Trilobite parts. Bellacartwrightia? Buffalo New York

[Al Tahan]

Hello everyone,

 

I kept these from fossil hunts in buffalo years ago cause I knew they were different. I read they split Greenops boothi into 4 different species with 2 variations of Greenops and 2 variations of Bellacartwrightia in 1997. I have some pieces that I’m not really sure which trilobite I’m dealing with. I just know it’s not the Greenops grabaui variety. The cephalon came from basic Wanakah shale that surrounds the “trilo beds” as I was moving blocks. The pygidiums came from the “trilo beds” of the lower Wanakah shale at the Lake Erie shore in Buffalo, New York. I only have “a field guide to Devonian paleontology” by Karl Wilson and “Geology of 18 mile creek” by Grabau for reference. I can’t find anything reliable on the internet either so I’m curious if the kind folks on the forum have an opinion. I do have another book on Devonian paleontology of New York coming in the mail that is more recent but the new paper was written in 1997 and this book is a 1994 book so it may not have the update either. 

 

The last 2 pics are comparisons of the pygidium of a Greenops grabaui with the specimens in question to show you why I think they are different. 

 

I also just added a last photo of the other side of one of my unsure specimens that’s actually a full trilo but damaged beyond belief...may not help with the ID but maybe it could lol. 

 

Thanks 

Al

[Al Tahan]

This is the reference I have by Karl Wilson with the “field guide to Devonian paleontology” 

 

 

ill also say the cephalon i have is very odd. Sadly it was well weather from the highly weathered shale I collected it from that day. The glabella is in a different spot than I’m used to seeing....unless it’s a prefectly placed shale exfoliation. 

 

[Kane]

Here is an excerpted comparative table of diagnostic differences.

 

Whiteley, T., Kloc, G., and Brett, C. (2002). Trilobites of New York. Cornell UP, p. 130. 

[Al Tahan]

Thanks @Kane wow! More varieties than I thought. Very much appreciated. 

[Kane]

Any time. 

 

Given the stated location, I am somewhat (but not 100%) confident that you have Bellacartwrightia whiteleyi. The few I have in my own collection from a nearby area look nearly identical. The Greenops might likely be Greenops barberi (also on account of location, but also overall shape of the lappets). 

[Tidgy's Dad]

Very nice trilobite pieces! 

[FossilDAWG]

Just a note: the pygidia should be identifiable, but the cephalons are an internal mold and just the underside, neither preserving diagnostic features needed for identification.

 

Don

[Al Tahan]

Thanks for your opinion/insight on the ID @Kane These trilos are kinda tough ones to distinguish from one another. 

 

@FossilDAWG I was afraid that may be the case but I was hoping there would be enough clues from the glabella and maybe parts of the genial spine. Would it be safe to assign it the Bellacartwrightia genus but species unknown? It appears to have a cephalic boarder and very forward glabella...thats all I can say with somewhat certainty 

[GerryK]

From the lower Wanakah Shale the trilobite on the left would be Bellacartwrightia whiteleyi and the other Greenops grabaui..

[Al Tahan]

16 hours ago, GerryK said:

From the lower Wanakah Shale the trilobite on the left would be Bellacartwrightia whiteleyi and the other Greenops grabaui..

Thanks Gerry!!