The paradoxical frog Pseudis paradoxa: larval habitat, growth and metamorphosis

J. R. Downie, I. Ramnarine, K. Sams, P. T. Walsh

Research output: Contribution to journalArticlepeer-review


The genus Pseudis is unique amongst anuran amphibians in that body growth occurs mostly or entirely in the larva I phase, with huge tadpoles metamorphosing into adult-sized frogs. Tadpole growth rate, metamorphic duration and tadpole habitat were studied in the paradoxical frog Pseudis paradoxa in Trinidad, West Indies, in order to assess the factors which may have led to the evolution of this unique life history. Growth rate was shown to be similar to other tropical tadpoles: Pseudis simply continued to grow, rather than progress to metamorphosis. Metamorphic duration fitted well with a model based on tadpole size. Sexual dimorphism in tadpole size was apparent, with females larger than males at metamorphosis. Pseudis tadpoles initially possess highly cryptic patterning, which is lost as they grow larger. The costs and benefits of continued growth in the larval phase in a permanent tropical swamp habitat are discussed in terms of potential predators and food availability to both Pseudis larvae and adults.

Original languageEnglish
Pages (from-to)11-19
Number of pages9
JournalThe Herpetological Journal
Issue number1
Publication statusPublished - Jan 2009


  • Amphibian tadpoles
  • Anurans
  • Maturation
  • Trinidad


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