Phylogeography of the armadillo Chaetophractus villosus (Dasypodidae Xenarthra): post-glacial range expansion from Pampas to Patagonia (Argentina).

LIZARRALDE MARTA S.; POLJAK SEBASTÍAN; CONFALONIERI VIVIANA; FASANELLA MARIANA; GABRIELLI MAGALI

Mendoza

Congreso; 10 th. International Mammalian Congress; 2009

SAREM

Phylogeography of the armadillo Chaetophractus villosus (Dasypodidae Xenarthra): post-glacial range expansion from Pampas to Patagonia (Argentina). Lizarralde Marta¹, Poljak Sebastián¹, Confalonieri Viviana ², Fasanella Mariana ¹ and Gabrielli Magalí ¹. ¹ Laboratorio de Ecología Molecular, Centro Regional de Estudios Genómicos, Universidad Nacional de La Plata, Av. Calchaquí km 23,5. Piso 4. CP 1888, Florencio Varela, Buenos Aires, Argentina. ² Laboratorio de Investigación en Filogenias Moleculares y Filogeografía, Departamento de Ecologia, Genetica y Evolución, Fac. de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina. Armadillos (Cingulata, Dasypodidae) are the most diverse xenarthran lineage. They split after the isolation of South America from other continental masses at the end of the Cretaceous. Previous studies have provided a view of the intra-ordinal relationships and phylogeny of Xenarthra. In accordance with a relaxed molecular clock the genus Chaetophractus may have split from other related genera about 6 Myr ago. However, the first paleontological record of this genus is represented by plates assignable to the living species Chaetophractus villosus from the Chapadmalalense mammal age (4 – 3,2 Ma). It is endemic to southern South America, where it is one of the most widely distributed species of the order. Its range extends from Bolivia and Paraguay to Argentina and Bio Bio and Magallanes in Chile. Ch villosus was also introduced in Isla Grande of Tierra del Fuego, the southernmost insular region of Argentina, about 25 years ago. We report a phylogeographic study of Chaetophractus villosus in Argentina. Control Region sequences were obtained for 76 Chaetophractus villosus from 20 locations across its argentine whole range. Seventeen new haplotypes were identified. The highest genetic variation were found in the Pampean region, thus appearing as the most probable area of the species origen. A general pattern of contiguous range expansion was revealed by Nested Clade Analysis (NCA) while population expansion was suggested by the mismatch distribution analyses. The Pampean region would have been the preexpansion area, while from its center to the east and west and to Patagonia, would have been the main dispersal routes of contiguous expansion, possibly very recently in the case of the last mentioned region. Besides, we propose the existence of a ghost lineage of Chaetophractus vellerosus, a sister species of Chaetophractus villosus. The accurate identification of the fossils in the collections is essential for more realistic phylogeographic studies.