ADAM'S SILURIAN

[Tidgy's Dad]

This next little group of common Waldron Shale bryozoan species had a very impressive way of avoiding the mud. At first glance they look a lot like the usual trepostome ramose bryozoans, but if you look at the broken ends of them you can clearly see that they are hollow and it is thought that they grew around filamentous algae, or a few sources suggest soft sponges as an alternative. So the algae grew out of the mud, these cystoporid bryozoans grew around them and when the algae died they rotted away leaving no trace and the bryozoan colonies were sometimes fossilized, the hollow centres filling up with sediment and sometimes pyrite. 

Two of the species belong to the genus Cheilotrypa, sometimes inaccurately called Chilotrypa, and originally assigned to Trematopora when it was more of a waste basket taxon. 

The differences between the two species are mostly observed in polished sections, but the differences in external morphology are that C. variolata has branches mostly 1 to 1.5 mm in diameter, though in some locations this may be as wide as 2.5 mm, and it has raised ridges around the zooaria much like Hallopora,, while C. varia (confusingly similar name) is more robust with branches 2 to 7 mm in diameter and less obvious rings around the zooecia. 

Here are m probable Cheilotypa variolata :

Many specimens are partly worn, but you can often find some evidence of the raised ridges :

They are often better preserved when still in the matrix and not weathered out :

Hollow interior, filled with sediment or calcite : 

Often very worn but still recognizable :

 

[Tidgy's Dad]

Cheilotrypa belongs to the same family as Fistulipora: the Fistuliporidae, which was an enormously successful group in the Wenlock with Fistulipora nummulina being the most common bryozoan in the Much Wenlock Limestone Formation and Cheilotrypa osteolata comprising 57% of the bryozoan fauna of the Rochester Shale of New York. I must try to get a specimen of C. osteolata at some time in the near furture. 

The following group are the Waldron Shale species C. varia, stems 2 to 7 mm in width and less ridged around the zooecia. A couple of the smaller ones here are actually C variolata that got in the wrong photo by mistake. I blame Tidgy. 

Still recognizable when worn down :

Bifurcating :

Love the colour of this one :

 

 

 

 

[Tidgy's Dad]

The other genus of hollow cystoporid found in the Waldron Shale is Diamesopora, which has been separated out from Cheilotrypa. Diamesopora is also thought to have grown around a filamentous algae. I have not been able to find much information on the Waldron shale species, mainly a photo or two. In some pictures the exterior looks smooth, in some the zooarium seems covered in tiny sharp bumps or monticules, one diagram seems to show that there are little protrusions with the apertures opening in the top so that they are not visible from looking straight at the branches. Perhaps the differences can be explained by the fact that there are two species that occur in the Waldron, D. infrequens and D. subimbricata and I don't know the differences between them other than that D. infrequens seems to be quite common and D. subimbricata comparatively rare. Perhaps one species appears smooth due to hooded apertures or the zoecia just being very tiny? Perhaps the other species has tiny lumps bearing the zooecia on the upper side so they are not clearly visible? I don't know. 

Here are some hollow bryozoan pieces that don't seem to be Cheilotrypa so may be Diamesopora :

This one is really nice, whatever it is :

The wide end is flattened :

And the two branches are more rounded :

Unusually nice detail of the internal structure on this one: 

Other specimens with bigger lumps or monticules :

The apertures would be on top of the bumps on their right sides in this picture, but are difficult to see : 

Worn down ? 

Smooth ones, maybe covered in a mineral such as calcite? 

Speckled with pyrite :

 

Edited April 26, 2022 by Tidgy's Dad

[Tidgy's Dad]

There are some other species of stick / ramose / branching bryozoans found in the Waldron Shale and these include the cryptostomes Stictopora orbipora, S. similis, Ptilodictya angusta and Nematopora macropora. There's also the fenestrid Pseudohornera niagarensis, (was Thamniscus). The first photo might be this species. I'm not sure about identifying any of these in hand sample or the exterior under magnification and I don't have cut and polished sections.

