Mueller: So some of them have an aquatic larval stage, which is sort of analogous to a frog-tadpole stage and then metamorphose and live the rest of their lives on land. Some of them have an aquatic larval stage that they retain through sexual maturity.
Narrator: Then there are some which have actually forgone the larval stage all together and are instead, fully terrestrial.
Mueller: The eggs are laid on land and out of the eggs pops a little, tiny miniaturized terrestrial salamander. So from the perspective of diversity, those are very different strategies. In salamanders, direct development, which is the case where you have an egg laid on land and a little terrestrial salamander walking out of it, only happens in Plethodontids, itís not seen anywhere else.
Adding to their biodiversity, Mueller recently
discovered through genetic analysis that three of
the four known groups of Plethodontid salamanders
arenít actually groups at all. For Science Today,
Iím Larissa Branin.