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Monica

Unknown item (sponge?) from the Credit River in Mississauga, Ontario

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Monica

Hello there!

 

Last month, I visited the Credit River in Mississauga, Ontario, Canada (Georgian Bay Formation, Upper Ordovician) to look for some fossilized corals.  In addition to a bunch of weathered colonial rugose corals, I found an item that I think is something, but I'm not sure what - perhaps a sponge?  Here are some photos of it:

 

Side view - dry:

DSC00480.thumb.JPG.2b36622c71568da294c2ee6d7d1cbe63.JPG

 

Top view - dry:

DSC00481.thumb.JPG.bdc2b4fb7a96014021cd8401d53d54ea.JPG

 

Top view - wet:

DSC00579.thumb.JPG.4539ce72b4e2fa4c94c0269006d931df.JPG

 

Thanks so much!

 

Monica

 

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TqB

It does look like Chaetetes, or a chaetetid anyway (calcisponge).

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Monica
6 minutes ago, TqB said:

It does look like Chaetetes, or a chaetetid anyway (calcisponge).

 

Thanks, Tarquin!  This would be my first sponge from my local area!!!

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Mark Kmiecik
5 hours ago, Monica said:

 

Thanks, Tarquin!  This would be my first sponge from my local area!!!

Yay!

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grandpa
7 hours ago, Monica said:

my first sponge from my local area!!!

Congratulations, Monica.  What a nice addition.  I love sponges, corals and bryozoans and their aesthetic patterns.  But I still struggle to distinguish between the 3 on ID'ing any single sample.  Good job!

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DPS Ammonite
4 minutes ago, grandpa said:

Congratulations, Monica.  What a nice addition.  I love sponges, corals and bryozoans and their aesthetic patterns.  But I still struggle to distinguish between the 3 on ID'ing any single sample.  Good job!

Lots of convergent evolution going on. All three of the creatures have structures that look like tabulae. Even the experts have debated what Chaetetes was: bryozoan; coral and sponge. Latest belief is that it is a sponge based on spicules found in a similar living sponge.

 

3919

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FossilNerd
16 minutes ago, grandpa said:

Congratulations, Monica.  What a nice addition.  I love sponges, corals and bryozoans and their aesthetic patterns.  But I still struggle to distinguish between the 3 on ID'ing any single sample.  Good job!

I’m with you grandpa! It’s so hard sometimes to distinguish between them. Heck, even the Chaetetids that @TqB mentioned were once classified as corals.

 

 https://ucmp.berkeley.edu/porifera/chaetetids.html

 

Dang... @DPS Ammonite beat me to it. I really need to refresh or show replies when I’m posting. ;) 

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DPS Ammonite

For comparison, here is a Chaetetes from the Pennsylvanian Naco Formation near Payson, Arizona. It is about 15cm x15cm. Note the double terminated quartz crystals near the bottom of the sponge (left side of photo). Chaetetes that were meters in size formed reefs. I took years of hunting in Arizona to find one. Once I found one and recognized what they looked like, I found them all over.

E2440438-BA2E-4BC7-B775-48706A7E8A70.jpeg

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Monica

You guys have got me thinking - is it possible that my specimen pictured above is a bryozoan rather than a sponge?  I've never before found a bryozoan that looks like that, but I've also never found a sponge in my area - what do you think?

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JUAN EMMANUEL

I see a worn out Prismostylus sp. partial. Was this found up north of the Credit River near Streetsville?

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FossilDAWG

I agree with Prismostylus.

 

Don

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