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Re: Deinocheirus (was Sauropodz r kewl WAS: silly conversation on 2012 US presidential race)



Is it possible that feathers started as some kind of quill like structures for protection from predation, or as some sort of offensive capability? The central quill in the feathers I've seen looks like variants could be sharp enough to be part of a creature's weaponry.


Ar 4/20/2012 7:17 PM, scríobh Thomas R. Holtz, Jr.:
On Fri, April 20, 2012 5:41 pm, tyazbeck@comcast.net wrote:
Psittacosaurus? Also, isn't there a heterodontosaur w/feather-like
structures?
Yes, at least one Psittacosaurus has quill-like elements on its tail, and
the early Late Jurassic heterodontosaur Tianyulong has more typical
"protofeather" plumulose elements.

----- Original Message -----
From: "Joe Gilvary"<dinosaur@gilvary.net>
To: "DML List"<dinosaur@usc.edu>
Sent: Friday, April 20, 2012 9:06:08 AM
Subject: Re: Deinocheirus (was Sauropodz r kewl WAS: silly conversation on
2012 US presidential race)

This brought a question to my mind. Is there any evidence of dinosaurs
with quills (like porcupines)? Is it possible for feathers, or related
structures, to serve a similar purpose? Could something like that help
explain why feathers evolved?

   Thanks,

   Joe


Ar 4/20/2012 8:52 AM, scríobh Robert Schenck:
On Fri, Apr 20, 2012 at 8:45 AM, Thomas R. Holtz, Jr.<tholtz@umd.edu>
wrote:
From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]
On Behalf Of Robert Schenck
e know how feathered their hands were; if they have
feathers coming off the fingers that might've made using them
as defense less likely. But you have to think, any animal is
going to do whatever it can to defend itself.
Two things:

No, we do not know how feathered the hands of therizinosaurs or
ornithomimosaurs were, although we have oviraptorosaurs.

But why would being feathered make them less used in defense? Even
volant birds can be pretty violent in clubbing each other or
predators with wings, and those are animals that use those forelimbs to
fly (unlike the dinosaurs in question here).
Ah yes, as a reader of Naish's Tetrapod Zoology I should've remembered
all the different birds that have spurs and clubs on their limbs. Not
to mention that Hoatzin chicks can grasp branchs with their clawed and
feathered hands.




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