Chromosomal diversity in Crematogaster Lund, 1831 (Formicidae: Myrmicinae) from the Amazon rainforest.
<i>Crematogaster</i> Lund, 1831 is a speciose ant genus globally distributed and easily recognizable. Although biogeographical theories explain some variation among Neotropical <i>Crematogaster</i>, several taxonomical issues remain unresolved. While cytogenetic approaches can help to delimit species, cytogenetic data are only available for 18 taxa. In this study, classical and molecular cytogenetic analyses were performed on five <i>Crematogaster</i> species from the Brazilian Amazon to identify species-specific patterns. Two different cytotypes, both with 2n=22 chromosomes were observed in <i>Crematogaster erecta</i> Mayr, 1866, suggesting the presence of cryptic species, although with different karyotypic formulas. <i>Crematogaster</i> aff. erecta had 2n=28, while<i> C. limata</i> Smith, 1858, <i>C. tenuicula</i> Forel, 1904 and <i>Crematogaster </i>sp. had 2n = 38. The telomeric motif (TTAGG)<sub>n</sub> was found in all five species, and the (TCAGG)<sub>n</sub> motif was detected in the telomeres of <i>C. limata</i>. This peculiar motif was also detected in the centromeric regions of <i>C. erecta</i> cytotype I. The microsatellite (GA)<sub>n</sub> was dispersed in the chromosomes of all species studied which also had a single intrachromosomal rDNA site. The cytogenetic results revealed notable interspecific and intraspecific variation, which suggests different chromosomal rearrangements involved in the origin of these variations, also highlighting the taxonomic value of cytogenetic data on <i>Crematogaster</i>.
