Can't give you a specific cause, but from reading it seems to be a highly localised, (i.e. North Western American), phenomenon, occurring between 100-70 million years ago.
If you can get your hands on it:
LUCAS, S.G. & HUNT, A.P. (1989) Alamosaurus and the sauropod hiatusin the Cretaceous of the North American Western Interior. Geological Society of America Special Paper.
Might be useful. It appears that Alasmosaurus is interpreted as an immigrant from the south, bearing many similarities in common with the South American titanosaurids.
For sauropods to have been absent for a period of 30 million years, whilst other dinosaur species were present doesn't automatically invoke an extinction event. It may have been climatic - with not enough rainfall to support the growth of vegetation, or geographic - many species today are limited in range due to physical obstacles, i.e. Mountain ranges, cliffs etc. It may even be something as simple as a lack of suitable rocktypes for use as gastroliths, or it could be some hitherto unknown artefact of preservation which prevented sauropod bones from fossilizing.
That's basically just some random thoughts, needless to say, the hiatus is probably the result of several contributing factors...
Rank: Fluorite
Joined: 31/12/2004
Points: 478
Can't give you a specific cause, but from reading it seems to be a highly localised, (i.e. North Western American), phenomenon, occurring between 100-70 million years ago.
If you can get your hands on it:
LUCAS, S.G. & HUNT, A.P. (1989) Alamosaurus and the sauropod hiatus in the Cretaceous of the North American Western Interior. Geological Society of America Special Paper.
Might be useful. It appears that Alasmosaurus is interpreted as an immigrant from the south, bearing many similarities in common with the South American titanosaurids.
For sauropods to have been absent for a period of 30 million years, whilst other dinosaur species were present doesn't automatically invoke an extinction event. It may have been climatic - with not enough rainfall to support the growth of vegetation, or geographic - many species today are limited in range due to physical obstacles, i.e. Mountain ranges, cliffs etc. It may even be something as simple as a lack of suitable rocktypes for use as gastroliths, or it could be some hitherto unknown artefact of preservation which prevented sauropod bones from fossilizing.
That's basically just some random thoughts, needless to say, the hiatus is probably the result of several contributing factors...
Hope this helps!
Ben.
Rank: Fluorite
Joined: 14/09/2006
Points: 286
I had a look on that free lyellcollection website thing. here's the results - dont know if its any help!
http://sp.lyellcollection.org/cgi/search?journalcode=specpubgsl&fulltext=sauropod+hiatus&author=&x=16&y=13