Kunene River Research Articles

Population genetics and phylogeography of Trachylepis sulcata (Peters, 1867) and T. ansorgii (Boulenger, 1907) in south-western Africa

ABSTRACT Ansorge’s Rock Skink Trachylepis ansorgii (Boulenger, 1907) is an Angolan taxon, the taxonomic distinctiveness and geographic distribution of which are poorly understood. It is closely related to the widespread Western Rock Skink T. sulcata (Peters, 1867) from Namibia and South Africa, but heretofore a lack of samples has prevented a comprehensive assessment of T. ansorgii in a molecular phylogenetic context. We combine new genetic sampling from south-western Angola, including topotypical material of T. ansorgii, with published sequences from South Africa and Namibia to identify population structure, phylogenetic relationships, and divergence dates within this species complex. A multi-locus dataset of three nuclear and two mitochondrial loci recovered significant population structuring with a centre of diversity in south-western Angola and northern Namibia. Mitochondrial data recovered seven clades representing distinct geographic populations, while the nuclear data supported either two or three deeper groupings. Mito-nuclear discordance was observed with respect to the geographic boundary between T. ansorgii and T. sulcata. The nuclear data support a break along the western Kunene River (the political boundary between Angola and Namibia), while the mitochondrial data support this break ∼250 km to the north in south-western Angola. A time-calibrated BEAST phylogeny found the deepest species-level divergence to have occurred in the late Miocene/early Pliocene (∼6 mya), potentially related to the formation of the Kunene River. Our results support the recognition of both taxa at the species level, and add further evidence that south-western Angola is a centre of reptile diversity.

A new species of Sesamothamnus (Pedaliaceae) from Namibia and Angola

Sesamothamnus leistneri is formally described as a new species with a restricted range, only known from the mountains along the Kunene River in the Kaokoveld Centre of Endemism, a biogeographical region that spans southwestern Angola and northwestern Namibia. The designations “S. leistner(i)anus” or “S. leistneri” have been previously used to refer to this species, but they were not validly published until now. These trees grow in rocky places on mountain slopes, in kloofs (gorges) and on plateaus. Diagnostic characters for S. leistneri include the pronounced tree habit with thickset semi-succulent stem and branches, relatively large green leaves, the corolla lacking a spur, and flowers with a white to cream-white corolla limb. A comparison of some of the more prominent morphological features to differentiate between S. leistneri and its possibly closest relative, S. rivae, as well as the other four species, S. benguellensis, S. guerichii, S. lugardii, and S. busseanus are provided. Based on IUCN Red List categories and criteria, a conservation assessment of Least Concern (LC) is recommended for S. leistneri.

First record of Warren's sixgill sawshark Pliotrema warreni (Pristiophoriformes: Pristiophoridae) and the West African catshark Scyliorhinus cervigoni (Carcharhiniformes: Scyliorhinidae) in Namibia, and notes on the habitat of the bull shark Carcharhinus leucas (Carcharhiniformes: Carcharhinidae)

Abstract Warren's sixgill sawshark, Pliotrema warreni, is confirmed for the first time in Namibian waters, from two specimens. One specimen was collected by fisheries observers on a vessel fishing in southern Namibian waters in March 2010. The other was found dead on a beach in central coastal Namibia, in August 2014. The West African catshark, Scyliorhinus cervigoni, is documented for the first time in northern Namibia, from a specimen recorded during surveys of chondrichthyan bycatch on a commercial bottom trawler. This extends the species' range southwards from Angola. Records of bull sharks Carcharhinus leucas are also documented, providing a better understanding of their distribution in Namibia. Several anglers have reported catching bull sharks in the Kunene River (from the riverbank on the Namibian side) and just south of the river mouth, along the Namibian coast.

