45 results on '"Channing, Alan"'
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2. Disease driven extinction in the wild of the Kihansi spray toad, Nectophrynoides asperginis.
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Weldon, Ché, Channing, Alan, Misinzo, Gerald, and Cunningham, Andrew A
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HABITAT modification , *WILDLIFE reintroduction , *BATRACHOCHYTRIUM dendrobatidis , *TOADS , *HUMAN settlements , *HABITAT conservation , *AMPHIBIAN diseases - Abstract
The Kihansi spray toad, Nectophrynoides asperginis, became extinct in the wild despite population monitoring and conservation management of its habitat in the Kihansi gorge, Tanzania. Previous investigations have indicated human induced habitat modification, predators, pesticides and disease as possible causes of a rapid population decline and the species extirpation. Here, we systematically investigate the role of disease in the extinction event of the wild toad population. The amphibian chytrid fungus, Batrachochytrium dendrobatidis, was detected in spray toads that died during the extinction event and subsequently in other amphibian species in Kihansi Gorge and the adjacent Udagaji Gorge, but not in any toads collected prior to this. Following the population decline, the remaining spray toad population gradually disappeared over a nine-month period. We demonstrate how demographic (rare, low fecundity, high elevation species) and behavioural (congregate in high densities) attributes predisposed the spray toads to chytridiomycosis, as a result of B. dendrobatidis infections, and how epidemic disease could have been exacerbated by altered environmental conditions in the spray wetlands. Our results show that chytridiomycosis was the proximate cause of extinction in the wild of N. asperginis. This represents the first known case of extinction by disease of an amphibian species in Africa. Captive breeding programs, in both the US and Tanzania, have been introduced in order to ensure the survival of the species and a reintroduction program is underway. However, we caution that chytridiomycosis remains an existing threat, which requires a comprehensive mitigation strategy before the desired conservation outcome of an established population of repatriated toads can be achieved. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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3. The advertisement call and tadpole of the Ambangulu Puddle Frog (Phrynobatrachus ambanguluensis) (Anura: Phrynobatrachidae) from Tanzania.
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Channing, Alan
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ANURA , *TADPOLES , *FROGS - Abstract
The advertisement call, visual signalling, and tadpole of the recently described Phrynobatrachus ambanguluensis are described from the West Usambara Mountains, Tanzania. The call is a soft trill, similar but faster than the call of the sister species P. krefftii from the East Usambaras. Males have been observed flashing the bright yellow vocal sac without calling, which is the second reported non-vocal communication involving flashing the gular pouch in African frogs. The tadpole is generalised, identified by body shape and labial tooth row formula of 2(1)/4. [ABSTRACT FROM AUTHOR]
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- 2020
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4. Cryogenic silicification of microorganisms in hydrothermal fluids.
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Fox-Powell, Mark G., Channing, Alan, Applin, Daniel, Cloutis, Ed, Preston, Louisa J., and Cousins, Claire R.
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HYDROTHERMAL deposits , *METEOROLOGICAL precipitation , *ARCHAEBACTERIA , *TEMPERATURE measurements , *SALT , *MICROBIAL cells - Abstract
Silica-rich hydrothermal fluids that experience freezing temperatures precipitate cryogenic opal-A (COA) within ice-bound brine channels. We investigated cryogenic silicification as a novel preservation pathway for chemo- and photo-lithotrophic Bacteria and Archaea. We find that the co-partitioning of microbial cells and silica into brine channels causes microorganisms to become fossilised in COA. Rod- and coccoidal-form Bacteria and Archaea produce numerous cell casts on COA particle surfaces, while Chloroflexus filaments are preserved inside particle interiors. COA particles precipitated from natural Icelandic hot spring fluids possess similar biomorphic casts, including those containing intact microbial cells. Biomolecules and inorganic metabolic products are also captured by COA precipitation, and are detectable with a combination of visible – shortwave infrared reflectance, FTIR, and Raman spectroscopy. We identify cryogenic silicification as a newly described mechanism by which microbial biosignatures can be preserved within silica-rich hydrothermal environments. This work has implications for the interpretation of biosignatures in relic hydrothermal settings, and for life-detection on Mars and Enceladus, where opaline silica indicative of hydrothermal activity has been detected, and freezing surface conditions predominate. [ABSTRACT FROM AUTHOR]
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- 2018
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5. A review of active hot-spring analogues of Rhynie: environments, habitats and ecosystems.
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Channing, Alan
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HOT springs , *ECOSYSTEMS , *SILICA , *HABITATS , *LOW temperatures , *WETLANDS - Abstract
The Lower Devonian Rhynie chert formed as silica sinter entombed an early terrestrial ecosystem. Silica sinter precipitates only from water flowing from alkali-chloride hot springs and geysers, the surface expression of crustalscale geothermal systems that form low-sulfidation mineral deposits in the shallowsubsurface. Active alkali-chloride hot springs at Yellowstone National Park create a suite of geothermally influenced environments; vent pools, sinter aprons, run-off streams, supra-apron terrace pools and geothermal wetlands that are habitats for modern hot-spring ecosystems. The plant-rich chert, which makes Rhynie internationally famous, probably formed in lowtemperature environments at the margins of a sinter apron where frequent flooding by geothermal water and less frequent flooding by river waters created ephemeral to permanent wetland conditions. Here, the plants and associated microbes and animals would be immersed in waters with elevated temperature, brackish salinity, high pH and a cocktail of phytotoxic elements which created stresses that the fossil ecosystem must have tolerated. The environment excluded coeval mesophytic plants, creating a low-diversity hot-spring flora. Comparison with Yellowstone suggests the Rhynie plants were preadapted to their environment by life in more common and widespread environments with elevated salinity and pH such as coastal marshes, salt lakes, estuaries and saline seeps. [ABSTRACT FROM AUTHOR]
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- 2018
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6. Three new species of Arthroleptella Hewitt, 1926 (Anura: Pyxicephalidae) from the Cape Fold Mountains, South Africa.
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Turner, Andrew and Channing, Alan
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ANIMAL species , *MOLECULAR biology , *ANURA - Abstract
A comprehensive survey of the Cape Fold Mountains, South Africa, was undertaken for moss frogs of the genusArthroleptella. Advertisement calls were recorded and voucher specimens collected for all populations encountered. A molecular phylogeny was constructed for the entire genus using two mitochondrial and one nuclear marker. Standard morphological measurements were made and salient morphological characters described. Analysis of these data revealed the presence of three undescribed species: two that were previously obscured underArthroleptella bicolorand one obscured underA. landdrosiaare described herein. The advertisement calls of the three new species are described and contrasted with the calls of otherArthroleptellaspecies. Their distribution is described and spatial extent of occurrence quantified along with a brief discussion of conservation status for each species. ZooBank.—Arthroleptella draconella: urn:lsid:zoobank.org:act:341BABC2-63A8-4C60-A306-D232E92ECE69 Arthroleptella atermina: urn:lsid:zoobank.org:act:AC23D804-3075-40DB-9852-624C32A51547 Arthroleptella kogelbergensis: urn:lsid:zoobank.org:act:AA573B06-BA81-4B84-B436-5F5CCDF1D892. [ABSTRACT FROM AUTHOR]
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- 2017
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7. The larva of Schismaderma carens (Smith, 1849) (Anura: Bufonidae) - a redescription.