But here are some of my unidentified bryozoa that may belong to these species or others. These are all really, really small. But sometimes rather pretty and very interesting.

This one is a bit like Ptilodictya? 

Trematopora? 

 

 

Edited April 28, 2022 by Tidgy's Dad

[Tidgy's Dad]

Looking through my fenestrid pieces, I found some that I'm not sure belong to the Fenestrida but are perhaps broken bits of Ptilodictya angusta. The pieces seem to curve as though they are bits of a more ramose or slightly bifoliate or triangular form like Ptliodictya can be. And I remember the suspected Ptilodictya lanceolata fragments from the British Wenlock Limestone Formation were in a similar state. What do you think? They are 2 to 3 mm wide. 

 

[Tidgy's Dad]

The Order Fenestrida, sometimes still called the Fenestrata, are represented by several species in the Waldron Shale. Pseudohornera niagarensis may, or mat not, be shown two posts ago and the post above may be pictures of fenestrid fragments. 

Fenestella itself seems to be represented by three species; F. parvulipora, F. bellistriata and F. prolixa. A beautifully prepped example of F. parvulipora was posted on the forum some time back by the Waldron specialist @Ken K. Lovely example. Ken, if you should get the chance, it would be brilliant if you could cast your experienced eye over the Waldron specimens that I have posted on this page and the last and correct any of my probably many misidentifications. Thank you.  Or @RCFossils, I believe you have some knowledge of this formation too? 

These fragments seem likely to be Fenestella parvulipora : 

 

Another bit :

And another :

The reverse of these bits is usually completely covered by hard matrix, but on this specimen a little is see : 

But I don't dare risk any further prepping as the specimens are very thin and fragile :

The following two bits don't really go together, it just looks nice and is a reminder that finding bits of these fenestellids doesn't necessarily represent the number of colonies present at the time as each colony can produce an awful lot of little fossil pieces. 

There are lots of tiny pieces like the one below :

[Tidgy's Dad]

This one has greatly elongated and thin fenestrae. I think it's Fenestella bellistriata. 

And compared to F. parvulipora :

A second specimen? 

Edited April 29, 2022 by Tidgy's Dad

[Tidgy's Dad]

But my favourite bryozoan from the Waldron Shale has to be this one. 

It's Semicoscinium acmeum. Originally named Fenestella acmea, then transferred to its own family and genus as Semicoscinium acmea and then the species name amended to acmeum. 

It is so wonderful to have a fenestrid in three dimensions, even though this is only the base and it would have had much bigger fronds reaching up from this. Usually, fenestrids are just found as fragments of flattened fronds. 

Top of specimen :

And the holdfast :

A second, smaller specimen : 

Top :

Holdfast :

Part of a frond :

Reverse of this last specimen :

Other fenestrids can be found in the Waldron including Loculipora ambigua, Polypora tantula and Polypora conferta, but I don't think that I have those as yet. 

There are also many species of tiny encrusters that I may find as I sort out my brachiopods from the formation which I have only just begun............

 

 

Edited April 28, 2022 by Tidgy's Dad

[Tidgy's Dad]

Whilst prepping my Waldron Shale brachiopods, I have found another couple of bryozoan specimens that are worth sharing. 

This first one is a Nematopora sp. with its spines / acanthopores preserved in a couple of places. The zooarium is about a millimetre in diameter at it's widest. The row of Tentaculites looking things to the left are actually the ribs of a Fardenia subplana brachiopod : 

And this second one I think is a Loculipora ambigua fenestrid? 

Very pretty. 

Edited May 1, 2022 by Tidgy's Dad

[Tidgy's Dad]

Brachiopods, like the Bryozoa, are very common and extremely diverse in the Waldron Shale, the Subphyla Linguliformea, Craniiformea and Rhynchonelliformea are all present. 

