A new species of tuco-tuco, genus Ctenomys, is described from sandy soils on the western slopes of the state of Rio Grande do Sul in southern Brazil. This species is distinguished from other named members of this South American endemic genus by several characteristics. Diagnostic traits for this proposed species are a diploid number of 50 chromosomes and an autosomal fundamental number of 68 arms, with the 1st pair much longer than in other related species. Qualitative and quantitative (geometric morphometrics) analyses of the skull morphology and phylogenetic analysis of the mitochondrial cytochrome-b gene support species status, especially when compared with phylogenetically related and geographically neighboring species. Populations of this species have a narrow geographic distribution in a small area (~500 km 2 ) that has been suffering from anthropogenic pressure from soybean, pine, and eucalyptus plantations, as well as desertification. This scenario suggests that this species could be characterized as endangered.

Aim Subterranean rodents of the genus Ctenomys are widespread in open habitats; the collared tuco‐tuco, C. torquatus, has a wide range crossed by large water‐courses. Based on a phylogeographical approach to investigate the riverine barrier hypothesis, we evaluated the strength of a river as a barrier and characterized the effect of large rivers in structuring distinct populations of the collared tuco‐tuco. Location Grasslands of southern Brazil. Methods Sampling included 294 individuals from 33 localities throughout the geographical range of C. torquatus, especially around the main rivers. Phylogeographical patterns were estimated through two mitochondrial DNA sequences (control region and COI). Additionally, 22 microsatellite loci were surveyed to estimate the effect of rivers on population divergence through the FST index of genetic differentiation and AMOVAs. Spatial autocorrelation analyses were performed for both molecular markers. Molecular rates of change for mitochondrial DNA were estimated using fossil records and applied to Bayesian demographic analysis to test the relationship with the river geological data. Results Molecular‐clock analysis estimated the time to most recent common ancestor (TMRCA) to be c. 200 kyr and indicated a pattern of recent demographic expansion for C. torquatus. Fu's FS neutrality test was significant and negative (−13.7). High and significant FST and AMOVA among‐population comparisons (FSC) revealed highly differentiated populations, although no AMOVA groupings considering rivers as a segregating factor were significant. Spatial autocorrelation analysis revealed that isolation by distance was detected over approximately 200 km. Main conclusions The effect of the river was not proportionally larger from the headwaters to the mouth, and no population differentiation was observed after the later events of dispersal over the river or the formation of a water channel. This finding could result from the recent history of the occupation of C. torquatus in that region, combined with a dry Pleistocene climate and lower river levels.

ABSTRACT. Species with a broad distribution rarely have the same genetic make-up throughout their entire range. In some cases, they may constitute a cryptic complex consisting of a few species, each with a narrow distribution, instead of a single-, widely distributed species. These differences can have profound impacts for biodiversity conservation planning. The genetic differentiation of four populations of Aegla longirostri, a freshwater crab found in two geographically isolated basins in Rio Grande do Sul State, Brazil, was investigated by analyzing pentanucleotide multi-loci microsatellites in a heteroduplex assay. Although no morphological differences were evident, we found significant genetic differentiation among the four populations, based on F ST values and clustering analysis. This high level of differentiation may be indicative of cryptic species in these populations. If this hypothesis is correct, then the species occurring in the Ibicuí-Mirim ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 10 (4): 4133-4146 (2011) M.L. River, at the southern limit of the Atlantic Rain Forest, would be under threat, considering its very restricted distribution.

Protocols for microsatellite-enrichment libraries have been widely applied to several species in order to supply the most informative molecular markers for population and inbreeding studies. One drawback of these protocols is the ratio of designed primer pairs that fail to amplify the expected fragment, even after exhaustive optimization attempts. A possible cause of unsuccessful microsatellite primers may be that such loci are artifacts resulting from chimeric PCR products, instead of real genomic sequences. The microsatellite-enriched library constructed for Aegla longirostri (Crustacea, Decapoda, Anomura) showed that 29% of sequenced clones were chimeric products because these sequences shared one of the flanking regions around the same repeat motif but not the other. PCR-mediated recombination is a well-known event described for several procedures in which related sequences are used as a template. We have associated this phenomenon with microsatellite marker development. This study explained the high ratio of recombinant sequences generated in the A. longirostri microsatellite-enriched library. We discuss the mechanism and implications of PCR chimeric-product formation during microsatellite isolation

The aim of this study was to compare some DNA extraction methodologies for Aegla longirostri. The protocols were based on the traditional phenol-chloroform DNA extraction methodology and using a commercial kit for DNA extraction. They differed in tissues used, the addition -or not -of β-mercaptoethanol to the lysis buffer, times and methods for the animal's conservation (frozen, in ethanol or fresh

Filter Backwash Water (FBW) from water treatment plants (WTP) is composed of raw water waste, chemicals and microorganisms. Inappropriate disposal of this residue impacts negatively in the environment and in the health of human populations. Aiming to characterize the FBW from one WTP of Blumenau-SC, physiochemical, microbiological and parasitological assessments and tests with different flocculants polymers were performed in order to propose strategies for treatment and reuse of this residue. Subsequently treated liquid is discharged into the Itajaí-Açu River (Class 2). Physicochemical and microbiological analyses showed results higher than those permitted by CONAMA Resolution n° 430/2011 and Giardia duodenalis (Assembly B) cysts and Cryptosporidium spp. oocyst positivity was observed, characterizing as polluted and contaminated residue that shouldn't be released in the hydric body.  The anionic flocculant polymer showed satisfactory results in the turbidity sample reduction (99.49%), which may be a promising alternative in the treatment of this residue.

Eleven microsatellite markers were isolated from an enriched library developed specifically for the tuco-tuco Ctenomys torquatus, using tri and tetranucleotide probes. Ten of these were successfully amplified, and only one was monomorphic for the populations that have so far been analyzed. Analysis of two different populations yielded a mean of 2.6 (Cachoeira do Sul-CAC) and 4.3 (Butiá-BUT) alleles per locus, with a range from 1 to 6. The means for observed and expected heterozygosity were also lower in the CAC population (Ho = 0.37 and He = 0.39), but in BUT they were 0.63 and 0.61 respectively. These are the first microsatellite markers reported for a Brazilian species of tuco-tuco, and will be applied to investigate the genetic structure of their populations in the widely impacted Pampa Biome.

Endemic, small range species are susceptible to environmental changes and landscape modification. Understanding genetic diversity and distributional patterns is important for implementation of effective conservation measures. In this context, genetic diversity was evaluated to update the conservation status of an endemic tuco-tuco, Ctenomys ibicuiensis. Phylogeographic and population genetic analyses of mitochondrial DNA and microsatellite loci were carried out using 46 individuals sampled across the species’ distribution. Ctenomys ibicuiensis presented moderate to high genetic diversity and highly structured populations with low levels of gene flow and isolation by distance. Anthropogenic landscape changes threaten this restricted-range tuco-tuco. Considering its limited geographic distribution and highly structured populations with low gene flow, we consider C. ibicuiensis to be at significant risk of extinction.