Thursday, November 29, 2007

More sauropods on the horizon?

Somewhere in Spain, scientists have uncovered what Times Online is calling "Europe's largest boneyard." Not only is it the largest, but it's also diverse, with about 8 species of dinosaurs found so far amid the 8,000 fossils.

Picture from Times Online (reference below)

The boneyard was found in June and has been picked at vigorously since then. It's evidently going to play a big part in the dinosaur extinction investigation.

My favorite part: they've found three or four Titanosaurs! And they've found Titanosaurs with scutes, which has, according to the article, never happened in Europe before. AND they've found "more than 100 individual Titanosaurs"! That's great!

I would like to know what it all implies for sauropods. Do the scutes imply migratory behavior?

As far as I know, there was a land bridge connecting "North America" to "Asia," but I'm not 100% on that. I honestly don't know enough about all of this to have any answers, but I would love to hear from someone who does.

Reference

Thomas CatᎠin. "Dinosaur graveyard may unearth new reasons for their extinction." Times Online. November 29, 2007. http://www.timesonline.co.uk/tol/news/world/europe/article2963586.ece

6 comments:

Jerry D. Harris said...

My favorite part: they've found three or four Titanosaurs! And they've found Titanosaurs with scutes, which has, according to the article, never happened in Europe before. AND they've found "more than 100 individual Titanosaurs"! That's great!

I would like to know what it all implies for sauropods. Do the scutes imply migratory behavior?


Hmmmm...not positive what you're asking here; I'm hard-pressed to see how bits of armor would imply migratory behavior...? Such scutes appear to be rather common, though not universal, among titanosaurians, occuring in Late Cretaceous* taxa from South America, Madagascar, and France at the very least (if memory serves). If you're asking "Does the occurrence of scutes in Spain imply that these titanosaurians must have immigrated from outside Europe?" Given that armored taxa were known from France previously, I'd have to say "No," but of course the European titanosaurs have to have come from somewhere along the line. Funky things keep showing up in the Late Cretaceous of Europe lately, like marsupials, ceratopsians, and hadrosaurids that have a distinctly North American/Asian flavor, and things like abelisaurids that have a distinctly Gondwanan flavor -- in the Late Cretaceous, Europe seems to have been the great proverbial melting pot of dinosaurs! Whether these new Spanish taxa also have the Gondwanan flavor of heretofore known armored titanosaurians is, indeed, a good question!

*I say "Late Cretaceous" because, from my reading of the Times article, their comparisons to dinosaur faunas from places like Romania suggest to me that this is the age of the new Spanish site/taxa, although they don't say that explicitly. Early Cretaceous titanosaurians from Africa also had scutes.

As far as I know, there was a land bridge connecting "North America" to "Asia," but I'm not 100% on that. I honestly don't know enough about all of this to have any answers, but I would love to hear from someone who does.

There was, via Beringia, though I'm not certain how specific the known timing of its emergence was during the Late Cretaceous...

Jerry D. Harris said...

I stupidly said:

although they don't say that explicitly.

Well, duh, of COURSE they said that explicitly. Maybe I ought not read anything before I've had an ample quantity of coffee...

Amanda said...

Thanks Jerry! My questions was based on some information in the article: "More than 100 individual Titanosaurus have been found at the site, some of them with thick armour plating on their backs, a feature not previously seen in Europe." I should have checked out the facts! I assumed that they must have immigrated from outside Europe. But, if they were present in France, then my question is moot. :)

Amanda said...

I hear you...I haven't had any coffee yet, either, and I managed to say "my questions was." Ugh. I was so annoyed at the huge amount of spelling errors in that article, but I guess I should stop calling the kettle black!

Did all Titanosaurs with scutes belong to Saltisaurinae?

Jerry D. Harris said...

Did all Titanosaurs with scutes belong to Saltisaurinae?

Well, Upchurch et al. 2004 (the "Sauropoda" chapter of The Dinosauria 2) named a clade of titanosaurians the Lithostrotia ("stone skins") ostensibly in recognition of the presence of osteoderms (though it should be noted here that "has osteoderms" was NOT a synapomorphy of the clade!). They defined it as the most recent common ancestor (more and more often being abbreviated MRCA these days) of Malawisaurus dixeyi and Saltasaurus (presumably S. loricatus) and all its descendants. Given that Malawisaurus isn't a saltasaurid (or saltasaurine, depending on whose nomenclature you like), it's not just saltasaurids that have osteoderms, but it's not yet clear whether or not all lithostrotians have them either -- many of the taxa in that clade haven't had osteoderms definitively associated with them yet, either. Of course, that doesn't mean that they didn't have them; just that none have been discovered for them yet (and remember that one of the powerful things about modern phylogenetic analyses is that they enable us to make predictions about constituent taxa -- in this case, since they're within the Lithostrotia and the most basal known lithostrotian, Malawisaurus, has osteoderms, we can predict that these incompletely known taxa would have had them too, barring secondary loss). And there are some titanosaurians out there, like Agustinia, that have osteoderms but have not (yet) been recovered within the Lithostrotia, either (in the case of Agustinia, largely because it isn't that well known). The French armored sauropod is too poorly known as yet to say where it belongs; I did forget to mention earlier that the Romanian titanosaurian Magyarosaurus also has osteoderms (and was labeled a lithostrotian, but not a saltasaurid, in Upchurch et al.).

A long way of saying "No" to your initial question (see Julia? I said I was verbose!)...

Zach Miller said...

According to Tom Holtz Jr.'s new book (BUY THAT BOOK, AMANDA!), the Saltasaurines comprise a specific group with a greater Titanosauria. The phylogenetic relationships within the larger group are far from certain. In fact, it seems to change with every new discovery.

Jerry brings up one of my all-time favorite sauropods, though: Agustinia, while hideously incomplete, had enormous laterally-projecting bony spines coming off its back, and probably armor scutes like Saltasaurus. It wasn't very big, but it must have looked extremely wierd!