CYTOGENETIC STUDIES IN 6 SPECIES OF TROPIDURIDAE (SAURIA)

Cytogenetic studies were performed on six tropidurid lizards: Tropidur us mucujensis, T. hispidus, T. montanus, T. semitaeniatus, T. spinulos us and Uranoscodon superciliosus. Conventional and differential (C- an d R-bands and Ag-NORs) staining techniques were employed for the chara cterization of the karyotypes. The analyses were carried out in order to establish the morphological characterization of macro and microchro mosomes, the R- and C-banding patterns as well as the silver staining of nucleolus organizer regions (Ag-NORs). R-banding was obtained after in vitro incorporation of 5-bromodeoxyuridine (BrdU). For some specie s, the banding patterns are described for the first time. All species presented a diploid number of 2n=36, with a basic karyotype constitute d by 12 metacentric or submetacentric macrochromosomes and 24 microchr omosomes (12M+24m). Although these species present a conservative kary otype, most of them are distinguished by the morphology of the macro a nd microchromosomes, by location of Ag-NORs, and by amount and distrib ution of constitutive heterochromat in. Sex determination of the XX:XY type was found in T. hispidus, I: montanus and U. superciliosus. The presence of spec ies specific karyotypes in T. spinulosus and U. super ciliosus is suggested.