2 Materials and Methods.
The specimen described in this study was excavated at Orapa Diamond Mine
(ODM) (Fig. 1), located in the north-east of Botswana, approximately 240
km due west of Francistown (McKay 1991). A double eruption of
diamondiferous kimberlites from North and South pipe resulted in a
deposition of fossiliferous sediments in a crater lake. These were
subsequently uncovered by mining operations, and collected from 18 sites
between 1983 and 1988 (McKay 1990). Based on the decay of238U in zircons in the kimberlite, the sediments are
aged between 81.7 and 98.5 Ma, with a midpoint of 90.1 Ma (Haggerty et
al. 1983), and 93.1 Ma (Davis 1977), respectively. Thus, the deposits
are considered as Upper Cretaceous (Turonian, but possibly Cenomanian or
Coniacian). Orapa is the only major insect deposit from the Cretaceous
in Africa (Grimaldi and Engel 2005). The palaeofauna of the Orapa
deposit has been reviewed (McKay and Rayner 1986; Rayner and McKay 1986;
Rayner 1987; Rayner and Waters 1989, 1990; Waters 1989, 1990; McKay
1990, 1991; Brothers 1992; Rayner 1993; Rayner et al. 1991, 1994, 1997;
Kuschel et al. 1994; Brothers and Rasnitsyn 2003, 2008; Dlussky et al.
2004; Rasnitsyn and Brothers 2007, 2009; Kopylov et al. 2010; Woolley
2016; Mnguni 2022; and Mnguni et al. 2022).
The specimen described here is a well-preserved compression fossil. The
holotype is housed in the Herbarium of the Evolutionary Studies
Institute (ESI), at the University of the Witwatersrand, Johannesburg,
South Africa. Observation and photography were taken using a combination
of an Olympus SZX7 binocular microscope (with Olympus U-TV0.36XC camera)
and an Olympus DSX 110 digital microscope. Multiple images were stacked
and measured using an Olympus Stream 2.4. All the images were prepared
using Adobe Photoshop version 5.6.5.58 (Adobe Creative Cloud, University
of the Witwatersrand, Johannesburg, South Africa). The specimen was
examined under cross polars to clarify the outlines, and non-polarized
light was used at various angles to show relief. Polarizing filters were
attached to the swan necked lights (the objective lens of the
microscope), and were rotated to polarize the light and remove
reflection. A single specimen of an adult fossil with carbonaceous
material preserving both dorsal and ventral structures is described. The
antennae, eyes, legs, elytra, and mouthparts are preserved as part (120
x 90 x 38 mm) and counterpart (73 x 62 x 30 mm) in large pieces of brown
lacustrine mudstones. The scale in all the photographs is 1 mm.