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Re: Coelurus a maniraptoran (for how long?)



David and Mickey,
If you are going to code for ornithoid vs. non-ornithoid egg shells, you will need to code Therizinosaurs (segnosaurs) as non-ornithoid. And more importantly, ornithoid eggshells have also been found for Dromaeosauridae (Deinonychus), so this character would appear at least twice independently in David's tree (or have numerous reversals).
On a more humorous note, having Dromaeosauridae, Rahonavis, and Archaeopteryx, all jumping backwards so many nodes over the heads of the already dizzy ornithomimids, may drive them totally nuts or to finally demand that cladists stop using them as specifiers for such unstable clades. Sorry, I just couldn't let that one go by.
-------------Ken Kinman
********************************************************
From: "Mickey_Mortimer" <Mickey_Mortimer11@email.msn.com>
Reply-To: Mickey_Mortimer11@email.msn.com
To: <dinosaur@usc.edu>
Subject: Re: Coelurus a maniraptoran (for how long?)
Date: Tue, 5 Jun 2001 17:01:55 -0700

David Marjanovic wrote-

> And I haven't run anything through a computer, I
> can't say if the above cladogram is the most parsimonious that the
following
> may produce:

How would you like it if I made your list into a matrix and ran it on PAUP?
I have plenty of time now that school is out.  However, there are many
characters you list thatr must be specified.

> I was too lazy to look up *Bagaraatan* =8-) . Off the top of my head it's
> outside Eumaniraptora.


I could also code Bagaraatan for you.

> -+- Unnamed node Ornitholestidae + Coeluridae + Eumaniraptora:

> arms reaching at least the level of the ankles when fully extended
downwards (may be a
> plesiomorphy, but compsognathids have much shorter arms)

This should really be phrased better, probably as a ratio of forelimb to
hindlimb length.

> distal carpal 1 + 2 enlarged and semilunate (compsognathids have small
carpals and
> relatively immobile wrists like coelophysoids)

I'm not so sure about compsognathids having coelophysoid-like carpals.
After all, only three disarticulated elements may be referred to
Compsognathus' carpus, while Sinosauropteryx is undescribed.

> metacarpal I reduced in length and metacarpal II long and slender to
improve the
> opposability of the thumb.

This also needs a ratio (metacarpal I x% as long as metacarpal II)

> This node might collapse into Eumaniraptora because the following
character
> states are AFAIK unknown for ornitholestids and coelurids:
> - nearly all cervical and dorsal vertebrae (at least) pneumatised (to an
> extent often comparable to very large carcharodontosaurids and sauropods)


In both Coelurus and Ornitholestes, all cervicals and the first two dorsals
were pneumatic.  This is similar to ornithomimids and troodontids.

> furcula boomerang-shaped.

Not all of your eumaniraptoran taxa have this character.  The furculae of
Velociraptor, tyrannosaurids and oviraptorids at least are very similar to
those of Allosaurus and Scipionyx.

> -+- Eumaniraptora (*Deinonychus* + Neornithes): tail reduced in length and
> more lightly built (compsognathids have very long, rather heavy tails)


Again, you need a ratio (percent compared to femoral length, presacral
length, etc.).

> hindlimbs longer than usual (reversed in Dromaeosauridae sensu stricto, in
> compsognathids relatively as short as in coelophysoids IIRC)


Ratio.....

> probably wing and tail feathers (if not earlier).

This is a good character- just can't be scored for many taxa.....

> -+- Maniraptoriformes: more than 5 sacral vertebrae (is that right for
> tyrannosauroids?)

Nope.  Tyrannosaurids have five sacrals.

> separate exit for the cranial nerve V1.

Remember, Allosaurus has this too.  And oviraptorids lack it.

> I have forgotten whether the character "articulars and quadrates
pneumatised" is
> applicable... that's in the archives, however. :-]

Confuciusornis lacks a pneumatic quadrate, despite the fact it is a
maniraptoriform in your phylogeny.  Caenagnathids, Avimimus and
enantiornithines lack pneumatic articulars.

> -+- Arctometatarsalia:
> It may tell something, however, that ornithomimosaurs and tyrannosaurs at
> least have so similar proportions (stunning illustration in PDW), and that
> troodontids and tyrannosaurs have small, pointed interdental plates.


Troodontids lack interdental plates (or else they are fused
indistinguishably to the dentary), unlike the primitively unfused plates of
tyrannosaurids.  Then again, Eotyrannus has fused interdental plates....

> -+- Bullatosauria: Well, the namegiving feature ("bulbous area at forward
> region of the braincase"), overall similarities in proportions, and an
> increase in the number as well as a decrease in the size of the teeth,
along
> with reduced space between the teeth (trend to a more cutting bite).


Ratios, ratios, ratios.... :-)  Characters must be specific.

> -+- Maniraptora: even shorter tail, tail not stiffened distally,
> pneumatisation extending to mid-caudals, ornithoid eggshell, maybe a
> double-headed quadrate (though the heads can fuse...), maybe some sort of
> proto-pygostyle (but the vertebrae are not always fused...).


How short of tail?  Alvarezsaurids have distally stiffened tails.
Caudipteryx and Microvenator lack pneumatized caudals, as do segnosaurs and
any Mesozoic bird I've read about.  Caudipteryx may have a single-headed
quadrate (although Jaime disagrees), as do Erlikosaurus and Avimimus.  What
is a proto-pygostyle, if it doesn't have to be fused?

Mickey Mortimer
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