Bob Scholes: Multifaceted scientist with a genius for synthesis

Prof. Robert (Bob) Scholes passed away unexpectedly on April 28, 2021, while on an 11-day, 160-km hike along the Kunene River in northern Namibia. Energetic, enthusiastic, and larger than life to the very end, his sudden passing was a huge shock and loss to his colleagues and loved ones. But as one of his colleagues pointed out, “just like Bob—to go out in style, not while crouched over his computer like the rest of us.” The Kalahari and Miombo woodlands of northern Namibia were special to Bob. They were central to many of his formative scientific experiences. In a way, his career might be said to have come full circle. He was an International Member with a primary affiliation in Section 64 (Human Environmental Science) and a secondary affiliation in Section 63 (Environmental Sciences and Ecology) of the National Academy of Sciences, a Fellow of the South African Council for Scientific and Industrial Research (CSIR), a Fellow of the Royal Society of South Africa, Member of the South African Academy, a Research Associate of the CSIR, a National Research Foundation A-rated scientist, and a winner of the National Science and Technology Forum Lifetime Contribution to Science Award. Bob Scholes. Image credit: Benjamin Drummond (photographer). Bob, Mary, and Stirling Scholes. Image credit: Stirling Scholes (photographer). Bob called himself a “systems ecologist.” He was interested in “big-picture ecology” and used systems thinking to help address major national … [↵][1]1To whom correspondence may be addressed. Email: sally.archibald{at}wits.ac.za or cfield{at}stanford.edu. [1]: #xref-corresp-1-1

<p><strong>A new rheophytic species of <em>Syzygium</em> (Myrtaceae) from the lower Kunene River of Angola and Namibia</strong></p>

Syzygium kuneneense, here described as a new species, is known only from the northern part of the Namib Desert in the Kaokoveld Centre of Endemism, southwestern Angola and adjacent northwestern Namibia. These rheophytic shrubs or small trees grow among rocks on the floodplain and banks of the lower Kunene River on the international boundary between Angola and Namibia. Diagnostic characters for Syzygium kuneneense include the oblanceolate or narrowly elliptic leaves, dense flower heads and the pedicellate flowers. A comparison of some of the more prominent morphological features to differentiate between S. kuneneense and the morphologically most similar species, S. guineense, is provided. Based on IUCN Red List categories and criteria, a conservation assessment of Vulnerable (VU D1) is recommended for the new species.

Indigenous paradiplomacy and the Orokawe hydroelectric dam on the Kunene River

English Abstract: What role can non-diplomats play in managing and altering power relations in transboundary river basins? We answer this by investigating the lobbying efforts of indigenous peoples to stop the construction of the planned Orokawe (Baynes) dam on the Kunene River. The Kunene River forms part of the border between Angola and Namibia with several concluded treaties in place. These treaties set the context of bilateral state diplomacy concerning the allocation and management of a transboundary water resource. The theoretical foundation of our investigation are ideational power conceptualizations and practice theory. We discuss the employment of ideational power in transboundary rivers with numerous practices, such as lobbying and transnational network development. This article argues that actors consciously practice power during transboundary water diplomacy.Spanish Abstract: ¿Qué papel desempeñan los no-diplomáticos en la gestión y modificación de las relaciones de poder en las cuencas fluviales transfronterizas? Respondemos investigando los esfuerzos de cabildeo de los pueblos indígenas para detener la construcción de la presa Orokawe (Baynes) en el río Kunene, entre Angola y Namibia. La asignación y gestión de este recurso hídrico transfronterizo, cuenta con varios tratados concluidos que establecen el contexto de la diplomacia estatal bilateral. La base teórica de esta investigación son las conceptualizaciones del poder ideacional y la “teoría de la práctica”. El empleo del poder ideacional en ríos transfronterizos se refleja en prácticas como el cabildeo y el desarrollo de redes ransnacionales. Este artículo sostiene que los actores practican conscientemente este poder durante la diplomacia del agua transfronteriza.French Abstract: Quel rôle les non-diplomates peuvent-ils jouer dans la gestion et la modification des relations de pouvoir dans les bassins fluviaux transfrontaliers? Nous répondons à certe question en enquêtant sur les efforts de lobbying des peuples autochtones pour arrêter la construction du projet du barrage d’Orokawe (Baynes) sur le fleuve Kunene. Le Kunene forme une partie de la frontière entre l’Angola et la Namibie, pays entre lesquels plusieurs traités sont en vigueur. Ces traités définissent le contexte de la diplomatie bilatérale des États concernant le partage et la gestion de la ressource en eau transfrontalière. Les fondements théoriques de notre enquête reposent sur les conceptualisations du pouvoir idéationnel et la théorie de la pratique. L’article aborde les nombreuses pratiques du pouvoir idéationnel dans les cours d’eau transfrontaliers, telles que le lobbying et le développement de réseaux transnationaux. Il soutient que les acteurs exercent consciemment le pouvoir dans le cadre de la diplomatie transfrontalière de l’eau.

