[Taxacom] Objective synonyms?

Kim van der Linde kim at kimvdlinde.com
Sat May 29 07:47:44 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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