Browsing by Author "Cotterill, Fenton P. D."
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- ItemConservation of protists : the Krauthugel pond in Austria(MDPI, 2013) Cotterill, Fenton P. D.; Augustin, Hannes; Medicus, Reinhard; Foissner, WilhelmAlthough constituting more than 100,000 described species, protists are virtually ignored within the arena of biodiversity conservation. One reason is the widespread belief that the majority of protists have cosmopolitan distributions, in contrast to the highly hetereogenous biogeography of the “mega-Metazoa”. However, modern research reveals that about one third of the known protists have restricted distributions, which endorses their conservation, at least in special cases. Here, we report what probably ranks as the first successful conservation intervention focused directly on known protist diversity. It is justified by unique species, type localities, and landscape maintenance as evidence for legislation. The protected habitat comprises an ephemeral pond, which is now a “Natural Monument” for ciliated protozoa. This wetland occupies a natural depression on the Krauthügel (“cabbage hill”) south of the fortress of Salzburg City. When filled, the claviform pond has a size of ~30 × 15 m and a depth rarely surpassing 30 cm. Water is present only for some days or weeks, depending on heavy and/or prolonged rain. The pond occupied an agricultural field where root and leafy vegetables were cultivated for possibly more than 200 years. In the 1960s, this area became a grassland utilized as an autumn pasture, but was abandoned in the 1990s. Repeated sampling between 1982 and 2012 recovered a total of at least 150 ciliate taxa, of which 121 were identified to species level. Eight species were new to science, and an additional 10 poorly known species were reinvestigated and neotypified with populations from the Krauthügel pond. Both endemism and type localities justify the argument that the “integrative approach” in biodiversity and conservation issues should include protists and micro-metazoans. We argue that Krauthügel holds a unique reference node for biodiversity inventories to obtain the baseline knowledge—which is the prerequisite to monitor ecosystem integrity—and detect and evaluate impacts of natural and anthropogenic disturbances.
- ItemDated plant phylogenies resolve neogene climate and landscape evolution in the Cape Floristic Region(Public Library of Science, 2015) Hoffmann, Vera; Verboom, G. Anthony; Cotterill, Fenton P. D.In the context of molecularly-dated phylogenies, inferences informed by ancestral habitat reconstruction can yield valuable insights into the origins of biomes, palaeoenvironments and landforms. In this paper, we use dated phylogenies of 12 plant clades from the Cape Floristic Region (CFR) in southern Africa to test hypotheses of Neogene climatic and geomorphic evolution. Our combined dataset for the CFR strengthens and refines previous palaeoenvironmental reconstructions based on a sparse, mostly offshore fossil record. Our reconstructions show remarkable consistency across all 12 clades with regard to both the types of environments identified as ancestral, and the timing of shifts to alternative conditions. They reveal that Early Miocene land surfaces of the CFR were wetter than at present and were dominated by quartzitic substrata. These conditions continue to characterize the higher-elevation settings of the Cape Fold Belt, where they have fostered the persistence of ancient fynbos lineages. The Middle Miocene (13–17 Ma) saw the development of perennial to weakly-seasonal arid conditions, with the strongly seasonal rainfall regime of the west coast arising ~6.5–8 Ma. Although the Late Miocene may have seen some exposure of the underlying shale substrata, the present-day substrate diversity of the CFR lowlands was shaped by Pliocene-Pleistocene events. Particularly important was renewed erosion, following the post-African II uplift episode, and the reworking of sediments on the coastal platform as a consequence of marine transgressions and tectonic uplift. These changes facilitated adaptive radiations in some, but not all, lineages studied.
