ADAM'S SILURIAN

[Tidgy's Dad]

6 hours ago, TqB said:

Thank you! That's very helpful, and confirms the usual advice that 0.5-1.0 is generally the awkward range, apart from some odd but identifiable small tabulates.

I'm glad this is of some use to some people 

Certainly makes it worthwhile and hopefully will prove valuable to collectors in the future 

Convergent evolution is wonderful and fascinating, but sometimes makes life difficult as to ids! 

[Tidgy's Dad]

5. Batostomella maniformis. 

 

Accounting for 4% of the bryozoans in the Much Wenlock Limestone, Batostomella maniformis would have looked quite weird and wonderful. 

It is said to be a roundish basal disc with many branches rising up from it. The disc may be 3 cm wide and each branch is only 1 to 1.5 mm in diameter but up to 25 mm long. They branch at acute angles. The zooaria narrow through the exozone (outer part of the branch) to a tiny and largely concealed opening, so the outer surface appears smooth except for the occasional spine bases marking the positions of acanthopores (hollow spines). 

Simply put, the fossils you find are tiny, smooth sticks, usually in matrix pieces as they are very fragile.  

Notice the sharp angle of branching and the little spine bases that are often not visible or eroded smooth. 

 

This one shows a mix of different bits, but I think it's Batostomella maniformis with spine bases showing near the bottom between other objects. They can be very difficult to spot. 

[Tidgy's Dad]

6. Stenopora primaeva.

 

4% of the bryozoans found, but they may seem like more as they are quite large and solid, but can sometimes be ignored as they are smooth and look eroded and are a bit like worn horn corals, too. 

In some respects, Stenopora primaeva is similar to Batostomella maniformis in being smooth, ramose and having tiny spines but in this case marking the position of large acanthopores. But it is much bigger, with stems being from 2.5 to 4 mm in diameter. It is also moniliform in shape giving it a beaded or rather blobby appearance. 

I think these may be eroded specimens, but I'm far from certain.

 

 

[Bobby Rico]

Wow this thread has move on a bit. I love the last page Wren's Nest material been a few years since I have bern there. Nice to catch up on this thread. Cheers Bobby 

[Tidgy's Dad]

6 hours ago, Bobby Rico said:

Wow this thread has move on a bit. I love the last page Wren's Nest material been a few years since I have bern there. Nice to catch up on this thread. Cheers Bobby 

Thanks, Bobby, glad you found the thread again and enjoyed it. 

Lots of Wren's Nest material to come! 

[Tidgy's Dad]

7. Asperopora multispora

 

Also accounting for 4% of the bryozoans in the Much Wenlock Limestone Formation is Asperopora multispora. There are three species of Asperopora in this formation, and they used to be listed under the genus Lioclema. So a lot of the information on this species was found by searching for Leioclema multisporum. 

Asperopora multispora is an encrusting species which can be told apart from Fistulipora nummulina by it's more widely spaced zooecia, which are often more petaloid in shape due to the presence of acanthopores (hollows that mark the base of small hollow spines), and the presence of numerous mesopores (smaller apertures in between the larger openings of the zooecia). It is often found encrusting brachiopods and crinoids as well as ramose tabulates and bryozoa.   

This one's on a fellow bryozoan; Hallopora elegantula. You can see it at the bottom, creeping around from the other side........... 

..........which it completely covers, you can only see two or three of the hosts zooecia peeking out toward the left end of the specimen :

The host specimen is 9 mm in length. 

A close-up. The mesopores between the main zooecia are not always as clear as this :

Here's an A. multispora colony creeping over the end of another Hallopora: 

This one's on an Eridotrypa cava bryozoan:

On a section of crinoid stem, diameter of stem 9 mm.

This one's on a favositid coral:

And in nearer. It's not so clear as it's been a bit battered and eroded.

The little ramose tabulate coral Coenites striatopora :

And encrusting the other side of it :

 One supposes it killed some of the organisms in the corals and bryozoans it covered unless this happened post mortem. Smothered the poor things. 

Another Asperopora multispora encrusting a Coenites striatpora :

Here's one on an Atrypa reticularis brachiopod :

 

 

 

[Tidgy's Dad]

8. Asperopora aspera.

 

This second species of Asperopora accounts for 3% of the bryozoans found in the Much Wenlock Limestone Formation. 

Asperopora aspera is similar to A. multispora, but is usually found in a massive, often layered form, or as an encruster on the substrate or larger corals. It can reach a little over 10 cm in diameter, but most are only about a cm or two. It has larger petalloid zooecia and larger acanthopores marking the bases of spines that are usually only preserved in unworn specimens. There are fewer mesopores between the zooecia. 