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Viertel, Bruno and Channing, Alan
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TADPOLES , *BUFONIDAE , *FROG morphology , *RESPIRATORY organ physiology , *BIOMETRY , *PHYSIOLOGY - Abstract
We describe the outer morphology of Schismaderma carens larvae in greater detail than previous studies, with special attention to the histology of the unusual head fold in this taxa. The oral cavity is described for the first time. External morphology, including the oral disc (LTRF 2/3), overall shape, biometrical indices, oral cavity morphology, and the filter apparatus confirm that Schismaderma carens is a generalized filter-feeding tadpole, not very different from most toad tadpoles of the world. Internally some papillae around the choanae appear taller and fused than in common toad tadpoles, but their function is unclear. The dorsal horseshoe-shaped head fold is an integumental expansion, rich in blood vessels and surrounded by a thin epithelium consistent with it serving a respiratory function. Its role is interpreted as an additional gas exchange site allowing the utilization of alpha-mesosaprobic and polysaprobic waters. [ABSTRACT FROM AUTHOR]
- Published
- 2016
8. Wetland megabias: ecological and ecophysiological filtering dominates the fossil record of hot spring floras.
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Channing, Alan, Edwards, Dianne, and Orr, Patrick
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ECOPHYSIOLOGY , *HOT springs , *WETLAND biodiversity , *FRED (Information retrieval system) , *FOREST ecology , *SULFIDATION , *SURFACE of the earth - Abstract
Siliceous hot spring deposits form at Earth's surface above terrestrial hydrothermal systems, which create low-sulphidation epithermal mineral deposits deeper in the crust. Eruption of hot spring waters and precipitation of opal- A create sinter apron complexes and areas of geothermally influenced wetland. These provide habitat for higher plants that may be preserved in situ, by encrustation of their surfaces and permineralization of tissues, creating T0 plant assemblages. In this study, we review the fossil record of hot spring floras from subfossil examples forming in active hot spring areas, via fossil examples from the Cenozoic, Mesozoic and Palaeozoic to the oldest known hot spring flora, the Lower Devonian Rhynie chert. We demonstrate that the well-known megabias towards wetland plant preservation extends to hot spring floras. We highlight that the record of hot spring floras is dominated by plants preserved in situ by permineralization on geothermally influenced wetlands. Angiosperms (members of the Cyperaceae and Restionaceae) dominate Cenozoic floras. Equisetum and gleicheniaceous ferns colonized Mesozoic ( Jurassic) geothermal wetlands and sphenophytes and herbaceous lycophytes late Palaeozoic examples. Evidence of the partitioning of wetland hydrophytic and dryland mesophytic communities, a feature of active geothermal areas, is provided by well-preserved and well-exposed fossil sinter apron complexes, which record flooding of dryland environments by thermal waters and decline of local forest ecosystems. Such observations from the fossil record back-up hypotheses based on active hot springs and vegetation that suggest removal of taphonomic filtering in hot spring environments is accompanied by an increase in ecological and ecophysiological filtering. To this end we also demonstrate that in the hot spring environment, the wetland bias extends beyond broad ecology. We show that ecosystems preserved from the Cenozoic to the Mesozoic provide clear evidence that the dominant plants preserved in situ by hot spring activity are also halophytic, tolerant of high p H and high concentrations of heavy metals. By extension, we hypothesize that this is also the case in Palaeozoic hot spring settings and extended to the early land plant flora of the Rhynie chert. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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9. Distribution and conservation status of the desert rain frog Breviceps macrops.
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Channing, Alan and Wahlberg, Kirsty
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FROG ecology , *MINES & mineral resources , *ZOOLOGICAL specimens , *HOUSING development , *SAND dunes , *HOUSING & the environment - Abstract
The desert rain frog, Breviceps macrops, is found along the greater Namaqualand coast, an area of acute conservation concern. We reconstruct the distribution of this species from museum specimens to the north and quantitative surveys in the south. In addition, a small (0.6 ha) study site near McDougall's Bay was searched on eight visits, each between two and seven nights long, between October 2002 and September 2007. The unique dorsal patterns of frogs were used as ‘marks’. Recaptured animals moved between 0 and 380 m (mean±SD = 29±73 m, n=26). The highest counts in September 2006 of 66 adults and 39 juveniles show the population at a density of 110 adults ha−1. Voucher specimens held in museum collections were examined, and demonstrate the northernmost locality in Lüderitz, Namibia, with all 11 localities in white sandy habitat where coastal fog exceeds 100 days per year. The most southerly record from active searches was just south of Kleinzee in South Africa. A new threat to this species is housing development in prime coastal sand dunes. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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10. EQUISETUM THERMALE SP. NOV. (EQUISETALES) FROM THE JURASSIC SAN AGUSTÍN HOT SPRING DEPOSIT, PATAGONIA: ANATOMY, PALEOECOLOGY, AND INFERRED PALEOECOPHYSIOLOGY.
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CHANNING, ALAN, ZAMUNER, ALBA, EDWARDS, DIANNE, and GUIDO, DIEGO
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EQUISETUM , *EQUISETALES , *GEOTHERMAL ecology , *WETLAND ecology , *PALEOECOLOGY - Abstract
• Premise of the study: Dated molecular phylogenies suggest a Cenozoic origin for the crown group of Equisetum. but compression fossil equisetaleans that are morphologically indistinguishable from extant Equisetum and recently discovered anatomically preserved examples strongly suggest an earlier Mesozoic initial diversification. • Methods: In situ samples of Equisetum thermale sp. nov. from the Upper Jurassic San Agustin hot spring deposit were collected and studied with the use of polished blocks, thin sections, and light microscopy. • Key results: Equisetum thermale exhibits all the morphological and anatomical characteristics of the extant crown group Equisetum. It shows a mixture of features present in the two extant subgenera, e.g., superficial stomata typical of subgenus Equisetum allied with infrequently ramifying stems typical of subgenus Hippochaete. This appears to ally E. thenrude with the least derived extant species in the genus Equisetum bogotense (sister species to the two subgenera), its association of hydromorphic and xeromorphic characters allowed it to grow as an emergent aquatic in physically and chemically stressed geothermally influenced wetlands, where it formed dense monospecific stands. Equisetum thermale, because it is preserved in situ with intact anatomy, provides clear paleoecological, biological, plus inferred paleoecophysiological evidence of adaptations known in extant species. • Conclusions: As the earliest unequivocal member of the genus, E. thermale supports the hypothesis of a Mesozoic origin. Its interred tolerance of a similar range of stresses (e.g., high salinity, alkalinity, and heavy metal concentrations) to that seen in extant Equisetum suggests early evolution and subsequent maintenance of ecophysiological innovations in the genus. [ABSTRACT FROM AUTHOR]
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- 2011
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11. Life, death and fossilization on Gran Canaria – implications for Macaronesian biogeography and molecular dating.
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Anderson, Cajsa Lisa, Channing, Alan, and Zamuner, Alba B.
