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Indexación: Scopus Lambert et al. question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in amphibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and hampers conservation efforts. We reaffirm that our study provides unambiguous evidence that chytridiomycosis has affected at least 501 amphibian species.

Amphibian chytridiomycosis, an emerging infectious disease caused by the fungus Batrachochytrium dendrobatidis (Bd), has been a significant driver of amphibian declines. While globally widespread, Bd had not yet been reported from within Madagascar.Wedocument surveys conducted across the country between 2005 and 2014, showing Bd ’s first record in 2010. Subsequently, Bd was detected in multiple areas, with prevalence reaching up to 100%. Detection of Bd appears to be associated with mid to high elevation sites and to have a seasonal pattern, with greater detectability during the dry season. Lineage-based PCR was performed on a subset of samples. While some did not amplify with any lineage probe, when a positive signal was observed, samples were most similar to the Global Panzootic Lineage (BdGPL). These results may suggest that Bd arrived recently, but do not exclude the existence of a previously undetected endemic Bd genotype. Representatives of all native anuran families have tested Bd-positive, and exposure trials confirm infection by Bd is possible. Bd’s presence could pose significant threats to Madagascar’s unique ‘‘megadiverse’’ amphibians.

Morphological similarities between the tadpoles of Amietia umbraculata and A. vertebralis have led to confusion and incorrect descriptions and identifications in the literature. Based on 33 body measurements and ratios we revised the morphological descriptions of the tadpoles of the two species. Tadpole identification was verified through DNA sequencing using mitochondrial (16S) gene fragments. A combination of four morphological characters proved to be informative and consistent in distinguishing between tadpoles of the two species. Tadpoles of A. umbraculata are characterized by having four labial tooth rows in the lower jaw, extensive tail mottling, a dorsal fin that originates well behind the body, reaching a maximum depth at 50% of the tail length, and an average tail length of 1.9 times body length. Amietia vertebralis tadpoles on the other hand are characterized by having five or more labial tooth rows in the lower jaw, tail mottling that is confined to the upper half of the tail musculature, a dorsal fin that originates at the body-tail junction but retains a low profile, rising abruptly to reach a maximum depth at about 40% of the tail length, and an average tail length of 1.5 times body length. These four characters identify the two species without ambiguity.Key words: Amietia umbraculata, Amietia vertebralis, identification key, Drakensberg, Maluti-Drakensberg, Maloti-Drakensberg, tadpole morphology.

Morphological similarities between the tadpoles of Amietia umbraculata and A. vertebralis have led to confusion and incorrect descriptions and identifications in the literature. Based on 33 body measurements and ratios we revised the morphological descriptions of the tadpoles of the two species. Tadpole identification was verified through DNA sequencing using mitochondrial (16S) gene fragments. A combination of four morphological characters proved to be informative and consistent in distinguishing between tadpoles of the two species. Tadpoles of A. umbraculata are characterised by having four labial tooth rows in the lower jaw, extensive tail mottling, a dorsal fin that originates well behind the body reaching a maximum depth at 50% of the tail length, and an average tail length of 1.9 times body length. Amietia vertebralis tadpoles on the other hand are characterised by having five or more labial tooth rows in the lower jaw, tail mottling that is confined to the upper half of the tail musculature, a dorsal fin that originates at the body-tail junction but retains a low profile, rising abruptly to reach a maximum depth at about 40% of the tail length, and an average tail length of 1.5 times body length. These four characters identify the two species without ambiguity.

