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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.  :wub:

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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

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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. 

Generalized diagram of a living brachiopod showing pedicle and feeding mechanism.

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) : 

brachdraw3.GIF

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. :)

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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...:default_faint::drool::wub::envy:

 

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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. 

Generalized diagram of a living brachiopod showing pedicle and feeding mechanism.

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) : 

brachdraw3.GIF

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. ;) 

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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?

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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)

hebertella_occidentalis.jpg

(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 : 

 General comparison of several similar orthid brachiopods in Upper Ordovician strata of Kentucky.

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 :

20191116_165553-1.thumb.jpg.50fdbcadec26a52890a48f382171e079.jpg

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

20191116_165625-1.thumb.jpg.4aeb01327b1993d7ac5d12b1cdac9bab.jpg

20191116_165714-1.thumb.jpg.e7cd9db1206947924401e5b5ae05e1e1.jpg

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

20191116_165745-1.thumb.jpg.51793fd39a58cd211260a2d607e01175.jpg

20191116_165849-1.thumb.jpg.8cea71236b14ccd81a4a01114e524ac7.jpg

And interiors of brachial valves: 

20191116_165924-1.thumb.jpg.770503d46a95dfa6940d9bfae6429558.jpg

20191116_170000-1.thumb.jpg.2adaede5a824faf518dd342da692dee4.jpg

Brachial valve anterior :

20191116_170048-1.thumb.jpg.d81cb0a0fcc8fd796090aa2e5654afba.jpg

Brachial valve posterior :

 20191116_170115-1.thumb.jpg.a0aeea1f6d22e486395805c7f3c67877.jpg

Pedicle valve posterior : 

20191116_170202-1.thumb.jpg.bebdeae95c968656b6bf6e91c6db93d7.jpg

Pedicle valve anterior :

20191116_170223-1.thumb.jpg.ad451c3b41d33f97711b7c5682741282.jpg

 

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