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FOSSILIZATION , *GEOCHRONOMETRY , *BIOGEOGRAPHY ,GRAN Canaria (Canary Islands) - Abstract
The Canaries have recently served as a test-bed island system for evaluating newly developed parametric biogeographical methods that can incorporate information from molecular phylogenetic dating and ages of geological events. To use such information successfully, knowledge of geological history and the fossil record is essential. Studies presenting phylogenetic datings of plant groups on oceanic islands often through necessity, but perhaps inappropriately, use the geological age of the oldest island in an archipelago as a maximum-age constraint for earliest possible introductions. Recently published papers suggest that there is little chance of informative fossil floras being found on volcanic islands, and that nothing could survive violent periods of volcanic activity. One such example is the Roque Nublo period in Gran Canaria, which is assumed to have caused the extinction of the flora of the island ( c. 5.3–3.7 Ma). However, recent investigations of Gran Canaria have identified numerous volcanic and sedimentological settings where plant remains are common. We argue, based on evidence from the Miocene–Pliocene rock and fossil records, that complete sterilization of the island is implausible. Moreover, based on fossil evidence, we conclude that the typical ecosystems of the Canary Islands, such as the laurisilva, the Pinus forest and the thermophilous scrubland, were already present on Gran Canaria during the Miocene–Pliocene. The fossil record we present provides new information, which may be used as age constraints in phylogenetic datings, in addition to or instead of the less reliable ages of island emergences or catastrophic events. We also suggest island environments that are likely to yield further fossil localities. Finally, we briefly review further examples of fossil floras of Macaronesia. [ABSTRACT FROM AUTHOR]
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- 2009
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12. Yellowstone hot spring environments and the palaeo-ecophysiology of Rhynie chert plants: towards a synthesis.
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Channing, Alan and Edwards, Dianne
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ECOPHYSIOLOGY , *PLANTS , *ANIMALS , *MICROORGANISMS , *ECOSYSTEM management , *HABITATS - Abstract
Background: The Rhynie chert, Aberdeenshire, encapsulates the ecophysiological and anatomical information on all components, including plants, animals and micro-organisms, of an early terrestrial ecosystem as it existed some 400 million years ago (Early Devonian), as preserved by siliceous waters emanating from a hot spring system. Aims: This paper concentrates on the higher plants (tracheophytes) and brings together information on the habitats of the plants and the environmental pressures that they endured to answer issues relating to their endemism and their ecophysiology. Methods & Results: The synthesis includes detailed information on the palaeo-environments recorded in the chert, plus anatomical and autecological data from the plants themselves, and makes comparisons with the abiotic and biotic data obtained from an extant analogue, the alkali-chloride geothermal systems at Yellowstone National Park. Particular attention is paid to the physiological basis and evolution of osmotic and chemical tolerance of halophytes, the dominant colonisers of Yellowstone's wetlands and, to a lesser extent, metallophytes. Conclusions: The Rhynie plants colonised wetlands at the low temperature fringes of a hot spring system and were versatile, but physiologically highly specialised, capable of withstanding osmotic and chemical stresses in a dynamic environment, but were probably out-competed by mesophytic vegetation elsewhere. [ABSTRACT FROM AUTHOR]
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- 2009
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13. Cryogenic opal-A deposition from Yellowstone hot springs
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Channing, Alan and Butler, Ian B.
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WATER springs , *GEOTHERMAL resources , *SILICON compounds , *EARTH sciences - Abstract
Abstract: Sub-zero winter temperatures on the Yellowstone Plateau alter the opal-A precipitation pathway of fluid erupting from hot springs and geysers. Frozen fluid, often only meters from boiling pools, contains abundant opal-A particles, comprising sheet and filament-like aggregations of opal-A microspheres which are formed by opal-A precipitation in brine pockets, channels and veins by natural cryogelling. Unconsolidated cryogenic opal-A sediment accumulates in and below water-ice where it is locked until spring thaw conditions. Sediment is then either remobilized, contributing large volumes of opal-A particulate to geothermally influenced wetlands, or becomes adhered, in situ, by dehydration and cementation. This strongly seasonal opal-A precipitation regime has been overlooked in investigations of sinter deposition, accretion rates and microbe/mineral interactions. Natural opal-A textures recorded from Yellowstone may be replicated simply by freezing and thawing synthetic silica–salt solution in the laboratory. Cryogenic process may have influenced mineral precipitation and sediment accumulation in many other geothermal areas. Particularly, active terrestrial springs located at high altitude/latitude, fossil systems influenced by ancient glaciations, plus potential astrobiological targets e.g. Mars and Europa. [Copyright &y& Elsevier]
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- 2007
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14. A new Middle-Late Jurassic flora and hot spring chert deposit from the Deseado Massif, Santa Cruz province, Argentina.
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Channing, Alan, Zamuner, Alba B., and Zúñiga, Adolfo
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JASPEROID , *VOLCANIC ash, tuff, etc. , *VOLCANISM , *GEODYNAMICS , *JURASSIC stratigraphic geology - Abstract
We present an initial report of a well-preserved and relatively diverse Gondwanan plant assemblage from Bahia Laura Group, Chon Aike Formation strata of the Estancia Flecha Negra area, central-western region of the Deseado Massif, Santa Cruz province, Patagonia, Argentina. The locality contains the first richly fossiliferous chert with a diverse and well-preserved plant assemblage reported from the Mesozoic which is demonstrably associated with hot spring activity. A compression flora and petrified forest contained in associated clastic and volcaniclastic environments provide an indication of regional plant diversity during this as yet poorly represented stratigraphic interval. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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15. A new species of Phrynobatrachus (Anura: Ranidae) from Tanzania.
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Crutsinger, Greg, Channing, Alan, Pickersgill, Martin, and Moyer, David
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FROGS , *TAXONOMY , *BIOLOGICAL classification , *AMPHIBIANS - Abstract
A new species of puddle frog in the genus Phrynobatrachus (Ranidae) is described from central Tanzania. It is compared to all other East African species and found to be most similar to P. natalensis. The distinctive features of this species include the male advertisement call, visible tympanum, snout-vent length, and the lack of digital discs. [ABSTRACT FROM AUTHOR]
- Published
- 2004
16. Cryptic species of sharp-nosed reed frogs in the Hyperolius nasutus complex: advertisement call differences.
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Channing, Alan, Moyer, David, and Burger, Marius
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HYPEROLIUS , *ANIMAL calls , *ANIMAL classification - Abstract
Discusses the problems of assigning species labels to taxa in the group of cryptic species of sharp-nosed reed frogs found in localities in the western to southern parts of Africa. Analysis of the three groups of calls associated with cryptic species; Comparison of advertisement and aggression call parameters of three species; Recommendations for a revised taxonomy of the group.
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- 2002
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17. A Molecular Phylogeny of the Frog Genus Tomopterna in Southern Africa: Examining Species Boundaries with Mitochondrial 12S rRNA Sequence Data
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Dawood, Abeda, Channing, Alan, and Bogart, James P.
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FROGS , *PHYLOGENY - Abstract
Frogs of the genus Tomopterna occur throughout sub-Saharan Africa. Previous work has shown that there are seven cryptic species, which occupy diverse habitats from grasslands to deserts. The current paper proposes a phylogeny of Tomopterna based on partial sequences of the mitochondrial 12S rRNA gene. A gene tree for the genus, including all seven named species and three undescribed species which were discovered during the course of this study, is presented. [Copyright &y& Elsevier]
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- 2002
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18. The Advertisement call, breeding biology, description of the tadpole and taxonomic status of Bufo d.
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Channing, Alan and Vences, Miguel
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TOADS , *TADPOLES - Abstract
Focuses on a study on the advertisement call, breeding biology, description of the tadpole and taxonomic status of Bufo dombensis dwarf toad at Ongongo Waterfall, Namibia. Methodology of the study; Results and discussion; Conclusion.
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- 1999
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19. Description of the tadpole of Amietia wittei (Anura: Pyxicephalidae) from the highlands of Kenya.
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Wasonga, Domnick Victor and Channing, Alan
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TADPOLES , *ANURA , *FROGS , *UPLANDS - Abstract
The tadpole of Amietia wittei (Anura: Pyxicephalidae) is described from the highlands of Kenya. It is distinguished from the tadpoles of Amietia ruwenzoriensis and A. angolensis in the region by the numbers of labial tooth rows. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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20. A new bullfrog from southern Africa (Pyxicephalidae, Pyxicephalus Tschudi, 1838).
