A symmoriiform chondrichthyan braincase and the origin of chimaeroid fishes
- Coates, Michael I, Gess, Robert W, Finarelli, John A, Surname, Name - one for each creator, Criswell, Katharine E, Tietjen, Kristen
- Authors: Coates, Michael I , Gess, Robert W , Finarelli, John A , Surname, Name - one for each creator , Criswell, Katharine E , Tietjen, Kristen
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/72246 , vital:30021 , https://doi.org/10.1038/nature20806
- Description: Chimaeroid fishes (Holocephali) are one of the four principal divisions of modern gnathostomes (jawed vertebrates). Despite only 47 described living species1, chimaeroids are the focus of resurgent interest as potential archives of genomic data2 and for the unique perspective they provide on chondrichthyan and gnathostome ancestral conditions. Chimaeroids are also noteworthy for their highly derived body plan1,3,4. However, like other living groups with distinctive anatomies5, fossils have been of limited use in unravelling their evolutionary origin, as the earliest recognized examples already exhibit many of the specializations present in modern forms6,7. Here we report the results of a computed tomography analysis of Dwykaselachus, an enigmatic chondrichthyan braincase from the ~280 million year old Karoo sediments of South Africa8. Externally, the braincase is that of a symmoriid shark9,10,11,12,13and is by far the most complete uncrushed example yet discovered. Internally, the morphology exhibits otherwise characteristically chimaeroid specializations, including the otic labyrinth arrangement and the brain space configuration relative to exceptionally large orbits. These results have important implications for our view of modern chondrichthyan origins, add robust structure to the phylogeny of early crown group gnathostomes, reveal preconditions that suggest an initial morpho-functional basis for the derived chimaeroid cranium, and shed new light on the chondrichthyan response to the extinction at the end of the Devonian period.
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- Authors: Coates, Michael I , Gess, Robert W , Finarelli, John A , Surname, Name - one for each creator , Criswell, Katharine E , Tietjen, Kristen
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/72246 , vital:30021 , https://doi.org/10.1038/nature20806
- Description: Chimaeroid fishes (Holocephali) are one of the four principal divisions of modern gnathostomes (jawed vertebrates). Despite only 47 described living species1, chimaeroids are the focus of resurgent interest as potential archives of genomic data2 and for the unique perspective they provide on chondrichthyan and gnathostome ancestral conditions. Chimaeroids are also noteworthy for their highly derived body plan1,3,4. However, like other living groups with distinctive anatomies5, fossils have been of limited use in unravelling their evolutionary origin, as the earliest recognized examples already exhibit many of the specializations present in modern forms6,7. Here we report the results of a computed tomography analysis of Dwykaselachus, an enigmatic chondrichthyan braincase from the ~280 million year old Karoo sediments of South Africa8. Externally, the braincase is that of a symmoriid shark9,10,11,12,13and is by far the most complete uncrushed example yet discovered. Internally, the morphology exhibits otherwise characteristically chimaeroid specializations, including the otic labyrinth arrangement and the brain space configuration relative to exceptionally large orbits. These results have important implications for our view of modern chondrichthyan origins, add robust structure to the phylogeny of early crown group gnathostomes, reveal preconditions that suggest an initial morpho-functional basis for the derived chimaeroid cranium, and shed new light on the chondrichthyan response to the extinction at the end of the Devonian period.
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Colonised minds?: post-development theory and the desirability of development in Africa
- Authors: Matthews, Sally
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142213 , vital:38059 , DOI: 10.1080/01436597.2017.1279540
- Description: While post-development theory is very concerned with the ways in which development has impacted upon the countries of the Global South, there has been relatively little written on post-development theory from an African perspective. This paper identifies some of the ways in which post-development theory fails to adequately understand the African experience of development. In particular, I explore the difficulty that post-development theory confronts when faced with the continued desire on the part of many people in Africa for development.
- Full Text:
- Authors: Matthews, Sally
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142213 , vital:38059 , DOI: 10.1080/01436597.2017.1279540
- Description: While post-development theory is very concerned with the ways in which development has impacted upon the countries of the Global South, there has been relatively little written on post-development theory from an African perspective. This paper identifies some of the ways in which post-development theory fails to adequately understand the African experience of development. In particular, I explore the difficulty that post-development theory confronts when faced with the continued desire on the part of many people in Africa for development.
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Customary management as TURFs: social challenges and opportunities
- Authors: Aswani, Shankar
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145403 , vital:38435 , DOI: 10.5343/bms.2015.1084
- Description: There is a growing interest in working with customary management (CM) systems to effectively manage benthic resources and small-scale fisheries. The underlying notion is that CM institution as territorial use rights in fisheries (TURFs) can be sufficiently adaptive and dynamic to create the local incentives that are necessary for promoting sustainable fishing practices and marine conservation more generally in a given region. This paper reviews the social opportunities and challenges of working with CM systems as a form of TURF, particularly in Oceania. A key conclusion is that policy makers and managers not only need to recognize natural interconnectivity in any one marine space, but also consider the social interconnectivity of stakeholders that covers customary TURFs. Only by recognizing and working with the existing social networks that overlay any given marine territory can the operational principles of CM (as reviewed in this paper) be effectively deployed for achieving some kind of bioeconomic efficiency and creating an equitable rights-based fisheries management system.
- Full Text:
- Authors: Aswani, Shankar
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145403 , vital:38435 , DOI: 10.5343/bms.2015.1084
- Description: There is a growing interest in working with customary management (CM) systems to effectively manage benthic resources and small-scale fisheries. The underlying notion is that CM institution as territorial use rights in fisheries (TURFs) can be sufficiently adaptive and dynamic to create the local incentives that are necessary for promoting sustainable fishing practices and marine conservation more generally in a given region. This paper reviews the social opportunities and challenges of working with CM systems as a form of TURF, particularly in Oceania. A key conclusion is that policy makers and managers not only need to recognize natural interconnectivity in any one marine space, but also consider the social interconnectivity of stakeholders that covers customary TURFs. Only by recognizing and working with the existing social networks that overlay any given marine territory can the operational principles of CM (as reviewed in this paper) be effectively deployed for achieving some kind of bioeconomic efficiency and creating an equitable rights-based fisheries management system.
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Interrogating citizen journalism practices: a case study of Rhodes University’s Lindaba Ziyafika Project
- Nyathi, Sihle, Garman, Anthea
- Authors: Nyathi, Sihle , Garman, Anthea
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158915 , vital:40240 , https://doi.org/10.1080/23743670.2016.1259740
- Description: Several scholars have noted that citizen journalism in the West is essentially an online phenomenon, driven by the affordability of Internet technologies. In Africa, projects such as Ushahidi in Kenya have been enabled by platforms such as cell phones and social networks. Voices of Africa, based in southern Africa, publishes on the web only. Publishing on the Internet presumes a citizenry which is relatively well educated; has familiarity with, and access to, new media as a form of social communication; and is confident in their right to participate in newly developed public spheres – particularly those online.
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- Authors: Nyathi, Sihle , Garman, Anthea
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158915 , vital:40240 , https://doi.org/10.1080/23743670.2016.1259740
- Description: Several scholars have noted that citizen journalism in the West is essentially an online phenomenon, driven by the affordability of Internet technologies. In Africa, projects such as Ushahidi in Kenya have been enabled by platforms such as cell phones and social networks. Voices of Africa, based in southern Africa, publishes on the web only. Publishing on the Internet presumes a citizenry which is relatively well educated; has familiarity with, and access to, new media as a form of social communication; and is confident in their right to participate in newly developed public spheres – particularly those online.
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