Here are the brachiopods I received from @connorp. These are from the Atkins Quarry, Jeffersonville, Clark County, Indian. Thanks again, matey, I'm enjoying these so much.  (Yup, a snail crept in there, too!) 

And this group are equally loved, so thanks once more @Paleome These are from the Illinois Basin, Indiana. 

Lingula gibbosa, as with many modern species of Lingula, was well adapted to living in the mud and the three species of Petrocrania were epibionts often living on brachiopod valves as was Craniops ovalis. If I am lucky, I will find some craniids as I prep my brachiopods. 

The major classes of rhynchonelliforms were the Rhynchonellata and Strophomenata, but there were other classes, a couple of which died out in the Cambrian and the Chileata which existed from the Early Cambrian to the Late Permian. They were never particularly abundant, but the species Eodictyonella reticulata is reasonably common in the Waldron Shale. It's a beautiful brachiopod with an etched, diamond-patterned shell. I have just one tiny fragment found amongst Debra's wonderful matrix : 

I said it was tiny! 

Definitely a bit of shell material and not a bryozoan or a receptaculitid. 

Shell interior : 

 

 

 

Edited May 3, 2022 by Tidgy's Dad

[Tidgy's Dad]

Orthids in the Waldron Shale are represented by a few genera, most commonly Dalejina, Resserella and Isorthis. 

There are two species of Dalejina; D. hybrida and D. newsomensis, which seem to be almost indistinguishable although the former is larger with the latter only obtaining a maximum width of 11 mm. These species used to be Rhipidomella but were reassigned when the genus was split up. Here is a Dalejina exactly 1 cm wide, so who knows? Anyway, it's prepped out beautifully, not that it took a lot of work.

Pedicle valve :

Brachial valve :

Posterior :

Anterior :

Lateral :

Close ups :

A brachial valve interior of Dalejina, this one is just 7 mm wide. No way I can remove this from the matrix intact :

This tiny brachiopod also seems to be an orthid. Maybe Ptychopleurella, sp. but it's too small and gooped up to be certain :

 

 

 

 

 

[Tidgy's Dad]

The biggest brachiopod that I have from the Waldron Shale is this pentamerid, Sieberella. Many other species do occur that are larger, but this is my biggest thus far. 

There are two species of  Sieberella present in the Waldron Shale; S. roemeri and S. knotti. The latter species is only found in Clark County, Indiana, which is where my specimen comes from. S knotti seems to be slightly smaller and smoother than S.roemeri without the prominent ribbing over the majority of the shell. The species were previously assigned to Gypidula. 

My specimen is only the pedicle valve but is rather nice, in my opinion.

The ribs become more pronounced towards the anterior margin : 

Side view :

Beak detail :

Surface close up showing fine striae. 

[Bobby Rico]

Thanks I enjoyed catching up on your thread. Some lovely stuff , nice corals but I liked the concentric circles bryozoan Lichenalia concentrica the most. Something struck me about this thread is how much you really appreciate and enjoy the specimens you’re gifted. Keep the good work up. 
 

cheers Bobby 

Edited May 3, 2022 by Bobby Rico

[Tidgy's Dad]

5 hours ago, Bobby Rico said:

Thanks I enjoyed catching up on your thread. Some lovely stuff , nice corals but I liked the concentric circles bryozoan Lichenalia concentrica the most. Something struck me about this thread is how much you really appreciate and enjoy the specimens you’re gifted. Keep the good work up. 
 

cheers Bobby 

Glad you are enjoying it, my friend. 

Thanks, yes, I am really jolly lucky to have been gifted so many great fossils by kind individuals. 

Though the Lichenalia photo was actually pinched from another member as I don't have any myself. Probably shows how bad my own photography is.  

