Despite rapid urbanization, the herpetofauna population of Guwahati has not been severely affected. There are some 63 species of herpetiles in this Assam city. "This is good news and can be termed as one of the best average populations," said herpetofauna researcher Jayaditya Purkayastha after release of his book "Urban Herpetofauna: Amphibians and Reptiles of Guwahati" on World Wetland Day on Thursday.