Evaporation loss along the Calueque-Oshakati Canal in the Cuvelai-Etosha Basin (Northern Namibia): evidence from stable isotopes and hydrochemistry

ABSTRACT Since 1973, Kunene River water has been carried from the Calueque reservoir in Angola along a 160 km open concrete canal to the town of Oshakati in the central part of the Cuvelai-Etosha Basin and has been supplying drinking water to the most densely populated rural area of Namibia. Despite its importance for the region, intra-seasonal water quality and the technical condition of the canal are not routinely checked. Water samples were collected during four field campaigns right before the onset of the rainy season (November 2013 and 2014), and after the rainy season (June 2014 and May 2015), at 16 sites along the canal for stable water isotopes (deuterium, oxygen-17 and oxygen-18) and hydrochemical analyses. The isotope patterns and chemical composition of the canal water is discussed in comparison to local rain, Kunene source water, surface water and groundwater. Clear isotope enrichment indicates evaporative loss of water. A Craig–Gordon model was used to estimate water loss. The loss increases with distance from the source with a maximum of up to 10 %, depending on the season. The results are discussed in context of water availability, vulnerability and water resources management in this water-scarce area.

Stacked megafans of the Kalahari Basin as archives of paleogeography, river capture, and Cenozoic paleoclimate of southwestern Africa

ABSTRACTThe Cenozoic Kalahari Basin covers large parts of southern Africa. A continuous 400 m core was obtained in northern Namibia and analyzed in detail. Here, we present sedimentological, geochemical, mineralogical, granulometric, and hydraulic data, which were used to derive the sedimentation history and the Cenozoic paleoclimate and paleogeography of SW Africa. The first absolute ages for the Kalahari Basin were obtained by dating of calcretes, which showed that the core covers almost the entire Cenozoic. Two megafans could be distinguished. The older, buried Olukonda Megafan stems from a mafic source rock, potentially the Kunene Intrusive Complex, and was deposited by a paleo–Kunene River towards the southeast and east, under a semiarid climate. The younger Cubango Megafan (Andoni Formation) has a completely different provenance, namely felsic metamorphic and granitoid rocks, transported from the north by the Cubango River. The capture of the Kunene towards the Atlantic during the Eocene resulted in this change in provenance. Despite the distinct differences between the formations, the temporal hiatus between them must have been short. The results are a showcase of the potential of megafans for hosting major deep freshwater aquifers.

<p><strong>A new species of <em>Hymenodictyon </em>(Rubiaceae, Cinchonoideae) from Namibia</strong></p>

Hymenodictyon kaokoensis, here described as a new species, has a restricted range and is only known from the mountains along the Kunene River in the Kaokoveld Centre of Endemism, northwestern Namibia. It is represented by shrubs or small trees growing in rocky places, on mountain slopes and river valleys. Diagnostic characters for H. kaokoensis include the thickset semi-succulent older stems, echinate (scabrid when dry) leaves that turn stramineous before falling, simple racemose, erect inflorescences, and ellipsoid fruits with round or elongated prominent lenticels. A comparison of some of the more prominent morphological features to differentiate between H. kaokoensis and its possible nearest relatives, H. floribundum and H. parvifolium, are provided. Based on IUCN Red List categories and criteria, a conservation assessment of Vulnerable (VU D1 & D2) is recommended for the new species.