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du Preez, Louis H, Netherlands, Edward C, Rödel, Mark-Oliver, and Channing, Alan
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BULLFROG , *MIDDLE ear , *DNA sequencing - Abstract
Four species of African bullfrogs are currently recognised. We describe a new species from southern Africa, which can be distinguished on the basis of morphology, advertisement call and DNA sequences. Morphologically it differs from other bullfrogs by a combination of characteristics including a tympanum that is smaller or equal in size to the eye, and smaller in diameter than the space between eye and tympanum, presence of a white dot on the tympanum, longitudinal skin ridges with speckling between dorsal mottles, pale vertebral line usually present, absence of cream coloured lateral stripes, absence of a pale interorbital-bar, upper jaw-barring absent or faint. It has been confirmed from north-eastern Namibia, southern Angola and north-western Botswana. Three further undescribed species are recognised but not formally named, pending further investigation. We confirm the genetic distinctiveness of P. angusticeps. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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21. The role of cultural norms in shaping attitudes towards amphibians in Cape Town, South Africa.
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Brom, Peta, Anderson, Pippin, Channing, Alan, and Underhill, Leslie G.
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WILDLIFE conservation , *CHILDHOOD attitudes , *AMPHIBIANS , *SOCIAL processes , *ENVIRONMENTAL education - Abstract
Urban ecosystems are increasingly viewed as an important component within strategies for wildlife conservation but are shaped as much by natural systems as they are by social and political processes. At the garden scale, attitudes and preferences govern design and maintenance choices including the decision to encourage or discourage specific faunal presence. At the global scale, charismatic taxa that are well-liked attract more conservation funding and volunteer stewardship. Amphibians are a class of animals that are both loved and loathed making them a suitable subject for comparing and unpacking the drivers of preference and attitudes towards animals. We conducted a mixed methods survey of 192 participants in three adjacent neighbourhoods in Cape Town, South Africa. The survey included both quantitative and qualitative questions which were analysed thematically and used to explain the quantitative results. The results revealed that attitudes formed during childhood tended to be retained into adulthood, were shaped by cultural norms, childhood experiences and the attitudes of primary care-givers. The findings are significant for environmental education programmes aimed at building connectedness to nature and biophilic values. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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22. Re-evaluation of the status of Bufo vertebralis grindleyi and Bufo jordani (Anura: Bufonidae).
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Rödel, Mark-Oliver, Becker, François S., Buiswalelo, Bertha, Conradie, Werner, and Channing, Alan
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BUFONIDAE , *BIOLOGICAL classification , *ANURA , *SYNONYMS , *MORPHOLOGY , *AMPHIBIANS - Abstract
We use mitochondrial and nuclear gene sequences and morphology to re-evaluate the taxonomy of Bufo vertebralis grindleyi Poynton, 1963, currently a junior synonym of Poyntonophrynus fenoulheti (Hewitt & Methuen, 1912); and morphology and advertisement calls to re-evaluate the status of Bufo jordani Parker, 1936, currently a junior synonym of Poyntonophrynus hoeschi (Ahl, 1934). According to our results including comparisons to other congeners, we elevate both taxa to full species as Poyntonophrynus grindleyi (Poynton, 1963) and Poyntonophrynus jordani (Parker, 1936). Our new P. grindleyi record is the first record of the species for Mozambique. [ABSTRACT FROM AUTHOR]
- Published
- 2023
23. Chromosomes in the African frog genus Tomopterna (Pyxicephalidae) and probing the origin of tetraploid Tomopterna tandyi.
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Bogart, James P., Dawood, Abeda, Becker, François S., and Channing, Alan
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CHROMOSOMES , *POLYPLOIDY , *BIOLOGICAL classification , *KARYOTYPES , *SPECIES hybridization , *BIOLOGICAL evolution , *GLUCOSE-6-phosphate dehydrogenase , *MALATE dehydrogenase ,REPRODUCTIVE isolation - Abstract
The article probes the origin of tetraploid Tomopterna tandyi and tests the hypothesis that T. tandyi is an allotetraploid species based on the revised taxonomy and chromosomes in the African frog genus Tomopterna (Pyxicephalidae). The summary distinguished tetraploid Tomoptera from diploids by counting the chromosomes and analyzed rRNA sequences for all the Tomoptera species. It determined haplotype networks for gene fragments, divergence ages, isozymes and Tomoptera advertisement calls.
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- 2022
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24. EVOLUTION OF THE MOSS FROGS (GENUS ARTHROLEPTELLA): FROM GENES TO CONSERVATION.
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TURNER, Andrew and CHANNING, Alan
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FROGS , *WILDLIFE conservation , *VICARIANCE , *ANIMAL genetics , *PHYLOGENY - Abstract
The article discusses the unusual pattern of evolution of the moss frogs, under the genus Arthroleptella, which complicates the species' conservation management. The species general pattern of allopatry, spatial arrangement of genetic distribution and restricted gene flow are briefly described. However, it cites that the distribution and phylogenetic information it has retrieved from the study can be used in the identification of species and area of conservation priority.
- Published
- 2010
25. Thirty years of amphibian surveys in the Ukagurus Mountains of Tanzania reveal new species, yet others are in decline.
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Liedtke, H Christoph, Lyakurwa, John V, Lawson, Lucinda P, Menegon, Michele, Garrido-Priego, Marina, Mariaux, Jean, Ngalason, Wilirk, Channing, Alan, Owen, Nisha R, Bittencourt-Silva, Gabriela B, Wilkinson, Mark, Larson, Joanna G, Gvoždík, Václav, and Loader, Simon P
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AMPHIBIANS , *HERPETOLOGICAL surveys , *NUMBERS of species , *AMPHIBIAN populations , *SPECIES , *FOREST reserves , *HABITATS - Abstract
Records of biodiversity over time are important resources for assessing conservation priorities. However, such baseline data are missing for regions of key biodiversity importance. The Eastern Arc Mountains of Tanzania are known for their species richness and endemism, but not all mountain blocks have received the same attention. The Ukaguru Mountains, for example, have only infrequently been surveyed by herpetologists, with the first known herpetological survey in 1990. Here we compile and quantify all amphibian survey efforts in the Ukaguru Mountains in the past 30 years, publish an updated species list and comment on the health of amphibian populations and their habitat. We report on fourteen described species of amphibians, with potentially three additional species awaiting formal description. Of these seventeen lineages, seven are endemic to the Ukaguru Mountains. Although total species numbers remain low, compared with other Eastern Arc Mountains, surveys frequently recorded new species for the Ukaguru Mountains and for science. Worryingly, however, endemics, such as the monotypic bufonid Churamiti maridadi, have not been recorded in the past fifteen years. Our analyses show the region is becoming warmer and drier and is experiencing an alarming rate of deforestation. We find that over the past 30 years, dense forest cover inside the boundaries of the forest reserves has reduced by 8.4%. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
26. DNA sequencing resolves species of Spongites (Corallinales, Rhodophyta) in the Northeast Pacific and South Africa, including S. agulhensis sp. nov.
- Author
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VAN DER MERWE, ELIZABETH, MIKLASZ, KEVIN, CHANNING, ALAN, MANEVELDT, GAVIN W., and GABRIELSON, PAUL W.
