For sure, and this goes for cladistics too... just a tool, not the be-all.


Don't fall into that tray of Clithon...

Hey Andrew!!  Yes, I believe cladistics is just that - a tool.  Like DNA,
like shell morphology, like radula characteristics, etc. - it can present
one way of ordering and looking at a group.  Again, an artificial construct
that may or may not represent actual relationships between species.  A
superb cladogram was contructed by Holthuis (1995) for the Neritidae.  I
have found this a useful tool in understanding (in a limited way) the
relationships between different genera - but she would be the first to admit
her diagram is not the final word.  Too much depends upon the criteria used,
samples available, etc.  This can be especially difficult in variable
families where a single genus can have specimens with spines or without,
with spiral ridges or without, with axial grooves or without, etc.  But it
does provide one with a method of looking at the group and gives a bit of a
handle on "Should this genus be moved into its own family?" type issues.

As for falling into the tray of Clithon - I am feeling pretty good about
that genus!  Still some holes and unanswered questions and tricky issues -
but on the whole it looks pretty solid.  I am still not sure if your
specimens are C. rarispina as indicated in Haynes or C. angulosa as
indicated by earlier authors.  There is also a bit of a problem with C.
diadema and of course with C. corona.  However, I just started messing with
the Theodoxus.  This genus makes Clithon look clear cut and simple.  Luckily
I contacted Klaus Bandel who has done a lot of work in this genus and I was
able to get a number of his publications.  However, even he admits to big
questions about the number of valid species.  Theodoxus have a 60 million
year history of life in European rivers and lakes as well as from the Nile
to the Caspian and and Morocco to England.  Lots of variation and a ton of
names!  I have gone from species that have been forgotten for the last 100
years to species that have been described and named from every water hole
and river in Europe.  It sure does make it interesting.

Just finished digging through a couple pounds of mixed nerites from the
Philippines.  Was able to pull out a few nice examples of color/pattern
variation for a number of species.  Now the remainder goes to the local
natural history museum for the kids discovery area as well as to a couple of
teachers who have asked for help in obtaining shells for their students.  I
am hoping that the COA convention will provide something - maybe one of my
missing species.

Have fun in New Zealand.

Tom E.