Uncommon Phacops?

[Kane]

Recently, a kind TFF member posted a comment on my blog post on some Arkona finds and suggested I * might * have misidentified a somewhat twisted trilo as Eldredgeops rana when it is possible it could be P. iowensis southworthi. I don't want to get my hopes up too high, but I thought I'd take the opportunity to let the trilo experts confirm whether or not I might have a slightly less common trilobite. It is a fairly distorted specimen, as though wrenched or twisted. Found in the HH formation. If it helps identification, I have focused on the pictures that show the eye and glabella, which is usually the better way to distinguish between the various phacops/eldredgeops subspecies.

Edited August 18, 2016 by Kane

[doushantuo]

if that's tectonic deformation,the job doesn't get any easier,identificationwise

BTW:

https://www.researchgate.net/publication/251700805_Morphological_and_ontogenetic_criteria_for_defining_a_trilobite_species_The_example_of_Siluro-Devonian_Phacopidae

Edited August 18, 2016 by doushantuo

[Guest11596]

It doesn't appear to be a southworthi. If you want to investigate further there's a link to 'Systematics and evolution of Phacops rana (Green, 1832) and Phacops iowensis Delo, 1935 (Trilobita) from the Middle Devonian of North America' below.

http://digitallibrary.amnh.org/handle/2246/1095

One further note; the Hungry Hollow is no longer a formation. It is a member of the Widder Formation.

[Kane]

Thanks! A minor bummer, but it's still an interesting bug given its condition. And, yes, I actually should have known there is no HH Fm - I keep referring to it as one out of habit!

[Shamalama]

Hi Kane,

I was the guy who suggested you post this and I apologize that it is not what I thought it might be. The really pustulose (lots of bumps on the surface) Eldregeops I thought were Phacops iowensis but maybe this doesn't have all the diagnostic features necessary. Keep up the hunting though, they do exist there and can be found.

[Kane]

No apologies necessary. It was a good chase! I agree that the "goosebumps" all over made me start to second guess as well after you suggested it could have been P.is. I'll take it as some kind of omen that I have to find one next time I'm out there, and perhaps one good enough I can donate to UMMP, which only has a cephalon at the moment.