DNA Barcode Authentication of Devil’s Claw Herbal Dietary Supplements

Devil’s claw is the vernacular name for a genus of medicinal plants that occur in the Kalahari Desert and Namibia Steppes. The genus comprises two distinct species: Harpagophytum procumbens and H. zeyheri. Although the European pharmacopeia considers the species interchangeable, recent studies have demonstrated that H. procumbens and H. zeyheri are chemically distinct and should not be treated as the same species. Further, the sale of H. zeyheri as an herbal supplement is not legal in the United States. Four markers were tested for their ability to distinguish H. procumbens from H. zeyheri: rbcL, matK, nrITS2, and psbA-trnH. Of these, only psbA-trnH was successful. A novel DNA mini-barcode assay that produces a 178-base amplicon in Harpagophytum (specificity = 1.00 [95% confidence interval = 0.80–1.00]; sensitivity = 1.00 [95% confidence interval = 0.75–1.00]) was used to estimate mislabeling frequency in a sample of 23 devil’s claw supplements purchased in the United States. PCR amplification failed in 13% of cases. Among the 20 fully-analyzable supplements: H. procumbens was not detected in 75%; 25% contained both H. procumbens and H. zeyheri; none contained only H. procumbens. We recommend this novel mini-barcode region as a standard method of quality control in the manufacture of devil’s claw supplements.

Eolian chronology reveals causal links between tectonics, climate, and erg generation

The onset and intensification of eolian activity mark climatic transitions that promote wide-scale aridification, recorded by the generation and preservation of massive sand deposits. Evaluating the impact and implications of such repositories on Earth systems requires knowledge about the timing of their emplacement and the mechanisms responsible for their generation, which remain highly uncertain. Here we provide time constraints for the establishment of the Kalahari Erg, which is the largest continuous body of sand on Earth. We apply cosmogenic nuclide dating of sand from the Kalahari Desert combined with numerical modeling to determine when sand was introduced into the interior of southern Africa. Through the consideration of several scenarios, we show that major events of eolian sand transport and accumulation occurred between ~2.5 and 1 Myr ago. This substantial activity, which significantly altered environmental settings, corresponds to regional, continental, and global scale morphotectonic and climatic changes that contributed to the mass production and widespread dispersion of sand. These changes substantially altered existing habitats, thus constituting a crucial milestone for hominin evolution and migration throughout the African continent during the Pleistocene.

On the role of aerosol radiative effect in the wet season onset timing over the Congo rainforest during boreal autumn

The boreal summer dry season length is reported to have been increasing in the last 3 decades over the Congo rainforest, which is the second-largest rainforest in the world. In some years, the wet season in boreal autumn starts early, while in others it arrives late. The mechanism behind such a change in the wet season onset date has not been investigated yet. Using multi-satellite data sets, we discover that the variation in aerosols in the dry season plays a major role in determining the subsequent wet season onset. Dry season aerosol optical depth (AOD) influences the strength of the southern African easterly jet (AEJ-S) and, thus, the onset of the wet season. Higher AOD associated with a higher dust mass flux reduces the net downward shortwave radiation and decreases the surface temperature over the Congo rainforest region, leading to a stronger meridional temperature gradient between the rainforest and the Kalahari Desert as early as in June. The latter, in turn, strengthens the AEJ-S, sets in an early and a stronger easterly flow, and leads to a stronger equatorward convergence and an early onset of the wet season in late August to early September. The mean AOD in the dry season over the region is strongly correlated (r=0.7) with the timing of the subsequent wet season onset. Conversely, in low AOD years, the onset of the wet season over the Congo basin is delayed to mid-October.

