title: Karyologic evidence of diversification of the genus Thrichomys (Rodentia, Echimyidae).
abstract: Karyologic analysis of Thrichomys specimens from different Brazilian localities, in Pantanal, Cerrado and Caatinga biomes, shows different chromosome complements. The 2n = 34, FN = 64 karyotype is found in Mato Grosso do Sul state; the 2n = 30, FN = 54 karyotype in Bahia, Pernambuco, Piauí and Ceará states; the 2n = 30, FN = 56 karyotype in Goiás and Tocantins states, the 2n = 28, FN = 50 karyotype in Minas Gerais state, the 2n = 28, FN = 52 and 2n = 26, FN = 48 karyotypes in Bahia state. Comparisons of G-band patterns allowed the identification of homologies shared by all karyotypes and show that the two karyotypes with the lowest diploid number (2n = 26 and 2n = 28) belong to two different evolutionary lineages. The most proper names for each karyomorphic population are: Thrichomys pachyurus for 2n = 34; Thrichomys apereoides apereoides for 2n = 28, FN = 50; Thrichomys apereoides laurentius for 2n = 30, FN = 54 and Thrichomys inermis for 2n = 26. Two karyotypes (2n = 28, FN = 52 and 2n = 30, FN = 56) could not be attributed to any subspecies. These different karyomorphotypes are allopatric and/or parapatric.
authors.affiliation: Genetics Division, Instituto Nacional de Câncer, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. cibelerb@inca.gov.br
authors.forename: C R
authors.initials: CR
authors.lastname: Bonvicino
authors.forename: I B
authors.initials: IB
authors.lastname: Otazu
authors.forename: P S
authors.initials: PS
authors.lastname: D'Andrea
mesh_terms: D000818:Animals; D007621:Karyotyping; D012377:Rodentia / Q000145:classification / Q000235:genetics*; D013045:Species Specificity