- Title
- The contribution of silverfish (insecta: zygentoma) to Australian invertebrate biodiversity and endemism
- Creator
- Smith, Graeme
- Date
- 2018
- Type
- Text; Thesis; PhD
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/164489
- Identifier
- vital:13073
- Identifier
- https://library.federation.edu.au/record=b2758682
- Abstract
- Silverfish (Order Zygentoma) are quite abundant in Australia but have been largely overlooked. This thesis examines the biodiversity of the Australian fauna at the level of genus, describing at least one representative species from each named genus and some new genera. The endemism of the fauna is evaluated and likely zoogeographic origins proposed. Over 4000 specimens were examined, either collected by the author, borrowed from or examined within museum collections or supplied by organisations and individuals conducting fauna surveys. Twenty- seven new native species are described and two redescribed, bringing the number of named species recorded in Australia to 74. Five new genera are described and four additional genera recorded in Australia for the first time including autochthonous representatives of three subfamilies previously unrecognised as native to Australia (Acrotelsatinae, Lepismatinae and Coletiniinae). No representatives of the families Maindroniidae, Tricholepidiidae and Protrinemuridae were found. The subfamily Acrotelsatinae was redefined following a revision of the enigmatic genus Anisolepisma Paclt, 1967 with the unique structure of the thoracic sterna identified as diagnostic for the subfamily. Contrary to existing opinion, it is suggested that this is a fundamentally different and plesiomorphic character, rather than an apomorphic reduction of the free thoracic sterna. A monograph of the Australian Zygentoma is presented, including a summary of the biology of the order, a key to and diagnoses of the genera, as well as information on the known habitat and distribution of each genus and a discussion of their zoogeography. At the suprageneric level the fauna is less diverse than seen in other zoogeographic regions but appears to be rich in the number of species. The fauna displays a high degree of endemism with 91% of described species and 52% of the genera known only from Australia. Some genera appear to be ancient and probably represent a Pangean element in the Australian fauna. Others appear to have emerged in the late Jurassic when Africa was still joined to Gondwana, while some may have appeared in the Cretaceous or Palaeocene when Australia and South America were connected to Gondwana. More recent links with the Asian fauna are limited and there appears to be no widespread highly mobile global species other than the six introduced anthropophilic species. Maps of the worldwide distribution records extracted from the taxonomic literature are used to discuss the zoogeography of the subfamilies and tribes present in Australia. Molecular data using two mitochondrial genes (16S and COI) as well as a nuclear gene (28S) were compared with detailed morphological and morphometric analysis to examine populations initially determined as Heterolepisma sclerophylla or close to it. Distances of 0.9– 1.8% or greater in 28S, and 7.2–14% in COI were associated with morphologically distinct species. A southern Queensland population was found to be genetically, morphometrically and morphologically very distinct from those collected in NSW and was described as new (Heterolepisma sp. B). Six well-defined barcode clusters (“lineages”) were identified within the NSW populations, each with >4% divergence in COI sequences and each geographically restricted. Intracluster divergences are also large, and despite the well-supported phylogeny no clear “barcode gap” (distinction between intracluster and intercluster distances) was found for three of the six NSW populations. The 28S data distinguished only four of the six COI clusters from NSW with essentially no variation within each cluster. The 28S data generally aligned well with morphological evidence, clearly identifying Heterolepisma sp. B as a distinct species, and supporting also the description of Heterolepisma sp. A even though it only appears to differ from H. sclerophylla in the number of styli. Similar genetic distances are observed in 28S data for H. sclerophylla populations from North Nowra, Glenbrook/Burralow/Nattai and Megalong, however the Broulee and Wellington populations have identical 28S sequences. The low levels of variation in 28S sequences between NSW populations accord with the lack of unambiguous morphological differences.; Doctor of Philosophy
- Publisher
- Federation University Australia
- Rights
- Copyright Graeme Smith
- Rights
- Open Access
- Rights
- This metadata is freely available under a CCO license
- Subject
- Silverfish (Order Zygentoma); Australia; Biodiversity
- Full Text
- Thesis Supervisor
- Palmer, Grant
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