Amphibian animals belonging to order Anura were listed 23 families, 302 genera and 3512 species (Frost 1985). In the whole amphibian species about 87% are anurans which distribute all over the world except the arctic and antarctic regions. Karyological studies have been accelerated in a couple of decades by the development of sophisticated techniques in anuran cytogenetics.
The present paper prepared for overviewing the modern karyological studies for considering the karyoevolution in frogs and toads, as well as the systematic relations among families and genera.
Duellman and Trueb (1986) described on hypothesized phylogenetic relationsips of 22 families of anurans including Palaeobatrachidae. They grouped these families into 7 branches on the cladgram based on analyzing 16 characters according to osteological, anatomical and behavioral evidences. These are as follows: 1) Leiopelmatidae and Discoglossidae, 2) Rhinophrynidae and Papidae, 3) Pelobatidae and Pelodytidae, 4) Myobatrachidae, Heleophrynidae, and Sooglossidae, 5) Leptodactylidae, Bufonidae, Brachycephalidae, Rhinodermatidae, Pseudidae , Hylidae, and Centrolenidae, 6) Dendrobatidae, Ranidae, Hyperoliidae and Rhacophoridae, and 7) Microhylidae. Although ambiguous premise remains on the cladgram as they mentioned, I am describing the article following their grouping of 21 families of living frogs and toads.
The present paper concerns the karyological evidence of 11 families placed in the groups 1, 2, 3, 4 and two families of the group 5, as the first half part of the article on anuran karyoevolution.