“ANURAN AMPHIBIANS such as Xenopus are intermediate between urodele amphibians and other vertebrates in terms of their regenerative capacity, in that they can completely regenerate developing hindlimb buds prior to the onset of metamorphosis, but regenerative capacity declines gradually as metamorphosis proceeds.”
http://onlinelibrary.wiley.com/doi/10.1111/j.1440-169X.2007.00973.x/full