bivalves and brachiopods from Toronto/Mississauga

[Monica]

Hello everyone!

 

Now that I've started to split some rocks from my local creeks (Mimico Creek and Etobicoke Creek, Georgian Bay Formation, Upper Ordovician), I'd like some help to identify what I've found. @JUAN EMMANUEL, can you help?

 

Rock #1: This type of bivalve is very common, but I can't decide if it's Ambonychia sp. or Byssonychia sp.  The book I have says that they both occur in the Georgian Bay Formation, and they look very similar except Byssonychia sp. "has strong radiating ribs rather than (fine radiating) striae," which is what Ambonychia sp. has. (Hessin, p. 148)  What do you think?

 

Rock #2: I've started to find this type of bivalve quite frequently.  It looks like the pictures of Cymatonota sp. in the book that I have (Hessin, p. 145), but I'm not sure if this genus exists in the Georgian Bay Formation since Hessin states that "it is moderately common in the Verulam and Coburg formations" (p. 145) but he makes no mention of it occurring in the Georgian Bay Formation.  Hessin does state that another similar-looking bivalve can be found in the Georgian Bay Formation: Colpomya sp. (p. 146), so perhaps it could be that?  Hessin also discusses a bivalve community that is commonly found in the Georgian Bay Formation that consists of Ambonychia/Byssonychia and Modiolopsis (p. 52), so could this be Modiolopsis sp. instead?  As you'll see in Rock #3, the bivalves in Rock #1 and Rock #2 are often found together.

 

Rock #3: "front" - bivalve community, but which genera?

 

Rock #3: "back" - bivalve community (which genera?) along with a couple of brachiopods (I think).  It may be a bit too difficult to identify the brachiopods, but I'm hoping that someone out there might be able to - perhaps Onniella sp. or Strophomena sp. for the one on top (positive and negative)?

 

Rock #4: positive and negative of a brachiopod - again, it may be too faint to identify but I'll keep my fingers crossed that someone can help me.  Maybe Dalmanella sp. or Paucicrura sp. or Resserella sp.?

 

Thanks everyone!

 

Monica

[JUAN EMMANUEL]

Hey Monica let me see my notes for a minute. Your Ambonychia is an Ambonychia radiata and Byssonychia is an old synonym for Ambonychia. I dont know why the old synonym is still persisting in some websites on the net.

http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=310961

 

 

[JUAN EMMANUEL]

Rock#2 could be a Cymatonota lenior? But it doesnt appear elongated enough to be one (maybe its in juvenile stage?). I agree that it is a Cymatonota. Im looking at my notes from the Stratigraphy and Paleontology of Toronto book.

Rock #3 front, left edge, could be a Pholadomorpha pholadiformis if it has the criss crossing striations on it. You will have to look closely for this as the shells are preserved as black films.

To the right edge of the same rock front looks like an Orthodesma subangulatum.

[JUAN EMMANUEL]

Rock #3 back again is an Ambonychia radiata. These guys are really common and you can tell right away what they are even when they are shell fragments. You dont have to worry about coming across different Ambonychias species with where we are as the only one you will find is A. radiata.

 The top brachiopod is most likely a Sowerbyella sericea; the shell doesnt look like it has the defined striations but the shell shape tells me it is.

 

[JUAN EMMANUEL]

Your last fossil looks like a Zygospira erratica if it has the sulcus or "cleavage" in the middle of the shell.

[Pumpkinhead]

I have found a bivalve that looks similar to the second one you found in Georgian Bay formation rock and I seem to remember being able to attach a name to it. I just forget what name it is. I'll get back to you once I'm home and have my ID books

[Monica]

39 minutes ago, JUAN EMMANUEL said:

Hey Monica let me see my notes for a minute. Your Ambonychia is an Ambonychia radiata and Byssonychia is an old synonym for Ambonychia. I dont know why the old synonym is still persisting in some websites on the net.

http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=310961

 

 

 

Thanks for clearing that up!  Now I can label all of these guys as Ambonychia radiata - hooray!

[Monica]

26 minutes ago, JUAN EMMANUEL said:

Rock#2 could be a Cymatonota lenior? But it doesnt appear elongated enough to be one (maybe its in juvenile stage?). I agree that it is a Cymatonota. Im looking at my notes from the Stratigraphy and Paleontology of Toronto book.

