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Re: Ichthyornis paper




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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