Cytogenetics of South American Akodont Rodents (Cricetidae): New Karyotypes and Chromosomal Banding Patterns of Argentinian and Uruguayan Forms

Abstract

Cytogenetic analysis was performed in Akodon (Akodon) puer (= Akodon coenosus ) , Akodon azarae bibianae, Akodon ( Hypsimys ) budini, Bolomys temchuki elioi, Bolomys temchuki liciae, Oxymycterus rufus rufus, Oxymycterus ruf us platensis , and Oxymycterus paramensis . Diploid numbers, chromosomal morphology, and lengths and banding patterns (G and C) were determined for each taxon. Chromosomal number and gross morphology are also described in topotypical specimens of Akodon ( Akodon ) arenicola (= Akodon ( Akodon ) azarae azarae ) and Oxymycterus nasutus . A 2n = 34 karyotype, similar to one previously reported as Akodon coenosus , was confirmed in Akodon puer. A. budini showed a 2n = 38 karyotype peculiar within the genus as regards chromosomal morphology and C bands. A. a. bibianae has a 2n = 38 karyotype closely related with that of A. a. azarae . The two subspecies of B. temchuki , which differ strikingly in fur color, showed an identical 2n = 34 karyotype, which was quite similar in diploid number, chromosomal morphology, and banding patterns to that reported for B. lasiurus , but was different in the morphology of the Y and in G and C bands when compared with B. obscurus from the south of Buenos Aires Province. The three species of Oxymycterus , which markedly differ in morphometric character states, showed an identical 2n = 54 karyotype, and no banding differences were observed between O. rufus and O. paramensis .