Environmental parameters such as temperature and rainfall influence the biology of amphibians and are likely to similarly influence the growth and prevalence of associated pathogens. Amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), causes an infectious disease, chytridiomycosis, in amphibians worldwide. Field studies on post-metamorphic anurans from tropical Australia have correlated increased prevalence with cool winter temperatures, but similar studies are lacking from Africa. We monitored the seasonality of amphibian chytrid in the Highveld of South Africa through microscopic examination of common river frog (Amietia angolensis) tadpoles over 12 months.Within the study area Bd was found to be widespread, but largely limited to riverine systems. The seasonal infection pattern was inconsistent with the findings of past studies, which showed that prevalence usually peaks during the cooler months of the year. This study indicates that infection levels increased during spring in the Grassland Biome, when temperatures favoured optimum thermal growth of the fungus and when streams reached minimum flow levels.Key words: conservation, Vredefort Dome, UNESCO, stream flow.

http://www.plosbiology.org/article/info:doi%2F10.1371%2Fjournal.pbio.0060118

A putative driver of global amphibian decline is the panzootic chytrid fungus Batrachochytrium dendrobatidis (Bd). While Bd has been documented across continental Africa, its distribution in West Africa remains ambiguous. We tested 793 West African amphibians (one caecilian and 61 anuran species) for the presence of Bd. The samples originated from seven West African countries - Be´nin, Burkina Faso, Coˆ te d’Ivoire, Ghana, Guinea, Liberia, Sierra Leone - and were collected from a variety of habitats, ranging from lowland rainforests to montane forests, montane grasslands to humid and dry lowland savannahs. The species investigated comprised various life-history strategies, but we focused particularly on aquatic and riparian species. We used diagnostic PCR to screen 656 specimen swabs and histology to analyse 137 specimen toe tips. All samples tested negative for Bd, including a widespread habitat generalist Hoplobatrachus occipitalis which is intensively traded on the West African food market and thus could be a potential dispersal agent for Bd. Continental fine-grained (30 arc seconds) environmental niche models suggest that Bd should have a broad distribution across West Africa that includes most of the regions and habitats that we surveyed. The surprising apparent absence of Bd in West Africa indicates that the Dahomey Gap may have acted as a natural barrier. Herein we highlight the importance of this Bd-free region of the African continent - especially for the long-term conservation of several threatened species depending on fast flowing forest streams (Conraua alleni (‘‘Vulnerable’’) and Petropedetes natator (‘‘Near Threatened’’)) as well as the ‘‘Critically Endangered’’ viviparous toad endemic to the montane grasslands of Mount Nimba (Nimbaphrynoides occidentalis) http://www.plosone.org/ http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0056236 DOI: 10.1371/journal.pone.0056236 German Ministry for Education and Research (BMBF) through the BIOTA-West project (01LC0617J). In Ghana, fieldwork for GBA, COB and WO was supported by Defra’s Darwin Initiative/ZSL’s Wildlife Wood Project and the Rufford Small Grants Foundation respectively. German Science Foundation (DFG PL 213/6-1). DFG (VE 183/4-1, RO 3064/1-2), the Rapid Assessment Program and Critical Ecosystem Partnership Fund of Conservation International, the World Wide Fund for Nature and BirdLife International

The elygium is a darkly pigmented projection over the pupil of the tadpoles of certain species that live mostly at high altitudes. It has been suggested that this structure shades the retina, protecting it from high UV levels. In post-metamorphic individuals, the elygium is replaced by a structure known as an umbraculum. Confusion arose in the past from the inconsistent use of terminology when referring to these two structures. While they may serve the same function, these structures differ fundamentally in structure and origin. Our investigation of the ultrastructure of the eye in Amietia vertebralis tadpoles, using electron and light microscopy, revealed that the elygium consists of an accumulation of melanophores situated within the inner cornea, whereas the umbraculum is a dorsal extension of the iris pigment epithelium, analogous to the ventral pupillary nodule, which is present in most frog species. In A. vertebralis, the umbraculum starts to develop on the iris of older tadpoles (Gosner [1960] stage 37 Herpetologica 16:183– 190), medial to the overlying elygium. A smaller, ventral elygium is also present in this species and is similar in structure to the dorsal elygium. The development of the elygium over a six-month period is also described. http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291097-4687

