Ghost Sheller

I think you answered your own question "Occasionally a researcher discovers a
species which is so unique that it is obvious to him or her that it is new to
science".

In such an event then one specimen lodged in an appropriate institution as a
holotype is sufficient but more of the same species are desirable as paratypes
if available.

A rule of thumb criterea is that a new species should have three distinguishing
characters to separate it from any others species in the genus, to do this one
must be familiar with all the other species.

To know if a species is juvenile is not so easy but comparison with similar
material, thin edges or lips, immature sculpture etc are all guides. Have fun it
only takes a lifetime to become an expert and even then one is often proved
wrong.

Kev
Age is a very high price to pay for maturity.