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- Using remote sensing and machine learning to reconstruct paleoenvironmental features in the Koobi Fora FormationPublication . Dorans, Elizabeth R.; Coelho, Joao D'Oliveira; Anemone, Robert L.; Bobe, Rene; Carvalho, Susana; Forrest, Frances; Braun, David R.Advances in Geographic Information Systems and Remote Sensing technologies have the potential to revolutionize archaeological and paleontological fieldwork. Machine learning models have been effective in identifying conditions ideal for preservation, exposure, and discovery of fossils in a range of geographic contexts. Researchers working in the Koobi Fora Formation of northern Kenya have long inquired about the geographic patterning of extinct fauna and their respective paleoenvironments. This project is the first attempt to use machine learning techniques to capture paleoecological patterns utilizing topographical and spectral variables that may be predictive of the input of aquatic components in the paleoenvironments of the Koobi Fora Formation.
- The ecology of Australopithecus anamensis in the early Pliocene of Kanapoi, KenyaPublication . Bobe, Rene; Manthi, Fredrick Kyalo; Ward, Carol, V; Plavcan, J. Michael; Carvalho, SusanaAustralopithecus anamensis is a pivotal species in human evolution. It is likely to be the direct ancestor of Australopithecus afarensis and the species that may have given rise to the Homo and Paranthropus lineages. It had a suite of adaptations for habitual bipedalism and a diet that differed from that of earlier hominin species. Under what environmental and ecological conditions did this suite of adaptations arise? The early Pliocene site of Kanapoi in the Lake Turkana Basin of Kenya has the largest sample of A. anamensis in eastern Africa and a rich record of fossil vertebrates. Most Kanapoi fossils are chronologically well constrained by radiometrically dated tephras between the ages of 4.2 and 4.1 million years ago. Sedimentological, isotopic, and faunal data indicate that the environments of Kanapoi during the early Pliocene had a complex range of vegetation types that included closed woodlands, shrubs, and grasslands near a river (for most of the sequence) or lake. These were dynamic landscapes that could shift rapidly from fluvial to lacustrine conditions, and then back. Australopithecus anamensis shared its environments with at least 10 species of very large herbivores, which undoubtedly played a major role in modifying the landscape by opening wooded areas and providing pathways for bipedal hominins. Hominins may have competed for terrestrial resources with abundant suids (Nyanzachoerus and Notochoerus) and for arboreal resources with monkeys (Parapapio being the most common cercopithecid). Kanapoi had a formidable group of predators that included a very abundant species of hyena (Parahyaena howelli), two sabre-tooth felids (Dinofelis and Homotherium), a giant otter (Enhydriodon cf. dikikae), and three species of crocodiles. Various measures of abundance indicate that A. anamensis was an important component of the Kanapoi early Pliocene ecosystems, and that its key adaptations allowed this species to thrive in complex and dynamic landscapes. (C) 2019 Elsevier Ltd. All rights reserved.
- Primate adaptations and evolution in the Southern African Rift ValleyPublication . Bobe, Rene; Martinez, Felipe I.; Carvalho, SusanaGorongosa National Park in central Mozambique offers an unparalleled setting for the study of primate adaptations to complex and highly dynamic environments. Located at the southern end of the East African Rift System, Gorongosa hosts a mosaic of forests, woodlands, grasslands, swamps, rivers, and a major lake, Lake Urema, which fluctuates extensively with the seasonal cycles (Figures 1 and 2).1 Renowned biologist E. O. Wilson has described Gorongosa as “ecologically the most diverse park in the world.” 2 The park is home to five species of nonhuman primates, among them 219 troops of baboons,3 whose phenotypic diversity suggests an extended history of admixture between chacmas (Papio ursinus) and yellow baboons (Papio cynocephalus) (Figure 3).4 With its dynamic mix of environments in the African Rift Valley, and highly adaptable primates, Gorongosa brings to mind the vegetation mosaics in which Pliocene and Pleistocene hominins evolved
- Carbon, nitrogen, and oxygen stable isotopes in modern tooth enamel: A case study from Gorongosa National Park, central MozambiquePublication . Lüdecke, Tina; Leichliter, Jennifer N.; Aldeias, Vera; Bamford, Marion K.; Biro, Dora; Braun, David R.; Capelli, Cristian; Cybulski, Jonathan D.; Duprey, Nicolas N.; Ferreira da Silva, Maria J.; Foreman, Alan D.; Habermann, Jörg M.; Haug, Gerald H.; Martínez, Felipe I.; Mathe, Jacinto; Mulch, Andreas; Sigman, Daniel M.; Vonhof, Hubert; Bobe, Rene; Carvalho, Susana; Martínez-García, AlfredoThe analyses of the stable isotope ratios of carbon (delta C-13), nitrogen (delta N-15), and oxygen (delta O-18) in animal tissues are powerful tools for reconstructing the feeding behavior of individual animals and characterizing trophic interactions in food webs. Of these biomaterials, tooth enamel is the hardest, most mineralized vertebrate tissue and therefore least likely to be affected by chemical alteration (i.e., its isotopic composition can be preserved over millions of years), making it an important and widely available archive for biologists and paleontologists. Here, we present the first combined measurements of delta C-13, delta N-15, and delta O-18 in enamel from the teeth of modern fauna (herbivores, carnivores, and omnivores) from the well-studied ecosystem of Gorongosa National Park (GNP) in central Mozambique. We use two novel methods to produce high-precision stable isotope enamel data: (i) the "oxidation-denitrification method," which permits the measurement of mineral-bound organic nitrogen in tooth enamel (delta N-15(enamel)), which until now, has not been possible due to enamel's low organic content, and (ii) the "cold trap method," which greatly reduces the sample size required for traditional measurements of inorganic delta C-13(enamel) and delta O-18(enamel) (from >= 0.5 to <= 0.1 mg), permitting analysis of small or valuable teeth and high-resolution serial sampling of enamel. The stable isotope results for GNP fauna reveal important ecological information about the trophic level, dietary niche, and resource consumption. delta N-15(enamel) values clearly differentiate trophic level (i.e., carnivore delta N-15(enamel) values are 4.0 parts per thousand higher, on average, than herbivores), delta C-13(enamel) values distinguish C-3 and/or C-4 biomass consumption, and delta O-18(enamel) values reflect local meteoric water (delta O-18(water)) in the park. Analysis of combined carbon, nitrogen, and oxygen stable isotope data permits geochemical separation of grazers, browsers, omnivores, and carnivores according to their isotopic niche, while mixed-feeding herbivores cannot be clearly distinguished from other dietary groups. These results confirm that combined C, N, and O isotope analyses of a single aliquot of tooth enamel can be used to reconstruct diet and trophic niches. Given its resistance to chemical alteration, the analysis of these three isotopes in tooth enamel has a high potential to open new avenues of research in (paleo)ecology and paleontology.
- Late Miocene Primates and the Biogeography of Hominin Origins: A Role for the Unknown South?Publication . Bobe, Rene; Carvalho, Susana