This study aims to investigate the hypothesis that a big island can be divided into a number of smaller islands, which have the same pattern of area-species curve as the real islands do. To address this question, we use published data on amphibians and reptiles and their distribution on the island of Puerto Rico and landbridge islands of the Puerto Rican Bank, which were frag-mented from the main island only within about 10,000 years ago. Several different methods of sub-dividing the island into smaller semi-islands are employed. Our results show that in Puerto Rico there are...