Weird Shape

[Coco]

I am OK with you John, I have to do a pic of this part of a recent sea urchin to compare.

Coco

[JohnJ]

I am OK with you John, I have to do a pic of this part of a recent sea urchin to compare.

Coco

Thank you. I'm looking forward to it, Coco. I think I see this rotula (in the bottom left photo) in the link provided by Al Dente of the Echinothuria floris (Woodward, 1863)!

[AgrilusHunter]

For those like me who had no idea what a rotula was, here is some more information. Once you see where this structure is located and what it does the odd shape starts to make sense.

http://www.asnailsod...IN/urchFeed.php

I've really enjoyed watching, and learning from, this thread. Thanks for posting and best of luck with your identification.

Edited September 7, 2012 by AgrilusHunter

[Scott S.]

If you can get access to a good dissecting microscope (aka stereoscope) and you can get a good close look at these pieces, echinoderms have a very distinct "tell" about them called a "Stereom". All of there skeletal elements, no matter from what anatomical piece, or which family or order (Blastoids, crinoids, sea stars etc.) see attached pic. Granted these specimens from Science magazine are exceptially tiny (100 microns for some of the scale bars) but I have some pieces from the Pennsylvanian Finis Shale that have obvious stereom patterning just visible to the naked eye! The best part is no matter how small the chunk of echinoderm is, you can still recognize the web-like pattern!

Edited September 7, 2012 by Scott S.

[Coco]

Hi,

Here is a pic of a recent Stomopneustes variolaris from Reunion Island piece :

And here a jaw (Aristotle's lantern) pic of a recent Echinometra mathaei species :

I coloured in pink the position of this small part (there are 5 of them on a sea urchin), it is put under another small part.

Coco

[erose]

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

That looks right. I think you have that figured out quite well.

Thank you. I'm looking forward to it, Coco. I think I see this rotula (in the bottom left photo) in the link provided by Al Dente of the Echinothuria floris (Woodward, 1863)!

I agree that looks like it. At least from the back, or plain, side.

Hi,

Here is a pic of a recent Stomopneustes variolaris from Reunion Island piece :

And here a jaw (Aristotle's lantern) pic of a recent Echinometra mathaei species :

I coloured in pink the position of this small part (there are 5 of them on a sea urchin), it is put under another small part.

Coco

That is very close to what we see. Now I need to go back and find the odd piece that I left behind (ARGH! I never do that. Must have been the sun baking my brain that day.) that looked a bit like one of the teeth.

[JohnJ]

Hi,

Here is a pic of a recent Stomopneustes variolaris from Reunion Island piece :

And here a jaw (Aristotle's lantern) pic of a recent Echinometra mathaei species :

I coloured in pink the position of this small part (there are 5 of them on a sea urchin), it is put under another small part.

Coco

Coco, thank you very much for your photos. I knew you would most likely have a modern analog.

Erich, it could be that the Echinothuria urchins have their parts scattered all over that formation. Whatever species it is could account for many unidentified "weird" finds or misidentified fragments. All in all, it's been a pretty cool discovery process.

[Herb]

Very cool and very informative!

[Bill Thompson]

As to the x-shaped items. I found one similar in the lower glenrose, creataceous TX. I was told by someone else that it was one part of the Aristotoles Lantern of an echinoid. The blade like pieces with "tubercles" also look like echinod parts. Very nice find.

[erose]

Bill,

We (JohnJ and I) have other pieces we believe are part of the lanten. The x-shaped pieces are the rotulas but we have two other "things" that appear very "echinodermish" and occur along with the plates and rotulas.

The plates are most likely from an echoinoid in the Family Echinothuriiidae. See: http://www.nhm.ac.uk...axon.jsp?id=884

JohnJ and I are pursuing this with more and better fossils. John has taken some good photos and we are sending stuff to Prof. Andrew Smith to get his educated opinion. He confirmed my ID at the family level. We would need better (articulated?) plates to even begin to ID this at a higher level. But this family of echinoids is partially defined by the fact that they had flexible tests with imbricated plates. In other words: they were a bunch of loose parts and tended to fall apart even quicker than other echinoids. But both John and I have found a few associated bits so maybe one day after a hard rain we will find that elusive specimen.

Here is a photo of a few plates that appear to be articulated. And note that there are two more on the flip side, again articulated.

[ashcraft]

Since it is cretaceous, my first thought was part of a fish spinal column on the x shaped thing. Just a random thought.

