Re: Opisthocoelicaudia (was Re: Titanosaurids)

["Mickey_Mortimer11" <Mickey_Mortimer11@email.msn.com>]

Tracy Ford wrote-

> AH, the lazy way, Don't look at the whole skeleton. I get it. Now I know
how
> cladistic works :) Or ignoring partial or fragmentary individuals or
> ignoring them all together. Ok, lets say they do it as you say, how do we
> know what they choose is right? Or, how do we know they haven't missed an
> important variation in their characters? Me, I always like the one where
> they say the cladagram didn't turn out the way they wanted it to so they
> Twiked it to fit :) If it don't work , make it work.

Who says I don't look at the whole skeleton now?  If the primitive condition
is to have no pleurocoelous sacrals, and you look at every taxon and note
that the variation consists of that, having the first pleurocoelous, having
the first two pleurocoelous and having all six pleurocoelous, you simply
make an ordered multistate character-
pleurocoels in sacral centra
0- absent
1- in sacral one only
2- in sacrals 1-2 only
3- in sacrals 1-6
This is how it happens in coelurosaurs, if I remember correctly (haven't
revised this character yet).  You know what you choose is right once you've
covered all variation and I never tweek a cladogram to fit preconceptions.

> You did read what I wrote right? I wrote Late Cretaceous. Rebbachisaurids
> are Early Cretaceous. You probably don't know this but the brachiosaur
that
> Kirkland et al talk about is actually a large hadrosaur. He was rather
upset
> about that at the SVP in Mexico City :(. Right about Rauhut et al. Check
my
> list for other Late Cretaceous sauropods, and found some more diplodocids.
> But they do lump late Cretaceous sauropods into titanosaurs as I
previously
> mention.

Indeed I did read what you wrote.  Ever heard of these?

undescribed Rebbachisaurid (Novas 1997)
Cenomanian-Coniacian, LC
Lower Bajo Barreal Formation, Argentina
Material- cervical vertebra
Comments- Identified due to the accessory lamina connecting the
spinoprezygopophyseal and postzygodiapophyseal laminae.
References- Lamanna, Martinez, Luna, Casal, Dodson and Smith, 2001. Sauropod
faunal transition through the Cretaceous Chubut Group of Central Patagonia.
JVP 21(3) 71A.

undescribed Rebbachisaurid (Lamanna, Martinez, Luna, Casal, Dodson and
Smith, 2001)
Turonian, Late Cretaceous
Upper Bajo Barreal Formation, Argentina
Material- (UNPSJB-PV 580) caudal vertebra
Reference- Lamanna, Martinez, Luna, Casal, Dodson and Smith, 2001. Sauropod
faunal transition through the Cretaceous Chubut Group of Central Patagonia.
JVP 21(3) 71A.

Mickey Mortimer