Assessing the phylogeographic structure of the southern-three banded armadillo Tolypeutes matacus

FERREIRO, A.M.; POLJAK, S. ; SOIBELZON, E.; CHIAPPERO M.B.

Evento on-line

Congreso; Congresso Internacional de Conservação de Xenarthra; 2020

Instituto de Investigación y Conservación de Osos Hormigueros de Brasil

The southern three-banded armadillo (Tolypeutes matacus) is currentlydistributed in xeric areas of the Chacoan Region (Eastern Bolivia,Argentina, and Paraguay) and it extends its distribution to the PantanalRegion (South-western Brazil). To date, no study has focused on trying tounderstand how the populations of this species evolved to reach thedistributional range that we are seeing nowadays. To contribute withknowledge that helps recognize conservation priorities for the species,here we share preliminary results from a phylogeographic study aimed tobetter understand the patterns and processes that ruled the evolutionaryhistory of this species? populations. We obtained 44 tissue samples from18 localities throughout Argentina during field trips and collected bycolleagues. We obtained DNA sequences for the control region of themitochondrial genome and generated a haplotype network and ahaplotype frequency map using PopArt v 1.7. We estimated the number ofgenetic clusters and their limits using Geneland v. 4.9.2, and calculatedseveral genetic diversity indices for each cluster and populationdifferentiation indices using Arlequin v. 3.5. The haplotype network for the44 sequences obtained showed a complex pattern with most of thehaplotypes being connected to their neighbors by only one mutationalstep. The exceptions were two haplotypes from northern Argentina thatwere connected with their neighboring haplotypes by four to sixmutational steps. The most frequent haplotype was present in southernlocalities, being almost the only haplotype found in this region. Genelandanalysis detected two genetic clusters (K=2): a northern cluster includinglocalities from Salta, Formosa, Chaco, Tucuman, Santiago del Estero, andnorthern of Cordoba provinces, whereas the southern cluster includedlocalities from western Cordoba, La Rioja, San Juan, and San Luis. Bothclusters showed significant genetic differentiation (FCT = 0.153, P =0.006). Diversity indices were in general higher for northern group(H=0.942 +/- 0.033; π=0.172 +/- 0.100) than those found for southerncluster (H=0.649 +/- 0.110; π=0.096 +/- 0.061). The haplotype networksuggests low population genetic structure for T. matacus in Argentina.However, our data support the existence of two genetic groups, withgeographical coherence. Lower genetic variability in the southern clustermay be associated with their proximity to glaciers and expansion of thePatagonian steppe during Pleistocene glacial periods. Also, the northernregion, where we found the highest genetic diversity, are in agreementwith climatic refugia proposed for a chacoan tree. These are preliminaryresults and a further step to a better understanding of the evolutionarypatterns of the species would be to include localities in the most northernregions of its range from Bolivia, Paraguay, and Brazil. The informationgenerated from this phylogeographic study contributes to increase theknowledge on the species and will enable establishing better conservationstrategies