06 noviembre 2007

Bufo anderssoni synonym of Rhaebo guttatus

The taxonomic status of Rhaebo anderssoni (Melin, 1941) (Anura: Bufonidae)

Abstract.-- Bufo anderssoni Melin, 1941 is synonymised with Rhaebo guttatus (Schneider, 1799) based on direct comparison of the holotypes of both and fresh material. All characters of the former fall within the intraspecific variation of R. guttatus. The few characters used in the original description to distinguish anderssoni from guttatus (narrower interorbital space, smaller tympanum and smaller size) are not considered important interspecific differences, but rather dependent on ontogenetic development.

Cita / Citation: Barrio-Amorós, C. L. & Castroviejo-Fisher, S. (2007) The taxonomic status of Rhaebo anderssoni (Melin, 1941) (Anura: Bufonidae). Salamandra 43(4): 250-253.

Correos electrónicos de los autores: Cesar L. Barrio-Amoros cesarlba@yahoo.com, Santiago Castroviejo-Fisher santiago.castroviejo@ebc.uu.se.

Stress in Invasive Cane Toads

Invasion, stress, and spinal arthritis in cane toads

Abstract.-- The impact of invasive species on biodiversity has attracted considerable study, but impacts of the invasion process on the invaders themselves remain less clear. Invading species encounter conditions different from those in their ancestral habitats and are subject to intense selection for rapid dispersal. The end result may be significant stress on individual organisms, with consequent health problems. Our studies on invasive cane toads in Australia reveal severe spinal arthritis in c. 10% of large adult toads, associated with the same factors (large body size, frequent movement, and relatively long legs) that have enabled toads to invade so rapidly across the Australian tropics.

Cita / Citation: Brown, G. P., Shilton, C., Phillips, B. L. & Shine, R. (2007) Invasion, stress, and spinal arthritis in cane toads. PNAS 104(45). 10.1073/pnas.0705057104

Autor a quien correspondencia debe ser dirigida: Richard Shine rics@bio.usyd.edu.au

Enlace al Abstract (acceso gratis a la publicación completa en paises de Latinoamerica):

04 noviembre 2007

Underestimation of Species Richness in Neotropical Frogs

Underestimation of Species Richness in Neotropical Frogs Revealed by mtDNA Analyses

Abstract.-- Background. Amphibians are rapidly vanishing. At the same time, it is most likely that the number of amphibian species is highly underestimated. Recent DNA barcoding work has attempted to define a threshold between intra- and inter-specific genetic distances to help identify candidate species. In groups with high extinction rates and poorly known species boundaries, like amphibians, such tools may provide a way to rapidly evaluate species richness. Methodology. Here we analyse published and new 16S rDNA sequences from 60 frog species of Amazonia-Guianas to obtain a minimum estimate of the number of undescribed species in this region. We combined isolation by distance, phylogenetic analyses, and comparison of molecular distances to evaluate threshold values for the identification of candidate species among these frogs. Principal Findings. In most cases, geographically distant populations belong to genetically highly distinct lineages that could be considered as candidate new species. This was not universal among the taxa studied and thus widespread species of Neotropical frogs really do exist, contrary to previous assumptions. Moreover, the many instances of paraphyly and the wide overlap between distributions of inter- and intra-specific distances reinforce the hypothesis that many cryptic species remain to be described. In our data set, pairwise genetic distances below 0.02 are strongly correlated with geographical distances. This correlation remains statistically significant until genetic distance is 0.05, with no such relation thereafter. This suggests that for higher distances allopatric and sympatric cryptic species prevail. Based on our analyses, we propose a more inclusive pairwise genetic distance of 0.03 between taxa to target lineages that could correspond to candidate species. Conclusions. Using this approach, we identify 129 candidate species, two-fold greater than the 60 species included in the current study. This leads to estimates of around 170 to 460 frog taxa unrecognized in Amazonia-Guianas. Significance. As a consequence the global amphibian decline detected especially in the Neotropics may be worse than realised.

Cita / Citation: Fouquet, A., Gilles, A., Vences, M., Marty, C., Blanc, M. & Gemmellet, N. J. (2007) Underestimation of Species Richness in Neotropical Frogs Revealed by mtDNA Analyses. PLoS ONE 2(10): e1109. doi:10.1371/journal.pone.0001109

Acceso libre al artículo y al pdf / Open access to the article and its pdf: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0001109

<<PLoS ONE (eISSN-1932-6203) is an international, peer-reviewed, open-access, online publication. PLoS ONE welcomes reports on primary research from any scientific discipline. PLoS ONE is published by the Public Library of Science (PLoS), a nonprofit organization. PLoS ONE's start-up phase is supported by a grant from the Open Society Institute.>>