Search for: All records

The genus Chiropterotriton is endemic to Mexico with a geographical distribution along the Sierra Madre Oriental, the Trans Mexican Volcanic Belt and the Sierra de Juárez. The recent use of molecular tools has shown that Mexico’s amphibian diversity is highly underestimated, including a large number of cryptic, unnamed species. Chiropterotriton has 18 described species including terrestrial, arboreal and cave-dwelling species. In previous molecular studies, the presence of multiple undescribed species was evident. We present a phylogenetic hypothesis based on mitochondrial data, which includes all described species and six undescribed taxa. Based on the morphological analyses and, when available, combined with molecular data, we describe five new species of the genus; Chiropterotriton casasi sp. nov., C. ceronorum sp. nov., C. melipona sp. nov., C. perotensis sp. nov. and C. totonacus sp. nov. In addition, we redescribe two others: Chiropterotriton chiropterus and C. orculus , and provide a comparable account of one additional sympatric congener. This increases the number of species in the genus to 23, which represent a considerable component of Mexican plethodontid richness.

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 didmore »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 .« less

Biodiversity loss is one major outcome of human-mediated ecosystem disturbance. One way that humans have triggered wildlife declines is by transporting disease-causing agents to remote areas of the world. Amphibians have been hit particularly hard by disease due in part to a globally distributed pathogenic chytrid fungus ( Batrachochytrium dendrobatidis [ Bd ]). Prior research has revealed important insights into the biology and distribution of Bd ; however, there are still many outstanding questions in this system. Although we know that there are multiple divergent lineages of Bd that differ in pathogenicity, we know little about how these lineages are distributed around the world and where lineages may be coming into contact. Here, we implement a custom genotyping method for a global set of Bd samples. This method is optimized to amplify and sequence degraded DNA from noninvasive skin swab samples. We describe a divergent lineage of Bd , which we call Bd ASIA3, that appears to be widespread in Southeast Asia. This lineage co-occurs with the global panzootic lineage ( Bd GPL) in multiple localities. Additionally, we shed light on the global distribution of Bd GPL and highlight the expanded range of another lineage, Bd CAPE. Finally, we arguemore »that more monitoring needs to take place where Bd lineages are coming into contact and where we know little about Bd lineage diversity. Monitoring need not use expensive or difficult field techniques but can use archived swab samples to further explore the history—and predict the future impacts—of this devastating pathogen.« less

We describe three new species of minute salamanders, genusThorius, from the Sierra Madre del Sur of Oaxaca, Mexico. Until now only a single species,T. minutissimus, has been reported from this region, although molecular data have long shown extensive genetic differentiation among geographically disjunct populations. AdultThorius pinicolasp. nov.,T. longicaudussp. nov., andT. tlaxiacussp. nov. are larger thanT. minutissimusand possess elliptical rather than oval nostrils;T. pinicolaandT. longicaudusalso have longer tails. All three new species occur west of the range ofT. minutissimus, which has the easternmost distribution of any member of the genus. The new species are distinguished from each other and from other namedThoriusin Oaxaca by a combination of adult body size, external morphology and osteology, and by protein characters (allozymes) and differences in DNA sequences. In addition, we redescribeT. minutissimusand a related species,T. narisovalis, to further clarify the taxonomic status of Oaxacan populations and to facilitate future studies of the remaining genetically differentiatedThoriusthat cannot be satisfactorily assigned to any named species. Populations of all five species considered here appear to have declined dramatically over the last one or two decades and live specimens are difficult to find in nature.Thoriusmay be the most endangered genus of amphibians in the world. All species maymore »go extinct before the end of this century.

« less