Literaturdatenbank
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Daniels, S. R., Hofmeyr, M. D., Henen, B. T., & Baard, E. H. W. (2010). Systematics and phylogeography of a threatened tortoise, the speckled padloper. Animal Conservation, 13(3), 237–246.
Added by: Admin (28 Dec 2009 19:56:59 UTC) Last edited by: Beate Pfau (21 May 2010 18:21:24 UTC) |
| Resource type: Journal Article BibTeX citation key: Daniels2010 View all bibliographic details  |
Categories: General Keywords: Genetik = genetics, Homopus, Homopus signatus, Schildkröten = turtles + tortoises, Südafrika = Southern Africa, Systematik = taxonomy, Testudinidae Creators: Baard, Daniels, Henen, Hofmeyr Collection: Animal Conservation |
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| Abstract |
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Testudinidae This study investigated the systematics and phylogeography of a threatened tortoise of South Africa, the speckled padloper Homopus signatus. Sixty three specimens were collected from 17 localities that covered the distributional range of the two subspecies in western South Africa and a north-eastern population that was recently discovered near Pofadder. The Pofadder sample could not be assigned to either subspecies based on morphology. The samples were sequenced for two partial mtDNA fragments, nicotinamide adenine dinucleotide dehydrogenase component four and cytochrome b, which yielded ∼1.1 kb, while a subset of the samples were sequenced for a 390 bp nuclear DNA (nDNA) fragment of prolactin. Phylogenetic analyses of mtDNA using minimum evolution, maximum parsimony and Bayesian inferences supported the monophyly of H. signatus and revealed that the Pofadder specimen was basal in the topology and sister to the remainder. The phylogenetic analyses did not support the recognition of two subspecies; there was statistical support for a Homopus signatus signatus clade but Homopus signatus cafer was not monophyletic. The nDNA analysis showed no difference between the subspecies and placed the Pofadder sample distant but not distinct from H. s. signatus. The mtDNA and the nDNA data suggest that the subspecies are invalid taxonomic units. The structure of the mtDNA network corresponded to the geographical distribution of populations. The north-western populations formed one haplocluster, corresponding to H. s. signatus, whereas the south-western populations formed three haploclusters, corresponding to H. s. cafer. The Pofadder sample was unconnected to the network. The morphology of the northern and southern morphotypes probably reflects selection for crypsis on the different substrate types of the regions, granites and sedimentary rocks, respectively. These results highlight that subspecies designations should be authenticated by molecular techniques because morphological plasticity can obfuscate phylogenetic relationships. We consider the western H. signatus populations as one taxonomic unit and recommend wider sampling of the Pofadder locality to clarify the taxonomic status of this lineage.
Added by: Admin Last edited by: Beate Pfau |