Papers by Fredrick Manthi
Journal of Human Evolution, 2015
For more than 80 years, Proconsul has held a pivotal position in interpretations of catarrhine ev... more For more than 80 years, Proconsul has held a pivotal position in interpretations of catarrhine evolution in East Africa. From early hypotheses of phyletic relationships with modern apes to more recent debates over their position within Hominoidea, the well-preserved fossils of this genus have been a foundation for most evolutionary scenarios regarding the early diversification of hominoids. The majority of what we "know" about Proconsul, however, derives from abundant younger fossils found at the Kisingiri localities on Rusinga and Mfangano Islands rather than from the smaller samples found at Koru-the locality of the type species, Proconsul africanus-and other Tinderet deposits. One outcome of this is seen in recent attempts to expand the genus "Ugandapithecus" (considered here a junior subjective synonym of Proconsul), wherein much of the Tinderet sample was referred to that genus based primarily on differentiating it from the Kisingiri specimens rather than from the type species, P. africanus. This and other recent taxonomic revisions to Proconsul prompted us to undertake a systematic review of dentognathic specimens attributed to this taxon. Results of our study underscore and extend the substantive distinction of Tinderet and Ugandan Proconsul (i.e., Proconsul sensu stricto) from the Kisingiri fossils, the latter recognized here as a new genus. Specimens of the new genus are readily distinguished from Proconsul sensu stricto by morphology preserved in the P. africanus holotype, M 14084, but also in I 1 s, lower incisors, upper and lower canines, and especially mandibular characteristics. A number of these differences are more advanced among Kisingiri specimens in the direction of crown hominoids. Proconsul sensu stricto is characterized by a suite of unique features that strongly unite the included species as a clade. There have been decades of contentious debate over the phylogenetic placement of Proconsul (sensu lato), due in part to there being a mixture of primitive and more advanced morphology within the single genus. By recognizing two distinct clades that, in large part, segregate these character states, we believe that better phylogenetic resolution can be achieved. East African Archaeological Expedition and British-Kenya Miocene Expedition gradually revealed substantial size variation in the type species, Proconsul africanus, and both the Kisingiri and Tinderet localities were re-interpreted as having a smaller and a larger Proconsul species. This prompted Le Gros Clark and Leakey (1950) to erect two new species: Proconsul major for the large specimens from Tinderet, and Proconsul nyanzae for the large Kisingiri specimens. The smaller species, P. africanus, continued to be recognized in both areas by most workers. Large-bodied catarrhines discovered in Uganda expanded the geographic range of P. major (Bishop, 1964), although some of this sample was later reassigned to a new taxon, Morotopithecus bishopi, by Gebo et al. (1997). <Figure 1 about here> This basic taxonomic arrangement remained relatively stable for three decades, although individual specimen identifications did not always adhere to these simple geographic distinctions (e.g., 5
‡ These authors contributed equally to this work.
Evolutionary Anthropology: Issues, 2017
Journal of Paleontology
Brochuchus is a small crocodylid originally based on specimens from the early Miocene of Rusinga ... more Brochuchus is a small crocodylid originally based on specimens from the early Miocene of Rusinga Island, Lake Victoria, Kenya. Here, we report occurrences of Brochuchus from several early and middle Miocene sites. Some are from the Lake Victoria region, and others are in the Lake Turkana Basin. Specimens from the middle Miocene Maboko locality form the basis of a new species, Brochuchus parvidens, which has comparatively smaller maxillary alveoli. Because of the smaller alveoli, the teeth appear to be more widely spaced in the new species. We also provide a revised diagnosis for Brochuchus and its type species, B. pigotti. A phylogenetic analysis supports a close relationship between Brochuchus and tube-snouted Euthecodon, but although relationships among crocodylids appear poorly resolved in the set of optimal trees, this is because Brochuchus and Euthecodon, along with early Miocene “Crocodylus” gariepensis from the early Miocene of Namibia, jointly adopt two distinct positions—ei...
Science Advances
Africa hosts the greatest human genetic diversity globally, but legacies of ancient population in... more Africa hosts the greatest human genetic diversity globally, but legacies of ancient population interactions and dispersals across the continent remain understudied. Here, we report genome-wide data from 20 ancient sub-Saharan African individuals, including the first reported ancient DNA from the DRC, Uganda, and Botswana. These data demonstrate the contraction of diverse, once contiguous hunter-gatherer populations, and suggest the resistance to interaction with incoming pastoralists of delayed-return foragers in aquatic environments. We refine models for the spread of food producers into eastern and southern Africa, demonstrating more complex trajectories of admixture than previously suggested. In Botswana, we show that Bantu ancestry post-dates admixture between pastoralists and foragers, suggesting an earlier spread of pastoralism than farming to southern Africa. Our findings demonstrate how processes of migration and admixture have markedly reshaped the genetic map of sub-Sahara...
