[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
This message was submitted by Thomas_R_HOLTZ@umail.umd.edu to list
firstname.lastname@example.org. If you forward it back to the list, it will
be distributed without the paragraphs above the dashed line. You may edit the
Subject: line and the text of the message before forwarding it back.
If you edit the messages you receive into a digest, you will need to remove
these paragraphs and the dashed line before mailing the result to the list.
Finally, if you need more information from the author of this message, you
should be able to do so by simply replying to this note.
----------------------- Message requiring your approval----------------------
>>n a proposed new family of sauropods, the Andesauridae? I am
>>familiar with the divison of sauropods into
>>Vulcanodontidae, Cetiosauridae, Camarisauridae, Brachiosauridae,
>>Diplodocidae and Titanosauridae, and the suggestion made several
>>years ago that the following classes should be added: Barapasauridae
>>(intermediate between Vulcanodontidae and Cetiosauridae), Dicraeosauridae
>>(sometimes trated a a subfamily
>>of the Diplodocidae: fairly similar but shorter necks), and Euhelopidae
>>(Chinese sauropods with diplodocid like tails and chevron bones but
>>Camarasaur like heads, e.g. Euhelopus, Mamenchisaurus, Omeisaurus.)
One note: that's "Euhelopodidae" (add an "od" between "p" and "i").
In Paul Upchurch's 1994 phylogeny (Phil. Trans. Roy. Soc.), Euhelopodidae is
the sister taxon to a group called "Neosauropoda" containing cetiosaurids, the
camarasaurid + brachiosaurid group (for which 'Camarasauroidea' would be the
proper name) and a titanosauroid + diplodocoid group. Euhelopodids,
although they show many similarities to diplodocoids, lack many derived
characters of the neosauropods.
> Now, I
>>understand that a new family of (mainly South American Upper Cretaceous)
>>sauropods, all formerly classified as titanosaurids, has been proposed, the
>>Andesauridae. All of these sauropods were formerly classed as Titanosaurids.
>> What is the justification for the new family; i.e. what special
>>characteristics set the Andesauridae apart from the Titanosauridae? Could
>>they be a subfamily of Titanosauridae?
Andesaurids lack the strongly procoelous caudal centra of true
Titanosauridae. They may be the sister taxon to Titanosauridae, or even a
paraphyletic assemblage of basal members of Titanosauria (basically,
Titanosauridae + "andesaurids").
>>A related (maybe) question: where does Opithocoelicaudia fit in?
According to Paul Upchurch's phylogeny, Opisthocoelicaudia is the sister
group to Titanosauria within Titanosauridae.
Thomas R. Holtz, Jr.
Vertebrate Paleontologist Webpage: http://www.geol.umd.edu
Dept. of Geology Email:email@example.com
University of Maryland Phone:301-405-4084
College Park, MD 20742 Fax: 301-314-9661