[Taxacom] How many species have been reported only once

[Bob Mesibov]

David Patterson wrote:

"I have heard suggestions that our understanding of 50% and 65% of all species is limited to the information that was included in the original description. That is, for very many species, there have not been any further publications that add new information. These are the 'once only' species. If the proportion is as high as this, it bears upon the reliability and effectiveness of the discovery process, how many species there are, and on asymmetry within our discipline."

You seem to be heading towards a lot of different conclusions from one rubbery number. It's almost certainly true in the wonderful world of arthropods that a majority of species are known from single lots (sometimes single specimens) from one or a small number of localities, as reported in the original description. What this reflects is that the vast majority of arthropod species are rare. A ranking of abundance of species within a taxon in any one area, or of species range sizes within a taxon, gives you a small number of abundant, widespread species and a very much larger number of low-abundance species with restricted ranges.

That's just the way Nature is. It doesn't have very much to do with taxonomic practice. Even with unbiased sampling and description, this is the pattern you'd get.
-- 
Dr Robert Mesibov
Honorary Research Associate
Queen Victoria Museum and Art Gallery, and
School of Zoology, University of Tasmania
Home contact: PO Box 101, Penguin, Tasmania, Australia 7316
(03) 64371195; 61 3 64371195
Website: http://www.qvmag.tas.gov.au/mesibov.html