[Tidgy's Dad]

The other fairly common pentamerid found in the Waldron Shale is Anastrophia internascens. The genus is represented in my collection from the British Much Wenlock Limestone Formation by A. deflexa. They look a bit like rhynchonellids but don't have a fold and the sulcus is only on the anterior portion of the brachial valve. The commisure is almost flat. 

This one is 1.4 cm wide and from the Atkins Quarry site in Indiana. 

Brachial valve:

Pedicle valve :

Commisure :

Beak :

Lateral view. 

 

 

[Tidgy's Dad]

At least one source mentioned that the most common brachiopod in the Waldron Shale is Atrypa reticularis. Whether this is true or not, I couldn't say with the very limited material in my possession, but it's certainly one of the more common ones found according to my research. The trouble is that A. reticularis was, and still seems to be, a "bucket taxon" where anything that looks rather like it is labelled as it. Some authors list the Waldron species as Atrypa "reticularis", or have created a new subspecies; Atrypa reticularis newsomensis, or a species; Atrypa newsomensis, though this might refer to some uneven looking specimens with more frilly growth lines and "proto-spine bases". The Atrypa reticularis I am familiar with have an convex to highly convex brachial valve with a moderately inflated pedicle valve that becomes flat or even a little concave toward the valve anterior. The Waldron specimens I have are moderately biconvex, though I have seen this with some specimens from Europe as the species morphology is quite variable. Still, there is no doubt that this was a highly successful, widespread and long ranging species and genus. 

Brachial view :

Pedicle view :

Large specimen, pedicle valve :

Brachial valve :

Beak :

Commissure : 

 

Lateral view :

Detail :

Smaller specimen :

Smallest and broken specimen :

 

 

 

[Tidgy's Dad]

Another atrypid found in the Waldron Shale is Atrypina disparilis. I think this species is often overlooked because it is so small and could easily be confused with a spiriferid, a rhynchonellid or even an athyrid. But the potential specimens I have are seemingly not strophic like a spiriferid, the ribs are two broad and widely spaced for a rhynchonellid and they just don't seem to match any of the athyrids found in the formation. 

Notice the two broad plications spreading out from the beak and just one more each side of those :

 

It's only an isolated pedicle valve, but you can see the valve edges, showing it is nearly complete and is astrophic, so not a spiriferid. 

A second specimen : 

And a third : 

[Tidgy's Dad]

There are quite a number of rhynchonellid species known in the Waldron Shale, many of them confusingly similar in appearance. They are the most numerous group in my little samples, but a certain amount of this may be due to factors such a preservation bias (rhynchonellids are tough, strongly ribbed and the valves often don't separate after death), collecting bias ( they tend to erode nicely out of the matrix due to their round shape and toughness) and size (some of them are quite large and non extremely tiny). The ribbing and roundness makes them quite attractive and easy to spot, too.  

Perhaps the most easily identifiable species is Rhynchotreta americana. This was originally named as R. cuneata, as this is the similar species from the British Wenlock, then R. cuneata var. americana and finally R. americana, not to be confused with R. americanifomis which is a Canadian species. 

I only have one damaged specimen, but the extended beak is unmistakable. 

Brachial valve with sulcus :

Pedicle valve, more than half the shell has broken off leaving an internal mold : 

Posterior view :

Anterior showing zigzag commissure : 

The sides :

Quite pretty ribbing in close-up :

And a bryozoan epibiont, possibly Ceramopora sp. 

 

[Tidgy's Dad]

Other species of rhychonellid in the Waldron Shale include several species of what used to be Rhynchonella, then Camarotoechia and then Stegerhynchus. 

A couple of these have since been moved to Uncinulus as they are clearly very different being quite spherical, having more costae and a low fold and shallow sulcus which ends in a squared-off tongue. U. stricklandi is large, 2 to 3 cm across, whilst U. saffordi, despite being smaller, at approximately a centimetre wide, has more costae on the flanks, on the fold and in the sulcus than the larger species. Some authors have now moved these to Sphaerirhynchia and consider Uncinulus to be a later Silurian or primarily Devonian genus. 

