KARYOTYPIC DIVERSITY OF THE GENUS GRAOMYS THOMAS, 1916 (RODENTIA, CRICETIDAE, SIGMODONTINAE)

DE CENA, ROMINA; LABARONI CAROLINA; MARTINEZ JUAN JOSE; BALDO DIEGO; FERRO IGNACIO; OJEDA AGUSTINA; RODRÍGUEZ, MARÍA DANIELA; LANZONE CECILIA

Mastozoologia Neotropical

SAREM

Lugar: Mendoza; Año: 2023

The genus Graomys contains four species and presents signicant karyological diversity.Graomys griseoavus, inhabiting mainly the Monte Desert ecoregion, shows variations in diploid number (2n) from 33 to 38 due to Robertsonian translocations and in fundamental number of autosomal arms (FNa) from 44 to 48 due to inversions. Graomys chacoensis, which occurs in the ecoregions of the Chaco and the Espinal, has 2n=42 and FNa=44-46 due to a pericentric inversion. Graomys domorum, which inhabits the Yungas ecoregion and the Yungas-Chaco transitional zones and exhibits 2n=28 and FNa=46, but its karyotype is known only by a schematic representation for two specimens from Bolivia. The karyotype of G. edithae has not yet been described. In this report, we studied 29 individuals of the three former species from dierent localities of theirdistribution, using conventional and dierential cytogenetic techniques and chromosome measurements. In G. griseoavus, we have identied the pairs involved in the three Robertsonian translocations, supporting an independent, not sequential origin of this polymorphism. The nearby area of Mendoza City showed the greatest chromosomal diversity for G. griseoavus. The banding pattern associated with the chromosomal measurements allowed us to suggest the possible pairs involved in the pericentric inversions of G. griseoavus and G. chacoensis. The presence of heterochromatin indicates more signicant chromosomal variability and complexity than previously recognized. The chromosome complements of G. chacoensis and G. griseoavus are more similar to each other. The karyotype of G. domorum from Argentina diers from the previously reportedfrom Bolivia, and is the most divergent within the genus.