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Two Bryozoa


JeanB

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Hi,

I found this nice bryozoa, which I think is Rhinidictya sp. The second one is somewhat a mystery to me. A piece of the rock broke off and revealed two types of structures underneath: The wall at the left is circular (approx 5 cm in diameter and 1 cm thick) and is made of microtubules. At the bottom the structure is more familiar but there is a wave-like imprint and what I interpret as concentric rings.

Any ideas?

Thanks

Jean

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Edited by JeanB

JeanB

Montreal, QC, Canada

Ordovician, Trenton group

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Very helpful Roadrunner! Your first specimen is of the same kind as the one I found last year. It may be Prosopora sp. but I am not sure.

Jean

JeanB

Montreal, QC, Canada

Ordovician, Trenton group

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Very helpful Roadrunner! Your first specimen is of the same kind as the one I found last year. It may be Prosopora sp. but I am not sure.

Jean

Thank you. I'll look more at the Prosopora sp.

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Sorry it is Prasopora.

Jean

JeanB

Montreal, QC, Canada

Ordovician, Trenton group

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Bryozoa are always hard to identify with much certainty unless you can do thin sections in various directions and have all the literature to weed through. I have been attempting for years to get a better handle on the hundreds(!?) of specimens I collected from the Cincinnatian Series. And there are dozens of genera and hundreds of listed species. Guaranteed insanity for an amateur like me. But I have come closer to my goal of at least a generic ID for all. To do that I have been steadily gathering any and all references I can get my hands on. That is coupled with known species* lists as well as stratigraphic ranges* to at least begin a process of elimination.

*both the species lists and the stratigraphic ranges were created by scanning the literature and compiling the info on spread sheets. And there are many species that are probably synonymous and stratigraphic ranges that are not complete.

A big project.

Good luck with these.

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Seconded, thin section and serious expertise are the only real ways to go with these. I admire your dedication though - most people would simply leave it a 'bryozoan'!

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Hey Jean,

I found this great research article on Bryozoans. I don't know if you've already read it.

http://icb.oxfordjournals.org/content/early/2010/10/07/icb.icq146.full

It seems I may be diving further into this subject, too. I'm putting what may be another one I can't identify this morning on my thread for things I haven't yet identified, here;http://www.thefossilforum.com/index.php?/topic/35702-finds-today-that-i-cant-id/page-4#entry507884

I can't tell if it is a trace fossil of one laid over another, or a single organism.

Anyway, I hope the research paper helps you too!

Edited by Roadrunner
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Could your second photo be a partial brachiopod shell, and a bryozoa? Your photos are very well done. :)

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Thanks everyone!

Erose: I know what you mean, there is so much to read and sort out it could drive me banana. The thin slices with acetate would be something to try... with a lot of time ahead of me.

Roadrunner: your links will help me a lot. I found a couple of review articles too (provided to me by Jean-Marc Ethier from the Société de Paléontologie du Québec: a terrific guy to have around). I will post these here tonight for those of you interested in bryozoa.

4circle: as I have said before, for me the ID search and discussion is as much (maybe more) exciting as finding specimens.

Tethys: I first thought that it could be from a brachiopod shell, but no it can be ruled out. Could be a dome bryozoa, but the structure at the base is a mystery: Is it part of the whole fossil or another one beneath?... Thanks for your nice compliment on my photos. My other hobby is macrophotography: it helps me a lot with fossils: Nikon D5000, Tamron 90mm macro, flash, macro tripod and focus rail. Some of my samples are just too large and heavy to bring them home: I take pictures and note on the site. Sometimes I use focus stacking.

Regards

Jean

Edited by JeanB

JeanB

Montreal, QC, Canada

Ordovician, Trenton group

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And this excellent book from the icon James Hall (old (1887) but very nice plates): You can read it on google. I decided to buy it (80$) to have it in my collection. I know that since then some genera and species have probably changed, but it is a nice reference document.

http://books.google.ca/books?id=oUNAAQAAIAAJ&printsec=frontcover#v=onepage&q&f=false

Jean

Edited by JeanB

JeanB

Montreal, QC, Canada

Ordovician, Trenton group

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Nice links, thanks. If you are sure if the critter under the bryozoa isn't a brachiopod like Atrypa, perhaps Cerampora maculata is a good candidate for a bryozoa ID. It is figured on page 361 of the book link, with text preceding on 359.

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If you are sure if the critter under the bryozoa isn't a brachiopod like Atrypa, perhaps Cerampora maculata is a good candidate for a bryozoa ID. It is figured on page 361 of the book link, with text preceding on 359.

Well it would certainly be a good fit. However this genera is not part of the bryozoa fauna in my locality. I am thinking more as a Prasopora sp. (http://www.paleoportal.org/index.php?globalnav=fossil_gallery&sectionnav=detail&submission_id=970&taxon_id=&state_id=&period_id=15&assemblage_id=&last_section=search)

The specimen is probably too partial to give up its identity. I searched for another sample yesterday and today but have not found any yet.

I will keep you informed if something new come into light.

Jean

Edited by JeanB

JeanB

Montreal, QC, Canada

Ordovician, Trenton group

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