Prasapora expert needed!!

[minnbuckeye]

Whenever I visit the Decorah Shale the gumdrop bryozoans called Prasapora stand out. The vast majority have a domed top to them. But once or twice a summer, I stumble on a few that are distinctively pointy. Are these separate species or just variants of the same one? The species eludes me even if they are one in the same. HELP!!

 

 Mike

 

 Normal domed ones: 

 

 

 

Pointy one:

 

 

 

[Wrangellian]

Can't help you but I like 'em. Good name for the domed ones, gumdrop!

[ClearLake]

In the Fosils of Ohio book they describe Homotrypella as forming hemispherical, gumdrop shaped colonies. The apertures are rounded as opposed to Prasopora where the aperture are subpolygonal. No picture is provided but I think the apertures on your specimen fit that description when I zoom in. Homotrypella is an Ordovician genus. Iowa is not too far from Ohio 

[Mark Kmiecik]

3 hours ago, ClearLake said:

Iowa is not too far from Ohio 

Only 250 miles of Illinois and Indiana in between! 

[doushantuo]

I wish to point out I don't feel I'm that much of an "expert" on Paleozoic bryozoan systematics, but here goes anyway

The Journal of Paleontology has some articles on Prasopora, I think (e.g.,Marintsch?)

 

FRITZ

Life Sciences Contributions Royal Ontario Museum 107
Redescription of Type Specimens of Species
of the Bryozoan Genera Monticulipora,Mesotrypa, Peronopora, and Prasopora,from the Upper Ordovician Rocks of
Toronto and Vicinity, Ontario, Canada
Madeleine A. Fritz

or:

 

Ok, Canada is not the USA, but

redescriptionoft00frit.pdf

Of course, additional expertise might be provided by others.

[Northern Sharks]

The only way to properly identify a lot of bryozoans is through thin sectioning then looking at the structure through a microscope. This obviously will destroy the sample piece, but if you find damaged ones, it may be worth a try. When I had access to great ordovician material here in Ontario, I'd find both styles of Prasopora as well, but I never got to the point of sectioning them.

[minnbuckeye]

@ClearLake, the apertures appear polygonal like to me from the pictures. From your perspective, they look round? I will try and get a better look/ picture.

 

@doushantuo, thanks for the info!!! Very educational but didn't give me that SIMPLE answer I was hoping for. 

 

@Northern Sharks, doushantou's reference spells this out vividly. I have many "prasapora" that would love to be thin sectioned, but I have no capability of such an undertaking. So they  will just be filed with my general "prasapora" label.

 

 Thanks for everyone's participation!!!

 Mike

 

 

[minnbuckeye]