Bumastoides ??

[kurdelmb]

I found this in a newly created quarry about the middle of the Elgin member, Maquoketa formation, upper Ordovician of Fayette County Iowa last week. I'm thinking (judging from the little indentations on what I think is a cephalon) that this is some sort of Bumastoides??  I have never found one and it seems a fair bit larger (45mm x 35mm) than what the research that I have of this area indicates. Any thoughts would be greatly appreciated! Thanks.  

[Raggedy Man]

I can't say for sure. There's not much to go on here other than it has a general shape consistent with Bumastoides sp. 

Maybe @piranha will have a better take on this.

[abyssunder]

I'm not a specialist in trilobites, but if it is a Bumastoides, according to the location of the find and using as reference *,**,***, I would start the research of  Illaenids at the point of Bumastoides beckeri (Slocom, 1913).

Figs. 11-12 of *

 

 

*Jesse R. Carlucci et al. A systematic revision of the Upper Ordovician trilobite genus Bumastoides (Illaenidae), with new species from Oklahoma, Virginia and Missouri.Journal of Systematic Palaeontology, Vol. 10, Issue 4, December 2012, 679–723.  https://www.researchgate.net/publication/257656692_A_systematic_revision_of_the_Upper_Ordovician_trilobite_genus_Bumastoides_Illaenidae_with_new_species_from_Oklahoma_Virginia_and_Missouri

** Slocom, A. W. 1913. New trilobites from the Maquoketa beds of Fayette County, Iowa. Field Museum of Natural History Geological Series, 4, 43–83.  http://ir.uiowa.edu/cgi/viewcontent.cgi?article=1179&context=igsar
or https://ia600208.us.archive.org/18/items/newtrilobitesfro43sloc/newtrilobitesfro43sloc.pdf

*** Walter, O. T. 1927. Trilobites of Iowa and some related Paleozoic forms. Iowa Geological Survey Annual Reports 1923 and 1924, 31, 1–388.  http://ir.uiowa.edu/cgi/viewcontent.cgi?article=1260&context=igsar

 

I agree with Raggedy Man, so just wait for piranha's opinion.