Weird Shape

[erose]

Does anyone recognize this? Found in the Lower Cretaceous here in Texas. I'm talking about the objects in the center of the photo with the sorta x-like shape. But the blade-like things to the right are also stumping me.

[Auspex]

There's nothing random in the bilateral symmetry, and there is more than one of them, so I feel that it is a part of a larger critter, and built for a particular function...

What does the material they are made of seem like to you?

[Herb]

The 2 pieces look very similar, they look biological to me. But I have to admit I've never seen anything like them. Very interesting!

[erose]

Speculation is echinoderms. Maybe crinoid for the first, but the saber-shaped ones are completely mysterious, yet fairly abundant. I had ignored them until collecting the site with JohnJ who pointed them out.

[Indy]

If I found these shapes in the Mississippian of Missouri

Which is probably of little help ...

I would speculate the 2 shapes in the center are crinoid

and the blade-like shapes are burrows.

Question regarding the blade-like shapes.

Did you only notice these weathered free or did you also notice

some appearing on the surface of matrix?

[erose]

If I found these shapes in the Mississippian of Missouri

Which is probably of little help ...

I would speculate the 2 shapes in the center are crinoid

and the blade-like shapes are burrows.

Question regarding the blade-like shapes.

Did you only notice these weathered free or did you also notice

some appearing on the surface of matrix?

Yes I do believe the first items may be crinoid but the reference is vague in my memory.

The blades are definitely a distinct fossil, not a burrow. They occur loose in the soft matrix. Until JohnJ pointed them out I had assumed they were bivalve fragments. But he was right, they are distinct fossils.

[Auspex]

...The blades are definitely a distinct fossil...

They appear flattened, with both a curve and a bow, and seem to lack any ornament...

What size are they? Do you have other pictures?

[erose]

They appear flattened, with both a curve and a bow, and seem to lack any ornament...

What size are they? Do you have other pictures?

They have little nodes, tubercles, nipples, whatever you want to call them on the surface.

The lines on the cards are 1/4" apart. Size varies a bit but this is a typical sampling.

[Auspex]

Very echinodermish!

[Indy]

Very echinodermish!

I agree ...

The new picture appears to show echodirm spine attachement areas

[erose]

For the Blade like things....After a few hours going thru books and other references the closest I can come is the Echinoid order Echinothurioida. These were low hemispherical echinoderms with flexible imbricating plates. See this example from the Upper Cretaceous: http://www.nhm.ac.uk...axon.jsp?id=884

[Scylla]

I don't know if this helps but look at figure 3b and 3e here

[erose]

I don't know if this helps but look at figure 3b and 3e here

Hmm...E is interesting...another lead...back to the Treatise!

[JohnJ]

Erich, your Echinothurioid lead is very interesting. It would be nice to add something new to the faunal knowledge of that formation. Here are some additional photos.

[erose]

Thanks John, These are much better photos than I can currently take. I'm going to include them in an e-mail to Prof. Andrew Smith if that's OK with you?

[erose]

With the addition of JohnJ's better photos Prof. Andrew Smith of the British Natural History Museum has identified the blades as belonging to the family Echinothuriiidae. These are plates from the test of a large echinoid which was flexible and not all cemented together. Chock up a new taxon for the Glen Rose!

Now back to the X things.

[Herb]

We have Echiniderms here in the Mississippian with the paddle shaped wing plates 1-3" long that look very similar.

[erose]

We have Echiniderms her in the Mississippian with the paddle shaped spines 1-3" long that look very similar.

Those are not spines. They are the plates that would make up the test. But the family is known for having spines with "hoof-shaped" ends. But I have seen no sign of those, despite collecting with a magnifying visor. See the link I posted above.

[Herb]

Those are not spines. They are the plates that would make up the test. But the family is known for having spines with "hoof-shaped" ends. But I have seen no sign of those, despite collecting with a magnifying visor. See the link I posted above.

You're right, they're really not spines even though they stick out to the sides. They are wing plates from "Pterotocrinus sp."

[erose]

You're right, they're really not spines even though they stick out to the sides. They are wing plates from "Pterotocrinus sp."

OK. I was confused and thought you meant another urchin not a crinoid. Crinoids have so many cool forms....

[Herb]

Bad writing on my part.

[Al Dente]

Here are some British examples that are partially articulated: http://www.chalk.dis...uria floris.htm

[erose]

Here are some British examples that are partially articulated: http://www.chalk.dis...uria floris.htm

Cool. But now I think I passed a bit of the Aristotles lantern, again thinking it was just a scrap of oyster.

[JohnJ]

With the addition of JohnJ's better photos Prof. Andrew Smith of the British Natural History Museum has identified the blades as belonging to the family Echinothuriiidae. These are plates from the test of a large echinoid which was flexible and not all cemented together. Chock up a new taxon for the Glen Rose!

Now back to the X things.

Been out of pocket all day. Wow, Erich! Good work following up with Andrew Smith. It's so cool when your fieldwork adds to the science.

[JohnJ]

The "x things" appear to be the rotula (part of Aristotle's Lantern) of an undetermined echinoid in the Glen Rose Formation.