Qinornis (was Re: Cenozoic dino)

[Tim Williams <tijawi@yahoo.com>]

Evelyn Sobielski wrote:

> browsing through Mayr's new "Paleogene Fossil Birds", I
> came across:
> 
> Qinornis paleocenica Xue, 1995 - juvenile(?), incomplete
> metatarsal fusion (different from at least crown
> Neornithes). Mayr indicates that the assumption that it lies
> outside crown Neornithes[*] is in need of falsification.
> 
> Does any listmember have more info on this? (I have the
> original description, but as a bad scan where details of the
> fossils are impossible to discern)


Mayr (2007) previously raised the prospect of _Qinornis_ being a 
non-neornithean bird.  These are his reasons (Mayr, 2007; J. Vert. Paleontol. 
27:394â408; p.394):

"Controversial hypotheses exist on the timing of the origin of neornithine 
birds and the effect of a possible mass extinction event at the K/T boundary on 
the avian diversity (e.g., Feduccia, 1995, 2003; Cooper and Penny, 1997). In 
particular, it is often assumed that non-neornithine birds became extinct at 
the end of the Cretaceous (e.g., Feduccia, 2003; Dyke and van Tuinen, 2004). 
The evidence therefore is, however, very weak because the fossil record of 
birds in the Late Cretaceous and around the K/T boundary is extremely scanty 
and largely restricted to North America. By the incomplete fusion of the 
metatarsalia, the tarsometatarsus of _Qinornis paleocenica_ from the early 
Paleocene of China corresponds well with that of the Late Cretaceous 
non-neornithine _Apsaravis_ (Clarke and Norell, 2002:fig. 21), and _Qinornis_ 
thus suggests survival of some basal ornithurines across the K/T boundary. It 
is unlikely that the presence of incompletely fused
 metatarsalia in _Q. paleocenica_ indicate a juvenile condition of the specimen 
(contra Xue, 1995), because the distal tarsalia are completely fused with the 
metatarsalia and the articular ends of the tarsometatarsus do not exhibit the 
blurred surfaces characteristic for the growing bones of juvenile neornithine 
birds."

> [*] There were probably no or very few stem Neornithes
> (lineages originating before the paleognath-neognath split)
> left at the end of the Mesozoic. Off the top of my head,
> even their Maastrichtian record is Neognathae, and indeed
> seems to be mostly Neoaves and 2-3 Galloanserae.

In a publication entitled "Europeâs last Mesozoic bird", Dyke et al. (2002; 
Naturwissenschaften 89:408â411) reported an unnamed non-neornithean bird from 
the latest Cretaceous (Maastricht Formation) of Belgium.  It was a large bird, 
apparently closely related to _Ichthyornis_.

The large hesperornithid _Asiahesperornis_ also comes from the end of the 
Cretaceous (Maastrichtian-aged Zhuravlovskaya Svita of Kazakhstan).  See Dyke 
et al. (2006; Cret. Res. 27: 947-953).

Also, based on Sylvia Hope's work, it's my understanding that a large number of 
Late Cretaceous and/or early Paleocene "shorebirds" (e.g., "graculavids", 
_Volgavis_) have been referred to modern orders (especially Charadriiformes) on 
less-than-compelling grounds.  Many of the derived neornithean & 
charadriiform-like characters actually have a wider distribution in Neornithes, 
and may be associated with a seabird or shorebird ecology.  Given their 
retention of many plesiomorphic characters, these birds might actually be stem 
neornitheans.


Cheers

Tim