Mariopteris ferns?

[Dpaul7]

Hello!

 

I received these two pieces as a nice gift!  I WANT to say Mariopteris - I think definitely in photo #1 - but photo #2, while I WANT to say Mariopteris, I am leaning a bit toward Eusphenopteris!

[Fossildude19]

@fiddlehead @paleoflor

[fiddlehead]

Mariopteris is based on frond architecture, but they also demonstrate asymmetrical pinnae with the basiscopic pinnules more developed. Lastly the venation pattern is seen to have lateral veins entering the pinnule from the rachis on the basiscopic (lower) side only. These specimens are too small (like most all examples) to determine frond architecture and too poorly preserved to make out more than a few pinnule margines. The venation is thin and the midveins are weak, or not developed in most of the pinnules. Where veins are clear they are decurrent to the rachis. The pinnules are decurrent and constricted at the base. Due to the preservation it is hard to see this in most of the pinnules, but some have a square or rectangular aspect, while others are clearly more tapered. This leads me t o conclude these are most likely examples of Eusphenopteris neuropteroides which shares all the observable features. Attached is a better preserved example of E. neuropteroides from Mazon Creek for comparison.

 

Hope that helps,

Jack

[Dpaul7]

Thank you so much!   An excellent post - and one while I will definitely print and save!!!! 

[Plantguy]

Great finds. Glad Jack was able to provide the technical description/reasoning. I wish I could do that! 

Regards, Chris