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NUCLEOTIDE sequencing , *CORALLINE algae , *CLASSIFICATION of algae , *ALGAE , *PHYLOGENY , *ALGAE physiology - Abstract
DNA sequence data from a 296 base pair variable region of the plastid encoded rbcL gene was obtained from 19th century type material of Spongites decipiens and of Lithophyllum tumidum (=Pseudolithophyllum neofarlowii) and matched to field-collected material, confirming the application of these specific epithets in the northeast Pacific. Phylogenetic analyses of separate and concatenated rbcL and psbA gene sequences show that both species belong in Spongites. Based on DNA sequences, the distribution of S. decipiens is confirmed from Haida Gwaii, British Columbia, Canada, south to its type locality at San Pedro, Los Angeles County, California, whereas, Spongites tumidum is distributed from near Sitka, Alaska, to Monterey County, California. Sequence data from S. decipiens and South African specimens called Spongites yendoi confirm anatomical studies that these two species are distinct but that a previously undescribed, cryptic species, Spongites agulhensis, also is present in South Africa. Anatomically and morphologically S. agulhensis is very similar to both northeast Pacific 5. decipiens and South African 5. yendoi, differing from the former by a single anatomical character and from the latter by two anatomical characters. Anatomy, ecology and distributions are useful in separating the South African species of Spongites, as well as the northeast Pacific species. Sequence divergence values align with biogeographic patterns and not with anatomical similarities for these Spongites species. We question the practice of placing into synonymy geographically widely separated non-geniculate coralline algal species based solely on anatomical features that likely have resulted from convergent evolution. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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27. Jurassic geothermal landscapes and fossil ecosystems at San Agustín, Patagonia, Argentina.
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Guido, Diego M., Channing, Alan, Campbell, Kathleen A., and Zamuner, Alba
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JURASSIC stratigraphic geology , *GEOTHERMAL ecology , *BIOTIC communities - Abstract
An extensive, well-preserved, Late Jurassic (c. 150 Ma) geothermal system at San Agustín farm in the Deseado Massif, Patagonia, Argentina, is described. This deposit, along with others previously known from the same region, partially fills a considerable gap between Cenozoic and scattered Palaeozoic hot spring localities reported worldwide. The San Agustín deposit is novel because it represents a large (1.4 km2) and nearly complete geothermal landscape. Siliceous hot spring facies, both subaerial and subaqueous, are exposed side by side in their original spatial and geological context, set amongst intrusive rhyolite domes and fluviolacustrine sediments. The Jurassic hot springs have preserved an entire local ecosystem containing microbes, arthropods, gastropods and plants exhibiting Lagerstätten-style preservation. Plant preservation, in particular, ranges from decayed litter, to seedling sprouts, and to dense stands in life orientation with intact anatomy. The San Agustín deposit shares some ecological, taphonomic and sedimentological characteristics with modern hot springs. As it formed in a pre-angiosperm world, it is akin to the famous hot spring-related Devonian Rhynie cherts of Scotland. It differs in having excellent exposure, and thus will probably contribute to a better understanding of biosignal preservation in extreme environments in the geological record. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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- View/download PDF
28. Overseas dispersal of Hyperolius reed frogs from Central Africa to the oceanic islands of São Tomé and Príncipe.
- Author
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Bell, Rayna C., Drewes, Robert C., Channing, Alan, Gvoždík, Václav, Kielgast, Jos, Lötters, Stefan, Stuart, Bryan L., Zamudio, Kelly R., and Emerson, Brent
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HYPEROLIUS , *COLONIZATION (Ecology) , *ANIMAL dispersal , *PHYLOGEOGRAPHY , *AMPHIBIAN population genetics , *GEOGRAPHICAL distribution of amphibia - Abstract
Aim To infer the colonization history of reed frog species endemic to the oceanic islands of São Tomé and Príncipe, Hyperolius molleri and H. thomensis, we quantified phylogeographical structure in the closely related H. cinnamomeoventris species complex, which is broadly distributed across continental Central Africa. Location The Lower Guineo-Congolian Forest and the Gulf of Guinea islands of São Tomé and Príncipe, Central Africa. Methods We combined gene and species tree analyses to investigate diversity and divergence among H. cinnamomeoventris populations, to identify the most likely dispersal route to the islands, and to infer the order in which the islands were colonized. One of the endemics ( H. molleri) is distributed on both islands and we quantified genetic divergence between populations. Results We recovered three clades in H. cinnamomeoventris corresponding to West-Central, North/East-Central and South-Central Africa. The island endemics form a monophyletic group most closely related to the West-Central African H. cinnamomeoventris clade. Populations of H. molleri on São Tomé and Príncipe are reciprocally monophyletic at mitochondrial loci but nuclear gene trees do not support this divergence. Main conclusions Genetic structure in the H. cinnamomeoventris species complex coincides with biogeographical barriers identified in previous studies of Central African rain forest taxa. Individual gene tree and species tree analyses support a single dispersal event from the Ogooué or Congo river basins (West-Central Africa) to the island of São Tomé, with subsequent divergence within São Tomé and dispersal to Príncipe. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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29. Emily's Legacy.
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Channing, Alan, Ananth, Sita, and Thornell, Mike
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AUTHORS , *BEREAVEMENT , *EDITORS - Abstract
Several letters to the editor in response to the passing of contributing editor and healthcare teacher Emily Friedman are presented.
- Published
- 2016
30. Catching Up with Public Health.
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Baird, Kristin and Channing, Alan H.
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HEALTH attitudes , *PUBLIC health - Abstract
A letter to the editor is presented in response to the article "Before It's Too Late: Defending Public Health," by Emily Friedman in the April 5, 2016 issue.
- Published
- 2016
31. Systematics of `Little Brown Frogs' from East Africa: recognition of Phrynobatrachus scheffleri and description of a new species from the Kakamega Forest, Kenya (Amphibia: Phrynobatrachidae).
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Schick, Susanne, Zimkusz, Breda M., Channing, Alan, Köohler, Jorn, and Lötters, Stefan
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FROG physiology , *ANIMAL morphology , *ANIMAL species , *NUCLEOTIDE sequence , *FOURIER transforms , *MOLECULAR genetics , *POPULATION density , *ZOOLOGICAL specimens - Abstract
The article discusses a morphological study on the systematics of Phrynobatrachus scheffleri and P. kakamikro sp. n. which are frog species both found in East Africa. It says that the study used the specimens from museum collections and that morphological characters include snoutvent length (SVL), dorsal skin texture, and interorbital space (IO). It tells that DNA Sequence alignment was conducted and that frequency information was acquired via Fast Fourier Transformation. It explores the physical characteristics, the molecular genetics, and the distribution and life history of P. scheffleri and P. kakamikro sp. n.
- Published
- 2010
32. A New Species of Callulina (Anura: Microhylidae) from the West Usambara Mountains, Tanzania.
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De Sá, Rafael O., Loader, Simon P., and Channing, Alan
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LIZARDS , *SQUAMATA , *AMPHIBIANS , *HERPETOLOGY , *ZOOLOGY , *REPTILES , *AMPHIBIAN populations - Abstract
The description of the species Callulina kreffti was based on specimens collected in the East Usambara Mountains of Tanzania. Successive collecting has shown this species to be widely distributed through the Eastern Arc Mountains. Advertisement calls from populations in the type locality of Callulina kreffti were compared with calls from populations in the West Usambara Mountains. Analysis of the calls suggested that these two populations of Callulina represent two separate taxa. Subsequent morphological and molecular investigations indicated that these two populations are distinct. Herein, we describe a new Callulina species on the basis of call, morphology and molecular sequences. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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33. Phylogenetic relationships within the Hyperolius viridiflavus complex (Anura: Hyperoliidae), and comments on taxonomic status.