Rock #3 front, left edge, could be a Pholadomorpha pholadiformis if it has the criss crossing striations on it. You will have to look closely for this as the shells are preserved as black films.

To the right edge of the same rock front looks like an Orthodesma subangulatum.

 

Thanks for the ID help!  I'm happy to simply label Rock #2 as Cymatonota sp. - I'm okay without attaching a species name to it.

 

Re: Rock #3 front, left edge - that bivalve does indeed seem to have criss-crossing striations on it, and it appears to have the correct shape of Pholadomorpha pholadiformis (I did a quick google search for images) so I'll go ahead and call it that.  Very cool!  The book I have doesn't list this genus or species, so thanks!    As for the right edge of that side of the same rock - I did a quick google search and came up pretty much empty-handed for images of Orthodesma subangulatum, so it may be that species but I was just wondering - is another possibility Cymatonota sp.?

[Monica]

48 minutes ago, JUAN EMMANUEL said:

Rock #3 back again is an Ambonychia radiata. These guys are really common and you can tell right away what they are even when they are shell fragments. You dont have to worry about coming across different Ambonychias species with where we are as the only one you will find is A. radiata.

 The top brachiopod is most likely a Sowerbyella sericea; the shell doesnt look like it has the defined striations but the shell shape tells me it is.

 

 

Thanks for helping with the brachiopod - I didn't consider Sowerbyella sericea because I thought that they were more rectangular than my specimen, but I think you're right - it is a good match!

[Monica]

30 minutes ago, JUAN EMMANUEL said:

Your last fossil looks like a Zygospira erratica if it has the sulcus or "cleavage" in the middle of the shell.

 

Hi again!  I was expecting more well-defined "ribs" for Zygospira sp., but the shape is right on the money, and since this genus is found in the Georgian Bay Formation (as stated in Hessin, p. 131), then I think you're right!  I have one question, though - the book I'm using says that the only species belonging to this genus that's found in Ontario is Zygospira modesta - is this synonymous with Zygospira erratica?

 

Thanks again for all of your help!

 

By the way - have you found any promising fossil-hunting locations in Hamilton?  I hope so! 

 

Monica

[JUAN EMMANUEL]

1 hour ago, Monica said:

 

Hi again!  I was expecting more well-defined "ribs" for Zygospira sp., but the shape is right on the money, and since this genus is found in the Georgian Bay Formation (as stated in Hessin, p. 131), then I think you're right!  I have one question, though - the book I'm using says that the only species belonging to this genus that's found in Ontario is Zygospira modesta - is this synonymous with Zygospira erratica?

 

Thanks again for all of your help!

 

By the way - have you found any promising fossil-hunting locations in Hamilton?  I hope so! 

 

Monica

Both names are not synonymous. Z. modesta has fewer but more pronounced plications on the shell. Z. erratica has more and finer plications on the shell and the sulcus is a lot easier to notice. 

http://www.ordovicianatlas.org/atlas/brachiopoda/rhynchonellata/atrypida/anazygidae/zygospira/zygospira-modesta/

[Herb]

http://strata.uga.edu/cincy/fauna..  This will help some

[doushantuo]

copper

For what it's worth: recommended

[doushantuo]

Not entirely certain about the taxonomy(old piece!!),but hey ,I trust Pojeta on rep alone

[erose]

1 hour ago, doushantuo said:

Not entirely certain about the taxonomy(old piece!!),but hey ,I trust Pojeta on rep alone

 

This is a great publication for sorting out these bivalves for species. Genera may have been reassigned but the link that Herb included will get you to the more up to date generic names.

 

[Pumpkinhead]

8 hours ago, JUAN EMMANUEL said:

Rock#2 could be a Cymatonota lenior? But it doesnt appear elongated enough to be one (maybe its in juvenile stage?). I agree that it is a Cymatonota. Im looking at my notes from the Stratigraphy and Paleontology of Toronto book.

Rock #3 front, left edge, could be a Pholadomorpha pholadiformis if it has the criss crossing striations on it. You will have to look closely for this as the shells are preserved as black films.

To the right edge of the same rock front looks like an Orthodesma subangulatum.

