Type specimens

Robert Mesibov mesibov at SOUTHCOM.COM.AU
Sun Apr 28 20:26:33 CDT 2002

Doyle Chadwick wrote:

"I have a question about basic procedure regarding the description of
species. I've always assumed that only mature (definitive, as opposed to
immature) specimens were used as type species specimens, but I can't find a
written reference to that principle. I realize this is rather arcane, but
it's something I need for a discussion group."

The Code regulating zoological nomenclature neither requires nor recommends
matures. Taxonomists try to choose as type a specimen which has
characteristics clearly distinguishing the new species from all already
described species. In some cases no mature specimens are available, and a
'sufficiently different' juvenile can do the job.

Juvenile types have created all sorts of problems, but they're types just
the same. In my own favourite groups, centipedes and millipedes, juvenile
types are a pain in the bum. Unless  species A is well known as both adult
and juvenile, a name B based on a juvenile A is likely to wind up in the
Incertae Sedis box when the group containing A & B is revised.

If you're looking for a readable introduction to type selection and other
taxonomic arcana, see Judith Winston's "Describing species: Practical
taxonomic procedure for biologists" (Columbia University Press, New York ,
1999, ISBN 0-231-06824-7 and 0-231-06825-5).

Dr Robert Mesibov
Honorary Research Associate
Queen Victoria Museum and Art Gallery
Home contact: PO Box 101, Penguin, Tasmania, Australia 7316
(03) 64371195; 61 3 64371195

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