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The fossil record of macroscelidean mammals is notoriously patchy, with a significant spatial and temporal gap separating faunas from the early Oligocene localities of northern Africa and the early Miocene localities of eastern and southern Africa. Here we describe fossil macroscelideans representing Myohyracinae and Rhynchocyoninae recovered from a rift-fill sequence of richly fossiliferous sandstones in the late Oligocene Nsungwe Formation in the Rukwa Rift Basin of southwestern Tanzania. Radiometrically dated to 25.2 Ma, a new Palaeogene myohyracine taxon (Rukwasengi butleri) is represented by a partial maxilla (RRBP 05409) preserving a lightly worn M2-M3. The M2 exhibits a less hypsodont and mesiodistally elongate morphology than the early Miocene Myohyrax oswaldi, and the three-rooted M3 exhibits a tiny mesially positioned fossette. A new rhynchocyonine (Oligorhynchocyon songwensis) is represented by specimens more brachyodont than the early Miocene Miorhynchocyon. Taken together these finds document a rare window into macroscelidean evolutionary history with diversification of the group near the Palaeogene-Neogene Transition (PNT). Continued exploration offers a refined perspective on mid-Cenozoic faunal and ecosystem dynamics on continental Africa, expanding opportunities for recognising trends in palaeobiological diversity across habitat types and through time. [ABSTRACT FROM AUTHOR]

Abstract The early Paleogene is critical for understanding global biodiversity patterns in modern ecosystems. During this interval, Southern Hemisphere continents were largely characterized by isolation and faunal endemism following the breakup of Gondwana. Africa has been proposed as an important source area for the origin of several marine vertebrate groups but its Paleogene record is poorly sampled, especially from sub-Saharan Africa. To document the early Paleogene marine ecosystems of Central Africa, we revised the stratigraphic context of sedimentary deposits from three fossil-rich vertebrate localities: the Landana section in the Cabinda exclave (Angola), and the Manzadi and Bololo localities in western Democratic Republic of Congo. We provide more refined age constraints for these three localities based on invertebrate and vertebrate faunas, foraminiferal and dinoflagellate cyst assemblages, and carbon isotope records. We find an almost complete absence of Danian-aged rocks in the Landana section, contrary to prevailing interpretations over the last half a century (only the layer 1, at the base of the section, seems to be Danian). Refining the age of these Paleocene layers is crucial for analyzing fish evolution in a global framework, with implications for the early appearance of Scombridae (tunas and mackerels) and Tetraodontiformes (puffer fishes). The combination of vertebrate fossil records from Manzadi and Landana sections suggests important environmental changes around the K/Pg transition characterized by an important modification of the ichthyofauna. A small faunal shift may have occurred during the Selandian. More dramatic is the distinct decrease in overall richness that lasts from the Selandian to the Ypresian. The Lutetian of West Central Africa is characterized by the first appearance of numerous cartilaginous and bony fishes. Our analysis of the ichthyofauna moreover indicates two periods of faunal exchanges: one during the Paleocene, where Central Africa appears to have been a source for the European marine fauna, and another during the Eocene when Europe was the source of the Central Africa fauna. These data indicate that Central Africa has had connections with the Tethyian realm. Graphical abstract Image 1 Highlights • An almost complete absence of Danian-aged rocks in the Landana section. • Important faunal shifts during the Selandian and between the Ypresian and Lutetian. • Central Africa had important connections with the Tethyian realm. [ABSTRACT FROM AUTHOR]

