Jump to content

Illinois Silurian Trilobite Cephalon


deutscheben

Recommended Posts

This partial cephalon was found in rip rap near a quarry that exposes the Silurian Racine Dolomite in Kankakee County, Illinois. I have seen similar examples listed on the auction site, but without IDs. Looking at older publications leads me to think it is Dalmanites, but I'm not positive, and definitely unsure what the species designation would be. Thanks for any help! 

 

5cbe084b34c33_2019-04-2211_10_07.thumb.jpg.74ea0cdd30bdff0fcd439e901fc7a956.jpg

  • I found this Informative 1
Link to comment
Share on other sites

And with a little more research I think I have found the answer- based on some previous posts here and elsewhere, it looks like this is actually Cheirurus. 

 

http://www.thefossilforum.com/index.php?/topic/84651-silurian-trilobites-id-help-needed-ontario-canada/

http://www.thefossilforum.com/index.php?/topic/74584-the-mysterious-cheirurus/

 

However, the species still seems a little unclear- In the 1916 work that defined the US species of Cheirurus, Percy Raymond separated out C. niagarensis and C. welleri, as well as a few other species, and this one seems closer to C. welleri, with a fairly smooth glabella and glabellar furrows that curve backwards. But I can't seem to find any more recent references to that species. Any trilobite systematists out there want to weigh in?

 

Bulletin of the Museum of Comparative Zoology at Harvard College.

New and old Silurian Trilobites from Southeastern Wisconsin, with notes on the genera of the Illaenidae

https://www.biodiversitylibrary.org/page/30207254#page/9/mode/1up

  • I found this Informative 1
Link to comment
Share on other sites

Holloway 1980 synonymized Cheirurus welleri with Ceraurus niagarensis (explaining the pygidium is not Cheirurus) and placed it in the genus Hadromeros

There is an important upcoming revision of the Cheiruridae from Congreve, Amati, and Kloc, that will hopefully provide additional details on this species.

 

Holloway, D.J. 1980

Middle Silurian Trilobites from Arkansas and Oklahoma, U.S.A.

Palaeontographica Abt.A, 170:1-85 

  • I found this Informative 5

image.png.a84de26dad44fb03836a743755df237c.png

Link to comment
Share on other sites

Outstanding, thank you! I will keep an eye out for that future paper. 

Link to comment
Share on other sites

  • 1 year later...

Found CHERIRURUS NIAGARENSIS , Kankakee illinois, by rock quarry last week! Adding info to help! 

1365E66D-7C3D-4F11-AE94-A0B29EB1F15E.png

92EB2F2F-071B-4FED-906B-690706D80581.png

55BF5385-364C-4E63-90F5-DD3DDB05CCA6.jpeg

285541A5-0B8F-4DDA-83C7-F8BBAC1BC85A.jpeg

0A9D2EF3-8142-46C6-847B-F029F1C7235B.jpeg

Link to comment
Share on other sites

10 hours ago, Carl-Lewis said:

Found CHERIRURUS NIAGARENSIS , Kankakee illinois, by rock quarry last week! Adding info to help!

 

 

Congrats on the trilobite and discovering this year old thread, but the taxonomy has been revised as was posted above.  Here is the updated info again:

 

Holloway 1980 synonymized Cheirurus welleri with Ceraurus niagarensis (explaining the pygidium is not Cheirurus) and placed it in the genus Hadromeros

 

The correct name is: Hadromeros niagarensis

 

image.thumb.png.1859cc95db8193e655054b279e95c02a.png

 

Holloway, D.J. 1980

Middle Silurian Trilobites from Arkansas and Oklahoma, U.S.A. Palaeontographica Abt.A, 170:1-85 

  • I found this Informative 6

image.png.a84de26dad44fb03836a743755df237c.png

Link to comment
Share on other sites

Hi Carl-Lewis,

 

Welcome to the Fossil Forum!  You will find quite a few trilobite aficionados here, and we are always glad for more company!

 

We do ask that people post the sources for the images they post here (apart from their own personal photos/data of course).  Not everyone complies all the time, of course, but nevertheless it is a standard we strive for.  After all, if someone is interested in the material you post it is important that they be able to go to the source and pull up the relevant publication.  Also it is just courteous to the author to have their work properly cited.  Hope you understand.

 

Don

  • I found this Informative 2
Link to comment
Share on other sites

It appears the last image in Carl-Lewis's post with a trilobite cephalon showing the numbers 4 and 7 in was from Plate 4, Figure 7 - photo by George Nelson of New and Old Silurian Trilobites from Southeastern Wisconsin, with Notes on the Genera of the Illaenidae
by Percy E. Raymond Bulletin of the Museum of Comparative Zoology at Harvard College Volume LX No. 1 - January 1916.

 

I have used this reference before for identifications. Did not realize it has a new genus name, thanks for that.

  • I found this Informative 1
Link to comment
Share on other sites

25 minutes ago, Kentuckiana Mike said:

It appears the last image in Carl-Lewis's post with a trilobite cephalon showing the numbers 4 and 7 in was from Plate 4, Figure 7 - photo by George Nelson of New and Old Silurian Trilobites from Southeastern Wisconsin, with Notes on the Genera of the Illaenidae
by Percy E. Raymond Bulletin of the Museum of Comparative Zoology at Harvard College Volume LX No. 1 - January 1916.

 

I have used this reference before for identifications. Did not realize it has a new genus name, thanks for that.

 

 

This figured specimen was actually used in a few different publications.

 

image.thumb.png.1e66a0230ba81491ada2eec9108ff88d.png

 

Barton, D.C. 1913. 

A New Genus of the Cheiruridae, with Descriptions of Some New Species.

Bulletin of the Museum of Comparative Zoology, 54(21):547-556

  • I found this Informative 1

image.png.a84de26dad44fb03836a743755df237c.png

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...