Adam's Ordovician.

[Bobby Rico]

10 minutes ago, Tidgy's Dad said:

Thanks, Bobby, I've just added a load more to the above post. 

Just lovely brachiopods mate. I could spend hours with a microscope and a bag of fossils. Keep them coming.  

[Coco]

Hi,

 

Adam, I don’t know anything about brachiopods. How do you tell the difference between a pedicle valve and a brachial valve ?

 

Coco

[Tidgy's Dad]

1 hour ago, Coco said:

Hi,

 

Adam, I don’t know anything about brachiopods. How do you tell the difference between a pedicle valve and a brachial valve ?

 

Coco

The pedicle is a kind of foot that protrudes through a hole in one valve of most brachiopods to anchor it to the substrate (or another creature). The valve with the hole, when present is called the pedicle valve and the other valve, the brachial valve contains the brachia, structures that support the lophophore, the soft structures used for respiration and filtering food particles. 

From the Kentucky Geological Survey. 

So we have some evidence of that in specimens like the last one I posted similar to this (a terebratulid rather than an orthid, but the idea is the same) : 

Some brachiopods don't have a pedicle ,but still usually a small hole or foramen, but the valve is still called the pedicle valve as the other one still contains the brachidium. 

I love it when people take an interest in brachiopods. 

Thanks, Coco. 

[FossilNerd]

3 hours ago, Tidgy's Dad said:

Okay so here are the prepped specimens of Cincinnetina multisecta from the Upper Ordovician of the Lawrenceburg Roadcut, Indiana

Emojis are worth a thousand words...

 

[FossilNerd]

1 hour ago, Tidgy's Dad said:

The pedicle is a kind of foot that protrudes through a hole in one valve of most brachiopods to anchor it to the substrate (or another creature). The valve with the hole, when present is called the pedicle valve and the other valve, the brachial valve contains the brachia, structures that support the lophophore, the soft structures used for respiration and filtering food particles. 

From the Kentucky Geological Survey. 

So we have some evidence of that in specimens like the last one I posted similar to this (a terebratulid rather than an orthid, but the idea is the same) : 

Some brachiopods don't have a pedicle ,but still usually a small hole or foramen, but the valve is still called the pedicle valve as the other one still contains the brachidium. 

I love it when people take an interest in brachiopods. 

Thanks, Coco. 

I’ve heard people say dismissive statements similar to “Oh... It’s just a shell” and the like. I think that this posts shows that the “lowly” brachiopod is way more complicated than most people think.  

[Wrangellian]

I love brachiopods too. Your prep jobs are impressive considering you're just using a pin. Maybe the matrix is that easy... Nothing I have experience with is that easy - it's either too hard or too soft and you risk breaking it either way!)

Have you considered a diluted vinegar solution to remove the last traces of matrix, after the pin work, or do these shells not stand up well to acid?

[Tidgy's Dad]

On 11/15/2019 at 3:29 AM, Wrangellian said:

I love brachiopods too. Your prep jobs are impressive considering you're just using a pin. Maybe the matrix is that easy... Nothing I have experience with is that easy - it's either too hard or too soft and you risk breaking it either way!)

Have you considered a diluted vinegar solution to remove the last traces of matrix, after the pin work, or do these shells not stand up well to acid?

Matrix is usually pretty soft from Lawrenceburg, though there are some harder and impossible bits sometimes. 

I have taken your advice and dumped a spare specimen in vinegar solution. I'll keep you informed.

On 11/15/2019 at 3:01 AM, FossilNerd said:

I’ve heard people say dismissive statements similar to “Oh... It’s just a shell” and the like. I think that this posts shows that the “lowly” brachiopod is way more complicated than most people think.  

The diversity of brachs in the Paleozoic is amazing, shame the Permian extinction clobbered them so badly, though there are still some pretty good ones after that. It's nice that in more recent times the relatively new (from Triassic) order Thecideida has been diversifying and is at its greatest diversity today. 

I love brachiopods and thankfully we have people who adore bivalves like @Max-fossils. Ralph @Nimravis, who supplied me with these Lawrenceburg specimens loves his Cenozoic gastropods from Florida. It's nice we all have our favourites.

