[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Greg Paul is right (again); or "Archie's not a birdy"

Been very hard to keep quiet about this one for oh these looooonnnnnggggg

An Archaeopteryx-like theropod from China and the origin of Avialae

Xing Xu,         Hailu You,      Kai Du  & Fenglu Han
Nature 475, 465?470 (28 July 2011) doi:10.1038/nature10288
Received 16 November 2010 Accepted 10 June 2011 Published online 27 July 2011

Archaeopteryx is widely accepted as being the most basal bird, and
accordingly it is regarded as central to understanding avialan origins;
however, recent discoveries of derived maniraptorans have weakened the
avialan status of Archaeopteryx. Here we report a new Archaeopteryx-like
theropod from China. This find further demonstrates that many features
formerly regarded as being diagnostic of Avialae, including long and
robust forelimbs, actually characterize the more inclusive group Paraves
(composed of the avialans and the deinonychosaurs). Notably, adding the
new taxon into a comprehensive phylogenetic analysis shifts Archaeopteryx
to the Deinonychosauria. Despite only tentative statistical support, this
result challenges the centrality of Archaeopteryx in the transition to
birds. If this new phylogenetic hypothesis can be confirmed by further
investigation, current assumptions regarding the avialan ancestral
condition will need to be re-evaluated.


Larry Witmer's News & Views:


Various media reports:




Basic gist of story: discovery of (yet another boring generic-looking)
feathered paravian from China that, when included in a phylogenetic
matrix. pulls Anchiornis and Archaeopteryx together with itself to form
Archaeopterygidae, and Archaeopterygidae pulled over as basal
deinonychosaurs rather than avialians.

(Hence the Greg Paul comment: Greg and Ken Carpenter had argued as early
as the mid-1980s that Archaeopteryx was a basal member of the
Dromaeosauridae-line rather than the bird line.)

Statistical support for this position is not tremendously strong, so this
is by no means written in stone. (Indeed I know of at least one study
coming soon which will turn all of this inside out: however, that paper
lacks the Xiaotingia zhengi data).

Cool stuff.

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
Fax: 301-314-9661

Faculty Director, Science & Global Change Program, College Park Scholars
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