These don't seem to weather free, so you find them on actual rock pieces which are pretty much always 'hash plates' at the Much Wenlock Limestone.

Some of these are from my own collecting days in Forest of Dean, along the Wenlock Edge and in the Malvern Hills, but others are from @JohnBrewerand @thelivingdead531 from the Wren's Nest. So, thanks again, friends! 

All about 1 to 2 cm across. 

A nice little Platyceras haliotis gastropod here as well as a bit of crinoid stem 

Lots going on here, too. Crinoid columnals and a fragment of a fenestellid : 

Close up of the details of various specimens:

Another specimen in close up : 

This one's less than a cm across. 

Not sure if this is one. It looks to be rather small next to this fenestellid. 

 

 

[Tidgy's Dad]

9. Trematopora sp.

 

Trematopora makes up 3% of the bryozoan fauna in the Much Wenlock Limestone.

I have seen this listed as Trematopora tuberculata, which seems to be taken from the Niagaran species T. tuberculosa  (was T. tuberculosus)  , but as far as I'm aware, this British species is yet to be formally described. T. tuberculosa  is the second most common species in the North American equivalent to the Wenlock Limestone; the Lower Rochester Shale, where it accounts for 17% of the bryozoans found. But it is much bigger and less spinose than its British counterpart. The genus is not found in the Wenlock of the same age in Gotland, Sweden. 

Despite being relatively common, it seems this  is found poorly preserved. The zooaria is tiny, ramose and rather spiny. The zooecia are separated by polygonal mesopores. 

I'm really not sure about these, as i say they seem to be found poorly preserved, so many of the huge number of unidentifiable bryozoan bits that I have found may be this genus. Or not.  

This may perhaps be Trematopora sp. It's about a mm and a half wide , seems to have tiny spines and the right shaped zooecia and mesopores, it doesn't seem to fit anything else, but I'm still very uncertain.

The black dots are little spines or perhaps mineralogical

[Tidgy's Dad]

10. Fenestellids.

 

This is a bit of a cheat as Owen has clumped all the Fenestellidae together, possibly because they can be very had to tell apart, particularly as they are mostly preserved as fragments. Anyway, together they comprise 5% of the bryozoan specimens found in the Wenlock Limestone Formation at Dudley, this is still before the increasing success of the family during the Devonian until they reached their peak in the Carboniferous. In his paper "Wenlockian Bryozoa From Dudley, Niagara, and Gotland and their Palaeogeographic Implications." 1969, David E. Owen lists all the species of bryozoans he knows of from Dudley, even the rarer ones, except the fenestellids. Which is odd, as Miller has revised them fairly comprehensively in 1962. 

When I was a young collector, I remember that the common Wenlock bryozoan was listed, in the publications to which I had access as Fenestella subantiqua, though this species seems not to occur at the Wren's Nest, or at least is incredibly rare,  but can be found elsewhere in the Wenlock Limestone (see previous page). 

Three species and a couple of subspecies occur. 

 

A) Fenestella pseudosubantiqua 

 

Fenestella pseudosubantiqua is the typical fenestellid in the Wren's Nest, most of the specimens are probably this species, though it is smaller on average than the species F. subantiqua, as well as having other microscopic differences. They are mostly found highly fragmented, my pieces being between 3 mm to 2 cm across.Some of the smaller bits are found loose in the micro-matrix. 

Note that these branches bifurcate quite often as the genus opens out into a fan shape.

Some people may be mistaken in thinking that the rectangular openings are the zooecia, but this is not the case, these are actually spaces between the branches created by dissepiments linking neighbouring branches. The zooecia where the animals actually lived are in a double row up the branch itself, separated by a central line, but all this detail is very hard to see in hand sample or even with my microscope. 

Close up. Notice the lack f visible details, a polished section is needed for this. And a more powerful microscope, probably would help. Not that I'm complaining; this one's great.

This one is a bit worn, so you can see a few of the zooecia.

A couple of shots of details of this one: 

Different specimens: 

There's lots going on in some of these pieces!

Tiny fragments which are the most common finds : 

 

[Tidgy's Dad]

10A i) Fenestella pseudosubantiqua catrionae.

 

There is also a subspecies of Fenestella pseudosubantiqua recognized; Fenestella pseudosubantiqua catrionae. 

This form is very close to the regular F. pseudosubantiqua, but has square, rather than oblong, fenestrules. (the 'windows'.) 

One or two of the photos above are quite close, but is this one, I wonder? Not sure, as the subspecies is also supposed to have slightly thicker, straighter branches usually.. Top right.

