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

Various thoughts re: implictions of _Microraptor_ and bird flight origins



Just tying some various threads together:

A) At present we have absolutely no (count them, no) evidence that the
elongated leg feather condition was present outside of (DELTRANS
optimization) _Microraptor_ or (ACCTRANS) Deinonychosauria.  There is at
present, given currently known specimens and most well-supported
phylogenies, no reason to suspect this trait was present in the lineage
leading to birds.

B) In my view, Dial's discovery demolishes the split between "ground up" and
"trees down": it shows that people have been talking at cross-purposes.
Despite what people have been arguing for years, this isn't an "either/or"
situation, but might better be explained as two different steps in bird
flight origins, with Dial's Wing-Assisted Incline Running (WAIR) as the
functional missing link between the two.

C) "Butt-fans".  Now that's a different way of putting it!

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796