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Re: Lots'a questions after a ref.-tiding-up!



At 06:23 PM 8/28/98 -0700, DinosØMP wrote:

>
>1)
>       Sinraptorines, like Sinraptor and Mamenchisaurus has quite tall neural
spines, 

I assume you mean "Yangchuanosaurus"(the sinraptorid carnosaur), not
"Mamenchisaurus" (the giant sauropod).

Also, both "standard" and phylogenetic taxonomy recognizes the group
Sinraptoridae, not Sinraptorinae.

>compared to other Allosauroides. Sinraptorinae may then be a group of
Allosaurides whith 
>taller backs,- maybe a evolutionary base for a back-sail. Acrocanthosaurus
has a lot of 
>features whith Acrocanthosaurus and Giganotosaurus, which again has a lot of 
>similarities whith Yangchuanosaurus changyouensis (mostly skull). Therefore
I've built a 
>cladogram like this one:

Based on...

Note that a cladogram should be based on more than one character.

>Sinraptorinae.
> |-Sinraptor (whith base for a back-sail)
> |-Yangchuanosaurus (Whith base for a back-sail, or a very low sail)
>  |
>  |-Carcharodontosaurini.
>   |-Carcharodontosaurus (?Tall back-sail)
>   |-Acrocanthosaurus (Tall back-sail)
>   |-Giganotosaurus (?Tall back-sail)

What is known of the vertebrae of Carcharodontosaurus and of Giganotosaurus
do not show, as far as I have seen, anything approaching the tall neural
spines of Acrocanthosaurus nor the moderate spines of the sinraptorids.

>Other species that may belong to these groups are Szechuanosaurus,
Bahariasaurus and 
>Chilantaisaurus.

Could be, but this has to be demonstrated by character evidence.
(Incidentally, at least ONE of these taxa will be discussed in detail at SVP
this year, though not by me).

>2) Look up D. Normans "The Illustrated Dinosaur Encyclopedia", at pp. 78.
What has 
>happened to that Massospondylus' skull? IS is Massospondylus at all?

I think that is still considered a Masso skull.  It is crushed, of course,
which is why it has such a peculiar appearance.

>3) What is known about the cladistic position of Nyasasaurus?

Nyasaurus has never been formally described, and only mentioned (to my
knowledge) as a name in a listing in the 1967 edition of The Fossil Record.
Maybe someone else has more up to date information.

>4) What are the similarities/differences between Gasosaurus/Kaijiangosaurus?

Will have to go back and look at Kaijiang in more detail (haven't had a
chance to work with that material yet).

As Molnar et al. suggested in the Dinosauria, these guys might be the same
animal.  Unfortunately, I don't think there is that much overlap in what is
known (the cervicals, maybe: as I said, must check myself).

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:tholtz@geol.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661