From: "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>
Reply-To: tholtz@geol.umd.edu
To: <jhecht@world.std.com>, "Dinosaur mailing list" <dinosaur@usc.edu>
Subject: RE: _Microraptor zhaoianus_
Date: Thu, 7 Dec 2000 09:57:55 -0500
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Jeff Hecht
>
> Tom Holtz wrote
> >*The metatarsal I and pedal digit I are very distally placed, and the
penultimate phalanx of each of the toes is elongate: Xu et al. interpret
this as indicating a climbing habit.
>
> Xu says that the foot structure indicates a ground-living ancestry.
(Specifically, Xu was referring to the arctometatarsalian nature of the
foot in this context).
> Suppose the common ancestor was a Microraptor-like animal adapted for
predation both on the ground and in trees, so it never truly gave up
ground-dwelling but spent a significant part of its life in the trees. The
ability to glide down from the trees might offer an evolutionary benefit,
giving an advantage to any dino-bird with flight feathers. Perhaps it
started by extending pouncing range from tree limbs.
>
> It's just a thought, but I think Xu may be onto something.
Indeed. Wish I had proposed something like that back at SVP 1994. Oh,
wait... :-)
(To be fair, others have thought of similar aspects too: recent studies of
the proportiopns of the toes and fingers of maniraptorans near or just past
the origin of birds show a decidedly intermediate aspect to their
proportions: neither fully arboreal nor fully cursorial).
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