Advancing Reconnaissance and Valorisation: Map Series of German South West Africa (Namibia), 1892–1918

Abstract. Although the Portuguese discovered the shores of south-western Africa as early as 1487, its hostile coastal desert Namib delayed even limited European reconnaissance of the hinterland until late in the eighteenth century. It was not before the second half of the nineteenth century that serious commercial and missionary interest took off. These explorations resulted in route and basic overview maps of a rugged and for the most only sparsely populated region of about one million square kilometres, stretching from the coastal Namib Desert across a central highland to the slopes of the Kalahari basin in the heart of the subcontinent. The need for more detailed mapping arose with the ‘Scramble for Africa’, when German merchant Adolf Lüderitz in 1883 bought Angra Pequena, one of only two natural harbours on that coast. Along with subsequent acquisitions between the Orange River in the south and the Kunene River in the north with a substantial hinterland, in April 1884 was declared Schutzgebiet Deutsch-Südwestafrika, the first and soon most important German colony in Africa. After establishing the boundaries (1885 with Portugal, 1890 with United Kingdom) and succeeding in pacifying the indigenous communities, colonial penetration and valorisation only was possible based on topographical knowledge. To facilitate this, official series ranged from small-scale coverage with scattered features for peripheral regions, often based on simple route traverses, to very detailed and triangulation backed large-scale series with significant private supplement series by land and mining concessionaires. This paper discusses the relevant characteristics of nine topographical map series and one atlas, which reflect the scope, achievements and inevitable shortcomings of just a quarter of a century of intense official and private surveying and mapping in German South West Africa: 1892–94 [Francois Sheets], first de facto official series, mostly in 1:300,000 1894–96 Deutscher Kolonial-Atlas by P. Langhans, first completed atlas, 1:2,000,000 1904 Hartmann-Karte of the northern protectorate, first private series, 1:300,000 1904 Kriegskarte by P. Sprigade & M. Moisel, watershed official series, 1:800,000 1906–08 Deutsch-Südwestafrika, “proto”-version of the official series in medium scale, 1:400,000 1908–12 Krokierblätter Deutsch-Südwestafrika, official series in large scale, 1:100,000 1910 Übersichtskarte des Diamantengebietes, largest scale private series, 1:50,000 1910–12 Deutsch-Südwestafrika, preliminary official series in medium scale, 1:400,000 1913 Karte des Sperrgebiets in the south-western protectorate, private series, 1:100,000 1913–[21?] [Bergrechtskarte] of the central protectorate, last private series, 1:200,000 That scope and output of surveying and topography was only reached again half a century later, after two world wars, a recession and a long-time cartographic indifference by South Africa, custodian of the territory in 1919–90, which also by renewed mapping efforts since the 1970s tried to counter movements towards the ultimate independence of Namibia in 1990.

<strong>The Trichoptera (Insecta) of the lower Kunene River in Namibia and Angola</strong>

The Trichoptera of the lower Kunene River were collected at irregular intervals from 1994 to 2012 by the first author. Samples were taken mainly at several localities on the Namibian side of the border downstream of the Ruacana hydroelectric power plant. Field work concentrated on adults, which were collected by light traps. Together with results of previous investigations a total of 41 species in 16 genera covering five families are now recorded from the river. About four species were found as immatures in the past, and were identified to generic level only. The first author has collected 27 species including nine undescribed ones: Catoxyethira kunenica sp. nov., Orthotrichia epupae sp. nov., O. vadalis sp. nov., O. kunenensis sp. nov., Ecnomus magnus sp. nov., E. quadrangulatus sp. nov., E. (Psychomyiellodes) statzneri sp. nov., E. (Psychomyiellodes) angonamus sp. nov. and Ceraclea (Pseudoleptocerus) lepidopterella sp. nov. Descriptions and illustrations of the genitalia of the new species are provided. Two species were synonymized: Oecetis kunenensis Barnard, 1934 = Oectis reticulatella Kimmins, 1957, syn. nov. and Oecetis tripunctata (Fabricius, 1793) = Oecetis ovamboensis Barnard, 1934, syn. nov.

