Re: Many mysteries
"Species" is one of those words that attempts to draw lines in continuous spectrums.
Sharp lines in spectrums are inherently troublesome. Even the slightest zoom into the transitional or boundary cases leads to endless issues in the definition *of the boundaries*.
We need to acknowledge this most general of points to minimize pointless arguments.
A solution is: NEVER BIFURCATE A SPECTRUM.
Always provide at least a third middle option.
This is a highly-useful clarification of thinking. It should be taught in Elementary school. Yet hardly anyone is aware of it.