Jose Leal asks about the 1/'3 proportion of useless taxa (junior synonyms
and homonyms).

Hmm. I think I overstated the case in my enthusiasm, but I remember reading
this back in the 70's while first learning about taxonomy, and I have kept
my eyes open since then. It was probably anecdotal to begin with, and
certainly is now. Actually, I thought it was one of those maxims that all
taxonomists know. Evidently it should be tested properly, like anything
else that we only think we know.

First, let's think like an ancient Greek, deducing from information already
stored in the brain. Over the years, I have noticed that the typical
revision of a group of organisms contains:

(1) Taxa that are deemed to be valid (available) as they stand.
(2) Taxa that are deemed to be junior synonyms or homonyms (or on very rare
occasions, both simultaneously!).
(3) New taxa that somehow were missed altogether by previous
investigators--usually in surprising numbers, considering the great number
of useless names that are rejected in the same work.

The numbers range quite a bit from monograph to monograph; in general, the
more attention is paid to a group, paradoxically the more useless names are
erected. But my impression is that the proportion of rejected names hovers
around 1/3, and it does not seem to matter how old the paper is, within
reason (I haven't tried to examine Linnaeus's work for this, for instance).
As Kurt Auffenberg points out, the total number of valid species rises with
time in almost every group, with occasional setbacks when the work of a
spectacular splitter is mundanely lumped.

Obviously, it isn't enough to think like an ancient Greek. We need hard
data, but why work too hard for it? Anyone can test the idea rapidly by
taking a few pages at random from the indices of the "Treatise on
Invertebrate Paleontology", and counting the valid and invalid names. This
is easy, because the valid names are printed in roman font and the invalid
names in italic. So, for instance, flipping part N (Bivalvia), volume 2 to
page N923 (Cydippe to Dictys), I count:

Valid genera: 74
Invalid genera: 71 (49 percent)

Again, on p. N945:

Valid genera: 100
Invalid genera: 51 (34 percent)

And flipping it a third time, to p. N918:

Valid genera: 87
Invalid genera: 55 (39 percent)

Hmm. With the numbers ranging so greatly within small samples (they should
be at least 300 each, and preferably higher--obeying a statistician's rule
of thumb!), and with only one book index being consulted, I can't say that
I've made my case scientifically. To quote another old maxim, "Further work
is needed." However, I can say that the old taxonomist's rule of thumb has
not been disproven, even though these numbers are running a bit higher than
1/3.

Jose, you are right: This is a really interesting question, at least to a
taxonomist. It may have some practical value too. Ideas?

Andrew K. Rindsberg
Geological Survey of Alabama