Brachiopods And Blastoids

[Scott S.]

Here are the Blastoids and Brachios from my previous post, rescanned from different angles in hopes of getting a more confident ID on them, and from that potential locations of origin. Maybe knowing one will lead to solving the other. Any help from anyone who knows these things would be appreciated!

If it helps to track down the sources, these were being sold in the '80s in the Fossil Shop, Drumheller Alta. I doubt they would be from formations that didn't produce these by the number.

So far I'm pretty sure the Spirifers are Mucrospirifer sp, most likely from Arkona Ont.

The Leptaena sp. could be from L. Devonian Camden Fm of Decacore Co, TN (as suggested by the outfit I bought it from)

The others were labelled as Delthyris (orange brachio), Dinorthis (flat one) and Platystrophia which was reidentified by forum members as Lepidocyclus (Ordovician).

Any other ID (species, location, etc) that might have come with them when they were bought has been lost so I'm hoping to recover as much as possible, even if it's not certain, just the possibilities would be better than nothing!

On some of them you might notice a dark stain that resulted from me stupidly using a sticky substance to stick them in a display case when I was a kid.

Hi Wrangellian,

I think I can help a bit on your brachiopods. Aside from the two spirifer types, the rest are definitely Ordovician. From the coloration and preservation I would say the Cincinnatian Series with about a good 95% confidence. Lepidocyclus and Hiscobeccus are the two possible genera for the small rhynchonelliform brachs. They are a little distorted but Lepidocyclas is a little more gracile and has more prominent delicate lamellae so that's probably what you have. The Leptaena is most likely L. richmondensis and the last one labled as Dinorthis is more likely Plaesiomys subquadrata. The dental sockets are too small and the costae are too numerous for Dinorthis.

Their similarities in preservation, and consistent color suggest that these were all collected together from similar localities. Therefore the fact that you have Lepidocyclus in the group would limit the group to the Richmondian (late Cincinnatian). Some great resources are the Cincinnati Dry Dredgers and Steve Holland's UGA Stratigraphy Lab. Unfortunately since the Cincinnatian is so huge there's no way of identifying which specific locality. I'll admit, I have quite the love for the Cincinnatian, It has taught me countless lessons! Beautiful little brachs aren't they?

http://drydredgers.org/

http://www.uga.edu/strata/

Cheers,

Scott

[Wrangellian]

Hi Wrangellian,

I think I can help a bit on your brachiopods. Aside from the two spirifer types, the rest are definitely Ordovician. From the coloration and preservation I would say the Cincinnatian Series with about a good 95% confidence. Lepidocyclus and Hiscobeccus are the two possible genera for the small rhynchonelliform brachs. They are a little distorted but Lepidocyclas is a little more gracile and has more prominent delicate lamellae so that's probably what you have. The Leptaena is most likely L. richmondensis and the last one labled as Dinorthis is more likely Plaesiomys subquadrata. The dental sockets are too small and the costae are too numerous for Dinorthis.

Their similarities in preservation, and consistent color suggest that these were all collected together from similar localities. Therefore the fact that you have Lepidocyclus in the group would limit the group to the Richmondian (late Cincinnatian). Some great resources are the Cincinnati Dry Dredgers and Steve Holland's UGA Stratigraphy Lab. Unfortunately since the Cincinnatian is so huge there's no way of identifying which specific locality. I'll admit, I have quite the love for the Cincinnatian, It has taught me countless lessons! Beautiful little brachs aren't they?

http://drydredgers.org/

http://www.uga.edu/strata/

Cheers,

Scott

Ah, that's the kind of certainty I like to hear.. I havent checked out your links yet, first I want to be clear about which ones you're referring to - Which two are spiriferid and which two rhynchonelliform? In the 2nd pic there are 2 Mucrospirifers, one smaller and more worn than the other, and then multi shots of one Lepidocyclus(?). There are 3 specimens in each picture. Is the orange one a spiriferid?

I dont know about sockets but the 'Dinorthis' does have largish teeth on it, perhaps the pic doesnt show them very well but I could do another shot from a diff angle.

