Conservation status, protected area coverage of Ctenomys (Rodentia, Ctenomyidae) species and molecular identification of a population in a national park

Filling the gap in distribution ranges and conservation status in Ctenomys (Rodentia: Ctenomyidae)

South American subterranean rodents of the genus Ctenomys (Rodentia, Ctenomyidae, tuco-tuco) are one of the most diverse genera among mammals. Recently described species, new taxonomic revisions, and new distribution range delimitation made the revision of distribution areas and conservation status of these mammals mandatory. Implementing the first part of the DAMA protocol (document, assess, monitor, act), here we compile updated sets of species distribution range maps and use these and the number of collection localities to assess the conservation status of ctenomyids. We integrate potential for conservation in protected areas, and levels of habitat transformation to revise previous conservation status assessments and propose the first assessment for all Data Deficient or not evaluated species of tuco-tucos. Our results indicate that 53 (78%) of these species are threatened and that 47 (69%) have little or no overlap with protected areas, emphasizing the urgent need to conduct conservation efforts. Here, 18 of 22 species previously classified as Data Deficient resulted in them being put in an at-risk category (VU, EN, CR). In addition, nine species that have not been previously evaluated were classified as threatened, with these two groups comprising more than 47% of the known species. These results posit that the Ctenomyidae are the rodent family with the greatest number of species at risk of extinction. Finally, a total of 33 (49%) species have been reported from three or fewer localities; all considered threatened through the approach implemented in this study. These geographically restricted taxa should be given more attention in conservation programs since the richness of this genus relies on the survival of such species.

Disentangling the taxonomic status of Ctenomys (Rodentia: Ctenomyidae) populations inhabiting northern areas of La Rioja Province, Argentina

The Ctenomys population from Anillaco, La Rioja Province, Argentina has been the subject of detailed studies of circadian rhythms, vocalization, ecology and spatial dynamics. However, the taxonomy and systematics of this population as well as populations of Ctenomys inhabiting Andean areas of this province is unknown. In this study, we present the phylogenetic relationship of the “Anillaco tuco-tuco” as well as of two other populations of Ctenomys, all distributed in the northern portion of La Rioja Province, Argentina. Based on molecular analyses and morphological comparisons, we reached to the conclusion that the “Anillaco tuco-tuco” population corresponds to the species Ctenomys famosus. In addition, an undescribed species, member of the “mendocinus” lineage of Ctenomys, is recognized in the Andean portions of the province.

Redefining the Distributional Boundaries and Phylogenetic Relationships for Ctenomids From Central Argentina

With about 68 recognized living species, subterranean rodents of the genus Ctenomys are found in a multiplicity of habitats, from the dunes of the Atlantic coast to the Andes Mountains, including environments ranging from humid steppes of Pampas to the dry deserts of Chaco region. However, this genus needs an exhaustive reevaluation of its systematic and phylogenetic relationships regarding the different groups that compose it. This knowledge is essential to propose biodiversity conservation strategies both at species level and at higher hierarchical levels. In order to clarify the taxonomy and the recent evolutionary history from populations of Ctenomys in the Pampas region, Argentina, phylogenetic relationships among them were evaluated using mitochondrial DNA sequences: gene encoding cytochrome b protein (1,140 bp) and the non-coding D-loop region (434 bp). To infer the divergence times inside the Ctenomys clade, a Bayesian calibrate tree using fossil remains data from different families within Caviomorpha was performed at first. Secondly, that calibration data was used as priors in a new Bayesian phylogenetic inference within the genus Ctenomys. This phylogenetic tree emphasized on species currently distributed on the Pampas region, more precisely considering both the talarum and mendocinus groups. Bayesian inferences (BI) were integrated with the results of a Maximum Likelihood approach (ML). Based on these results, the distributional limits of the mendocinus and talarum groups appear to be related to the physiognomy of the Pampas region soils. On the other hand, the validity of C. pundti complex as a differentiated species of C. talarum is debated. According to previous evidence from morphological and chromosomal studies, these results show a very low divergence between those species that originally were classified within the talarum group. Mitochondrial DNA sequences from populations associated with these putative species have not recovered as reciprocal monophyletic groups in the phylogenetic analyses. In conclusion, C. talarum and C. pundti complex might be considered as the same biological species, or lineages going through a recent or incipient differentiation process. The results obtained in this study have important implications for conservation policies and practices, since both species are currently categorized as Vulnerable and Endangered, respectively.

Taxonomy of Ctenomys (Rodentia: Ctenomyidae) in northwestern Patagonia, Argentina: the occurrence of the “mendocinus” lineage

Subterranean rodents Ctenomys are iconic representatives of the mammalian fauna from southern South America. Based on molecular data, eight lineages have been identified within the genus, although species-level identifications and relationships are still debated. Until now, the “magellanicus” clade has been the only lineage mentioned from arid, extra-Andean portions of Patagonia. Here, we report the presence of a Ctenomys population from northern Patagonia that is unambiguously associated with the Central Argentinean “mendocinus” lineage. Most of the 160,000 km2 comprising the northern portion of Patagonia – an area consisting primarily of Monte Desert shrub-land – are inhabited by Ctenomys populations of unknown taxonomy.