COMPARATIVE CYTOGENETIC STUDIES OF 11 SPECIES OF THE TROPIDURUS-TORQUATUS GROUP (SAURIA, TROPIDURIDAE), WITH BANDING-PATTERNS

The chromosomes of 173 specimens representing eleven species of the Tr opidurus torquatus group, from 33 localities in Brazil, were analysed after Giemsa staining, C-banding, NORs, and replication banding techni ques. A karyotype with 2n = 36, including 12 macrochromosomes and 24 m icrochromosomes (12 M + 24 m), and sex determination of the XY:XX type were found in Tropidurus cocorobensis, T. erythrocephalus, T. etherid gei, T. hispidus, T. hygomi, T. montanus, T. mucujensis, T. oreadicus, and T. torquatus. The two other species, T. itambere and T. psammonas tes, presented 2n = 36 (12 M + 23 m) karyotype only in females while m ales had 2n = 35 (12 M + 23 m), due to the sex determination of the X( 1)X(2)Y:X(1)X(1)X(2)X(2) type. Other interspecific differences as well as some intraspecific variation regarding the NORs and C-banding patt erns have been observed, mainly in the microchromosome set. On the con trary, the macrochromosomes were highly conservative. Although consist ent karyotypic diversity occurred in the torquatus group, the cytogene tic data obtained up to now did not allow us to clarify the phylogenet ic relationships of the species. Nevertheless, the geographical distri bution of the distinct cytotypes in T. hispidus and T. torquatus sugge sted that more than one species might be involved in each case.