Erythrococca kaokoensis (Euphorbiaceae), a new species from Namibia and Angola

Erythrococca kaokoensis, here described as a new species, is only known from the mountains along the Kunene River in the Kaokoveld Centre of Endemism, southwestern Angola and northwestern Namibia. These shrubs or small trees grow among rocks of anorthosite, gneiss or limestone. Diagnostic characters for E. kaokoensis include the leaves that are subcordate or lanceolate to ovate, rarely elliptic, drying dark green, yellow-green, blue-green or violet to black, and the interruptedly racemose or subpaniculate inflorescences with flowers in clusters along the axis. A comparison of some of the more prominent morphological features to differentiate between E. kaokoensis and its possible nearest relative, E. trichogyne, is provided.

Sources of fish in the ephemeral western iishana region of the Cuvelai–Etosha Basin in Angola and Namibia

The triangle between the Kavango and Kunene rivers is drained by the Cuvelai, an ephemeral and deltaic drainage system covering more than 100 000 km2. In good rainfall years, the area becomes populated by fish communities dominated by five species migrating southward towards the endorheic Etosha Pan, the basin’s terminal sump. When water dries up, fish subsequently die-off and their sudden appearance in rainy years has captivated scientists for decades. The current study was prompted by hitherto untapped indigenous knowledge through narratives of opportunistic fish harvesting of migrating fish at temporary connections between the Kunene River and the Cuvelai- Etosha Basin. A reconnaissance fish survey in 2017 was complemented by digital satellite images and elevation data analyses. Results support the presence of at least three major ephemeral fish migration routes. The dominant fish genera migrating upstream in Kunene tributaries comprise Enteromius, Oreochromis and Clarias, all eurytopic and known to undertake upstream, lateral and downstream migrations on floodplains. Although other notable fish refugia in the Cuvelai–Etosha Basin are yet to be identified, there is a necessity for the protection and management of these migration routes in tandem with studies on the nature and extent of this inter-basin fish migration under climate change and variability.

Detection of <i>Escherichia coli</i> and Harmful Enteric Bacterial Pathogens in Domestic Hand-Dug Wells in the Cuvelai Etosha Basin of Namibia

The Cuvelai Etosha Basin of Namibia is characterised by complex aquifer systems with multi-layered aquifers and various water qualities. Some parts of the basin have been covered with a pipeline system that supplies purified surface water from the Kunene River. Locations that lack a pipeline system utilise hand-dug wells as a source of drinking water. These wells draw water from shallow perched aquifers and are not protected from surface contamination nor is the water quality monitored. Sanitised water supply is relevant for the growth and development of societies and is a priority of the United Nations Millennium Development Goals. A bacteriological water quality study aimed at investigating the presence and seasonal variation of; Citrobacter, Escherichia, Klebsiella, Enterobacter, Proteus, Salmonella, Shigella, and Pseudomonas species was conducted on 44 hand-dug wells in the Ohangwena and Omusati regions of the Cuvelai Etosha Basin. Samples were collected from both the wet and dry seasons. Results disclosed the presence of Salmonella, Shigella, Citrobacter, Escherichia, Klebsiella, Enterobacter, Proteus, and Pseudomonas species. Chi-square confirmed a significant seasonal variation in Salmonella (P Shigella (P Citrobacter (P > 0.05), Escherichia (P > 0.05), Klebsiella (P > 0.05), Entero-bacter (P > 0.05), Proteus (P > 0.05) and Pseudomonas (P > 0.05) species. Water from these hand-dug wells is not safe for drinking unless it is subjected to appropriate treatment. It is recommended that hand-dug wells should be properly constructed at safe distances from contaminating structures such as pit latrines and routinely assessed for pathogens, and the water should be sanitized prior to consumption.

Phylogeographic, morphometric and taxonomic re-evaluation of the river sardine, Mesobola brevianalis (Boulenger, 1908) (Teleostei, Cyprinidae, Chedrini).