Journal of Human Evolution
Science Advances, 2020
Africa hosts the greatest human genetic diversity globally, but legacies of ancient population in... more Africa hosts the greatest human genetic diversity globally, but legacies of ancient population interactions and dispersals across the continent remain understudied. Here, we report genome-wide data from 20 ancient sub-Saharan African individuals, including the first reported ancient DNA from the DRC, Uganda, and Botswana. These data demonstrate the contraction of diverse, once contiguous hunter-gatherer populations, and suggest the resistance to interaction with incoming pastoralists of delayed-return foragers in aquatic environments. We refine models for the spread of food producers into eastern and southern Africa, demonstrating more complex trajectories of admixture than previously suggested. In Botswana, we show that Bantu ancestry post-dates admixture between pastoralists and foragers, suggesting an earlier spread of pastoralism than farming to southern Africa. Our findings demonstrate how processes of migration and admixture have markedly reshaped the genetic map of sub-Sahara...
Science
How food production first entered eastern Africa ~5000 years ago and the extent to which people m... more How food production first entered eastern Africa ~5000 years ago and the extent to which people moved with livestock is unclear. We present genome-wide data from 41 individuals associated with Later Stone Age, Pastoral Neolithic (PN), and Iron Age contexts in what are now Kenya and Tanzania to examine the genetic impacts of the spreads of herding and farming. Our results support a multi-phase model in which admixture between northeastern African-related peoples and eastern African foragers formed multiple pastoralist groups, including a genetically homogeneous PN cluster. Additional admixture with northeastern and western African-related groups occurred by the Iron Age. These findings support several movements of food producers, while rejecting models of minimal admixture with foragers and of genetic differentiation between makers of distinct PN artifacts.
Science, 2019
How food production first entered eastern Africa ~5000 years ago and the extent to which people m... more How food production first entered eastern Africa ~5000 years ago and the extent to which people moved with livestock is unclear. We present genome-wide data from 41 individuals associated with Later Stone Age, Pastoral Neolithic (PN), and Iron Age contexts in what are now Kenya and Tanzania to examine the genetic impacts of the spreads of herding and farming. Our results support a multi-phase model in which admixture between northeastern African-related peoples and eastern African foragers formed multiple pastoralist groups, including a genetically homogeneous PN cluster. Additional admixture with northeastern and western African-related groups occurred by the Iron Age. These findings support several movements of food producers, while rejecting models of minimal admixture with foragers and of genetic differentiation between makers of distinct PN artifacts.
Journal of Paleontology
The partial skull of a lion from Natodomeri, northwest Kenya is described. The Natodomeri sites a... more The partial skull of a lion from Natodomeri, northwest Kenya is described. The Natodomeri sites are correlated with Member I of the Kibish Formation, dated to between 195 ka and ca. 205 ka. The skull is remarkable for its very great size, equivalent to the largest cave lions (Panthera spelaea [Goldfuss, 1810]) of Pleistocene Eurasia and much larger than any previously known lion from Africa, living or fossil. We hypothesize that this individual represents a previously unknown population or subspecies of lion present in the late Middle and Late Pleistocene of eastern Africa rather than being an indication of climate-driven size increase in lions of that time. This raises questions regarding the extent of our understanding of the pattern and causes of lion evolution in the Late Pleistocene.
Journal of Human Evolution
Fossil bats from the Pliocene of Africa are extremely rare, especially in East Africa where meage... more Fossil bats from the Pliocene of Africa are extremely rare, especially in East Africa where meager records have been reported only from two localities in the Omo River Basin Shungura Formation and from a scattering of localities in the Afar Depression, both in Ethiopia. Here we report on a diverse assemblage of bats from Kanapoi in the Turkana Basin that date to approximately 4.19 million years ago. The Kanapoi bat community consists of four different species of fruit bats including a new genus and two new species as well as five species of echolocating bats, the most common of which are two new species of the molossid genus Mops. Additionally, among the echolocating bats, a new species of the emballonurid Saccolaimus is documented at Kanapoi along with an additional Saccolaimus species and a potentially new species of the nycterid Nycteris. Compared to other East African Pliocene bat assemblages, the Kanapoi bat community is unique in preserving molossids and curiously lacks any evidence of cave dwelling bats like rhinolophids or hipposiderids, which are both common at other East African sites. The bats making up the Kanapoi community all typically roost in trees, with some preferring deeper forests and larger trees (molossids), while the others (pteropodids, nycterids and emballonurids) roost in trees near open areas. Living fruit bats that are related to Kanapoi species typically forage for fruits along the margins of forests and in open savannah. The echolocating forms from Kanapoi consist of groups that aerially hawk for insects in open areas between patches of forest and along water courses. The habitats preferred by living relatives of the Kanapoi bats are in agreement with those constructed for Kanapoi based on other lines of evidence.
