt, new species (holotype). Scale bar is 2 mm.

FIGURE 2. Elytral and pronotal sculpture of Garreta australugens Davis & Deschodt, new species, Garreta lugens (Fairmaire, 1891) and Garreta namalugens Davis & Deschodt, new species. Scale bar is 0.5 mm.

FIGURE 3. Aedeagi of the holotype of (A) Garreta australugens Davis & Deschodt, new species, (B) Garreta lugens (Fairmaire, 1891) and (C) Garreta namalugens Davis & Deschodt, new species. Scale bar is 1 mm.

FIGURE 4. Map showing the distribution of Garreta australugens Davis & Deschodt, new species (red circle) and Garreta namalugens Davis & Deschodt, new species (red triangle); Kaokoveld (red star).

FIGURE 5. Garreta namalugens Davis & Deschodt, new species, seen rolling and fighting over fresh dung pellets of the Rock Hyrax (Procavia capensis (Pallas, 1766)). Note some dried out dung pellets that are being ignored by the beetles. Image taken by CMD at Namibrand Nature Reserve, March 14, 2017.

FIGURE 6. Habitat of Garreta namalugens Davis & Deschodt, new species. Note the white urine streaks on the boulders indicating the presence or past presence of Rock Hyrax (Procavia capensis (Pallas, 1766)). Image taken by CMD at Namibrand Nature Reserve, March 14, 2017.