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Wieczorek, Ania M., Drewes, Robert C., and Channing, Alan
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HYPEROLIUS viridiflavus , *FROGS , *ANIMAL classification - Abstract
The taxonomy of the Hyperolius viridiflavus complex, a group of African frogs, has been problematic. Mitochondrial DNA sequence data were used to reconstruct the phylogenetic history of these frogs. The phylogeny showed that subspecies were grouped into clades, within which certain taxa were not supported by fixed characters. We used the phylogenetic species concept to identify the smallest monophyletic clades supported by at least one fixed character, and suggest taxonomic revisions based on our results. We identify ten species within the H. viridiflavus complex. [ABSTRACT FROM AUTHOR]
- Published
- 2001
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34. Biogeography and evolutionary history of Hyperolius species: application of molecular phylogeny.
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Wieczorek, Ania M., Drewes, Robert C., and Channing, Alan
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HYPEROLIUS , *EVOLUTIONARY theories , *PHYLOGENY - Abstract
Abstract Aim We propose a phylogeny of selected Hyperolius species (Anura: Hyperoliidae), based on mtDNA sequence data and parsimony analysis. This phylogeny was used to interpret the historical biogeography of the genus in Africa. Location Samples were collected throughout the distribution of Hyperolius in Africa. Methods We compiled distributional maps of all species, summarized historical changes in vegetation and climate in Africa since the late Cretaceous, and used these in combination to identify historical factors that may have contributed to speciation in these frogs. A phylogeny for Hyperolius was derived from mtDNA sequence data and interpreted in terms of climatic and vegetation changes in Africa. Main conclusions Lowland rainforest is proposed to have been the ancestral habitat of Hyperolius . The expansion of savannah and reduction of lowland rainforest were identified as important factors in the differentiation of the more basal species. Finally, the development of the Rift Valley system played an important role in the speciation of derived species with relatively limited distributions. [ABSTRACT FROM AUTHOR]
- Published
- 2000
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35. Species-specific or assemblage-wide decline? The case of Arthroleptides dutoiti Loveridge, 1935 and the amphibian assemblage of Mount Elgon, Kenya.
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Ngwava, Jacob M, Barratt, Christopher D, Boakes, Elizabeth, Bwong, Beryl A, Channing, Alan, Couchman, Olivia, Lötters, Stefan, Malonza, Patrick K, Muchai, Vincent, Nguku, Julius K, Nyamache, Joash, Owen, Nisha, Wasonga, Victor, and Loader, Simon P
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- *
BIOTIC communities , *ECOLOGICAL niche , *TWENTIETH century , *HABITATS , *FROGS , *EXTINCT animals , *ANURA , *WILDLIFE reintroduction - Abstract
The frog Arthroleptides dutoiti Loveridge, 1935, endemic to Mount Elgon, East Africa was last collected in 1962 and has not been observed since. The species is regarded as Critically Endangered by the IUCN Red List and is a priority species on the Zoological Society of London's EDGE (Evolutionarily Distinct, Globally Endangered) project, given its Red List status and phylogenetic distinctiveness. We analyse temporal patterns of abundance (1934–2014) of A. dutoiti and the remainder of the Mount Elgon amphibian assemblage to infer the probability of re-encountering A. dutoiti and assess whether declines are species specific to A. dutoiti, or whether they are assemblage-wide phenomena. Our results show that for localities where surveys have been repeatedly conducted, A. dutoiti is likely to be locally extinct. Declines are observed in other Mount Elgon amphibians, encompassing both specialists and generalists. Causal factors for declines are unknown, but habitat change might be important, given the high degree of forest loss in the area, especially since the turn of the 20th century. Urgent sampling of preferred microhabitats of A. dutoiti at the type locality and surrounding areas beyond those included in our study are required to determine whether or not the species is extinct. Impacts on other taxonomic groups would also be useful to understand so that it can be determined how broad the changes are for the Mount Elgon biota. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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36. A Model Asthma Program.
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Channing, Alan H.
- Subjects
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LETTERS to the editor , *ASTHMA treatment - Abstract
A letter to the editor is presented in response to the article "Hospitals Rethink Their Role in Asthma Care" which was published in the June 2009 issue of the magazine "H&HN."
- Published
- 2009
37. Chytrid Pathogen (Batrachochytrium dendrobatidis) in African Amphibians: A Continental Analysis of Occurrences and Modeling of Its Potential Distribution.
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Zimkus, Breda M., Baláž, Vojtech, Belasen, Anat M., Bell, Rayna C., Channing, Alan, Doumbia, Joseph, Fokam, Eric B., Gonwouo, LeGrand N., Greenbaum, Eli, Gvoždík, Václav, Hirschfeld, Mareike, Jackson, Kate, James, Timothy Y., Kusamba, Chifundera, Larson, Joanna G., Mavoungou, Lise-Bethy, Rödel, Mark-Oliver, Zassi-Boulou, Ange-Ghislain, and Penner, Johannes
- Subjects
- *
BATRACHOCHYTRIUM dendrobatidis , *AMPHIBIAN declines , *AMPHIBIANS , *PLANT-fungus relationships , *PATHOGENIC microorganisms - Abstract
The fungal pathogen Batrachochytrium dendrobatidis (Bd) is implicated in global declines of amphibian populations and has been documented in African specimens originally collected as far back as the 1930s. Numerous recent surveys focusing on regional pathogen prevalence have greatly increased the number of known occurrences of Bd in African species, but few studies have focused on continental distribution patterns. We analyzed all known positive occurrences of Bd in African amphibians to date, including newly reported data from Cameroon, the Democratic Republic of the Congo, Gabon, Namibia, and the Republic of the Congo. Records from both Namibia and the Republic of the Congo reported herein represent first positive occurrences for these countries. With this most comprehensive sampling of the African continent to date we identified patterns of Bd-positive occurrences associated with (1) location (i.e., biogeographic region, country), (2) taxonomy, (3) life history, and (4) threat of extinction. We used fine-grained (30 arc seconds) environmental niche models (ENMs) to predict the continental distribution of Bd and identify hotspots for the pathogen, including areas not previously modeled to have high suitability for the fungus, and areas of high amphibian biodiversity from which Bd has not yet been documented. Our ENMs predicted that the environmentally suitable range of Bd encompasses vast areas of high amphibian biodiversity, including the Congo Basin and the Albertine Rift. Although our ENMs indicated that West Africa is environmentally suitable for Bd, the fungus has not been reported west of the Dahomey Gap. Likewise, the ENMs also identified regions across the Congo Basin and coastal Angola that are environmentally suitable for the pathogen but from which Bd has not yet been reported, underscoring a need for Bd surveys in these regions. Although amphibian declines in Africa have not been directly attributed to chytridiomycosis, Bd has been detected in over one fifth of the most-threatened African amphibians. Given the presence of the hypervirulent Bd global panzootic lineage (BdGPL) in Africa, we believe that the threat of Bd as a novel pathogen may be underestimated and that focused research is urgently needed to identify which species are susceptible to Bd-driven declines. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
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38. Sexual Dichromatism Drives Diversification within a Major Radiation of African Amphibians.
