What's the Deal with Ambystoma 'Unisexual Complex?'

Every now and then, I see observations from unisexual mole salamanders, blue-spotted salamanders, Jefferson salamanders, and occasionally, small-mouthed salamanders. I’m slightly confused on how the taxonomy works on these guys, and how to tell them apart (if possible). If anyone has some information on them, I’d really appreciate it.

I am certainly no expert on these, but you may find these fact sheets from the Massachusetts Natural Heritage and Endangered Species Program useful, as Jefferson/Blue-spots/unisexual salamanders are state-listed here:

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I think you’re asking about how to identify them, which I don’t know, but I know something about the biology that allows for unisexual populations of amphibians. They have a really interesting and complicated means of producing offspring that are (mostly) clones of themselves with no males. In short, meiosis (the process by which almost all eukaryotes produce haploid gametes) is broken in these lineages, such that they rarely produce viable eggs. But they have a mechanism that, to oversimplify, takes the results of this failed meiosis and pieces it back together into a viable whole cell that functions as a successful egg much of the time. The rate of developmental failure with this mechanism is much higher than regular sexual reproduction, but it does allow for cloning, which can be useful if good mates are hard to find, or the genotype being cloned is particularly well suited to the environment.


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