Hyainailourine hyaenodonts are among the largest terrestrial carnivorous mammals known. The clade is widely dispersed, found in Eurasia, North America, and Afro-Arabia in the Paleogene and early Neogene. In this study, we describe dental and postcranial material from Simbakubwa kutokaafrika, gen. et sp. nov., the most complete hyainailourine known from sub-Saharan Africa. The material is from a relatively young adult from the early Miocene locality of Meswa Bridge, Kenya. Simbakubwa differs from Hyainailouros in exhibiting lingually oriented molar protocones, gracile metastyles, and buccolingually compressed, shearing canines. Like other large Miocene hyainailourines, Simbakubwa has deep carnassial notches on the molars and tall paracones fused to shorter metacones forming single piercing cusps. A Bayesian phylogenetic analysis recovers Simbakubwa as the sister taxon of a clade of large-bodied Miocene hyainailourines that includes Hyainailouros and Megistotherium. Bayesian ancestral state reconstruction supports an Afro-Arabian origin for Hyainailourinae with subsequent dispersal to Eurasia during the early Miocene. Regression analysis based on carnassial size is applied to Simbakubwa and closely related hyainailourines, recovering a body mass up to 1,500 kg for the new taxon. The evolution and extinction of Hyainailourinae offers important insights for interpreting ecological transitions from Paleogene to Neogene faunas in Afro-Arabia and Eurasia. [ABSTRACT FROM AUTHOR]

Throughout the Paleogene, most terrestrial carnivore niches in Afro-Arabia were occupied by Hyaenodonta, an extinct lineage of placental mammals. By the end of the Miocene, terrestrial carnivore niches had shifted to members of Carnivora, a clade with Eurasian origins. The transition from a hyaenodont-carnivore fauna to a carnivoran-carnivore fauna coincides with other ecological changes in Afro-Arabia as tectonic conditions in the African Rift System altered climatic conditions and facilitated faunal exchange with Eurasia. Fossil bearing deposits in the Nsungwe Formation in southwestern Tanzania are precisely dated to ~25.2 Ma (late Oligocene), preserving a late Paleogene Afro-Arabian fauna on the brink of environmental transition, including the earliest fossil evidence of the split between Old World monkeys and apes. Here we describe a new hyaenodont from the Nsungwe Formation, Pakakali rukwaensis gen. et sp. nov., a bobcat-sized taxon known from a portion of the maxilla that preserves a deciduous third premolar and alveoli of dP4 and M1. The crown of dP3 bears an elongate parastyle and metastyle and a small, blade-like metacone. Based on alveolar morphology, the two more distal teeth successively increased in size and had relatively large protocones. Using a hyaenodont character-taxon matrix that includes deciduous dental characters, Bayesian phylogenetic methods resolve Pakakali within the clade Hyainailouroidea. A Bayesian biogeographic analysis of phylogenetic results resolve the Pakakali clade as Afro-Arabian in origin, demonstrating that this small carnivorous mammal was part of an endemic Afro-Arabian lineage that persisted into the Miocene. Notably, Pakakali is in the size range of carnivoran forms that arrived and began to diversify in the region by the early Miocene. The description of Pakakali is important for exploring hyaenodont ontogeny and potential influences of Afro-Arabian tectonic events upon mammalian evolution, providing a deep time perspective on the stability of terrestrial carnivore niches through time. [ABSTRACT FROM AUTHOR]

The extant snake fauna has its roots in faunal upheaval occurring across the Paleogene - Neogene transition. On northern continents, this turnover is well established by the late early Miocene. However, this transition is poorly documented on southern landmasses, particularly on continental Africa, where no late Paleogene terrestrial snake assemblages are documented south of the equator. Here we describe a newly discovered snake fauna from the Late Oligocene Nsungwe Formation in the Rukwa Rift Basin of Tanzania. The fauna is small but diverse with eight identifiable morphotypes, comprised of three booids and five colubroids. This fauna includes Rukwanyoka holmani gen. et sp. nov., the oldest boid known from mainland Africa. It also provides the oldest fossil evidence for the African colubroid clade Elapidae. Colubroids dominate the fauna, comprising more than 75% of the recovered material. This is likely tied to local aridification and/or seasonality and mirrors the pattern of overturn in later snake faunas inhabiting the emerging grassland environments of Europe and North America. The early emergence of colubroid dominance in the Rukwa Rift Basin relative to northern continents suggests that the pattern of overturn that resulted in extant faunas happened in a more complex fashion on continental Africa than was previously realized, with African colubroids becoming at least locally important in the late Paleogene, either ahead of or as a consequence of the invasion of colubrids. The early occurrence of elapid snakes in the latest Oligocene of Africa suggests the clade rapidly spread from Asia to Africa, or arose in Africa, before invading Europe. [ABSTRACT FROM AUTHOR]