Madagascar harbors a rich and diverse amphibian fauna, with over 280 nominal species of native frogs, all of which are endemic to the island. Although many species are threatened predominantly by habitat destruction, so far this fauna has not experienced any enigmatic declines as amphibians have in other parts of the globe. The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), associated with mass amphibian die offs in Europe, the Americas and Australia has so far not been detected in Madagascar, but surveys so far were based mainly on histological examination of frog samples, with molecular data from only a single site. Here, we present results from a molecular screening of altogether 300 frog specimens belonging to 53 species in 13 genera, from 12 sites throughout Madagascar spanning all of Madagascar`s major bioclimatic regions and an array of different elevations from 20 to 2400 m above sea level. All samples were analyzed using a standard quantitative real time polymerase chain reaction (qPCR) assay and yielded only negative results, suggesting the widespread absence or very localized and low prevalence of the amphibian chytrid fungus across Madagascar during the sampling years 2006 and 2007., This research was supported by Conservation International, by the Spanish Ministry of Science, by the Volkswagen Foundation, and by The US National Science Foundation (EF-0723563 and 1120283)

Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2005. The sudden appearance of chytridiomycosis, as the cause of amphibian deaths and population declines in several continents suggests that its etiological agent, the amphibian chytrid fungus Batrachochytrium dendrobatidis, was introduced into the affected regions. However, the origin of this virulent pathogen is unknown. Efforts were directed to determine the occurrence of chytridiomycosis in Africa, whether the disease had been introduced into South Africa in recent years and how wild frog populations were affected by infection. A chytridiomycosis survey of 2,300 archived and live specimens involving members of the Pipidae family in sub-Saharan Africa, as well as a number of unrelated frog species in South Africa was conducted by histological diagnosis of skin samples. The epidemiological evidence indicated that chytridiomycosis has been a stable endemic infection in southern Africa for 23 years before any positive specimens were found outside Africa. The occurrence of chytridiomycosis in South Africa can be described as widespread both in terms of geographical distribution and host species and generally infection is not associated with adverse effects at the individual or population level. It was proposed that the amphibian chytrid originated in Africa and that the international trade in the African clawed toad Xenopus laevis that commenced in the mid 1930s was the means of dissemination. A risk assessment of the X. laevis trade demonstrated that chytridiomycosis could spread through this pathway and culminated in the development of a management protocol to reduce the risks of spreading disease through this animate commodity. Initial comparative genetic analysis of B. dendrobatidis strains isolated from South African frogs with a global set of 35 strains, suggests that analysis of a more geographically diverse set of southern African strains is needed before this line of argument can support or reject the "out of Africa" hypothesis. Doctoral

The sudden appearance of chytridiomycosis, as the cause of amphibian deaths and population declines in several continents suggests that its etiological agent, the amphibian chytrid fungus Batrachochytrium dendrobatidis, was introduced into the affected regions. However, the origin of this virulent pathogen is unknown. Efforts were directed to determine the occurrence of chytridiomycosis in Africa, whether the disease had been introduced into South Africa in recent years and how wild frog populations were affected by infection. A chytridiomycosis survey of 2,300 archived and live specimens involving members of the Pipidae family in sub-Saharan Africa, as well as a number of unrelated frog species in South Africa was conducted by histological diagnosis of skin samples. The epidemiological evidence indicated that chytridiomycosis has been a stable endemic infection in southern Africa for 23 years before any positive specimens were found outside Africa. The occurrence of chytridiomycosis in South Africa can be described as widespread both in terms of geographical distribution and host species and generally infection is not associated with adverse effects at the individual or population level. It was proposed that the amphibian chytrid originated in Africa and that the international trade in the African clawed toad Xenopus laevis that commenced in the mid 1930s was the means of dissemination. A risk assessment of the X. laevis trade demonstrated that chytridiomycosis could spread through this pathway and culminated in the development of a management protocol to reduce the risks of spreading disease through this animate commodity. Initial comparative genetic analysis of B. dendrobatidis strains isolated from South African frogs with a global set of 35 strains, suggests that analysis of a more geographically diverse set of southern African strains is needed before this line of argument can support or reject the "out of Africa" hypothesis. Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2005.