[Tidgy's Dad]

10 B. )  Archaeofenestella rigidula.

 

The two fenestellids Fenestella rigidula and F. lineata were first concluded to be conspecific and then moved to the more primitive genus Archaeofenestella. 

Archaeofenestella rigidula is properly distinguished from F. pseudosubantiqua by having internal diaphragms inside the zooecia and an internal straight dividing line on the branches, separating the zooecia on either side, but this detail cannot be seen in hand sample or under the microscope without a good polished cross-section. 

In hand sample Archaeofenestella has much straighter branches that do not divide very often and so forms a more funnel shaped zooarium rather than the fan shape of Fenestella. 

They are found in my samples as fragments up to 1.5 cm long. 

You can faintly see the central ridge in this first couple of specimens and some of the others.

Nice rhynchonellid here! 

Often found as just one or two straight lines with very elongated fenestrules. 

Maybe? 

 

 

 

 

[Tidgy's Dad]

10 C) Reteporina reticulata.

 

This includes some of the specimens that were once assigned to Fenestella lineata. 

Comparatively recently, the fenestellids and their kin have been given their own order the Fenestrida, and Reteporina, though still a fenestrid, has been moved to the family Semicosciniidae, so not technically a fenestellid anymore.  

It still shows the typical fenestellid fan shape and fenestrules, but they are more irregular in shape and the branches are not as straight.

Not sure about this one. 

 

 

10 C i) Reteporina psygma. 

 

A new species was identified by Snell in 2004, this was Reteporina psygma. 

I don't think i have any of these, but one mat turn up later.

Until then this is from Snell's 2004 Pal Soc Monograph " Bryozoa From The Much Wenlock Limestone". 

 

[TqB]

Fascinating stuff and a fine collection, Adam. I love fenestellids (and other bryozoans, of course  ).

 

16 hours ago, Tidgy's Dad said:

The zooecia where the animals actually lived are in a double row up the branch itself, separated by a central line, but all this detail is very hard to see in hand sample or even with my microscope.

The zooecial apertures are on the obverse side which tends to stick to the matrix better, so the great majority of fenestellids show the unperforated reverse, to the frustration of bryozoan specialists!

Edited October 24, 2020 by TqB

[Tidgy's Dad]

9 hours ago, TqB said:

Fascinating stuff and a fine collection, Adam. I love fenestellids (and other bryozoans, of course  ).

 

The zooecial apertures are on the obverse side which tends to stick to the matrix better, so the great majority of fenestellids show the unperforated reverse, to the frustration of bryozoan specialists!

And to the frustration of rank amateurs like me!

Thanks, Tarquin, I didn't know that. It explains why I'm usually unable to see the darned things. 

[TqB]

40 minutes ago, Tidgy's Dad said:

It explains why I'm usually unable to see the darned things. 

That's right - there's a Victorian reverse prepping technique for ones in shale where you pour pitch over it, let it harden then prep the shale away, by soaking where possible. I've got some black resin I'm going to try sometime (to look nice against the white bryozoan).

Edited October 24, 2020 by TqB

[Tidgy's Dad]

5 hours ago, TqB said:

That's right - there's a Victorian reverse prepping technique for ones in shale where you pour pitch over it, let it harden then prep the shale away, by soaking where possible. I've got some black resin I'm going to try sometime (to look nice against the white bryozoan).

If you ever do get around to doing that, I'd be very interested to see the results! . 

 

[Tidgy's Dad]

Those 'Top Ten' bryozoa between them account for 86% of the specimens found in the Much Wenlock Limestone Formation. At least at Dudley and the surrounding area, anyway. 

So, putting my calculations hat on, all the other species account for 14% of bryozoan specimens found there. These aren't listed anywhere by the percentages found, so could be anything from 2% down to, well, very rare indeed, I suppose. 

I shall post all of the other species that I have and have had at least a guess at identifying. I apologize that some of these I posted a couple of years back on this thread, but I'll try to picture newer or different specimens where possible. 

 

11. Favositella interpuncta. 

 

Meaning 'small favosite', this genus was long considered to be a favositid with small corallites , which it does pretty much resemble, but closer examination revealed it to be a cyclostome bryozoan. It can be free or encrusting, thin layered or massive and is quite variable. It can form quite large dome shaped colonies, sometimes starting off by smothering some poor gastropod, brachiopod, coral etc. Other colonies are flatter and layered. 

I posted a Favositella interpuncta on the previous page, so here are photos of some others. There are about 4 to 5 zooecial openings per 2 mm. 

This one is 15 mm tall and 10 mm wide at its maximum. It seems to have grown over a small horn coral or sponge. 