This next brachiopod is a good example of the variation and similarity they can exhibit. Here is a picture of Hebertella occidentalis, just look at the variation in size and shape (partly down to age)

(photo from DryDredgers, not mine, unfortunately).

And that is just one species of this varied genus, but some species very closely resemble several other not terribly closely related forms as shown in this illustration from the University of Kentucky website : 

 

Luckily for me, in this case the other species don't occur at Lawrenceburg, so here are my Hebertella occidentalis, bottom four prepped, two on left pedicle valves, two on right brachial valves :

I forgot to include a scale, the largest one is 2.4 cm at its widest point, the smallest 1.8 cm

Interior of the pedicle valves. Sadly the beaks are broken. (not by me) : 

And interiors of brachial valves: 

Brachial valve anterior :

Brachial valve posterior :

 

Pedicle valve posterior : 

Pedicle valve anterior :

 

[Tidgy's Dad]

I only have one of these so I've been pretty cautious with the prepping, but here is Plectorthis fissicosta. 

Same family as Hebertella but a completely different suborder to Cincinnetina. Orthids dominate the brachiopod fauna here, it seems. 

 

 

 

 

 

[Tidgy's Dad]

Lawrenceburg has fossils from the Economy, Southgate and McMicken Members of the Kope Formation which are overlain by the Mount Hope and Fairmount Members of the Fairview Formation and then, at the top, part of the Bellvue Member of the McMillan Formation. Most of the fossils seem to be from the Fairview, but it's often difficult to tell as some species range across several members. 

There are four species of Plectorthis found here and all of them are limited to the Fairview Fm. P. fissicosta, shown above occurs in both members but P. neglecta, shown in this post, only occurs in the Mount Hope member. The other two species i don't have and only occur in the Fairmount member but this doesn't mean all the fossils are from here as i have species of brozoan and brachiopod that don't occur in the Mount Hope but are present in the Fairmount. The loose material is of mixed origin. 

Here then, is Plectorthis neglecta, smaller, and not as elongated as P. fissicosta and with a gentle fold in the commisure which P. fissicosta does not exhibit. 

Unfortunately, I only have the one and it's a bit damaged :

Here are the two species shown together :

Below :Note the slight fold in the commisure of P. neglecta compared with the straight line of P. fissicosta. 

Close ups :

 

[Tidgy's Dad]

And the final orthid genus from this site that i have is the easily recognized Vinlandostrophia. I love the way they look like spiriferids but aren't. 

There are ten species listed for these formations, but with a bit of practice they are possible to tell apart. Well, sometimes, anyway. 

The most common is said to be V. hopensis found, unsurprisingly, only in the Hope member of the Fairview Formation. 

My sample seems to concur as i have several of this species. 

Here are four prepped and one unprepped. 

 

 

[Tidgy's Dad]

On 11/15/2019 at 3:29 AM, Wrangellian said:

I love brachiopods too. Your prep jobs are impressive considering you're just using a pin. Maybe the matrix is that easy... Nothing I have experience with is that easy - it's either too hard or too soft and you risk breaking it either way!)

Have you considered a diluted vinegar solution to remove the last traces of matrix, after the pin work, or do these shells not stand up well to acid?

Oh, and Eric, I have discovered that with specimens from Lawrenceburg, the brachiopod shells dissolve faster than the matrix  

[Wrangellian]

Oh dear!

Oh well, at least it comes off reasonably well with the pins..?

[Tidgy's Dad]

On 12/6/2019 at 1:37 AM, Wrangellian said:

Oh dear!

Oh well, at least it comes of reasonably well with the pins..?

Yup, pretty well with this matrix. 

Here's the other species of Vinlandostrophia I've identified from my Lawrenceburg bits. 

Low fold, deep sulcus, 7 plications on either side of the fold and the medial rib in the sulcus is slightly larger than the two lateral plications. 

This is V. laticosta. 

This specimen is a bit squashed but it goes to show how careful one must be with the prepping. The shells are really thin.

 

[Tidgy's Dad]

Gosh, it's been a while since I added to this. 

But I've just seen the thread has had nearly 10,500 views which rather encourages me to get back to it. 

So, in a temporary slight sidestep away from Lawrenceburg, here are two rather large  Vinlandostrophia ponderosa ponderosa sent to me by Ralph @Nimravis

These are pretty huge for orthids and rather chunky for any brachiopod at the time, though some productids and terebratulids got even bigger later on.

