Revisiting the polyploidy in the genus Odontophrynus (Anura: Odontophrynidae)

The genus Odontophrynus, composed of ten species, is found in practically the entire south South America. Odontophrynus americanus was first vertebrate registered to present natural polyploidy, considering that most individuals have 2N = 4x 44 chromosomes, although having 2x 22 chromosomes considered ancestral condition for all genera family Odontophrynidae. study aimed analyze karyotype O. americanus, providing a detailed and comparative description conventional chromosomal markers, with focus on possible diploidization process operating this polyploid genome. were collected fragment Atlantic Forest south-central region Paraná State, Brazil. analyzed presented tetraploid pattern, biarmed chromosomes. C-banding showed heterochromatic regions restricted centromeres telomeres. Among homologous same quartet, small differences observed morphology, possibly result differentiation after polyploidization event. Finally, 45S rDNA (Nucleolar Organizer Regions) mapped short arm quartet 11, showing nucleolus organizing active four This genome, structurally polyploid, may be undergoing diploidization, by becoming functionally equivalent diploid via rearrangements, epigenetic mechanisms, and/or repetitive DNA dynamics.