 

Although lumpers would list only two other species of Stegerhyncus in the formation, most authorities still list three of four. 

Stegerhynchus indianensis, sometimes referred to as S. indianense, is 1 to 1.5 cm wide, between two and five costae on the fold, but usually three or four and normally four, but occasionally three on each flank of the brachia valve. They may be rounded to more teardrop shaped. They are quite common, but I only have a few bits, rescued from matrix pieces. 

   

Not the best, I know, but I have some nicer rhynchonellids to come, I promise! 

[Tidgy's Dad]

Well, this one's a little bit better, I suppose. Very happy to have it. 

Stegerhynchus neglectus, sometimes cited as Stegerhynchus neglecta, is usually smaller than S. indianensis at 7 to 10 mm wide on average, is flatter and normally has four costae, rarely three or five, on the fold and three in the sulcus, rarely two or four. There are four or five on the latera of the brachial valve.   

This one is a bit glooped up, but you can just about make out the four costae on the fold and the five on the flanks : 

And the three costae in the sulcus :

Flattened shape : 

You can perhaps see the costae on the fold and sulcus better here :

 

 

 

[Tidgy's Dad]

The third species of Stegerhynchus found in the Waldron Shale is S. whitii. 

This type has only two plications on the fold and one in the sulcus. It had five or six costae on each flank. It is usually between 7 and 12 mm wide and is quite rounded to sub-triangular. 

Specimen one :

Specimen two :

Specimen three :

Specimen four :

A nice bryozoan : 

 

[Tidgy's Dad]

The fourth and final species of Stegerhynchus from the Waldron Shale is S. acinus. This is sometimes referred to as Diabolirhynchia acinus, due its close resemblance to the North West African genus. It does seem to be externally more like Diabolirhynchus than Stegerhynchus, but the important beak plate details I am unable to see. 

The species has two costae, rarely three on the fold, which can be sharp, and there are three or sometimes four ribs on each side of these.

The sulcus has only one rib with four on each flank. 

Stegerhynchus acinus is usually 5 to 15 mm long and is often elongated and tear-drop shaped. 

Another specimen :

Just a bit of one :

And another :

One more :

 

[Tidgy's Dad]

Here are some smaller specimens that I found sifting through the matrix of the Waldron Shale. 

I think these are mostly little Stegerhynchus whitii, but they may be other rhynchonellids or even athyrids, it's hard to tell as some species don't develop a clear fold and sulcus until they get bigger. 

 

Another specimen :

An odd thing:

And one more :

 

 

 

[Tidgy's Dad]

This is probably one of the largest rhynchonellid that I have from the Waldron, it's rather squished but very pretty in the mineral replacement and covering. 11 mm long. 

I'm not sure if this is mineralogical or the cemented pedicle valve of a Petrocrania siluriana. (centre right) 

I know this craniid is found cemented to the contours of brachiopods and crinoid calyxes in the Waldron Shale, is about the right size and shape for a small one, but I might be suffering from another dose of brachiopod-pareidolia.

 

Edited May 23, 2022 by Tidgy's Dad

[Tidgy's Dad]

There' are a number of athyrids found in the Waldron shale, most of them are fairly smooth, as is typical for the Athyridida , but a common species is Homoeospira evax which has plenty of fine costae. Homoeospira baylei is the similar form that appears in the Much Wenlock Shale Formation of the UK. 

Homoeospira evax looks superficially like a rhynchonellid, but has no fold and a shallow sulcus only at near the anterior margin. It has a flat commissure rather than the zigzag form typical of a rhynchonellid. The beak is quite prominent. 

 

It's a bit squished. They seem a little more fragile than the rhynchonellids.

Notice the almost straight commissure, just a little bend when the shallow sulcus meets the opposite valve.

Another specimen : 

The prominent pedicle beak :

A large fragment :

And some smaller bits :