Unusual Pennsylvanian Pteridosperm Fossils

[Tom M.]

Hello all,

I came across the attached fossils in shales of the Breathitt Group in southeastern Kentucky, USA (Pennsylvanian, Atokan). The associated strata are full of typical foliage, like Alloiopteris, Neuopteris, etc, as well as calamites and pteridosperm stems (like the ones in the photos).

The specific fossils that I can't identify are the small, detached, orbicular "leaves" located near the pteridosperm rachis in the first photo (close up of a different one in the second). They're about 1-2cm in width, some have lost their carbon, some have kept it. There's about 11 of these on the slab and counterpart, all nearly identical.

I've collected Pennsylvanin foliage for a couple years now, and haven't seen this before. Textbooks, including Taylor and Taylor (2009), didn't seem to include structures like it. I've also asked around a bit - including a professional Kentucky paleobotanist - but to no avail.

And that brings me here . . . any ideas?

Tom

[piranha]

They look similar to Cordaicarpus seeds. According to Wittry 2006: "...Cordaicarpus seeds were probably borne on a cordaite type of tree".

[Plantguy]

Hey Tom, welcome. Looks like Scott just replied with what I was thinking also--about a possible seed. I'm curious about what the paleobotanist said.

Here's another neat PDF that Jack and Ian Glasspool put together that has some seeds/pollen structures at the very end.

http://fieldguides.fieldmuseum.org/sites/default/files/rapid-color-guides-pdfs/mazon_creek_flora_guides_v5.pdf

Sounds like you've got a neat hunting area. Thanks for showing us. Congrats.

Regards, Chris

[Tom M.]

Thanks for the quick replies, Scott and Chris! The paleobotanist, who specializes in pteridosperms, simply said he hadn't seen these structures in the EKY coalfields before - though cordaites foliage is pretty common in certain layers, and the pollen is, too.

Our paleo club has collected at this particular site for many years, but this is the first we've seen of Cordaicarpus. Thanks for the ID help!