The Study on The Karyotypes,C-Banding and Ag-NORs of Four Paa Species in China (Amphibia:Anura)

The Karyotypes,C-banding and Ag-NORs of four Anuran paa species in China.Have been investigated here.The results are as follows:Paa liui 2n=64T,all the centromeric regions have C-positive staining and Ag-NORs localized on 20qinter.Paa boulengeri and P.chayuensis both from Yunnan and P.quadrana from mount Taihang in Henan Province have 2n=26 consisted of SM or M and 5+8 formulae commonly,but the count and sequence of SM between them showed some dissimilarities.For the former two there are same 6pper Ag-NORs locations,but more differences are found in C-bands:some terminal and interstitial C-bands presented in P.Chayuensis,but light staining in centromeric regions.And in the latter--Paa quadrana there are more dense interstitial and terminal C-bands in some pairs except in centromeric ones that are less developed.No heteromorphic sex chromosomes occurred in four species studied.Finally the comparison and analysis of karyotypes and banding pattern and evolution way between species and geographical populations are discussed.