Department of Zoology and Wildlife Conservation

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Browsing Department of Zoology and Wildlife Conservation by Subject "Africa"

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    Bats are Not Birds – Different Responses to Human Land-use on a Tropical Mountain
    (2015-05) Bonitz, Maria H. B.; Ferger, Stefan W.; Gaese, Katrin B.; Tschapka, Marco; Howell, Kim; Kalko, Elisabeth K. V.
    Land-use intensification has consequences for biodiversity and ecosystem functioning, with various taxonomic groups differing widely in their sensitivity. As land-use intensification alters habitat structure and resource availability, both factors may contribute to explaining differences in animal species diversity. Within the local animal assemblages the flying vertebrates, bats and birds, provide important and partly complementary ecosystem functions. We tested how bats and birds respond to land-use intensification and compared abundance, species richness, and community composition across a land-use gradient including forest, traditional agroforests (home garden), coffee plantations and grasslands on Mount Kilimanjaro, Tanzania. Furthermore, we asked how sensitive different habitat and feeding guilds of bats and birds react to land-use intensification and the associated alterations in vegetation structure and food resource availability. In contrast to our expectations, land-use intensification had no negative effect on species richness and abundance of all birds and bats. However, some habitat and feeding guilds, in particular forest specialist and frugivorous birds, were highly sensitive to land-use intensification. Although the habitat guilds of both, birds and bats, depended on a certain degree of vegetation structure, total bat and bird abundance was mediated primarily by the availability of the respective food resources. Even though the highly structured southern slopes of Mount Kilimanjaro are able to maintain diverse bat and bird assemblages, the sensitivity of avian forest specialists against land-use intensification and the dependence of the bat and bird habitat guilds on a certain vegetation structure demonstrate that conservation plans should place special emphasis on these guilds.
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    A First Insight into the Barcodes for African Diplostomids (Digenea: Diplostomidae): Brain Parasites in Clarias Gariepinus(Siluriformes: Clariidae)
    (Elsevier, 2013) Chibwana, F. D.; Blasco-Costa, Isabel; Georgieva, Simona; Hosead, Kenneth M.; Nkwengulila, Gamba; Scholz, Tomáš; Kostadinova, Aneta
    Diplostomid trematodes comprise a large and diverse group of widespread digeneans whose larval stages are important parasitic pathogens that may exert serious impacts in wild and cultured freshwater fish. However, our understanding of their diversity remains incomplete especially in the tropics. Our study is the first application of a DNA-based approach to diplostomid diversity in the African continent by generating a database linking sequences for the mitochondrial cytochrome c oxidase subunit 1 (cox1) barcode region and ITS1-5.8S-ITS2 rRNA gene cluster for brain-infecting diplostomid metacercariae from the catfish Clarias gariepinus. Analyses of newly-generated partial cox1 sequences for 34 larval isolates of Tylodelphys spp. from Tanzania and Diplostomum spp. from Tanzania and Nigeria revealed three strongly supported reciprocally monophyletic lineages of Tylodelphys spp. and one of an unknown species of Diplostomum. The average intraspecific divergence for the cox1 sequences for each recognised novel lineage was distinctly lower compared with interspecific divergence (0.46–0.75% vs 11.7–14.8%). The phylogenetic hypotheses estimated from Bayesian inference and maximum likelihood analyses of ITS1-5.8S-ITS2 data exhibited congruent strong support for the cox1-derived lineages. Our study thus provides molecular-based evidence for the existence of three distinct brain-infecting species co-occurring in natural populations of C. gariepinus. Based on phylogenetic analyses, we re-allocated Diplostomum mashonense Beverley-Burton (1963) to the genus Tylodelphys as a new combination. We also generated cox1 and ITS1-5.8S-ITS2 sequences for an unknown species of Diplostomum from another African fish host, Synodontis nigrita.
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    A new species of Running Frog, (Kassina, Anura: Hyperoliidae) from Unguja Island, Zanzibar, Tanzania
    (2006-11) Msuya, Charles A.; Howell, Kim; Channing, Alan
    A new species of Kassina is described from Unguja Island, Zanzibar, East Africa. It is distinguished from other species in its genus by an advertisement call that is pulsed, frequency modulated, and with a longer duration than that of K. senegalensis or K. maculata, and its grey and white reticulated colour pattern. The gular strap, like that in K. senegalensis, is continuous with the thick, pleated skin of the vocal pouch, but unlike K. senegalensis, it is rounded and truncated posteriorly. In contrast, the gular gland of K. maculata is rounded and free at its posterior end. The finger and toe tips are not distinct disks, but are only very slightly rounded and truncated when viewed from above. In lateral view, the tips are noticeably flattened.