 

Now that I have had a minute to consult my resources, JUAN EMMANUEL seems to have a better ID than I do

[JUAN EMMANUEL]

9 hours ago, Monica said:

Re: Rock #3 front, left edge - that bivalve does indeed seem to have criss-crossing striations on it, and it appears to have the correct shape of Pholadomorpha pholadiformis (I did a quick google search for images) so I'll go ahead and call it that.  Very cool!  The book I have doesn't list this genus or species, so thanks!    As for the right edge of that side of the same rock - I did a quick google search and came up pretty much empty-handed for images of Orthodesma subangulatum, so it may be that species but I was just wondering - is another possibility Cymatonota sp.?

Cymatonota is another possibility. You should consult the Stratigraphy and Paleontology of Toronto but no pdf online is available for the entire book. I can show you the plates of the book that shows all the pelycopods of the Georgian Bay formation of Etobicoke. The book I mentioned is more useful in identifying pelycopods of the Georgian Bay formation than Hessin's book from what I have seen. 

[doushantuo]

Modiomorphid measurements after Babin(1966)

 

[Monica]

7 hours ago, JUAN EMMANUEL said:

Cymatonota is another possibility. You should consult the Stratigraphy and Paleontology of Toronto but no pdf online is available for the entire book. I can show you the plates of the book that shows all the pelycopods of the Georgian Bay formation of Etobicoke. The book I mentioned is more useful in identifying pelycopods of the Georgian Bay formation than Hessin's book from what I have seen. 

 

Hi again!

 

Thanks SO much for your help - I really appreciate it!

 

I was just wondering about the book that you use - do you photocopy from your library's copy or do you have your own copy?  Since I don't live downtown and I work north of the city from September to June and I have two kids to occupy my time in the summer, it would be a bit difficult for me to travel downtown on a regular basis to look at the library's copy, so I was wondering if it would even be possible to purchase a copy somewhere...

 

Monica

[doushantuo]

Credit

[doushantuo]

Sortofguide

[JUAN EMMANUEL]

3 hours ago, Monica said:

 

Hi again!

 

Thanks SO much for your help - I really appreciate it!

 

I was just wondering about the book that you use - do you photocopy from your library's copy or do you have your own copy?  Since I don't live downtown and I work north of the city from September to June and I have two kids to occupy my time in the summer, it would be a bit difficult for me to travel downtown on a regular basis to look at the library's copy, so I was wondering if it would even be possible to purchase a copy somewhere...

 

Monica

The Toronto Public Library has only one copy of it and it is held and can only be viewed in situ in the Toronto Reference Library near Bloor and Yonge St. When you get a look at the book, take pictures like I did of the pages. I had a notebook app on my phone that allowed me to scan the pages onto my phone via camera. What makes the book so rare is the fact that there are few copies going around of the complete book so it's unlikely you'll come across the complete book for sale.

 

29 minutes ago, doushantuo said:

Credit

This part is the 5th book in the complete six parts. There are other parts that focus on the Georgian Bay formation of Toronto. It is also the only part of the book  that is digitized and easily available on the net as far as I know.

[Monica]

@JUAN EMMANUEL

 

Hi once again!

 

I'm sorry to keep asking for your help, but here's another bivalve that I recently found in Etobicoke Creek - it seems to have "stripes" just like the one in Rock #3, front - could this one also be Pholadomorpha pholadiformis?

 

 

Thanks once again!!!

 

Monica

[JUAN EMMANUEL]

2 hours ago, Monica said:

@JUAN EMMANUEL

 

Hi once again!

 

I'm sorry to keep asking for your help, but here's another bivalve that I recently found in Etobicoke Creek - it seems to have "stripes" just like the one in Rock #3, front - could this one also be Pholadomorpha pholadiformis?

 

 

Thanks once again!!!

 

Monica

Looks like it except the dorsal part of the shell is partly buried in the matrix. The shell itself also looks partial.

[FossilDAWG]

3 hours ago, JUAN EMMANUEL said:

This part is the 5th book in the complete six parts. There are other parts that focus on the Georgian Bay formation of Toronto. It is also the only part of the book  that is digitized and easily available on the net as far as I know.

One frustrating thing about that pdf is that the plates (figures of fossils) are missing (except Plate 1) even though the figure captions are included.  Where the plates should be are just blank pages. 

 

Don