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Variation and the evolutionary drivers of diversity in the genus Paranthropus

Craniodental robusticity in Paranthropus has led many researchers to posit that all the species in this genus share a common adaptation to a diet of hard foods. Recent research on craniodental morphology, microwear, biomechanics, and isotopes, by contrast, has suggested that substantial variation ex...

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Main Author: Hlazo, Nomawethu
Other Authors: Ackermann, Rebecca Rogers
Format: Thesis
Language:English
Published: Department of Archaeology 2019
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access_status_str Open Access
author Hlazo, Nomawethu
author2 Ackermann, Rebecca Rogers
author_browse Ackermann, Rebecca Rogers
Hlazo, Nomawethu
author_facet Ackermann, Rebecca Rogers
Hlazo, Nomawethu
author_sort Hlazo, Nomawethu
collection Thesis
description Craniodental robusticity in Paranthropus has led many researchers to posit that all the species in this genus share a common adaptation to a diet of hard foods. Recent research on craniodental morphology, microwear, biomechanics, and isotopes, by contrast, has suggested that substantial variation exists within the genus Paranthropus, both in terms of ecological niches occupied by the three recognized species within the genus and the amount of consumed hard and compliant foods. Rather than pointing to a common adaptive suite, these studies suggest that the species were adaptively distinct from each other. However, current approaches to understanding craniodental morphology do not present a clear picture of how these speciesspecific adaptations differ. It is also not clear whether all aspects of morphology that have been attributed to adaptation are indeed adaptive, rather than the products of non-adaptive processes. This study examines variation across the three known Paranthropus taxa (P. aethiopicus, P. boisei and P. robustus; N=39) using an approach that tests for adaptive morphology against a null hypothesis of random change (i.e. drift). Extant species (Homo sapiens (N=150), Gorilla gorilla (N=150), Pan troglodytes (N=143) act as analogues for Paranthropus variance/covariance (V/CV). Results reveal a high magnitude of variation within and between species across mandibular and cranial regions, especially when including the P. robustus individuals DNH 7 & 8 from Drimolen. Drift cannot be rejected for the bulk of comparisons. Neutrality tests detect adaptive divergence between P. robustus and the other two species, but not between P. aethiopicus and P. boisei. Reconstructed selection vectors indicate that both positive and negative directional selection have driven diversification in mandibular and tooth dimensions and in the cranium, resulting in variable morphological responses including considerable evidence for correlated selection.
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license_str Not specified — see source repository
provenance_str_mv Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository
publishDate 2019
publishDateRange 2019
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spelling oai:open.uct.ac.za:11427/29651 Variation and the evolutionary drivers of diversity in the genus Paranthropus Hlazo, Nomawethu Ackermann, Rebecca Rogers Ritzman, Terrence Archaeology Craniodental robusticity in Paranthropus has led many researchers to posit that all the species in this genus share a common adaptation to a diet of hard foods. Recent research on craniodental morphology, microwear, biomechanics, and isotopes, by contrast, has suggested that substantial variation exists within the genus Paranthropus, both in terms of ecological niches occupied by the three recognized species within the genus and the amount of consumed hard and compliant foods. Rather than pointing to a common adaptive suite, these studies suggest that the species were adaptively distinct from each other. However, current approaches to understanding craniodental morphology do not present a clear picture of how these speciesspecific adaptations differ. It is also not clear whether all aspects of morphology that have been attributed to adaptation are indeed adaptive, rather than the products of non-adaptive processes. This study examines variation across the three known Paranthropus taxa (P. aethiopicus, P. boisei and P. robustus; N=39) using an approach that tests for adaptive morphology against a null hypothesis of random change (i.e. drift). Extant species (Homo sapiens (N=150), Gorilla gorilla (N=150), Pan troglodytes (N=143) act as analogues for Paranthropus variance/covariance (V/CV). Results reveal a high magnitude of variation within and between species across mandibular and cranial regions, especially when including the P. robustus individuals DNH 7 & 8 from Drimolen. Drift cannot be rejected for the bulk of comparisons. Neutrality tests detect adaptive divergence between P. robustus and the other two species, but not between P. aethiopicus and P. boisei. Reconstructed selection vectors indicate that both positive and negative directional selection have driven diversification in mandibular and tooth dimensions and in the cranium, resulting in variable morphological responses including considerable evidence for correlated selection. 2019-02-18T11:49:32Z 2019-02-18T11:49:32Z 2018 2019-02-13T07:24:45Z Master Thesis Masters MSc http://hdl.handle.net/11427/29651 eng application/pdf Department of Archaeology Faculty of Science University of Cape Town
spellingShingle Archaeology
Hlazo, Nomawethu
Variation and the evolutionary drivers of diversity in the genus Paranthropus
thesis_degree_str Master's
title Variation and the evolutionary drivers of diversity in the genus Paranthropus
title_full Variation and the evolutionary drivers of diversity in the genus Paranthropus
title_fullStr Variation and the evolutionary drivers of diversity in the genus Paranthropus
title_full_unstemmed Variation and the evolutionary drivers of diversity in the genus Paranthropus
title_short Variation and the evolutionary drivers of diversity in the genus Paranthropus
title_sort variation and the evolutionary drivers of diversity in the genus paranthropus
topic Archaeology
url http://hdl.handle.net/11427/29651
work_keys_str_mv AT hlazonomawethu variationandtheevolutionarydriversofdiversityinthegenusparanthropus