RE: Archaeopteryx

["Thomas R. Holtz, Jr." <tholtz@umd.edu>]

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of Brian Hathaway
> Sent: Wednesday, October 19, 2011 12:16 PM
> To: dinosaur@usc.edu
> Subject: Re: Archaeopteryx
> 
> As of today, where does Archie stand?  No longer the "first 
> bird" but where is it in the family/clade world-view?

Nothing definite. The case of an Archaeopterygidae (Archie, Anchiornis, 
Xiaotingia) is probably good. Whether archaeopterygids are
basal deinonychosaurs, basal avialians, or the sister group to Eumaniraptora (= 
Deinonychosauria + Avialae) is far from certain.
Each position is within just a step or two from the other.

In any case, both Anchiornis and Xiaotingia are older than Archaeopteryx, so it 
ain't the oldest known anything regardless of the
position of Archaeoptergyidae.

If Scansoriopterygidae is a clade within Avialae, it is likely BASAL to 
Archaeopteryx.

> And was it a ground-nester, or is that known?

It is not known from fossils. However, tree-nesting is relatively derived 
within the Aves (i.e., the modern clade of birds): most
ratites, tinamous, galliforms, and anseriforms are ground-nesters. Tree-nesting 
may have arisen within Neoaves, so if Archaeopteryx
(or ANY Mesozoic bird) was a tree-nester, it would have gotten there 
independantly of living tree-nesting birds.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA