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

LM BUSCHIAZZO; TORRES, JULIO; AGUSTINA A OJEDA; AGUSTINA NOVILLO; BENJAMIN BENDER; RICARDO OJEDA; CECILIA LANZONE

Congreso; 100TH ANNUAL MEETING OF THE AMERICAN SOCIETY OF MAMMALOGISTS; 2021

ASM

The genus Eligmodontia is a taxon of small rodents, comprehending 7 species, whosediversification process is linked to the Andean orogeny and the development of arid SouthAmerican biomes. The sister taxa E. puerulus and E. moreni are of recent cladogenesis, andcurrently distributed in the Puna and Monte Desert of Argentine, respectively. Preliminaryinvestigations, based on conventional cytogenetics and linear morphology, revealed that bothtaxa differ at morphological and chromosomal levels. However, molecular studies usingmitochondrial markers showed a strong polyphyletic pattern, not compatible withreproductively isolated species. In this study we integrate differential banding cytogenetictechniques, analyses of nuclear genes and geometric morphology applied to Eligmodontiaspecimens of both species, from different populations inhabiting northwestern Argentina. Ourresults at the chromosomal level showed a complex evolutionary scenario, associated with thepresence of multiple Robertsonian rearrangements with different frequencies and highinterpopulation variability in E. puerulus. At morphological and molecular levels, no hybridphenotypes nor mixture of nuclear haplotypes were detected. These results support theinterspecific separation of these taxa, with asymmetric introgression and mitochondrialcapture, only from E. moreni to E. puerulus. Our research highlights the importance and thecomplexity of hybridization and introgression in the speciation processes.