Judging by the pics on that 2nd link my Lepidocyclus looks more like the Hiscobeccus. How can 2 different genera look so similar?? I'd hate to try and distinguish different species within each! (if there are more than 1)

Edited January 12, 2011 by Wrangellian

[Wrangellian]

OK here is a combo shot of the 'Dinorthis' from different angles, to show the 'teeth' and internal surface.

[Xiphactinus]

For sure the blastoids are not Devonian. As Shamalama said, they are probably Mississippian. Unfortunately, there are several locations in the Midwest(USA) that produced these in abundance. The bottom row looks like they may have come from Milstadt, Illinois sometimes referred to as Floraville, Illinois. Blastoids from this locality are generally pristine and that is why I would not say that for the upper row. They have damage to them and that would be unusual for that locality. The other possible localities are Sulfur, Indiana or Hopkinsville, KY. Another possible locality is Hecker, Illinois but I think that was a Pennsylvanian locality. It did produce lots of Pentremites so it is also a possiblity. All of your blastoids are Pentremites and the bottom row looks to be godoni.

crinus

I've hunted the Milstadt locality and I immediately thought that's where those came from when I saw the photo.

[Scott S.]

Ah, that's the kind of certainty I like to hear.. I havent checked out your links yet, first I want to be clear about which ones you're referring to - Which two are spiriferid and which two rhynchonelliform? In the 2nd pic there are 2 Mucrospirifers, one smaller and more worn than the other, and then multi shots of one Lepidocyclus(?). There are 3 specimens in each picture. Is the orange one a spiriferid?

I dont know about sockets but the 'Dinorthis' does have largish teeth on it, perhaps the pic doesnt show them very well but I could do another shot from a diff angle.

Judging by the pics on that 2nd link my Lepidocyclus looks more like the Hiscobeccus. How can 2 different genera look so similar?? I'd hate to try and distinguish different species within each! (if there are more than 1)

Sorry for not being so clear. The mucrospirifers are accurately identified. The other brachs in the same grouping are the Lepidocyclus. They belong to the order Rhynchonellida. I think they may be Lepidocyclus because of how prominenet the fine little lines are (called lamellae) that run between the ridges called costae. The image I'll send of the Hiscobeccus you should notice how much weaker and nearly absent the lamellae are. Also Hiscobeccus has a tendancy to stop growing at the edges of the hinge but keep going at the margin opposite the beak so that it puffs up and looks more like a fat gum ball. The beaks of either valve start to curl in at times. I'll have to look around an photograph one of this kind.

So just a brief overview of the anatomy of a brach to clarify. Large ridges that run from the beak near the hinge radiating out like in your little orange spiriferids are called plications. Smaller ones that can run parallel in between the ridges or as fine ridges on their own as in your Plaesiomys are called costae. The fine toothed lines that run perpandicular to the costae as in your Lepidocyclus specimens are called lamellae. I'll attach images from the Treatise to help with your ID's.

The little orange ones are definitely spiriferids and NOT Ordovician. I'm not terribly strong on them but they may be Punctospirifer and are maybe Mississippian or Pennsylvanian in age. They look kinda like some speciems I've seen from Jacksboro TX in the Graham Formation.

Lastly, I'm 100% sure on the Plaesiomys now because of the interior anatomy. Dinorthis has very little muscle scars internally and the costae are easily visible and distinct externally from the outer edge (commisure) to the hinge region near the beak of the valve. You will be able to see the differences in the hinges as well as muscle scar shapes from the images I'll send.

Hope this clears everything up,

Happy hunting,

Scott

[Wrangellian]

OK, I'll sort it out.

On this page: http://www.uga.edu/strata/cincy/strata/cdpRichmond.html , the 'Plaesiomys' in the strat chart is followed by '(Dinorthis)', implying that they are synonymous..? But by your pics I would definitely say Plaesiomys. I never know what pics to believe; for every one I see there is another that seems to throw doubt on it!

Edited January 13, 2011 by Wrangellian