[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Triassic Sauropods
Tim Williams wrote:
"Just a clarification: the term I used was "titanosauriform".
Titanosauriformes = Brachiosauridae + Titanosauria. If the sauropod
material from the Isalo Group of Madagascar belings to some type of
brachiosaurid (or at least shows "brachiosaurid" features") then it is
probably basal titanosauriform."
"Actually, I was not referring at all to _Isanosaurus_ from Thailand. I was
referring to the Isalo Group of Madagascar. (No, I'm not confusing the
A Late Triassic age for the Isalo Group is given in :
Flynn, J.J. et al. (1999). A Triassic fauna from Madagascar, including
early dinosaurs. Science 286 (5440): 763-765.
Abstract: "The discovery of a Middle to Late Triassic (apprx 225 to 230
million years old) terrestrial vertebrate fauna from Madagascar is reported.
This fauna documents a temporal interval not well represented by continental
vertebrate assemblages elsewhere in the world. It contains two new
prosauropod dinosaurs, representing some of the earliest dinosaur
occurrences known globally. This assemblage provides information about the
poorly understood transition to the dinosaur-dominated faunas."
Yes, I understand now what you're getting at. I guess the e-mail thread ran
together and I had confused your idea with the Isanosaur stuff.
Needless to say, I still have my doubts about titanosauriforms appearing so
early based on current morphological evidence, but if they did it would be
interesting -- such an early appearance of titanosauriformes would suggest
that a whole line of sauropods that has numerous advanced characters
appeared before other Neosauropod groups. It would imply a basal sauropod
split much earlier than current evidence indicates, and might suggest, on
re-analysis of sauropod phylogeny, that many similar characters in
diplodocids, for instance, would have been independently acquired. For
these reasons, I will remain skeptical of Late Triassic or Early Jurassic
titanosauriforms until better evidence surfaces.
Get your FREE download of MSN Explorer at http://explorer.msn.com