2 results
New fossil sea turtle trackway morphotypes from the Pleistocene of South Africa highlight role of ichnology in turtle paleobiology
- Martin G. Lockley, Hayley C. Cawthra, Jan C. De Vynck, Charles W. Helm, Richard T. McCrea, Ronel Nel
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- Journal:
- Quaternary Research / Volume 92 / Issue 3 / November 2019
- Published online by Cambridge University Press:
- 23 August 2019, pp. 626-640
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- Article
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More than 130 late Pleistocene trackway sites from the coastal eolianites and beach deposits of the Cape south coast, South Africa, have previously mostly yielded tracks of large mammals and birds. However, two sites east of Still Bay, and a third near Garden Route National Park, yield distinctive trackways of hatchling sea turtles, made during the short posthatching (postemergence) interval when the trackmakers headed for the sea. One assemblage of approximately parallel trackways indicates smaller loggerhead turtle hatchlings, with alternating gaits, and contrasts with a wider trackway indicating a leatherback turtle hatchling. These are the world's first reports of fossil traces that document this brief “run-for the-sea” phenomenon. They help delineate late Pleistocene sea turtle breeding ranges and indicate climatic conditions along the Cape south coast. Ichnotaxonomically defined swim tracks of large adult sea turtles are known from a few Mesozoic sites. Likewise, walking and swim traces of terrestrial freshwater turtles are also known from the Mesozoic and Cenozoic. However, as no ichnotaxonomy exists for these diagnostic hatchling trails, we assign the trackways of the inferred loggerheads to the new ichnotaxon Australochelichnus agulhasii ichnogen. et ichnosp. nov., and the inferred leatherback trackway to Marinerichnus latus ichnogen. et ichnosp. nov.
3 - Open-coast sandy beaches and coastal dunes
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- By Thomas A. Schlacher, The University of the Sunshine Coast, Alan R. Jones, The Australian Museum, Jenifer E. Dugan, University of California, Santa Barbara, Michael A. Weston, Deakin University, Linda Harris, Nelson Mandela Metropolitan University, David S. Schoeman, The University of the Sunshine Coast, David M. Hubbard, University of California, Santa Barbara, Felicita Scapini, University of Florence, Ronel Nel, Nelson Mandela Metropolitan University, Mariano Lastra, University of Vigo, Anton McLachlan, University of Sydney, Charles H. Peterson, University of North Carolina
- Edited by Brooke Maslo, Rutgers University, New Jersey, Julie L. Lockwood, Rutgers University, New Jersey
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- Book:
- Coastal Conservation
- Published online:
- 05 June 2014
- Print publication:
- 27 March 2014, pp 37-94
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- Chapter
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Summary
Synopsis
Beaches and dunes of the open coast form one of the globe’s longest ecological interfaces, linking the oceans with the land. These systems are of great importance to society as prime sites for housing and recreation, buffers against storms, and providers of fisheries and mineral resources. By contrast, their unique ecological attributes and biodiversity are much less recognized. In this chapter, we provide a synthesis of the key ecological features and functions of beaches and dunes, outline the main elements of their faunal biodiversity, examine human threats and their biological consequences, and sketch some salient issues in management to achieve conservation of these unique ecosystems. It is apparent that the range of ecosystem goods and services is broad, but nutrient cycling, water filtration, and the provision of habitat and prey for a diverse range of animals are often the key ecological traits. Contrary to common perceptions, beaches and dunes contain a diverse and unique set of species, many of which are found nowhere else. In addition to the complement of highly adapted invertebrates, many wildlife species (e.g. birds, turtles, fishes) are dependent on beaches and dunes for nesting and feeding, and they use these habitats extensively. Human pressures on sandy shorelines and their biodiversity are numerous. Coastal squeeze is, however, the most pervasive, trapping beaches and their biota between the pressures of development from the terrestrial side and the consequences of climate change from the marine side. Beaches are also naturally malleable habitats whose interlinkages, including the exchange of organisms, with the abutting dunes and surf zones are essential to their functioning. Unfortunately, human actions intended to arrest the dynamics of beach habitats, such as seawalls and dune stabilizations, run counter to these natural dynamics and generally produce negative environmental outcomes. These present a set of formidable management challenges when the primary goal is to conserve intact ecosystems and biodiversity, calling for more systematic approaches in conservation design and implementation for beach and dune ecosystems.