Re: Ichthyornis paper

[Tim Williams <twilliams_alpha@hotmail.com>]

Christopher Taylor wrote:

> Julia has mis-interpreted this. _Ichthyornis dispar_ does indeed remain the
> type species of _Ichthyornis_, and will always be the type species. 
> However,
> as _dispar_ is a junior synonym of _Graculavus anceps_, the name _anceps_
> still takes priority. Note that under the ICZN, genus and species names are
> separate units - the validity of a species name is not dependent on its
> generic assignment (beyond that it must have one).

Agreed.  If two or more species are found to be synonymous, then the trivial 
name of the earliest-named species is given priority.  This is the case even 
if: (1) the later-named species is the type; and/or (2) the earlier-named 
species was originally assigned to a separate genus to the type species.

A special decision is required by the ICZN for a later-named species to have 
priority over an earlier-named species.  There is precedent for this.  For 
example, when _Pterodactylus crassipes_ was found to be synonymous with 
_Archaeopteryx lithographica_, then the new combination _A. crassipes_ 
should have had priority over _A. lithographica_, since _Pterodactylus 
crassipes_ was named in 1857 and _A. lithographica_ was named in 1861.  
However, the ICZN decided that _crassipes_ would be suppressed in favor of 
_lithographica_.  Thus, _A. lithographica_ won out over _A. crassipes_ (= 
_P. crassipes_).

This could be done to conserve _I. dispar_.  But in the normal course of 
events, _anceps_ trumps _dispar_ as the valid species of _Ichthyornis_ that 
contains the type speciemns of _I. dispar_ and _Graculavus anceps_ as its 
hypodigm.



Tim

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