Constitutive heterochromatin heteromorphism in the Neotropical armored catfish (Ihering, 1905) (Loricariidae, Hypostominae) from the Paraguay River basin (Mato Grosso do Sul, Brazil).

A cytogenetic analysis based on the integration of a number of different chromosomal methodologies, including chromosome microdissection was carried out to characterize the chromosomally polymorphic population from the Paraguay River basin, state of Mato Grosso do Sul in Brazil. All specimens had 2n=72 (FN=116) but two distinct karyotype formulas: karyomorph A (12m+14sm+18s+28a) and karyomorph B (13m+14sm+17st+28a). Karyomorph A and B differed only for pair 19 that consisted of two subtelocentrics in karyomorph A and a large metacentric and a subtelocentric in karyomorph B.

Chromosome mapping in (De Geer, 1773) (Orthoptera) from the Iguaçu National Park - Foz do Iguaçu, Paraná, Brazil.

In this paper, we present the cytomolecular analysis of a population of collected in the largest fragment of the Brazilian Atlantic forest, the Iguaçu National Park. The diploid number in males was 23 (22+X0), with two large pairs (1-2), 7 medium (3-9), 2 small (10-11) and the X chromosome of medium size. Heterochromatic blocks were evident in the pericentromeric regions of all chromosomes.

A New Approach to Chromosomal Evolution in the Giant Water Bug (Heteroptera: Belostomatidae).

The genus Belostoma, known colloquially as “giant water bugs,” presents striking cytogenetic diversity and extensive chromosome variability. Notwithstanding, its karyotype evolution is not well understood. We analyzed 8 species of Belostoma (77 samples).

Spreading of heterochromatin and karyotype differentiation in two Tropidacris Scudder, 1869 species (Orthoptera, Romaleidae).

Tropidacris Scudder, 1869 is a genus widely distributed throughout the Neotropical region where speciation was probably promoted by forest reduction during the glacial and interglacial periods. There are no cytogenetic studies of Tropidacris, and information allowing inference or confirmation of the evolutionary events involved in speciation within the group is insufficient. In this paper, we used cytogenetic markers in two species, Tropidacriscollaris (Stoll, 1813) and Tropidacriscristatagrandis (Thunberg, 1824), collected in different Brazilian biomes.