Review of the Geographic Distribution of Diploid and Tetraploid Populations of the Odontophrynus americanus Species Complex (Anura: Leptodactylidae)

ROSSET, S. D.; BALDO, D. D.; LANZONE, C.; BASSO, N. G.

JOURNAL OF HERPETOLOGY

Allen Press

Lugar: Salt Lake City; Año: 2006 vol. 40 p. 465 - 477

0022-1511

We review the geographic distribution of diploid and tetraploid populations of the Odontophrynus americanus species complex. Ploidy was determined using chromosome count as well as erythrocyte size. We found a complex geographic pattern of populations with different ploidy, including areas of syntopy and sympatry. The tetraploid O. americanus presents three disjunct population groups, which were isolated from one another by diploid populations. One of these tetraploid groups is distributed in central and eastern Argentina, southern Brazil, southern Paraguay, and Uruguay, with the other two population groups of the tetraploid O. americanus inhabiting southeastern Brazil, and northwestern Argentina respectively. We extend the distribution of both diploid Odontophrynus lavillai and Odontophrynus cordobae, and we present new records of three more allopatric diploid population groups, referred to here as Odontophrynus sp. Some of these population groups are associated with biogeographic regions. The karyotypes of the three currently known taxa of the O. americanus species complex are given. We report the occurrence of a naturally occurring triploid specimen and the first occurrence of B-chromosomes in the genus. Our review indicates that there is a complex distribution pattern of populations of different ploidy, including areas of syntopy and sympatry, and cytogenetic variability. This could indicate the presence of more species, occurrence of auto and allopolyploidy, and multiple origins of tetraploidy.