Journal of human evolution, Jan 12, 2017
Carbon isotope ratios of mammalian teeth from the Kanapoi site in northern Kenya are interpreted ... more Carbon isotope ratios of mammalian teeth from the Kanapoi site in northern Kenya are interpreted in the context of C3 and C4 derived resources to investigate the paleoecology of Australopithecus anamensis. δ13C values of large mammals, when compared at the taxon level, show an ecosystem that is strongly biased towards mixed feeders and browsers. However, sufficient C4 resources were present such that some C4 dominated grazers were also present in the large mammal fauna. Analyses of micromammals shows that their diets were C3 dominated or C3-C4 mixed. Carbon isotope studies of primates shows that the major primate tribes-Colobini, Papioini, Hominini-all made some use of C4 resources in their respective diets; the Hominini had a higher fraction of C3 diet resources than the other primate tribes represented in the fossil record.
Journal of Vertebrate Paleontology
ABSTRACT We describe here an ichthyological and herpetological assemblage that was obtained from ... more ABSTRACT We describe here an ichthyological and herpetological assemblage that was obtained from washing-screening sediments from the early late Oligocene locality of Lokone, Kenya. This provides original information on the hitherto oldest known fauna from the East African Rift since it started to open from north to south during the Oligocene. The description of the fossil remains allows the identification of crocodiles (crocodylids), squamates (lacertid and Serpentes), turtles (pelomedusoids cf. Erymnochelys group), dipnoan (?Protopterus sp.), and actinopterygian fishes (Polypterus sp., Heterotis sp., Gymnarchus sp., Hydrocynus sp., Sindacharax sp. and other alestids, a claroteid, a cichlid, possibly a Distichodus, and other indeterminate fish). The preservation of this material testifies to a certain level of hydrodynamism, and the ecology of these ectotherm vertebrates suggests that freshwater environment was developed in this area. Moreover, the assemblage corresponds to herpeto- and ichthyofaunas that prefigured the modern African diversity as early as the Oligocene, before the Miocene invasion by Asian fish. It thus testifies to connections between the newly formed hydrographical system in the Turkana Basin with the Lokone main hydrographical system beginning at a very early stage of the Eastern Rift development.
Journal of human evolution, Jan 9, 2017
Reconstructions of habitat at sites like Kanapoi are key to understanding the environmental circu... more Reconstructions of habitat at sites like Kanapoi are key to understanding the environmental circumstances in which hominins evolved during the early Pliocene. While Australopithecus anamensis shows evidence of terrestrial bipedality traditionally associated with a more open setting, its enamel has low δ(13)C values consistent with consumption of C3 foods, which predominate in wooded areas of tropical Africa. Habitat proxies, ranging from paleosols and their carbonates to associated herbivore fauna and their carbon isotope ratios, suggest a heterogeneous setting with both grass and woody plant components, though the proportions of each have been difficult to pin down. Here we bring dental microwear texture analysis of herbivorous fauna to bear on the issue. We present texture data for fossil bovids, primates, rodents, and suids (n = 107 individuals in total) from the hominin bearing deposits at Kanapoi, and interpret these in the light of closely related extant mammals with known dif...
Kenya Past and Present, 2008
Journal of Taphonomy, 2008
A taxonomic and taphonomic study was carried out on two assemblages of microfauna from the Plioce... more A taxonomic and taphonomic study was carried out on two assemblages of microfauna from the Pliocene locality of Kanapoi in north-western Kenya, in order to understand the agent/s responsible for their accumulation and the taphonomic processes that have influenced the assemblages. The two sites, namely, Nzube's Mandible Site and the Bat Site have yielded microfaunal remains comprising largely rodents and bats. The fauna at Nzube's Mandible Site derives from the same site as the holotype mandible of Australopithecus anamensis and comprises largely murids, while that from the Bat Site consists largely bats. Characteristics of the assemblages such as the high representation of nearly all skeletal elements suggest that, although pre- and post-depositional processes caused damage to the faunal remains, overall the samples are a fairly true reflection of the original assemblages that accumulated at the sites. Further, the high representation of virtually all skeletal elements, the minimal degree of etching among the murid incisors, and the high faunal diversity, particularly at Nzube's Mandible Site, indicate that the two assemblages accumulated in situ by way of predation. Even though several predators may have been involved, the barn owl (Tyto alba) or the giant eagle owl (Bubo lacteus), are the most likely accumulators of the two assemblages
Uploads
Papers by Fredrick Manthi