Brent Ashcraft

[erose]

Since it is cretaceous, my first thought was part of a fish spinal column on the x shaped thing. Just a random thought.

Brent Ashcraft

We have it nailed down tight as a "rotula" which is part of the Aristotle's lantern of an echinoid. See JohnJ's post #25 & Coco's #30 above. I suspect it is from the un-described echinoid of which we are finding these saber-shaped plates but that is just a S.W.A.G.

[CherylW]

I'm not familiar with the items in the lower part of the original photo, but the four fossils at the top are Selenia sp. echinoids. We find them all over the Texas Hill Country.

Edited September 28, 2012 by CherylW

[erose]

I'm not familiar with the items in the lower part of the original photo, but the four fossils at the top are Selenia sp. echinoids. We find them all over the Texas Hill Country.

Thanks Cheryl, I had no problem identifying those. In fact there were specimens of two different types of "Salenias" collected at the site: Leptosalenia texana and Hyposalenia phillipsae. They are both well documented and not hard to ID.

I have returned to the site along with JohnJ a few times since and we have found a number of new and odd bits. I'm going to share some here. We think a few may be more bits of the Aristotle's lantern of some unknown echinoid and in addition a few odd urchin spines.

[JohnJ]

Erich, I'm really liking the bottom spine in your photo.

...more Echinothuriid echinoid plates and additional lantern fragments we suspect may be related to this fragile urchin.

[Coco]

Hi,

I am OK with you : the second pic on your post n° 39 shows a part of an Aristotle's lantern.

Coco

[surfergirlatx]

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

Very wonderful find!!!!

[erose]

Very wonderful find!!!!

I don't want to say we found something new because I know others have picked these things up. But JohnJ got me interested in truly finding out what they are and that has lead us to maybe pointing out this odd echinoid to a scientist.

[Auspex]

Hidden in plain sight, so to speak!

[surfergirlatx]

Thanks Cheryl, I had no problem identifying those. In fact there were specimens of two different types of "Salenias" collected at the site: Leptosalenia texana and Hyposalenia phillipsae. They are both well documented and not hard to ID.

I have returned to the site along with JohnJ a few times since and we have found a number of new and odd bits. I'm going to share some here. We think a few may be more bits of the Aristotle's lantern of some unknown echinoid and in addition a few odd urchin spines.

Erose, I have also found some of those strange urchin spines at my hunting site also....

[surfergirlatx]

I don't want to say we found something new because I know others have picked these things up. But JohnJ got me interested in truly finding out what they are and that has lead us to maybe pointing out this odd echinoid to a scientist.

I will be very interested to find out what it really is. I did some research on the Aristotle's Lantern, found this pic....it does look similar. Cant wait to hear what it is!!! Congrats on finding them!!!

Source: http://www.mitchellspublications.com/guides/shells/articles/0058/

[erose]

Thanks Kim,

The spines you have found are probably from a "cidarid" sea urchin. They are not uncommon in the Glen Rose at certain levels and I know you are in the right zone at the lake. If you also find smooth spines they are probably from the Salenias. Complete Cidarids are special finds so keep looking.

That is an interesting pic of a modern Aristotle's Lantern. The bits and pieces we have found are definitely from one of those but the big question is which urchin? There are several suspects. Finding associated material is the task at hand.

While you are browsing paleo web sites you should visit this site for more about echinoids. It is where many of the images earlier in this post came from.

http://www.nhm.ac.uk/research-curation/research/projects/echinoid-directory/index.html

[surfergirlatx]

Thanks Kim,

The spines you have found are probably from a "cidarid" sea urchin. They are not uncommon in the Glen Rose at certain levels and I know you are in the right zone at the lake. If you also find smooth spines they are probably from the Salenias. Complete Cidarids are special finds so keep looking.

That is an interesting pic of a modern Aristotle's Lantern. The bits and pieces we have found are definitely from one of those but the big question is which urchin? There are several suspects. Finding associated material is the task at hand.

While you are browsing paleo web sites you should visit this site for more about echinoids. It is where many of the images earlier in this post came from.

http://www.nhm.ac.uk...tory/index.html

Thank you for the info and the link! That will help me a lot! I would love to find a Cidarid, so far only Salenias...I am sure they are there, its just a real "neck braker" to be bent over to find them yet for me. I am so excited you found something so rare!

Soon we have to do another lake hunt!!! Especially with the rain we just got!

[Quarryman Dave]

Great Find! Do you have dinosaurs in texas?

[erose]

Great Find! Do you have dinosaurs in texas?

Of course! Texas has everything.