A redescription of the poorly known Central American toad Inciliustacanensis (Anura, Bufonidae), with a summary of its biology and conservation status

Based on examination of most of the existing museum specimens of the rare bufonid frog Inciliustacanensis, we present a redescription and new diagnosis for this species. The species is limited to small region of the Pacific chain of volcanoes in southeastern Chiapas, Mexico, and adjacent areas of Guatemala. The species has not been observed in the wild since 1984 and may have been reduced or eliminated by regional epidemics of chytridiomycosis.

Fungal infection, decline and persistence in the only obligate troglodytic Neotropical salamander

The fungal pathogen Batrachochytrium dendrobatidis (Bd) is implicated in global mass die-offs and declines in amphibians. In Mesoamerica, the Bd epidemic wave hypothesis is supported by detection of Bd in historic museum specimens collected over the last century, yet the timing and impact of the early stages of the wave remain poorly understood. Chiropterotriton magnipes, the only obligate troglodytic Neotropical salamander, was abundant in its small range in the decade following its description in 1965, but subsequently disappeared from known localities and was not seen for 34 years. Its decline is roughly coincident with that of other populations of Neotropical salamanders associated with the invasion and spread of Bd. To determine the presence and infection intensity of Bd on C. magnipes and sympatric amphibian species (which are also Bd hosts), we used a noninvasive sampling technique and qPCR assay to detect Bd on museum specimens of C. magnipes collected from 1952 to 2012, and from extant populations of C. magnipes and sympatric species of amphibians. We also tested for the presence of the recently discovered Batrachochytrium salamandivorans (Bsal), another fungal chytridiomycete pathogen of salamanders, using a similar technique specific for Bsal. We did not detect Bd in populations of C. magnipes before 1969, while Bd was detected at low to moderate prevalence just prior to and during declines. This pattern is consistent with Bd-caused epizootics followed by host declines and extirpations described in other hosts. We did not detect Bsal in any extant population of C. magnipes. We obtained one of the earliest positive records of the fungus to date in Latin America, providing additional historical evidence consistent with the Bd epidemic wave hypothesis. Genotyping results show that at least one population is currently infected with the Global Panzootic Lineage of Bd, but our genotyping of the historical positive samples was unsuccessful. The lack of large samples from some years and the difficulty in genotyping historical Bd samples illustrate some of the difficulties inherent in assigning causality to historical amphibian declines. These data also provide an important historical baseline for actions to preserve the few known remaining populations of C. magnipes.

Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity

Anthropogenic trade and development have broken down dispersal barriers, facilitating the spread of diseases that threaten Earth's biodiversity. We present a global, quantitative assessment of the amphibian chytridiomycosis panzootic, one of the most impactful examples of disease spread, and demonstrate its role in the decline of at least 501 amphibian species over the past half-century, including 90 presumed extinctions. The effects of chytridiomycosis have been greatest in large-bodied, range-restricted anurans in wet climates in the Americas and Australia. Declines peaked in the 1980s, and only 12% of declined species show signs of recovery, whereas 39% are experiencing ongoing decline. There is risk of further chytridiomycosis outbreaks in new areas. The chytridiomycosis panzootic represents the greatest recorded loss of biodiversity attributable to a disease.

DNA Extraction Method Affects the Detection of a Fungal Pathogen in Formalin-Fixed Specimens Using qPCR

Museum collections provide indispensable repositories for obtaining information about the historical presence of disease in wildlife populations. The pathogenic amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has played a significant role in global amphibian declines, and examining preserved specimens for Bd can improve our understanding of its emergence and spread. Quantitative PCR (qPCR) enables Bd detection with minimal disturbance to amphibian skin and is significantly more sensitive to detecting Bd than histology; therefore, developing effective qPCR methodologies for detecting Bd DNA in formalin-fixed specimens can provide an efficient and effective approach to examining historical Bd emergence and prevalence. Techniques for detecting Bd in museum specimens have not been evaluated for their effectiveness in control specimens that mimic the conditions of animals most likely to be encountered in museums, including those with low pathogen loads. We used American bullfrogs (Lithobates catesbeianus) of known infection status to evaluate the success of qPCR to detect Bd in formalin-fixed specimens after three years of ethanol storage. Our objectives were to compare the most commonly used DNA extraction method for Bd (PrepMan, PM) to Macherey-Nagel DNA FFPE (MN), test optimizations for Bd detection with PM, and provide recommendations for maximizing Bd detection. We found that successful detection is relatively high (80-90%) when Bd loads before formalin fixation are high, regardless of the extraction method used; however, at lower infection levels, detection probabilities were significantly reduced. The MN DNA extraction method increased Bd detection by as much as 50% at moderate infection levels. Our results indicate that, for animals characterized by lower pathogen loads (i.e., those most commonly encountered in museum collections), current methods may underestimate the proportion of Bd-infected amphibians. Those extracting DNA from archived museum specimens should ensure that the techniques they are using are known to provide high-quality throughput DNA for later analysis.

Early 1900 s detection of Batrachochytrium dendrobatidis in Korean amphibians

The pathogenic fungus Batrachochytrium dendrobatidis (Bd) is a major conservation concern because of its role in decimating amphibian populations worldwide. We used quantitative PCR to screen 244 museum specimens from the Korean Peninsula, collected between 1911 and 2004, for the presence of Bd to gain insight into its history in Asia. Three specimens of Rugosa emeljanovi (previously Rana or Glandirana rugosa), collected in 1911 from Wonsan, North Korea, tested positive for Bd. Histology of these positive specimens revealed mild hyperkeratosis – a non-specific host response commonly found in Bd-infected frogs – but no Bd zoospores or zoosporangia. Our results indicate that Bd was present in Korea more than 100 years ago, consistent with hypotheses suggesting that Korean amphibians may be infected by endemic Asian Bd strains.