Synchronous polyandry and multiple paternity in the frog Crinia georgiana (Anura : Myobatrachidae)

Multiple paternity has rarely been reported in anuran amphibians, with only three previous documented. examples. For the Australian frog Crinia georgi ana, we observed synchronous polyandry in an average of 44% of matings obse rved at four field sites. This suggests matings involving more than one mal e are common in this species. One to eight males were observed in amplectan t groups with second males amplexed ventrally. Genetic analyses, using allo zyme electrophoresis, of offspring from two matings indicated that at least two of three possible males fathered offspring. Third males were unlikely to have shared paternity, explained by their inappropriate position during amplexus. Multiple paternity may be more common in frogs than has been repo rted. (C) 1999 The Association for the Study of Animal Behaviour.