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

Re: Deinonychus claw use and origin of flapping




Thanks to everyone for the comments and kind words. I had hoped that our paper 
might push some of the discussions on flight / predatory ecology in some new 
directions, and I welcome such studies as suggested by Dr Holtz on the troodon 
teeth.


A few notes based on what people have said so far.

1. Supp info.
I don't know if anyone read the supp info, but there is a bit of content in 
there (it would seem ppl generally don't, read supp; I'm going to stop writing 
so much),. Supp text contains some discussion of previous claw papers, notes 
about WAIR, Zanno & Mackovicky's herbivore/omnivore paper, comparisons to the 
Seriema bird and..

2. The Tendon Locking Mechanism (TLM) of the foot
I found this fascinating, and consider the different possibilities for the 
functional origin. On the discussion here about roosting... is it possible to 
roost without a TLM? I would guess all extant birds that roost have a TLM 
already (unless there is a group that lost it, that also roosts), but maybe 
there is a mammal (excluding bats; they have a TLM) or some lizard maybe that 
has solved the problem of sleeping in trees without the need to lock the feet 
for the night.

3. The ability to do something is not the same as selecting for it.
I agree that little theropods may have been able to climb trees, but the 
ability to perform an action is not the same as having a selectable pathway by 
which morphology can be changed. I remain skeptical about arboreal / scansorial 
adaptations or habits in these small theropods, especially regarding the 
subarctometatarsalian metatarsus of the basal deinonychosaurians. This is a 
cursorial adaptation, so why it would be selected for in an arboreal animal is 
currently unexplained.

Anyway, thanks again for the comments.

Best,


Denver.


----------------------------------
Denver Fowler
df9465@yahoo.co.uk
http://www.denverfowler.com
-----------------------------------


________________________________
From: Tim Williams <tijawi@gmail.com>
To: dinosaur@usc.edu 
Sent: Thursday, 15 December 2011, 22:22
Subj

Anthony Docimo <keenir@hotmail.com> wrote:

>  so you don't think dinosaurs could handle slopes,

Of course dinosaurs could handle slopes.  But *as well* as goats can...?


> and you don't think dinosaurs could handle trees.

I never said that.  I said I want evidence.  More than just "Why not?"


>  see bottom of the post.  I never said unscalable terrain - I said uneven 
> terrain.  you know...hills.  mountains both high and low.


You've gone off on a tangent here.  The ability to negotiate narrow
ledges and very steep terrain also makes goats adept at climbing
trees.  This is not the same as walking up a hill.


Plus, did I mention that goats are mammals?  Yes, I think I did.  ;-)


>  amphibious, maybe...but not specialized for an aquatic life (like manatees 
> are)


In this context, "aquatic" vs "amphibious" is a distinction without a
difference.  Check out Liu et al. (2008; PNAS 105: 5786-5791).  The
point is that early proboscideans like _Moeritherium_ are inferred to
have spent most of their time in water.


>  sure.  but *hills*?


What have "hills" got to do with it?  The ability to climb up a hill
is not the same as the ability to climb up a tree.






Cheers

Tim