Additional studies of chromosomes of anuran amphibians.

Chromosome numbers are reported for 30 species representing eight families of anurans. These, together with previously published records, provide some evidence of trends in numbers of chromosomes at the family level. With the exception of two genera of leptodactylids, diploid numbers range from 20 to 36 and haploid numbers, from 10 to 18 in anurans studied to date. Chromosome numbers have been reported for at least one representative species from 11 of the 17 Recent families of anurans, but relative to the number of species we really have little basic information. The present paper reports chromosome numbers for 30 species of anurans representing eight families, including one family (Dendrobatidae) for which chromosome numbers have not been reported previously. Additionally, pertinent published data on anurans are summarized and comments are made on certain possible phylogenetic relationships based on the significance of the different chromosome numbers. Chromosomes were studied by means of the technique employed by Duellman and Cole (1965), with one modification; frequently staining was accomplished simply by placing a few drops of propiono-orcein stain into the vials of fixative containing the testes. Chromosome numbers were determined by studying cells of the following stages of meiosis: diplotene, diakinesis, metaphase I, and metaphase II. Some cells at mitotic prophase and metaphase were examined. Abbreviations for the catalogue numbers of the specimens examined are: KU (University of Kansas Museum of Natural History) and AMNH (American Museum of Natural History). Chromosome numbers for frogs that were examined are given first in each familial account and followed, where appropriate, by counts given in the literature. Chromosome numbers for species listed by Duellman and Cole (1965) are not given here. RESULTS AND DISCUSSION Pelobatidae.-Scaphiopus bombifrons Cope, n = 13. The same haploid number was reported in this species and in S. hammondi Baird by Hughes (1962) and in S. holbrooki (Harlan) by Witschi (1933); Ting and Price (1950) determined the diploid number in S. holbrooki to be 2n = 26. The chromosome number has been reported for only one other member of the family, Pelobates fuscus Gunther which has n = 13, 2n = 26 (Makino, 1951). Thus, in the American Scaphio,pus and the European Pelobates, which constitute the subfamily Pelobatinae, the chromosome number seems to be constant. Chromosome numbers of the other nine pelobatid genera, comprising the subfamilies Megophryinae and Sooglossinae, are unknown. Leptodactylidae.-Eleutherodactylus augusti cactorum Taylor, n = 11; Tomodactylus nitidus nitidus (Peters), n = 11 (Fig. 3). Diploid numbers of 2n = 22 were reported by Barbieri (1950) for Leptodactylus bufonius Boulenger, L. chaquensis Cei, L. ocellatus (Linnaeus), and L. prognathus Boulenger. Presumably, Leptodactylus has n = 11 chromosomes. Subfamilial groupings of leptodactylids include the genera Eleutherodactylus and Tomudactylus in the Eleutherodactylinae and Leptodactylus in the Leptodactylinae (Gallardo, 1965). Saez and Brum (1960b) reported 2n = 22 chromosomes in Pseudopaludicola falcipes, a genus placed in a separate subfamily, Pseudopaludicolinae, by Barrio (1945). Barbieri (1954) reported chromosome numbers of