[Taxacom] Objective synonyms

Kim van der Linde kim at kimvdlinde.com
Sat May 29 09:27:46 CDT 2010

Hi Curtis,

Looks like that the same discussion has popped up again. What is new at

Anyway, this is my take on it.

Everything starts with the description of the species. When that happens,
it is often indicated with 'n. sp.'

When a species is moved to a new genus, it is called a new combination,
NOT a new name.

ICZN glossary: new combination
    The first combination of a generic name and a previously established
species-group name.

Logical, because it does not have a new description with assignment of
type specimens etc., it is a subjective call of the taxonomist to place
the species in a different genus.

So, now lets look at synonyms:

ICZN glossary: synonym, n.
    Each of two or more names of the same rank used to denote the same
taxonomic taxon.

The key here is "of the same rank":

ICZN glossary: rank, n.
    The level, for nomenclatural purposes, of a taxon in a taxonomic
hierarchy. The ranks of the family group, the genus group, and the
species group at which nominal taxa may be established are stated in
Articles 10.3, 10.4, 35.1, 42.1 and 45.1.

So, we talk here about the genus-group and species-group levels as
separate ranks. Now, lets interpreted objective synonym:

ICZN glossary: objective synonym
    Each of two or more synonyms that denote nominal taxa with the same
name-bearing type

Above, synonyms are at their specific rank, so it applies specifically to
the species-group name alone or the genus-group name alone, not to

So, to answer the question. Panthera uncia and Unica uncia are based on
one single description. The difference is the subjective placement of the
species in different genera. As it was described originally as Panthera
uncia, moving the species to the genus Uncia does not result in a new
name, but a new combination, Uncia uncia.

To sum it:
1 type,  1 description,  1 combination:  not synonyms
1 type,  1 description,  2 combinations: not synonyms
1 type,  2 description,  2 combination:  objective synonyms
2 types, 2 descriptions, 2 combination:  subjective synonyms

Now I will run and duck.


On 5/28/2010 10:16 PM, Curtis Clark wrote:
> Have there been recent changes to ICZN deprecating the concept of
> objective synonym? There is an editor on Wikipedia, otherwise
> well-respected, who is claiming that names in different genera with the
> same epithet (he doesn't say homotypic, but all of his examples are) are
> not synonyms. I know this is incorrect for ICBN (and with little effort
> I could find chapter and verse), but I don't have enough familiarity
> with the current ICZN to either correct myself or counter the argument.


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