10.6084/m9.figshare.5128861.v1 da Silva W.O. da Silva W.O. Pieczarka J.C. Pieczarka J.C. Rossi R.V. Rossi R.V. Schneider H. Schneider H. Sampaio I. Sampaio I. Miranda C.L. Miranda C.L. da Silva C.R. da Silva C.R. Cardoso E.M. Cardoso E.M. Nagamachi C.Y. Nagamachi C.Y. Supplementary Material for: Diversity and Karyotypic Evolution in the Genus <b><i>Neacomys </i></b>(Rodentia, Sigmodontinae) Karger Publishers 2015 Amazonia Bristly mouse Chromosomal evolution FISH Karyotype Spiny mouse 2015-11-21 00:00:00 Dataset https://karger.figshare.com/articles/dataset/Supplementary_Material_for_Diversity_and_Karyotypic_Evolution_in_the_Genus_b_i_Neacomys_i_b_Rodentia_Sigmodontinae_/5128861 <i>Neacomys</i> (Sigmodontinae) comprises 8 species mainly found in the Amazonian region. We describe 5 new karyotypes from Brazilian Amazonia: 2 cytotypes for <i>N. paracou</i> (2n = 56/FNa = 62-66), 1 for <i>N. dubosti </i>(2n = 64/FNa = 68), and 2 for <i>Neacomys</i> sp. (2n = 58/FNa = 64-70), with differences in the 18S rDNA. Telomeric probes did not show ITS. We provide a phylogeny using <i>Cyt</i>b, and the analysis suggests that 2n = 56 with a high FNa is ancestral for the genus, as found in <i>N. paracou</i>, being retained by the ancestral forms of the other species, with an increase in 2n occurring independently in <i>N. spinosus</i> and <i>N. dubosti</i>. Alternatively, an increase in 2n may have occurred in the ancestral taxon of the other species, followed by independent 2n-reduction events in <i>Neacomys</i> sp. and in the ancestral species of <i>N. tenuipes</i>, <i>N. guianae</i>, <i>N. musseri</i>, and <i>N. minutus</i>. Finally, a drastic reduction event in the diploid number occurred in the ancestral species of <i>N. musseri</i> and <i>N. minutus </i>which exhibit the lowest 2n of the genus. The karyotypic variations found in both intra- and interspecific samples, associated with the molecular phylogeny, suggest a chromosomal evolution with amplification/deletion of constitutive heterochromatin and rearrangements including fusions, fissions, and pericentric inversions.