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Portik, Daniel M, Bell, Rayna C, Blackburn, David C, Bauer, Aaron M, Barratt, Christopher D, Branch, William R, Burger, Marius, Channing, Alan, Colston, Timothy J, Conradie, Werner, Dehling, J Maximilian, Drewes, Robert C, Ernst, Raffael, Greenbaum, Eli, Gvoždík, Václav, Harvey, James, Hillers, Annika, Hirschfeld, Mareike, Jongsma, Gregory F M, and Kielgast, Jos
- Subjects
- *
LIBIDO , *SEXUAL dimorphism , *AMPHIBIANS , *RADIATION , *COMPARATIVE method , *FROGS , *NATURAL selection , *ANIMAL coloration - Abstract
Theory predicts that sexually dimorphic traits under strong sexual selection, particularly those involved with intersexual signaling, can accelerate speciation and produce bursts of diversification. Sexual dichromatism (sexual dimorphism in color) is widely used as a proxy for sexual selection and is associated with rapid diversification in several animal groups, yet studies using phylogenetic comparative methods to explicitly test for an association between sexual dichromatism and diversification have produced conflicting results. Sexual dichromatism is rare in frogs, but it is both striking and prevalent in African reed frogs, a major component of the diverse frog radiation termed Afrobatrachia. In contrast to most other vertebrates, reed frogs display female-biased dichromatism in which females undergo color transformation, often resulting in more ornate coloration in females than in males. We produce a robust phylogeny of Afrobatrachia to investigate the evolutionary origins of sexual dichromatism in this radiation and examine whether the presence of dichromatism is associated with increased rates of net diversification. We find that sexual dichromatism evolved once within hyperoliids and was followed by numerous independent reversals to monochromatism. We detect significant diversification rate heterogeneity in Afrobatrachia and find that sexually dichromatic lineages have double the average net diversification rate of monochromatic lineages. By conducting trait simulations on our empirical phylogeny, we demonstrate that our inference of trait-dependent diversification is robust. Although sexual dichromatism in hyperoliid frogs is linked to their rapid diversification and supports macroevolutionary predictions of speciation by sexual selection, the function of dichromatism in reed frogs remains unclear. We propose that reed frogs are a compelling system for studying the roles of natural and sexual selection on the evolution of sexual dichromatism across micro- and macroevolutionary timescales. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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39. Idiosyncratic responses to climate-driven forest fragmentation and marine incursions in reed frogs from Central Africa and the Gulf of Guinea Islands.
- Author
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Bell, Rayna C., Parra, Juan L., Badjedjea, Gabriel, Barej, Michael F., Blackburn, David C., Burger, Marius, Channing, Alan, Dehling, Jonas Maximilian, Greenbaum, Eli, Gvoždík, Václav, Kielgast, Jos, Kusamba, Chifundera, Lötters, Stefan, McLaughlin, Patrick J., Nagy, Zoltán T., Rödel, Mark‐Oliver, Portik, Daniel M., Stuart, Bryan L., VanDerWal, Jeremy, and Zassi‐Boulou, Ange Ghislain
- Subjects
- *
FRAGMENTED landscapes , *HYPEROLIUS , *FORESTS & forestry , *VICARIANCE , *LAND bridges , *BIOGEOGRAPHY , *FISHES - Abstract
Organismal traits interact with environmental variation to mediate how species respond to shared landscapes. Thus, differences in traits related to dispersal ability or physiological tolerance may result in phylogeographic discordance among co-distributed taxa, even when they are responding to common barriers. We quantified climatic suitability and stability, and phylogeographic divergence within three reed frog species complexes across the Guineo-Congolian forests and Gulf of Guinea archipelago of Central Africa to investigate how they responded to a shared climatic and geological history. Our species-specific estimates of climatic suitability through time are consistent with temporal and spatial heterogeneity in diversification among the species complexes, indicating that differences in ecological breadth may partly explain these idiosyncratic patterns. Likewise, we demonstrated that fluctuating sea levels periodically exposed a land bridge connecting Bioko Island with the mainland Guineo-Congolian forest and that habitats across the exposed land bridge likely enabled dispersal in some species, but not in others. We did not find evidence that rivers are biogeographic barriers across any of the species complexes. Despite marked differences in the geographic extent of stable climates and temporal estimates of divergence among the species complexes, we recovered a shared pattern of intermittent climatic suitability with recent population connectivity and demographic expansion across the Congo Basin. This pattern supports the hypothesis that genetic exchange across the Congo Basin during humid periods, followed by vicariance during arid periods, has shaped regional diversity. Finally, we identified many distinct lineages among our focal taxa, some of which may reflect incipient or unrecognized species. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
40. Leapfrogging into new territory: How Mascarene ridged frogs diversified across Africa and Madagascar to maintain their ecological niche.
- Author
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Zimkus, Breda M., Lawson, Lucinda P., Barej, Michael F., Barratt, Christopher D., Channing, Alan, Dash, Katrina M., Dehling, J. Maximilian, Du Preez, Louis, Gehring, Philip-Sebastian, Greenbaum, Eli, Gvoždík, Václav, Harvey, James, Kielgast, Jos, Kusamba, Chifundera, Nagy, Zoltán T., Pabijan, Maciej, Penner, Johannes, Rödel, Mark-Oliver, Vences, Miguel, and Lötters, Stefan
- Subjects
- *
FROG physiology , *ANIMAL diversity , *ANIMAL ecology , *ANIMAL species - Abstract
The Mascarene ridged frog, Ptychadena mascareniensis , is a species complex that includes numerous lineages occurring mostly in humid savannas and open forests of mainland Africa, Madagascar, the Seychelles, and the Mascarene Islands. Sampling across this broad distribution presents an opportunity to examine the genetic differentiation within this complex and to investigate how the evolution of bioclimatic niches may have shaped current biogeographic patterns. Using model-based phylogenetic methods and molecular-clock dating, we constructed a time-calibrated molecular phylogenetic hypothesis for the group based on mitochondrial 16S rRNA and cytochrome b ( cytb ) genes and the nuclear RAG1 gene from 173 individuals. Haplotype networks were reconstructed and species boundaries were investigated using three species-delimitation approaches: Bayesian generalized mixed Yule-coalescent model (bGMYC), the Poisson Tree Process model (PTP) and a cluster algorithm (SpeciesIdentifier). Estimates of similarity in bioclimatic niche were calculated from species-distribution models ( maxent ) and multivariate statistics (Principal Component Analysis, Discriminant Function Analysis). Ancestral-area reconstructions were performed on the phylogeny using probabilistic approaches implemented in BioGeoBEARS. We detected high levels of genetic differentiation yielding ten distinct lineages or operational taxonomic units, and Central Africa was found to be a diversity hotspot for these frogs. Most speciation events took place throughout the Miocene, including “out-of-Africa” overseas dispersal events to Madagascar in the East and to São Tomé in the West. Bioclimatic niche was remarkably well conserved, with most species tolerating similar temperature and rainfall conditions common to the Central African region. The P. mascareniensis complex provides insights into how bioclimatic niche shaped the current biogeographic patterns with niche conservatism being exhibited by the Central African radiation and niche divergence shaping populations in West Africa and Madagascar. Central Africa, including the Albertine Rift region, has been an important center of diversification for this species complex. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
41. No ecological opportunity signal on a continental scale? Diversification and life-history evolution of African true toads (Anura: Bufonidae).
- Author
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Liedtke, H. Christoph, Müller, Hendrik, Rödel, Mark‐Oliver, Menegon, Michele, Gonwouo, LeGrand Nono, Barej, Michael F., Gvoždík, Václav, Schmitz, Andreas, Channing, Alan, Nagel, Peter, and Loader, Simon P.