- ItemThe evolutionary history and taxonomy of the Kobus leche species complex of South-Central Africa in the context of palaeo-drainage dynamics(Stellenbosch : Stellenbosch University, 2006-12) Cotterill, Fenton P. D.; Matthee, Conrad A.; Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology.ENGLISH ABSTRACT: This multi-disciplinary study compiled taxonomic and biogeographical data to elucidate the extant diversity of lechwe antelopes (Kobus leche complex), and reconstruct their evolutionary history. Their diversification has been confined to wetlands across the south-central Africa plateaux. Lechwes are specialist grazers in water meadow floodplains; these stenotopic habitat requirements are invoked to explain why their evolution is atypical of terrestrial large mammals. Combined analyses of morphological (171 adult males), genetic (208 genotyped individuals) and palaeo-environmental datasets, revealed a recent (Middle Pleistocene) pulse of speciation in the K. leche complex. Multivariate morphometric analyses revealed the presence of five distinct groups that could be tied to the geography of the region. Furthermore, the genetic analyses supported the existence of at least four of these lineages, which show significant population separation at the level of the mtDNA control region. Most of the differences among populations were confined to frequency differences among populations and Bayesian analyses strongly suggest that the pattern obtained is the result of the retention of ancestral haplotypes with limited female geneflow among the extant populations. Evolution of the five lineages identified by the morphological and population genetic analyses were further investigated by making use of additional genetic data (mtDNA cyt b, SPTNB, SRY, Protamine 1, and b-Fibrinogen) and a subset of the samples. Topologies were largely unresolved due to the recent common ancestry of the lineages. Following the Evolutionary Species Concept, which was motivated by a philosophical review, five allopatric species could be recognized (anselli, kafuensis, leche, robertsi and smithemani). A model of drainage evolution compiled disparate facets of biological and geological evidence to detail interlinked histories of wetlands and their biota across the south-central Africa plateaux. This wetland archipelago is recognized as a distinct biogeographical unit in its own right - the Katanga-Chambeshi region. Evolutionary diversification of lechwes represents a dominant biogeographical signal reflecting how the aquatic biota have evolved in tandem with palaeo-drainage dynamics across this evolutionary theatre. Delimitation of key events in lechwe and drainage evolution was refined by archaeological dating of the Victoria Falls Formation, to decipher when the Zambezi river eroded the Batoka gorge. Demographic expansion in K. leche s.s (early Middle Pleistocene) corresponds to dessication of Palaeo-Lake Makakgadikgadi while more recent phylogeographic signals correspond to the tenure of Palaeo-Lake Bulozi. These speciation events in the Middle Pleistocene preceded peripatric speciation of K. kafuensis that accompanied the morphosis of the Kafue Flats (from palaeo-lake to floodplain), when the Kafue River attained its modern topology. The present study highlights that Lechwes represent a biota of evolutionary vibrant clades, rich in endemic species. As ecologically-dominant species in wetlands, lechwes deserve priority conservation attention, which is challenged to perpetuate evolutionary and ecological processes across an archipelago straddling five countries.
- ItemLake Tanganyika - a melting pot of ancient and young cichlid lineages (teleostei: cichlidae)?(Public Library of Science, 2015) Weiss, Juliane D.; Cotterill, Fenton P. D.; Schliewen, Ulrich K.A long history of research focused on the East Africa cichlid radiations (EAR) revealed discrepancies between mtDNA and nuclear phylogenies, suggesting that interspecific hybridisation may have been significant during the radiation of these fishes. The approximately 250 cichlid species of Lake Tanganyika have their roots in a monophyletic African cichlid assemblage, but controversies remain about the precise phylogenetic origin and placement of different lineages and consequently about L. Tanganyika colonization scenarios. 3312 AFLP loci and the mitochondrial ND2 gene were genotyped for 91 species representing almost all major lacustrine and riverine haplotilapiine east African cichlid lineages with a focus on L. Tanganyika endemics. Explicitly testing for the possibility of ancient hybridisation events, a comprehensive phylogenetic network hypothesis is proposed for the origin and diversification of L. Tanganyika cichlids. Inference of discordant phylogenetic signal strongly suggests that the genomes of two endemic L. Tanganyika tribes, Eretmodini and Tropheini, are composed of an ancient mixture of riverine and lacustrine lineages. For the first time a strong monophyly signal of all non-haplochromine mouthbrooding species endemic to L. Tanganyika (“ancient mouthbrooders”) was detected. Further, in the genomes of early diverging L. Tanganyika endemics Trematocarini, Bathybatini, Hemibatini and Boulengerochromis genetic components of other lineages belonging to the East African Radiation appear to be present. In combination with recent palaeo-geological results showing that tectonic activity in the L. Tanganyika region resulted in highly dynamic and heterogeneous landscape evolution over the Neogene and Pleistocene, the novel phylogenetic data render a single lacustrine basin as the geographical cradle of the endemic L. Tanganyika cichlid lineages unlikely. Instead a scenario of a pre-rift origin of several independent L. Tanganyika precursor lineages which diversified in ancient rivers and precursor lakes and then amalgamated in the extant L. Tanganyika basin is put forward as an alternative: the 'melting pot Tanganyika' hypothesis.
- ItemMammal taxonomy without taxonomists : a reply to Zachos and Lovari(Associazione Teriologica Italiana, 2013) Gippoliti, Spartaco; Cotterill, Fenton P. D.; Groves, Colin P.Ontological and epistemological properties of the Phylogenetic Species Concept (PSC) as applied in recent mammalian taxonomic works are redefined and defended against criticisms raised by Zachos and Lovari (2013), which we find inapplicable to taxonomy because they relate more to the field of population biology. We summarize the negative impacts of the polytypic species concept for conservation and evolutionary biology, with emphasis on Rhinocerotidae. The priority need to embrace and strengthen museum-based taxonomic research is emphasized.