Versicorpus daures Deschodt, 2019

Deschodt, Christian M. & Sole, Catherine L., 2019, A new species of Versicorpus Deschodt, Davis & Scholtz, 2011 (Scarabaeidae Scarabaeinae: Byrrhidiini) from the Brandberg Mountain, Namibia, Zootaxa 4671 (1), pp. 139-144 : 139-143

Versicorpus daures Deschodt , new species

( Figs. 1 , 2 A–C, 3, 4)

Type material. Holotype ♂: “ Brandberg Mountain | S21.105° E14.691° 839m | 16.iv.2019, C.M. Deschodt || Ex- cavated live from | accumulated silt under a | layer of hyrax dung” ( SMWN). The specimen was preserved in 99% ethanol for molecular study.

Additional material examined. Disarticulated parts of different specimens that include: elytra, pronota with and without front legs, a single pygidium and one complete set of abdominal sternites, all mounted together on cards . One lot from the same locality as the holotype with labels: “Brandberg Mountain | S21.105° E14.691° 839m | 16.iv.2019, C.M. Deschodt || Excavated from | accumulated silt under a | layer of hyrax dung” and a second lot: “Brandberg Mountain | S21.075° E14.677° 558m | 16.iv.2019, C.M. Deschodt || Excavated from | accumulated silt under a | layer of hyrax dung” about three kilometres away ( UPSA)

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Description of the holotype, male. Body: 9.1 (maximum length with head extended) x 5.5 mm (maximum width over elytra).

Head. Clypeus bidentate, with two small teeth that are well separated; clypeal margin between teeth very slightly sinuate. Surface clearly punctate with small punctures that are separated by less than one puncture diameter. One very small tooth on lower clypeal margin between dorsal teeth. Clypeogenal suture indistinct and forming a fairly straight line.

Pronotum. Convex, surface with small oval to round punctures covering the pronotal surface, punctures separated by less than one puncture diameter; most punctures with very short associated setae; clear puncture-free midline present.

Elytra. Convex, slightly elongated, surface covered with microscopically fine granules giving velutinous appearance under 40x or higher magnification. Striae shallow but visible, not punctate. Interstriae with punctures with associated short yellow setae arranged in fairly straight double lines except for the first which only has a single line.

Sterna. Prosternum with small and well separated punctures; with short yellow irregularly spaced setae. Meso- and metasternum fused, mesometasternal suture indistinct and straight. Surface of mesosternum shagreened, faint, medium-sized shallow punctures present. Surface of metasternum shagreened with a few small punctures.

Protibia. Internal margin approximately straight, with short yellow setae and lacking denticles. Tibial apex blunt with a small conical slightly outward curving spur. Tarsi attached under spur close to inner corner of tibia. Setae on internal margin of tarsi short. Apical external margin of protibiae with three teeth with the medial tooth being the smallest. Basal two thirds of external margin serrated.

Mesotibia. Curving slightly inward, with smooth margins and five rows of short yellow setae. Apically with two short spurs. Tarsi with short yellow setae, ending in two claws.

Metatibia. Fairly straight, with internal margin saw-toothed along entire length, external margin smooth; five rows of short yellow setae present. Tarsi with short yellow setae, ending with two claws.

Pygidium. Surface shagreened with large shallow punctures.

Aedeagus. Same general plan as for the other known Versicorpus species. Parameres asymmetrical at base with the left paramere forming a lobe slightly covering the base of the right one, nearly symmetrical towards apex; rows of setae dorsally on distal half of parameres ( Figs. 2B, C, E, F ).

Variability. Except for a very small size difference and that most specimens were quite worn out, there was very little other variation observed between the holotype and the disarticulated specimens. All pronota had very worn out front legs but still had the short setae present at almost every puncture.

Differential diagnosis. This new species clearly belongs to the genus Versicorpus by virtue of the somewhat elongated body and the basal part of front tibiae being serrated and the saw-toothed internal margin of the hind tibiae and very short clypeal horns. It is closest in appearance to Versicorpus streyi (Frolov, 2005) but can easily be distinguished from it by the presence of short setae on the pronotum (visible only under a microscope with 20x magnification and higher), whereas Ľ. streyi is glabrous. It is also smaller than Ľ. streyi ( Figs. 2A, D ). The setae on the aedeagus of V. daures new species are shorter and less dense than on the aedeagus of Ľ. streyi and the apex of the parameres of Ľ. streyi are also more elongated (see Figs. 2B, C, E, F ).

Etymology. The name Dâures is a noun and in the local Damara people’s language it is the name for the Brandberg Mountain which means “burning mountain”.

Distribution, ecology, conservation status, and potential threats. This new species is currently the most northerly recorded of all the known Byrrhidiini ( Fig. 3 ). However it is anticipated that there might be further species to the north in suitable habitats. The holotype and disarticulated body parts were collected between boulders ( Fig. 4 ) in a relatively small area against the lower slopes of the Brandberg, but the species might also occur higher up and probably all around the circumference of the mountain. As in all the other species of Byrrhidiini the live specimen was found amongst hyrax dung pellets which are probably used as a sustainable food source. It appears that the preferred dwelling area of specimens is deep in between boulders where the accumulated silt stays moist for much longer after rain. This species may be restricted to the isolated Brandberg massif in Namibia. As this is a declared National Monument of Namibia ( Voigt 2004), the hyrax colonies should remain protected, while anthropogenic activities should be limited and thus the new species is probably not facing any current threats. However, it should be assessed as Data Deficient (DD) as the true extent of occurrence remains unknown (this species could encompass a geographic area as small as or smaller than 450 square kilometres (main area of the Brandberg)).

Figures

FIGURE 1. Habitus of the live holotype of Versicorpus daures Deschodt, new species walking on granite rock. Scale bar = 2.0 mm. Photo: Hennie De Klerk at Brandberg, 16 April 2019.

FIGURE 2. Habitus of the holotype of Versicorpus daures Deschodt, new species (A) in comparison with the habitus of the holotype of Versicorpus streyi (Frolov, 2005) (D) with the aedeagus of the holotype of V. daures Deschodt, new species (B, C) and the aedeagus of the holotype of V. streyi (Frolov, 2005) (E, F) in lateral (left) and dorsal (right) view for comparison. Scale bar for habitus = 2.0 mm and scale bar for aedeagi = 1.0 mm.

FIGURE 3. Map indicating the Brandberg and the type locality of Versicorpus daures Deschodt, new species (*) with the distribution of all other Byrrhidiini (•), clearly following the Namibian section of the great escarpment of southern Africa. For detailed distribution of the other Byrrhidiini species see Deschodt & Davis (2018).

FIGURE 4. Habitat and collection site (with the arrow indicating the exact spot) in the Brandberg Mountain, Namibia. Photo: Hennie De Klerk at Brandberg, 16 April 2019.