Integrative evolutionary analyses in two Eligmodontia species (Rodentia, Cricetidae, Sigmodontinae): a speciation and hybridization case.

BUSCHIAZZO, L.M; TORRES J; OJEDA A; A. NOVILLO; BENDER B; OJEDA R.; C. LANZONE

Congreso; 100Th Annual Meeting of the American Society of Mammalogists; 2021

American Society of Mammalogists

The genus Eligmodontia is a taxon of small rodents, comprising 7 species, whose diversification process is linked to the Andean orogeny and the development of arid South American biomes. The sister taxa E. puerulus and E. moreni are of recent cladogenesis, and currently distributed in the Puna and Monte Desert of Argentina, respectively. Preliminary investigations, based on conventional cytogenetics and linear morphometry, revealed that both taxa differ at morphological and chromosomal levels. However, molecular studies using mitochondrial markers showed a strong polyphyletic pattern, not compatible with reproductively isolated species. In this study we integrate differential banding cytogenetic techniques, analyses of nuclear genes and geometric morphometry applied to Eligmodontia specimens of both species, from different populations inhabiting northwestern Argentina. Our results at the chromosomal level showed a complex evolutionary scenario, associated with the presence of multiple Robertsonian rearrangements with different frequencies and high interpopulation variability in E. puerulus. At morphological and molecular levels, no hybrid phenotypes nor mixture of nuclear haplotypes were detected. These results support the interspecific separation of these taxa, with asymmetric introgression and mitochondrial capture, only from E. moreni to E. puerulus. Our research highlights the importance and the complexity of hybridization and introgression in the speciation processes.Partially financed by PIP-CONICET 2015-0258