Hebeiornis the valid name for Vescornis

[Michael Mortimer <mickey_mortimer111@msn.com>]

I was recently sent a pdf of the description of Hebeiornis fengningensis, 
previously mentioned by Jerry- http://dml.cmnh.org/2005Nov/msg00108.html .  
Using Babelfish to translate the Chinese text, it became apparent this is a 
terribly written paper.  The Yixian Formation is referred to the Jurassic.  
There's a basic lack of details regarding the anatomy of Hebeiornis, with 
around ten morphological features noted along with measurements or several 
elements.  The description of the pose of the specimen is approximately as 
long.  The summary of the world's main Mesozoic bird taxa includes only 
Archaeopteryx, Cathayornis "shanwangensis" (a presumed misspelling), 
Hesperornis and Ichthyornis.  After a brief rundown of the characters found 
in Odontornithes, Palaeognathae, Neognathae and Archaeopteryx, Hebeiornis is 
concluded to be most similar to Archaeopteryx (it has teeth, lacks a 
prominent keel and supposedly a pygostyle), but more derived because of the 
partially fused carpometacarpus.  The paper was written in 1998, but none of 
the references are more recent than 1986, nor involve birds.  Hebeiornis is 
listed as gen. et sp. nov. and attributed to Yan, 1999, which I assume to 
mean they are the only author (perhaps a mispelling of Yang You-shi?) taking 
credit for the name, as opposed to there being a separate Yan, 1999 
publication.  This would all just be a sad, if interesting, case of an 
indeterminate Yixian bird if not for the fact a photograph is included.

The photograph is extremely poor, and only labeled "Bird fossils in the 
bottom of the Jurassic Yixian Formation".  However, only one Yixian bird 
specimen is described in the paper, and the pose described for Hebeiornis is 
the same (complete specimen exposed ventrally, neck curving to its left, 
deflected skull).  The important thing is that this is obviously a 
photograph of the holotype of Vescornis hebeiensis!  The latter taxon is of 
course also from the Yixian Formation of Senjitsu in Fengning County.  The 
measurements match fairly well with Vescornis (skull ~24 vs. 27 mm; scapula 
~17 vs. 13 mm; humerus ~24 vs. 25 mm; ulna ~25 vs. 30 mm; femur ~24 vs. 25 
mm; tibia ~30 vs. 30 mm), as do the few osteological details with the 
exception of the pygostyle.  As Babelfish translates, Hebeiornis "does not 
have the tail synthesis bone", while Vescornis has a pygostyle.  Then again, 
the authors were apparently unfamiliar with the numerous basal pygostylians 
with elongate pygostyles (with the exception of Cathayornis, which they 
never discuss, only list), so perhaps Vescornis' elongate pygostyle was too 
dissimilar to ornithurine sensu stricto pygostyles for them to count it?  Or 
perhaps it's just another failing of a poor description or translation.

So accepting the two names are based on the same specimen, Hebeiornis 
clearly has chronological priority by five years.  But is it valid?  After 
reading the revelent articles of the ICZN, I believe it is.  The publication 
is valid.  There is a description that purports to differentiate the taxon 
from other taxa, as poor as it may be.  Can anyone find a reason the name is 
invalid (remember it was published in 1999, so the post-1999 rules do not 
apply)?  I see no choice but to sink Vescornis hebeiensis as an objective 
junior synonym of Hebeiornis fengningensis, despite the fact the former has 
one of the most detailed and well illustrated descriptions of any Yixian 
bird and was written by three coauthors who are quite knowledgable on the 
subject.  Gotta love the principle of priority.  Maybe someone should 
petition the ICZN?

Xu, G.-L., Y.-S. Yang, and S.-Y. Deng. 1999. First discovery of Mesozoic 
bird fossils in Hebei Province and its significance. Regional Geology of 
China 18(4):444-448.

Mickey Mortimer