Extant snake faunas have their origins in the mid-Cenozoic, when colubroids replaced booid-grade snakes as the dominant species. The timing of this faunal changeover in North America and Europe based on fossils is thought to have occurred in the early Neogene, after a period of global cooling opened environments and made them suitable for more active predators. However, new fossils from the late Oligocene of Tanzania have revealed an early colubroid-dominated fauna in Africa suggesting a different pattern of faunal turnover there. Additionally, molecular divergence times suggest colubroid diversification began sometime in the Paleogene, although the exact timing and driving forces behind the diversification are not clear. Here we present the first fossil snake referred to the African clade Lamprophiinae, and the oldest fossil known of Lamprophiidae. As such, this specimen provides the only potential fossil calibration point for the African snake radiation represented by Lamprophiidae, and is the oldest snake referred to Elapoidea. A molecular clock analysis using this and other previously reported fossils as calibration points reveals colubroid diversification minimally occurred in the earliest Paleogene, although a Cretaceous origin cannot be excluded. The elapoid and colubrid lineages diverged during the period of global warming near the Paleocene-Eocene boundary, with both clades diversifying beginning in the early Eocene (proximate to the Early Eocene Climate Optimum) and continuing into the cooler Miocene. The majority of subclades diverge well before the appearance of colubroid dominance in the fossil record. These results suggest an earlier diversification of colubroids than generally previously thought, with hypothesized origins of these clades in Asia and Africa where the fossil record is relatively poorly known. Further work in these regions may provide new insights into the timing of, and environmental influences contributing to, the rise of colubroid snakes. [ABSTRACT FROM AUTHOR]

Lungfish (Dipnoi) date back to the Devonian, and some fossil taxa as well as extant African lungfishes are known for their ability to aestivate, tolerating low-oxygen environments associated with seasonal drying. Extant lungfishes are separated into two families: Lepidosirenidae (Protopterus in Africa and Lepidosiren in South America) and Neoceratodontidae (Neocerotadus in Australia). African lungfishes were more geographically and phylogenetically diverse on the continent in the past than they are today, with only 5% of extinct taxa recorded from the sub-Saharan fossil record. Given the sparse record of Lepidosirenidae fossils from continental Africa, any new materials are important for understanding diversification of the clade. Here we describe new lungfish fossils cautiously referable to Protopterus annectens and Protopterus aethiopicus , which are strongly supported sister taxa based on the molecular phylogeny. Specimens were collected from the late Oligocene Nsungwe Formation in the Rukwa Rift Basin (RRB) of southwestern Tanzania. The late Oligocene Nsungwe Formation represents a sequence of continental rift-fill deposits of the Songwe sub-basin of the RRB and is subdivided into the lower Utengule and upper Songwe members. Recovery of such material from the Paleogene of Africa below the equator addresses a sizable gap in the lungfish fossil record. It also expands the Nsungwe Formation fauna that includes invertebrates, alestid fishes, ptychadenid anurans, snakes, and several clades of mammals, deepening paleoecological insights into the late Oligocene record of the continental African interior. At present, P. aethiopicus and P. dolloi have an extensive modern eastern African distribution associated with the rift lakes and a region where extant members of P. annectens are not presently known. Fossil specimens described herein document presence of the clade during Paleogene volcanic activity in the western branch of the Eastern African Rift System. [ABSTRACT FROM AUTHOR]