- Subjects
- *
BUFONIDAE , *BIOLOGICAL evolution , *MOLECULAR phylogeny , *LIFE history theory , *HABITATS - Abstract
The niche-filling process predicted by the 'ecological opportunity' (EO) model is an often-invoked mechanism for generating exceptional diversity in island colonizers. Whether the same process governs lineage accumulation and trait disparity during continental colonization events is less clear. Here, we test this prediction by investigating the rate dynamics and trait evolution of one of Africa's most widespread amphibian colonizers, the true toads (Bufonidae). By reconstructing the most complete molecular phylogeny of African Bufonidae to date, we find that the diversification of lineages in Africa best conforms to a constant rate model throughout time and across subclades, with little support for EO. Evolutionary rates of life-history traits have similarly been constant over time. However, an analysis of generalists and specialists showed a shift toward higher speciation rates associated with habitat specialization. The overall lack of EO signal can be interpreted in a number of ways and we propose several explanations. Firstly, methodological issues might preclude the detection of EO. Secondly, colonizers might not experience true EO conditions and due to the size, ecological heterogeneity and age of landmasses, the diversification processes might be more complex. Thirdly, lower speciation rates of habitat generalists may have affected overall proliferation of lineages. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
42. The phylogenetic position and diversity of the enigmatic mongrel frog Nothophryne Poynton, 1963 (Amphibia, Anura).
- Author
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Bittencourt-Silva, Gabriela B., Conradie, Werner, Siu-Ting, Karen, Tolley, Krystal A., Channing, Alan, Cunningham, Michael, Farooq, Harith M., Menegon, Michele, and Loader, Simon P.
- Subjects
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FROG morphology , *AMPHIBIAN phylogeny , *MOLECULAR biology , *BIOGEOGRAPHY , *BIOLOGICAL evolution - Abstract
The phylogenetic relationships of the African mongrel frog genus Nothophryne are poorly understood. We provide the first molecular assessment of the phylogenetic position of, and diversity within, this monotypic genus from across its range—the Afromontane regions of Malawi and Mozambique. Our analysis using a two-tiered phylogenetic approach allowed us to place the genus in Pyxicephalidae. Within the family, Nothophryne grouped with Tomopterna , a hypothesis judged significantly better than alternative hypotheses proposed based on morphology. Our analyses of populations across the range of Nothophryne suggest the presence of several cryptic species, at least one species per mountain. Formal recognition of these species is pending but there is a major conservation concern for these narrowly distributed populations in an area impacted by major habitat change. The phylogenetic tree of pyxicephalids is used to examine evolution of life history, ancestral habitat, and biogeography of this group. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
43. Is The Amphibian Tree of Life really fatally flawed?
- Author
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Frost, Darrel R., Grant, Taran, Faivovich, Julian, Bain, Raoul H., Haas, Alexander, Haddad, Celio F. B., De Sa, Rafael O., Channing, Alan, Wilkinson, Mark, Donnellan, Stephen C., Raxworthy, Christopher J., Campbell, Jonathan A., Blotto, Boris L., Moler, Paul, Drewes, Robert C., Nussbaum, Ronald A., Lynch, John D., Green, David M., and Wheeler, Ward C.
- Subjects
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AMPHIBIANS , *FRESHWATER animals , *HERPETOLOGY , *MURIDAE , *PHYLOGENY - Abstract
Wiens (2007 , Q. Rev. Biol. 82, 55–56) recently published a severe critique of Frost et al.'s (2006, Bull. Am. Mus. Nat. Hist. 297, 1–370) monographic study of amphibian systematics, concluding that it is “a disaster” and recommending that readers “simply ignore this study”. Beyond the hyperbole, Wiens raised four general objections that he regarded as “fatal flaws”: (1) the sampling design was insufficient for the generic changes made and taxonomic changes were made without including all type species; (2) the nuclear gene most commonly used in amphibian phylogenetics, RAG-1, was not included, nor were the morphological characters that had justified the older taxonomy; (3) the analytical method employed is questionable because equally weighted parsimony “assumes that all characters are evolving at equal rates”; and (4) the results were at times “clearly erroneous”, as evidenced by the inferred non-monophyly of marsupial frogs. In this paper we respond to these criticisms. In brief: (1) the study of Frost et al. did not exist in a vacuum and we discussed our evidence and evidence previously obtained by others that documented the non-monophyletic taxa that we corrected. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
44. Nuclear gene phylogeny of narrow-mouthed toads (Family: Microhylidae) and a discussion of competing hypotheses concerning their biogeographical origins
- Author
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van der Meijden, Arie, Vences, Miguel, Hoegg, Simone, Boistel, Renaud, Channing, Alan, and Meyer, Axel
- Subjects
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ANURA , *BIOLOGICAL evolution , *AMPHIBIANS , *HEREDITY - Abstract
Abstract: The family Microhylidae has a large circumtropic distribution and contains about 400 species in a highly subdivided taxonomy. Relationships among its constituent taxa remained controversial due to homoplasy in morphological characters, resulting in conflicting phylogenetic hypotheses. A phylogeny based on four nuclear genes (rag-1, rag-2, tyrosinase, BDNF) and one mitochondrial gene (CO1) of representatives of all currently recognized subfamilies uncovers a basal polytomy between several subfamilial clades. A sister group relationship between the cophylines and scaphiophrynines is resolved with moderate support, which unites these endemic Malagasy taxa for the first time. The American members of the subfamily Microhylinae are resolved to form a clade entirely separate from the Asian members of that subfamily. Otophryne is excluded from the subfamily Microhylinae, and resolved as a basal taxon. The placement of the Asian dyscophine Calluella nested within the Asian Microhyline clade rather than with the genus Dyscophus is corroborated by our data. Bayesian estimates of the divergence time of extant Microhylidae (47–90Mya) and among the subclades within the family are discussed in frameworks of alternative possible biogeographic scenarios. [Copyright &y& Elsevier]
- Published
- 2007
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45. ORIGINAL ARTICLE Phylogeography of Ptychadena mascareniensis suggests transoceanic dispersal in a widespread African-Malagasy frog lineage.
- Author
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Vences, Miguel, Kosuch, Joachim, Rödel, Mark-Oliver, Lötters, Stefan, Channing, Alan, Glaw, Frank, and Böhme, Wolfgang
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PTYCHADENA , *FROGS , *PHYLOGENY , *BIOLOGICAL evolution - Abstract
The Mascarene ridged frog, Ptychadena mascareniensis, is the only African amphibian species thought to occur on Madagascar and on the Seychelles and also Mascarene islands. We explored its phylogenetic relationships and intraspecific genetic differentiation to contribute to the understanding of transoceanic dispersal in amphibians. Fragments of the mitochondrial 16S rRNA gene were sequenced from specimens collected over most of the distribution area of P. mascareniensis, including populations from Madagascar, Mascarenes and Seychelles. We identified five deeply divergent clades having pairwise divergences >5%, which probably all represent cryptic species in a P. mascareniensis complex. One of these seems to be restricted to Madagascar, the Mascarenes and the Seychelles. Sequences obtained from topotypic material (Réunion) were identical to the most widespread haplotype from Madagascar. The single Mauritian/Seychellean haplotype differed by only one mutation from a Malagasy haplotype. It is likely that the Mascarene and Seychellean populations were introduced from Madagascar by humans. In contrast, the absence of the Malagasy haplotypes from Africa and the distinct divergences among Malagasy populations (16 mutations in one divergent hapolotype from northern Madagascar) suggest that Madagascar was populated by Ptychadena before the arrival of humans c. 2000 years ago. Because Madagascar has been separated from Africa since the Jurassic, this colonization must have taken place by overseas rafting, which may be a more widespread dispersal mode in amphibians than commonly thought. [ABSTRACT FROM AUTHOR]
- Published
- 2004
- Full Text
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