[Taxacom] 75% rule for subspecies recognition

[Francisco Welter-Schultes]

> ----- Original Message -----
> From: "Oliver Hawlitschek" <oliver.hawlitschek at gmx.de>
> To: <taxacom at mailman.nhm.ku.edu>
> Sent: Monday, July 04, 2011 3:30 PM
> Subject: [Taxacom] 75% rule for subspecies recognition
>
>
>> Dear all,
>>
>> I have a question concerning the 75% rule for subspecies recognition. It
>> says that a subspecies should be considered valid if 75% or more of a
>> certain sample of individuals (a potential subspecies or operational
>> taxonomic unit) can be distinguished from 99% of all other individuals
>> of
>> the same species according to the characters examined (Amadon 1949, Mayr
>> et al. 1953, Patten and Unitt 2002).
>>
>> How could I handle a case of sexually dimorphic species in which only
>> males can be recognized at subspecies level, but not females? Does that
>> mean that <50% of the species can be recognized and the subspecies
>> should
>> be dismissed (<75%), or could I restrict the 75% rule to the
>> distinguishable sex (males)? I would be happy to read of any examples of
>> similar cases.
>>
>> Thanks
>>
>> Oliver Hawlitschek
>> Bavarian State Collection of Zoology
>> Muenchhausenstr. 21
>> 81247 Munich
>> Germany
>> +49-89-8107-115
>>
>>
>
> Oliver,
>
> This is an interesting question, since I also work on taxa with sexual
> polymorphism. However, I do not think there is a binding 75% rule
> anywhere,
> rather it is a guideline for good practice in defining subspecies.
>
> Certainly if most or all males of one population clearly differ from those
> of another locality there are good grounds for regarding them as distinct
> subspecies, but acceptance is as always in the purview of the users of the
> name and it could be synonymized by the next person who works on these
> taxa
> if they disagree.
>
> Adam Cotton.
>

It also depends on the animal group. I am sure you could describe hundreds
of subspecies of dogs if you only look at the morphological characters.
Evidence for partially restricted gene flow should also be a criterion.

See also the situation in parasitic cocoos. Female cuckoos are divided
into populations favouring a particular host species' nest and laying eggs
which match those of that species in colour and pattern. The colour
pattern is inherited. But these female phyletic lineages are not called
subspecies.

Francisco



Dr. F. Welter-Schultes
Zoologisches Institut, Berliner Str. 28, D-37073 Goettingen
Phone +49 551 395536, Fax +49 551 395579
http://www.animalbase.org