The specimens are Cincinnatian from the Cincinnati area, but no further locality details were available.

 

Then I prepped them a little but some of the matrix was immovable: 

[Tidgy's Dad]

In the photo below, notice the tiny Zygospira modesta in the interarea of the brachiopod on the right.

 

 

 

 

[FossilNerd]

I love your Ordovician thread Adam! I’ve probably added 500 of the 10,500 views! Keep them coming! It may be that I’m also a little 

 

I find a lot of Vinlandostrophia at the Ordovician exposure that I hunt. I’m quite fond of them myself and you have some lovely ones! 

[Tidgy's Dad]

1 hour ago, FossilNerd said:

I love your Ordovician thread Adam! I’ve probably added 500 of the 10,500 views! Keep them coming! It may be that I’m also a little 

 

I find a lot of Vinlandostrophia at the Ordovician exposure that I hunt. I’m quite fond of them myself and you have some lovely ones! 

Thank you very much.

Here's a photo showing the comparative size of the V. ponderosa ponderosa with, from the left, the tiny Zygospira modesta, the medium V. laticosta and a standard sized V. ponderosa :

Hmmm. 

Bit blurred but you get the idea of the sizes. 

 

[Tidgy's Dad]

The little Zygospira modesta bottom left in the post above is one of a cluster found on the underside of a coral from the Drakes Formation in Kentucky. You can find more photos of these a couple of pages back.(page 11) 

The Zygospira modesta below are much bigger, though still the smallest species of brachiopod that I have from Lawrenceburg.

Compared to the tiny Kentucky specimens:

Close ups of one of the Lawrenceburg specimens :

And close ups of another Lawrenceburg Zygospira modesta :

[Tidgy's Dad]

The last of my Lawrenceburg brachiopods now, though it's still three more species. 

Ralph, @Nimravissent me a few of these Rafinesquina, though I've given a couple a way and prepped three of these that are definitely here to stay. 

Watch out for the epibionts, very special stuff there. 

 

Now, of course, we can see that some of them are bigger than others, but does this justify the whole range of Rafinesquina species described?

Some say most at this site are the large and successful Cincinnatian species Rafinesquina ponderosa and that some of the other species, including the common R. alternata are actually just morphological versions of the same and that the reason size and shape vary are incidental or environment related (many brachiopds have great diversity of form within a species). 

This one is Rafinesquina ponderosa, big size rounded edges, rounder in profile etc. : 

(don't forget to spot the epibionts. )

Here is a posterior view of one balanced on another!   

And the anterior of them both :

And one of the special epibionts from the side : 

 

 

 

 

[Tidgy's Dad]

More info coming when wifey lets me..................

[FossilDAWG]

You are aware, I suppose, that one of your epibionts is an edrioasteroid?

 

Don

[Tidgy's Dad]

1 hour ago, FossilDAWG said:

You are aware, I suppose, that one of your epibionts is an edrioasteroid?

 

Don

But of course. 

And a jolly nice one too. 

And that has made me very, very happy indeed. 

Though it started out buried under a horrid black and very hard matrix that was most annoying and i still haven't finished removing.

Good spot, Don, i wondered who would see it first.

[FossilNerd]

Love the Rafinesquina .

 

 I believe that they can be found in the section of Ordovician that I hunt. Although I haven't found a good specimen yet...

 

The epibionts are icing on the cake and beautiful as well!  

 

 

[Scylla]

Great collection!

[Tidgy's Dad]

On 2/23/2020 at 3:36 AM, FossilNerd said:

Love the Rafinesquina .

The epibionts are icing on the cake and beautiful as well!  

 

On 2/23/2020 at 6:49 AM, Scylla said:

Great collection!

Thanks, chaps! 

 

Now, one of the reasons I agree with those that say Rafinesquina ponderosa and R. alternata are separate species is the difference in ornamentation, no matter the size of the specimen. 

Below is a close up of R. ponderosa; note that the costae are pretty much the same size and evenly spread :

But in the photos below one can see the costae of R. alternata which shows an alternation of the  slightly thicker costae being separated by two to three much thinner ones. 

Note the bryozoan on the specimen above. 

And below is the lovely hinge line and beak of an R. alternata :