Mauro N. Tammone

New data on the endemic cricetid rodent Holochilus lagigliai from central-western Argentina: fossil record and potential distribution

Abstract The recently described cricetid Holochilus lagigliai is a poorly known amphibious rat to this day restricted to its type locality in Mendoza Province, Argentina. Here, we provide and discuss several new late Holocene records enlarging its past distribution to cover the north portion of the province, indicating that this rodent was widespread in a recent past. We also performed a potential distribution analysis pointing to plausible areas of occurrence in neighboring provinces. Holochilus lagigliai seems to be a mammal negatively affected by the growing pressure of humans on wetlands in the context of drylands that characterizes western Argentina.

Dense sampling provides a reevaluation of the southern geographic distribution of the cavies Galea and Microcavia (Rodentia)

Abstract The southern distribution of the small cavies Galea leucoblephara and Microcavia australis is reviewed. It has been enriched through the addition of 36 new locality records for G. leucoblephara and 176 for M. australis. Both caviomorph rodents are widespread in Patagonia – the former occurs in the northern portion of the territory, whereas the latter is recorded up to the Strait of Magellan. The reference of Patagonian Galea populations to leucoblephara is still subject to confirmation. Therefore, the status of negrensis must be addressed in future studies. For southern Microcavia australis populations, a rich subspecifical scenario is proposed, including the names australis, kingii, and nigriana. The alpha taxonomy of this cavy needs a fresh approach that is based on a larger sample set coupled with the analysis of molecular markers.

The Quaternary record of Euneomys (Mammalia, Rodentia, Cricetidae) from northwestern Patagonia: evidence for regional extinction

SUPPLEMENTAL DATA Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Tammone, M. N., E. A. Lacey, A. Hajduk, M. Christie, and U. F. J. Pardiñas. 2016. The Quaternary record of Euneomys (Mammalia, Rodentia, Cricetidae) from northwestern Patagonia: evidence for regional extinction. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2016.1212363.

Rapid Increase in Genetic Diversity in an Endemic Patagonian Tuco-Tuco Following a Recent Volcanic Eruption

Catastrophic natural events can have profound impacts on patterns of genetic diversity. Due to the typically unpredictable nature of such phenomena, however, few studies have been able to directly compare patterns of diversity before and after natural catastrophic events. Here, we examine the impacts of a recent volcanic eruption in southern Chile on genetic variation in the colonial tuco-tuco (Ctenomys sociabilis), a subterranean species of rodent endemic to the area most affected by the June 2011 eruption of the Puyehue-Cordón Caulle volcanic complex. To provide a comparative context for interpreting changes in genetic variation in this species, we also analyze the effects of this eruption on genetic variation in the geographically proximate but more widely distributed Patagonian tuco-tuco (C. haigi). Our analyses indicate that while both C. sociabilis and C. haigi displayed significant post-eruption decreases in population density, the apparent impacts of the eruption on genetic diversity differed between species. In particular, genetic diversity at multiple microsatellite loci increased in C. sociabilis after the eruption while no comparable post-eruption increase in C. haigi was observed at these loci. No changes in post-eruption diversity at the mitochondrial cytochrome b locus were detected for either species. To place these findings in a larger spatiotemporal context, we compared our results for C. sociabilis to genetic data from additional modern and ancient populations of this species. These comparisons, combined with Bayesian serial coalescent modeling, suggest that post-eruption gene flow from nearby populations represents the most probable explanation for the apparent increase in post-eruption microsatellite diversity in C. sociabilis. Thus, detailed comparisons of pre- and post-eruption populations provide important insights into not only the genetic consequences of a natural catastrophic event, but also the demographic processes by which these changes in genetic diversity likely occurred.

Genomic data reveal a loss of diversity in two species of tuco-tucos (genus Ctenomys ) following a volcanic eruption

Marked reductions in population size can trigger corresponding declines in genetic variation. Understanding the precise genetic consequences of such reductions, however, is often challenging due to the absence of robust pre- and post-reduction datasets. Here, we use heterochronous genomic data from samples obtained before and immediately after the 2011 eruption of the Puyehue-Cordón Caulle volcanic complex in Patagonia to explore the genetic impacts of this event on two parapatric species of rodents, the colonial tuco-tuco (Ctenomys sociabilis) and the Patagonian tuco-tuco (C. haigi). Previous analyses using microsatellites revealed no post-eruption changes in genetic variation in C. haigi, but an unexpected increase in variation in C. sociabilis. To explore this outcome further, we used targeted gene capture to sequence over 2,000 putatively neutral regions for both species. Our data revealed that, contrary to the microsatellite analyses, the eruption was associated with a small but significant decrease in genetic variation in both species. We suggest that genome-level analyses provide greater power than traditional molecular markers to detect the genetic consequences of population size changes, particularly changes that are recent, short-term, or modest in size. Consequently, genomic analyses promise to generate important new insights into the effects of specific environmental events on demography and genetic variation.