On the Role of Aerosol Radiative Effect in the Wet Season Onset Timing over the Congo Rainforest during Boreal Autumn

The boreal summer dry season length is reported to have been increasing in the last three decades over the Congo rainforest, which is the second-largest rainforest in the world. In some years, the wet season in boreal autumn starts early while in others it arrives late. The mechanism behind such a change in wet season onset date has not been investigated yet. Using multi-satellite datasets, we discover that the variation of aerosols in dry season plays a major role in determining the subsequent wet season onset. Dry season aerosol optical depth (AOD) influences the strength of the southern African easterly jet (AEJ-S) and thus the onset of the wet season. Higher AOD associated with a higher dust mass flux reduces the net downward shortwave radiation and decreases the surface temperature over the Congo rainforest region, leading to a stronger meridional temperature gradient between the rainforest and the Kalahari Desert as early as in June. The latter, in turn, strengthens the AEJ-S, sets in an early and a stronger easterly flow, leads to a stronger equatorward convergence and an early onset of the wet season in late August to early September. The mean AOD in the dry season over the region is strongly correlated (r =0.7) with the timing of the subsequent wet season onset. Conversely, in low AOD years, the onset of the wet season over the Congo basin is delayed to mid-October.

Southern Africa’s Later Stone Age and Hunter-Gatherer Ethnography

Reviews of southern Africa’s Later Stone Age (LSA) have seen many different iterations. Generally, however, they summarize the technocomplex from its earliest industry until it ceases to be recognizable in the archaeological record, summarizing the variety of research topics, questions, and approaches. Binding much of this together, despite the diaspora of studies, is the use of ethnography to understand past hunter-gatherer lifeways. This resource has guided interpretations of the past and helped design research approaches since the 1970s. And yet, from as early as the 1980s, archaeologists as well as anthropologists have debated the influence ethnography plays in understanding the past. Nonetheless, without it, significantly less would be written of hunter-gatherer prehistory in southern Africa, which includes belief systems, settlement structures, mobility patterns, subsistence habits, and social relations. Using ethnography as a vehicle, it is possible to navigate the LSA pathways created by scholars and examine the aforementioned contributions this knowledge system has made to interpretations of the past. From this vantage, envisioning a future for ethnography within the field is possible. This should involve expanding the ethnographies archaeologists use, moving beyond the Kalahari Desert, creating a diverse group of LSA researchers, and decolonizing the discipline.

Ostrich eggshell bead strontium isotopes reveal persistent macroscale social networking across late Quaternary southern Africa

Hunter-gatherer exchange networks dampen subsistence and reproductive risks by building relationships of mutual support outside local groups that are underwritten by symbolic gift exchange.Hxaro, the system of delayed reciprocity between Ju/’hoãn individuals in southern Africa’s Kalahari Desert, is the best-known such example and the basis for most analogies and models of hunter-gatherer exchange in prehistory. However, its antiquity, drivers, and development remain unclear, as they do for long-distance exchanges among African foragers more broadly. Here we show through strontium isotope analyses of ostrich eggshell beads from highland Lesotho, and associated strontium isoscape development, that such practices stretch back into the late Middle Stone Age. We argue that these exchange items originated beyond the macroband from groups occupying the more water-stressed subcontinental interior. Tracking the emergence and persistence of macroscale, transbiome social networks helps illuminate the evolution of social strategies needed to thrive in stochastic environments, strategies that in our case study show persistence over more than 33,000 y.

Redescription of Paracrobeles laterellus Heyns, 1968 (Rhabditida: Cephalobidae) from Botswana

Summary Paracrobeles laterellus is redescribed from the North-West District (Koanaka Hill), Botswana, which forms part of the Kalahari Desert. A scanning electron microscopy study of the species is presented for the first time. This population is characterised by its adult body length, lateral field with three longitudinal incisures, lips with three tines, the middle one being shorter, primary and secondary axils with two guard processes, labial probolae bifurcate with basal ridge and smooth prongs, pharynx with very swollen and elongate metacorpus, spermatheca swollen, post-vulval uterine sac well developed, vagina sigmoid, female and male tails conoid, and characters of the spicules and gubernaculum. Morphologically, P. laterellus is very similar to P. kelsodunensis and P. mojavicus according to the morphology of the lip region, i.e., with two guard processes at the primary axils and robust spicules.