Spinosaurid tooth from the Sanchu Group

[Halichoeres]

Isolated tooth, terribly illustrated, but potentially interesting from a biogeography perspective.

http://www.gmnh.pref.gunma.jp/wp-content/uploads/Second-discovery-of-a-spinosaurid-tooth-from-the-Sebayashi-Formation-Lower-Cretaceous-Kanna-Town-Gunma-Prefecture-Ja1.pdf

[Newt]

Neat!

It's a bit of a puzzle to me why there aren't more good spinosaurid fossils. Their apparent preference for living in depositional environments would seem to make them ideal candidates for preservation, and they can't have been too rare judging by the quantities of isolated teeth found in the Kem Kem beds...

[Halichoeres]

Neat!

It's a bit of a puzzle to me why there aren't more good spinosaurid fossils. Their apparent preference for living in depositional environments would seem to make them ideal candidates for preservation, and they can't have been too rare judging by the quantities of isolated teeth found in the Kem Kem beds...

Good question. Scavenging? Wave action? Seems like either might be enough to preclude intact carcasses.

[stargatedalek]

Perhaps they were more marine than often given credit for, which would explain why there are so exponentially many teeth relative to bones.

[ZoPteryx]

Neat!

It's a bit of a puzzle to me why there aren't more good spinosaurid fossils. Their apparent preference for living in depositional environments would seem to make them ideal candidates for preservation, and they can't have been too rare judging by the quantities of isolated teeth found in the Kem Kem beds...

Good question. Scavenging? Wave action? Seems like either might be enough to preclude intact carcasses.

I recall a study where it was demonstrated that, in a normally functioning estuary or marsh, animal remains rot away very quickly due to those factors. The major exception of course, are the occasional oxygen deprived ecosystems that give rise to lagerstatten deposits.  It makes sense, I think, that spinosaurs wouldn't be likely to venture into these sorts of lagoons due to lack of prey.  On top of that, spinosaurs were probably pretty sparse in their ecosystems as it was.