Key Measurements

[Mike Dallwitz]

                                                                  21 June 1995

> From: Joost Romeu <Joost at JOOST.UCSF.EDU>
> To: Taxacom
>
> ... should all measurements be averages?

Note that identification methods often need, for each taxon, a range of values
of continuous measurements such as length, so you should try to measure or
estimate a range, even if you also record an average for other purposes.

> From: Margaret K. Thayer <thayer at fmnh.org>
> To: Taxacom
>
> Measurements are only useful when the ranges/averages/whatever are
> significantly different between the taxa or groups of taxa being compared.

The meaning of `significantly different' in this context may need
clarification. Ranges of values may be extremely useful for identification
even if they have substantial overlap, e.g. 5-10 vs. 7-14; 0-5 vs. 0-10; or
even 4-6 vs. 2-8.

Mike Dallwitz                                  Email md at ento.csiro.au
CSIRO Division of Entomology                   Fax +61 6 246 4000
GPO Box 1700, Canberra ACT 2601, Australia     Phone +61 6 246 4075