Ectenaspis Sp.

Very cool Trilobite!

Thanks for posting it!

Regards,

Tim

Hi kurdelmb,

I usually get a chance to make a road trip to Fayette Co. a few times a year to take advantage of the trilobites in your area. Great find! What formation did it come from? MaQ/ Elgin??? When I search "Ectenaspis" nothing comes up. Has the name been changed? Hope to see more of your posts!!

Merry Xmas

Mike

isotelines 

triloUSA

minnbuckeye -

Yes, this one was from the bottom 10 ft. of the Elgin member near Postville. It is odd to me that this Ectenaspis is documented as being more common than E.Beckeri (which I probably have at least half a dozen) yet this is the first one I have ever seen. 

 Doushantuo, thanks for the link.

kurdelmb, I have looked at a recent find that I label Isotoleus and look at your specimen posted. Now I am unsure what to call it. What differentiates Ecenaspis from Isotoleus. Anything simple to look at to tell?? I am terrible at trilobite identification in general and always get confused when trying to ID something.

What you found is a specimen of Isotelus iowensis, the first trilobite described from what would become the State of Iowa. It was described by David Owen in 1852. The type specimen came from the Village of Elgin on the Turkey River. The key features are the very rounded glabella and clearly defined axis on the pygidium. Finding specimens that retain the carapace is not an easy task. Though slightly disarticulated (missing the left free cheek ) and right eye and genal spine, it is a nice specimen.

Regarding your statement concerning Ectenaspis beckeri - I would love to see your specimens and maybe obtain some measurements.

Al

Thanks Al ! Wishful thinking and not enough research on my part I guess. And yes, we do need to get together and discuss E.Beckeri as I know you have done a LOT of work on this species. I will send you a private message.