This is a new poster designed by the Devonian Ecosystems Project assistant curator Shawn Johnstone as part of the lab's ever growing exhibition portfolio. It explores the topic of the extinction events that decimated global biodiversity at the end of the Devonian Period, and in particular, the hypothesis that the expansion of forests in the Late Devonian was the background cause for the extinctions.
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The Albany Museum’s Earth Science Department (Devonian collection) recently had the honour of hosting Distinguished Professor Kate Trinajstic from Curtin University in Perth, Australia for the second time. Professor Trinajstic is renowned internationally for her expertise in placorderms (armour-plated fish), an extinct group believed to be ancestral to all other jawed vertebrates. She visited South Africa to co-supervise Ryan Nel’s PhD project on South African placoderms. Her previous visit to South Africa was in 2013, where she and Dr. Rob Gess collaborated on describing two arthrodire placoderm species from Waterloo Farm (redescription of Africanaspis doryssa and first description of Africanaspis edmountaini) which was published in 2017 in PLosONE. Prof Trinajstic's extensive experience with Late Devonian placoderm fish from the Gogo Formation in Western Australia, has proven invaluable in guiding Ryan’s research. The fossils from the Gogo Formation, which are three-dimensionally preserved in limestone nodules, originated in tropical reef communities. Prof Trinajstic describes the fossils from the Gogo Formation as being encased in bacterial biofilm or sticky mucus, which gradually replaces soft tissue with individual crystals of calcium apatite. This preservation method allows for the extraction and reconstruction of entire fossils with minimal interpretation, providing a wealth of detailed information. In contrast, the fossils from Waterloo Farm were formed in a different manner, being flattened and with often disarticulated remains scattered on black shale bedding surfaces. They were deposited in a sub-polar estuarine environment near the end of the Devonian Period, approximately 360 million years ago. Prof Trinajstic emphasizes the importance of lagerstätte like Waterloo Farm and the Gogo Formation, as they provide a more complete picture of past ecosystems and interactions between organisms.
During her visit, Prof Trinajstic gave a talk at the Rhodes University Zoology Department on some of her findings from the Gogo Formation. Her research has revealed insights into muscle anatomy, organ preservation, and even live birth in early vertebrates. by Ryan Nel |
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