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    Persistence and stability of Eastern Afromontane forests: Evidence from brevicipitid frogs
    (2014-03) Loader, Simon; Ceccarelli, Fadia S.; Menegon, Michele; Howell, Kim; Kassahun, Roman; Mengistu, Abebe A.; Saber, Samy; Gebresenbet, Fikirte; de Sá, Rafael O.; Davenport, Tim R. B.; Larson, Joanna G.; Müller, Hendrik; Wilkinson, Mark; Gower, David
    AimThe persistence and stability of habitats through time are considered predictors of high levels of biodiversity in some environments. Long-term habitat persistence and stability may explain the species-rich, endemic forest fauna and flora of the Eastern Afromontane Biodiversity Region (EABR). Using complementary phylogenetic and biogeographical approaches, we examine evolutionary patterns in EABR brevicipitid frogs. Using these data, we test whether brevicipitid history reflects patterns of long-term forest persistence and/or stability across the EABR.LocationEast Africa.MethodsA dated phylogeny for brevicipitids was constructed using two nuclear and three mitochondrial markers. Alternative diversification models were used to determine signal for constant or varying net diversification rates. Using our dated tree, we identified areas of high phylogenetic diversity (PD), and inferred ancestral areas using likelihood and Bayesian approaches.ResultsBrevicipitids have a long history, with generic diversification among extant lineages pre-dating the Oligocene (> 33 Ma). Ancestral-area reconstructions indicate the presence of brevicipitids in the EABR since the Oligocene, and support a scenario of palaeoendemics surviving in EABR refugia. Ancestral-area reconstructions indicate that the central Eastern Arc Mountains (EAM) formed the initial centre of diversification of forest brevicipitids. Measures of PD show that diversity varies across the EABR but is highest in the EAM. Constant net diversification rate in brevicipitids is a significantly better fit than alternative, rate-variable models.Main conclusionsThe degree of persistence of forest habitats appears to be a contributing factor to the varying levels of diversity across the EABR in brevicipitids (and other organisms). In contrast to the Southern Highlands and Ethiopian Bale Mountains, the EAM stands out as an area that enabled the constant accumulation of brevicipitid species over a long period of time.
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    Phylogenetic relationships of African Microhylid frogs inferred from DNA sequences of mitochondrial 12S and 16S ribosomal rRNA genes. Org, Divers Evol 4:227-235
    (2004-12) Loader, Simon; Gower, David; Howell, Kim; Doggart, Nike; Rödel, Mark O.; Clarke, Barry T.; de Sá, Rafael O.; Cohen, Bernard L.; Wilkinson, Mark
    The phylogenetic relationships of microhylid frogs are poorly understood. The first molecular phylogeny for continental African microhylids is presented, including representatives of all subfamilies, six of the eight genera, and the enigmatic hemisotid Hemisus. Mitochondrial 12S and 16S rRNA sequence data were analysed using parsimony, likelihood and Bayesian methods. Analyses of the data are consistent with the monophyly of all sampled subfamilies and genera. Hemisus does not nest within either brevicipitines or non-brevicipitines. It is possibly the sister group to brevicipitines, in which case brevicipitines might not be microhylids. Phrynomantis and Hoplophryne potentially group with non-African, non-brevicipitine microhylids, in agreement with recent morphological and molecular data. Within brevicipitines, Breviceps is recovered as the sister group to a clade of Callulina+Spelaeophryne+Probreviceps. The relationships among the genera within this latter clade are unclear, being sensitive to the method of analysis. Optimal trees suggest the Probreviceps macrodactylus subspecies complex might be paraphyletic with respect to P. uluguruensis, corroborating preliminary morphological studies indicating that P. m. rungwensis may be a distinct species. P. m. loveridgei may be paraphyletic with respect to P. m. macrodactylus, though this is not strongly supported. Some biogeographic hypotheses are examined in light of these findings.
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    A remarkable young Scolecomorphus vittatus (Amphibia: Gymnophiona Scolecomorphidae) from the North Pare Mountains, Tanzania
    (2002-12) Loader, Simon; Wilkinson, Mark; Gower, David; Msuya, Charles A.
    A description is given of the external morphology of a single young caecilian (gymnophionan) amphibian from the North Pare Mountains, Tanzania, referable to Scolecomorphus vittatus (Boulenger, 1895). This is the smallest known free-living Scolecomorphus, and it is characterized by many remarkable features previously unrecorded for any life-history stage of any caecilian. The cheeks have conspicuous, posteroventrally divergent paraoral processes that border a concavity on the ventral surface of the snout. The mandibles are very flexible about their articulation with the cranium, and they have a broader curvature than the upper jaw. The dentition is heterogeneous, with adult-like monocusped teeth in single rows, but also some supernumerary teeth, some of which are bicornute. The posterior parts of the paraoral processes bear a small number of monocuspid teeth that lie outside, and project away from, the mouth. The nuchal region of the body bears a distinctive concavity on the underside of the throat, bordered by longitudinal ridges that terminate in fleshy nipples. All of these features are unknown in adult Scolecomorphus, and many are unique for caecilians, and they suggest a highly distinctive life-history stage. The discovery and description of this specimen adds substantially to the currently meagre information on the life history of scolecomorphids and of the diversity of caecilian reproductive biology. Two modes of viviparity in caecilians are identified, with S. vittatus resembling the caeciliid Geotrypetes in giving birth to small altricial young that seem to require extended post-parturition parental care.