The river sardine, Mesobola brevianalis (Boulenger, 1908), is the type species of Mesobola Howes, 1984. Standard phylogenetic analyses of partial sequences of the cytochrome oxidase I gene of individuals from populations across southern Africa that are currently identified as Mesobola brevianalis showed that these populations represent four genetically distinct allopatric lineages. Furthermore, Engraulicypris sardella (Günther, 1868), the type species of Engraulicypris Günther, 1894, was convincingly nested amongst these clades. These findings support synonymisation of Engraulicypris and Mesobola syn. n.; restoration of Engraulicypris gariepinus (Barnard, 1943), stat. rev. for the lower Orange River population; description of two new species, Engraulicypris ngalala sp. n. and Engraulicypris howesi sp. n. from the Rovuma and Kunene river systems, respectively; affirmation of the synonymy of Engraulicypris brevianalis (Boulenger, 1908), comb. n. sensu stricto and Engraulicypris whitei van der Horst, 1934; and restoration of Engraulicypris bredoi Poll, 1945, stat. rev. and Engraulicypris spinifer Bailey & Matthes, 1971, stat. rev. from Mesobola. Discriminant function analysis of a truss network of five traditional morphometric measurements and 21 morphometric measurements that characterised the shape of the fishes was used to seek morphological markers for the genetically distinct populations. Only Engraulicypris gariepinus was morphometrically distinctive, but live colouration differed between the lineages. Detailed taxonomic descriptions and an identification key for the species are provided.

Phosphorite deposits on the Namibian shelf

Phosphorite deposits provide a source of fertilizer to feed an increasingly populated world and they provide a record of paleoceanographic changes in upwelling systems linked to climate. The Benguela Upwelling System (BUS) is among the most productive today and is associated with major phosphorite deposits exposed over an area of 24,700km2 on the Namibian shelf. Analyses of cores associated with recent offshore mineral exploration provide new insights into the age and origin of these phosphorite deposits. The deposit consists of coarsening upward muddy to gravelly pelletal phosphorite sand, up to several meters thick, on the middle to outer shelf (190 and 350m water depth) offshore of Lüderitz and Walvis Bay. Less extensive and less continuous deposits occur offshore of Walvis Bay as far north as the Kunene River mouth on the inner to middle shelf (50 and 250m water depth). Pelletal phosphorite sand (some concentrically banded) and concretionary phosphorite pebbles are the dominant grain types consisting of up to 90wt.% carbonate fluorapatite (francolite) cement and inclusions of organic matter, pyrite and terrigenous mud. Strontium isotope stratigraphy and foraminiferal biostratigraphy indicate that phosphogenesis was initiated in the latest Miocene but that most phosphorite formed in the Plio/Pleistocene during early burial diagenesis of organic-rich mud as it does today in the Holocene diatomaceous mud belt. The highly-condensed, coarsening-upward succession reflects increasingly high-amplitude Pleistocene sea-level fluctuations. Phosphorite formation correlates to terrestrial aridification as well as to marine proxies of intensified coastal upwelling in the 600m thick equivalent successions on the upper slope. Repeated phosphorite formation and reworking over Pleistocene glacial to interglacial cycles resulted in the economic concentration of phosphorite, with an estimated total resource of 7800milliontons of phosphate rock at an average grade of 19wt.% P2O5 on the Namibian shelf.

Using a Binomial Mixture Model and Aerial Counts for an Accurate Estimate of Nile Crocodile Abundance and Population Size in the Kunene River, Namibia

The Nile crocodile,Crocodylus niloticus, is found throughout sub-Saharan Africa, including Namibia, Botswana and Angola. The species was transferred from CITES Appendix I to Appendix II in 2004, although it is recognized as peripherally endangered in Namibia due to diminishing habitat availability primarily from human encroachment. In 2013, a species management plan was approved in Namibia to assess the management of the Namibian Nile crocodile populations. During 2012, an aerial survey was conducted to provide an estimate of Nile crocodile population numbers. A recently developed N-mixture model for estimation of abundance and spatial variation was used. Detection probability correlated to animal size and environmental covariates. Our data also suggest that small crocodiles are easier to detect during the spring. The abundance for different size classes was influenced by river complexity (vegetation, depth, channels) and the distribution of human settlements. An estimated 806 individuals were counted alo...

