Joe here. A Very interesting question. We tackle this question in
practical application very often in invertebrate paleontology.
Firstly, anyone can name any species, whatever they want, whenever they
want.  The primary question is 'recognition' as a valid species. There
is only one absolute requirement: the new species name must appear 'in
print'. After this one requirement all types of debate arises over other
particulars. This includes items such as: Is the new name printed in a
'recognized' publication and, if so, says who? Is the 'type' specimen
accesible for others to study? Again, this is a real can of worms.
Accesible to who? How is it accesible? Has the name been used before?
How much description is necessary to call it a new species? what is a
species?......a 'zillion' variables.    Again, ALL that is needed is for
the new name to appear in print.  One of the simplest questions with one
of the most complicated answers is 'has the name been used before'.
Geesh! A hundred answers can follow; all start 'Yes, but....'.
 
      All science disciplines attempt to define requirements for species
recognition. Commissions, established, etc....conferences held...guide
lines published... etc. Mallacology certainly has stacks of papers on
publishing, naming species...
 
        Unfortunately, amateurs have been 'scared off' in recent years
in publishing their findings. New species identification has been
deferred to academics. There is nothing stopping a knowledgeable
amateur, an expert in his field, from self publishing new species names
and donating the type specimens to a local museum or university. This is
what was done with great enthusiasm and 'mostly' great success until
recent times.Computers, desk top publishing and related technology can
put the dedicated Nature enthusiast back on an even footing with those
who are paid. Yes, good to work with museums, university professionals
and others...but don't be deterred by not having a list of academic
credentials after your name.