Comments on: How an Ankylosaur Went Out to Sea

By: Doug

Doug — Tue, 31 Jan 2012 17:08:34 +0000

@ Boessse: I’ve heard that too.I remember hearing somewhere that the teeth of ankylosaurs would have been more suited to munching the soft vegetation found in riparian habitats.

And forget, the two most complete dinosaurs in California (a pair of Saurolophus skeletons collected by Chester Stock) were found in the marine sediments of the Panoche Hills in Fresno County.

By: Boesse

Boesse — Tue, 31 Jan 2012 12:06:00 +0000

One of Jack Horner’s earliest papers (1979 – J. Paleo) summarizes dinosaur fossils from the Bearpaw Shale of Montana (Maastrichtian, offshore marine), and at the time it turned out that there were more ankylosaurid skeletons known marine deposits than from terrestrial deposits, surprisingly enough.

There are a surprising number of dinosaurs found in marine sediments in North America; in fact, according to Schwimmer (1997), all east coast dinosaurs are from marine sediments and thus examples of bloat and float (or perhaps only maastrichtian dinosaurs).

Aletopelta is perhaps one of the more interesting cases, because it’s encrusted with oysters and has some weird taphonomic damage to the hindlimb bones.

An alternative taphonomic explanation (and possibly more likely) is that these ankylosaurids were hanging out near rivers, and their carcasses being dumped out by rivers; I’ve never bought the coastal hypothesis, simply because most carcasses that end up near the coast tend to float towards the beach (and not in the opposite direction, against the waves). Granted there are variations (rip currents, etc.) but I feel that washing terrestrial vertebrates out to sea is more common via rivers.

By: Zach Miller

Zach Miller — Mon, 30 Jan 2012 23:23:57 +0000

Our still-fuzzy-on-the-details Alaskan hadrosaur, Lizzie, was also found in marine sediments.

By: Stu Pond

Stu Pond — Mon, 30 Jan 2012 19:56:58 +0000

Of course Scelidosaurus was a victim of bloat and float too, being found in marine deposits at Lyme Regis. Perhaps thyreophorans were particularly vulnerable to being swept out to sea for some reason.

By: Mike Huggins

Mike Huggins — Mon, 30 Jan 2012 17:39:24 +0000

This is like the ankylosaur in the San Diego Natural History Museum, found in the Pt. Loma Formation (Aletopelta): http://www.sdnhm.org/archive/exhibits/mystery/fg_ankylosaur.html

By: drtachyon

drtachyon — Mon, 30 Jan 2012 17:09:10 +0000

This also reminds me of the Niobarasaurus material collected from Smoky Hill Chalk (obviously marine) in Kansas. There is a rather infamous (to KU grad students) display in the museum on campus proposing that ankylosaurs were marine or at least lived in near shore environments.

http://www.oceansofkansas.com/Dinosaur.html

By: Doug

Doug — Mon, 30 Jan 2012 16:36:12 +0000

I love that they put the lecture up in this way! More museum need to do that! In that vein, check out the New Zealand talk by Craig Dylke.

This ankylosaur reminds me of Nothronychus graffami. It too was found tens of miles out at sea from the nearest land and yet, like the ankylosaur, it was fairly complete. Too bad Aletopelta ( http://accpaleo.wordpress.com/2010/04/07/critters-abroad-aletopelta/ ) wasn’t as lucky. Just the hip region was preserved, but i can’t complain too much since he is an endemic California dinosaur.