Life cycle of hake and likely management implications

Despite its economic and social importance for Namibia and South Africa, limited documented information exists regarding key aspects of the biology of deep-water hake, including its life cycle. This study utilizes data collected through the demersal surveys of the R/V Dr Fridtjof Nansen in South Africa and F/V Blue Sea 1 in Namibia to describe the migratory patterns of deep-water hake in space and time. Furthermore the study investigates aspects of the life cycle of this important species in the Benguela region. Results show that deep-water hake spawns between the western Agulhas Bank and Elands Bay in South Africa with the main nursery ground between Hondeklip Bay and the northern tip of Orange Banks. Deep-water hake in Namibia (up to the Kunene River) and along the south coast of South Africa (eastwards to Port Alfred) originate from these grounds, and undertake long-range migrations across latitudes and longitudes, respectively. This hypothesis is supported by the finding that spawning has not been observed in Namibia and there are no small juveniles along the South African south coast from the eastern border of the Agulhas Bank. The proposed pattern implies an interconnection between the Namibian and the South African components of the stock and the consequent need for a revision of the present management regime based on the assumption of stocks confined within the respective national jurisdictions. This study has used length frequency distributions in space and time in order to investigate the life cycle, in terms of origin, movement and population structure in particular, an approach that may also be useful for other widely distributed species.

Zircon reconnaissance dating of Proterozoic gneisses along the Kunene River of northwestern Namibia

The northern margin of the Epupa Metamorphic Complex (EMC) along the Kunene River in NW Namibia is one of the geologically least known terranes in Africa because of its remoteness and difficult accessibility. We report field relationships and reconnaissance zircon ages for granitoid gneisses from a 120km foot-traverse along the Kunene River between the Ruacana Falls in the east and Marienfluss in the west. Most rocks are late Palaeoproterozoic in age and correlate well with similar rocks of the EMC farther south in Kaokoland (1757–1835Ma, one sample 1861Ma) and with granitoid rocks in the Kamanjab Inlier, some 400km SE of the Kunene River (1801–1836Ma). All these rocks constitute a large magmatic province on the southwestern margin of the Congo Craton, whose protoliths are possibly related to arc magmatism during the Africa-wide so-called Eburnian event (ca. 2000±200Ma). However, there are also Mesoproterozoic granitoids, 1520–1530Ma in age, whose tectonic significance remains uncertain but which seem to document a thermal event also seen in high-grade metamorphism and isotopic resetting in this part of SW Africa.

Developmentalist Attitudes and Old Habits: Portuguese Labour Policies, South African Rivalry, and Flight in Southern Angola, 1945–1974

At first glance, processes of colonial policy and subsequent migratory flows at the Angola–South West Africa border, in the region of the Kunene river, seem to present a straightforward narrative. In the period between the First and Second World Wars, we find an established pattern of Kwanyama/Ovambo leaving Portuguese Angola to escape repressive practices of forced labour, and as a reaction to the mistreatment of political leaders. Flight movements were encouraged by South African officials stationed in the Ovamboland district of South West Africa, directly south of the border, who practised, notably before 1945, a policy of co-optation of local chiefs.However, it has hitherto remained unnoticed that, between 1945 and 1974, changes in the policies of the authoritarian Portuguese empire had highly practical effects with regard to these flows. Until the 1960s, the comparative advantage of South African border policies lost its impact. In the early 1970s, a more liberal tax policy in the Angolan Cunene district had an even stronger impact on the decision-making processes on the part of local populations.The analysis shows quite clearly that, even under the auspices of late colonial social policies, which favoured grand schemes and more thorough control of populations, the initiative of local groups remained unbroken. In a scenario of colonial policy that favoured the power of the Ovambo chiefs on the southern side of the border, women and younger men used the border to escape social conditions they interpreted as repressive, and locals were capable of constantly reanalysing the advantages present on either side of the border. These results, which confirm the room for manoeuvre of potential forced labourers, also warn us not to generalise too readily about the consequences of under-equipped and authoritarian colonial policies, such as for Portuguese rule over southern Angola.