[log in to unmask] wrote:

> As Helmut Nisters says, forms and varieties (like cotypes) belong to
> yesteryear. The rule is that forms and varieties are to be treated as
> subspecies where possible.
>
> Andrew K. Rindsberg
> Geological Survey of Alabama

This type of treatment makes good sense in the case of animals that form
geographically isolated, or stable, populations that breed with each other and
produce characteristically predictable offspring.  I have often thought that
it would be nice if when naming such subspecies the protocol would be to base
the name on the locality (i.e. an "ensis" latinization at the end of the
locality name of the type locality of the subspecies population).

I have tended to reserve the term "form" for an unusual, but expected
variation, within a population of any species or subspecies.  For example:
Nucella lapillus (L., 1758) comes in white, yellow, orange, brown, and striped
"forms", as well as frilled, smooth, altispiral and squat (to name a few).
These can all be found, at times, within a single population.