Huge but moderately long-lived: age structure in the mountain chicken, Leptodactylus fallax, from Montserrat, West Indies

We applied skeletochronological methodology to assess the age and growth in one of the largest living anurans, the mountain chicken Leptodactylus fallax. We analysed bone cross-sections obtained from wild animals found dead after a chytrid outbreak in Montserrat in 2009, and from captive individuals which are part of a breeding program at Jersey Zoo. Lines of arrested growth (LAGs) were visible in both groups. Individuals reared in captivity reached an older age than their wild counterparts. At the same age, captive males and females were larger than wild individuals. A literature screening of age and snout-vent length (SVL) for 46 species ascribed to seven families (Bufonidae, Dicroglossidae, Leptodactylidae, Mantellidae, Microhylidae, Ranidae and Rhacophoridae) showed that the largest species were also the most long-lived. With a maximum documented SVL of 280 mm and a maximum longevity of 9 years, L. fallax reached a higher body size as predicted by age, representing a case of gigantism probably associated with adaptation to an insular environment.