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  • 1
    Language: English
    In: Nature (London), 2013-05-30, Vol.497 (7451), p.611-614
    Description: Apes and Old World monkeys are prominent components of modern African and Asian ecosystems, yet the earliest phases of their evolutionary history have remained largely undocumented. The absence of crown catarrhine fossils older than ∼20 million years (Myr) has stood in stark contrast to molecular divergence estimates of ∼25-30 Myr for the split between Cercopithecoidea (Old World monkeys) and Hominoidea (apes), implying long ghost lineages for both clades. Here we describe the oldest known fossil 'ape', represented by a partial mandible preserving dental features that place it with 'nyanzapithecine' stem hominoids. Additionally, we report the oldest stem member of the Old World monkey clade, represented by a lower third molar. Both specimens were recovered from a precisely dated 25.2-Myr-old stratum in the Rukwa Rift, a segment of the western branch of the East African Rift in Tanzania. These finds extend the fossil record of apes and Old World monkeys well into the Oligocene epoch of Africa, suggesting a possible link between diversification of crown catarrhines and changes in the African landscape brought about by previously unrecognized tectonic activity in the East African rift system.
    Subject(s): Hominidae - anatomy & histology ; History, Ancient ; Animals ; Mandible - anatomy & histology ; Cercopithecidae - classification ; Tanzania ; Cercopithecidae - anatomy & histology ; Phylogeny ; Tooth - anatomy & histology ; Hominidae - classification ; Fossils ; Apes ; Divergent evolution ; Old-World monkeys ; Research ; Observations ; Paleontology ; Natural history ; Index Medicus
    ISSN: 0028-0836
    E-ISSN: 1476-4687
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
    Source: © ProQuest LLC All rights reserved〈img src="https://exlibris-pub.s3.amazonaws.com/PQ_Logo.jpg" style="vertical-align:middle;margin-left:7px"〉
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  • 2
    Language: English
    In: Nature (London), 2010, Vol.466 (7307), p.748-751
    Description: Fossil crocodyliforms discovered in recent years have revealed a level of morphological and ecological diversity not exhibited by extant members of the group. This diversity is particularly notable among taxa of the Cretaceous Period (144-65 million years ago) recovered from former Gondwanan landmasses. Here we report the discovery of a new species of Cretaceous notosuchian crocodyliform from the Rukwa Rift Basin of southwestern Tanzania. This small-bodied form deviates significantly from more typical crocodyliform craniodental morphologies, having a short, broad skull, robust lower jaw, and a dentition with relatively few teeth that nonetheless show marked heterodonty. The presence of morphologically complex, complementary upper and lower molariform teeth suggests a degree of crown-crown contact during jaw adduction that is unmatched among known crocodyliforms, paralleling the level of occlusal complexity seen in mammals and their extinct relatives. The presence of another small-bodied mammal-like crocodyliform in the Cretaceous of Gondwana indicates that notosuchians probably filled niches and inhabited ecomorphospace that were otherwise occupied by mammals on northern continents.
    Subject(s): Earth, ocean, space ; Vertebrate paleontology ; Earth sciences ; Paleontology ; Exact sciences and technology ; Biological Evolution ; History, Ancient ; Mammals - classification ; Animals ; Dentition ; Mammals - physiology ; Tanzania ; Tomography, X-Ray Computed ; Phylogeny ; Mammals - anatomy & histology ; Fossils ; Crocodilia ; Natural history ; Index Medicus
    ISSN: 0028-0836
    E-ISSN: 1476-4687
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
    Source: © ProQuest LLC All rights reserved〈img src="https://exlibris-pub.s3.amazonaws.com/PQ_Logo.jpg" style="vertical-align:middle;margin-left:7px"〉
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  • 3
    Dissertation
    Dissertation
    2016
    ISBN: 1369432542  ISBN: 9781369432541 
    Language: English
    Description: The number of publications on and discoveries of new fossil lungfish species and genera has generally shown, despite some fluctuations, an increase in numbers. This is particularly the case in Africa, Australia and South America, where lungfishes still survive as an extant group. Australian lungfishes have received the most attention, with one possible reason being the declaration that the surviving Australian lungfish is an endangered species, and the number of research expeditions and active researchers based there over a long period of time. While Australia has received a great deal of attention, the evolution of African lungfishes, while noteworthy, has not been studied with the same level of intensity. This study focuses on newly discovered fossil lungfish specimens from Kenya and Tanzania, and then looks at Africa lungfish biogeography in a broader context. The Cretaceous fauna of Turkana, Kenya, includes a lungfish pterygopalatine tooth plate, which is here described as Ceratodus due to the possession of multiple ceratodontid features, including six separate ridges on the occlusal surface of the tooth plate, the characteristic curvature of the tooth plate, and the specimen’s length to width ratio of almost 2:1. Tooth plates from in the Late Oligocene fauna in the Rukwa Rift Basin (RRB) of southwestern Tanzania are here assigned to two different genera; Ceratodus and Protopterus. The i from RRB is smaller in size as compared to the Cretaceous specimen from Turkana but retains features typical of ceratodontid lungfish, and it is sufficiently distinct to be described as a new species -- Ceratodus mbedeae. Protopterus lungfish specimens from the RRB exhibit typical features of that genus, which survived to day in Africa, including three blade-like protruding tooth ridges and a relatively flat posterior angle in the upper jaw. The RRB Protopterus are not here consider sufficiently distinct to justify erection of a new species. Mapping parsimony analysis of endemism (PAE) of lungfish biogeography indicates significant changes over time. Of note are the much broader geographic distribution of lungfishes early in their history, contrasts in composition of Paleozoic versus Mesozoic assemblages, and the abrupt turnover of major groups at the end of the Devonian. Modern lungfish are today restricted to tropical regions of Africa, South America and Australia. The similarity dendogram generated by the PAE study results in three major clusters (clades), the first cluster that constitutes Australia and Europe appears to be very distinct from the other two, namely Africa, Madagascar and South America, and Asia and North America. Madagascar is shown to be more similar to South America than to Africa within that cluster.
    Subject(s): Geology ; Paleontology ; Geobiology
    ISBN: 1369432542
    ISBN: 9781369432541
    Source: ProQuest Dissertations & Theses Global
    Source: © ProQuest LLC All rights reserved〈img src="https://exlibris-pub.s3.amazonaws.com/PQ_Logo.jpg" style="vertical-align:middle;margin-left:7px"〉
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