Placed on top of a Favosites coral. You can see that  the bryozoan zooecia are considerably smaller than the corallites.  

A smaller colony.

There are other species of Favositella in the Wenlock. Gotland has its own Favositella gotlandica,, then there is F. squamata which can be found growing on brachiopods very rarely only in Dudley and Sedgwick, and F. anolotichoides found at Wren's Nest  in the upper part of the Middle Nodular beds , where it is common, but also in Wales and along the Wenlock Edge in Shropshire where it can be found encrusting on cephalopod shells, corals, stromatoporoids and, rarely, brachiopods. It differs from other Favositella in having mesopores between the zooecia. 

  

[Tidgy's Dad]

12. Monotrypella pulchella. 

 

Monotrypella pulchella is a ramose and much branching form, slightly flattened, rather than round stemmed as the other ramose forms I've mentioned were, but not bifoliate. The complete zooarium is very bushy looking. 

The zooecia are oval to a bit irregular with some, but few mesozooids. 

Close up of zooecia :

The broken branch areas, showing internal structure :

A second specimen : 

Another : 

There is another species, Monotrypella benthallensis, which does occur rarely at the Wren's Nest and, more commonly, along the Benthall Edge, Shropshire. 

It differs in having two sizes of polygonal zooecia. 

 

 

[Tidgy's Dad]

13. Amplexopora sp.

 

This was listed as Amplexopora microtoma back in the 19th century, but i find no mention of this specific name in more recent texts. It seems to be listed just as Amplexopora sp. and there is even some doubt as to whether the genus actually died out in the Lower Silurian and this should be listed as another species of Monotrypella. I dunno. It doesn't look like either from the outside and internally, I can't really tell, but I do think I see some thick diaphragms which would be more characteristic of Amplexopora. 

Few or no mesopores, thick walls to irregular zooecia.. 

Close up showing signs of the diaphragms dividing the zooecia, i think :

Another specimen :

And another :

Close in :

 

 

 

[Top Trilo]

Is there a limit to the amount of Silurian fossils one can have? You have more Silurian fossils than anybody I know. Is the Silurian your favorite geologic period? It seems to be getting more attention then your others.

[Top Trilo]

I forgot to mention, excellent fossils

[Tidgy's Dad]

1 hour ago, Top Trilo said:

Is there a limit to the amount of Silurian fossils one can have? You have more Silurian fossils than anybody I know. Is the Silurian your favorite geologic period? It seems to be getting more attention then your others.

Goodness! There is (almost) no limit to the fossils you can have from the Silurian. 

My favourite thing is Palaeozoic reefs. So that's Ordovician and Silurian so far for me, cos i'm doing things in order and haven't got to the Devonian yet, let alone the Carboniferous etc. 

So, for me, Middle to Late Ordovician, Middle Silurian more than late or Early, and things to come......................

My Ordovician thread has more species than this.  

  http://www.thefossilforum.com/index.php?/topic/78974-adams-ordovician/&

So far.

I love reef communities, from whatever age, I'm very fond of the late Ord and the Mid Dev.

But the Wrens Nest, Dudley is one of the most diverse. I'm only scratching the surface of one of the most incredible reefs of all time.  

 

[Tidgy's Dad]

14. Calamotrypa millichopensis.

 

Calamotrypa millichopensis is a small tubular species with a hole running through the centre. The hole is often infilled with sediment and can be quite small compared to the width of the zooarium, which is only 1 to 1.5 mm to begin with. It is known that this is due to the fact that this brypzoan actually grew around a filamentous algae. The zooarium is only about 3 to 5 mm tall. The zooecia are thick walled and close together.  I could not find a picture of the whole zooarium, only the microscopic details of the interior and I'm unable to cut and polish such tiny specimens, let alone be able to see such wee detail. 

So, I'm not sure if I've got any of these, this one's my best guess :

 

[Tidgy's Dad]

15. Asperopora denispora.

 

The third and rarest species of Asperopora, A.denispora is the ramose form of this genus in the English Wenlock. It has variably shaped zooecia, from round to oval but mainly irregular polygons separated by mesopores which are extremely tiny and often covered with a calcareous skin, so may not be visible externally. The zooecia are quite deep. 

Close up: 

Another specimen :

Close up:

And a third one: 

[Tidgy's Dad]

16. Fistulipora crassa

 

Fistulipora nummulina is the most common bryozoan in the Much Wenlock Limestone Formation and is an encrusting form, but Fistulipora crassa is the ramose form. It has very shallow, oval zooecia with thick, raised walls and mesopores that are covered in a calcite crust so usually cannot be seen in hand sample.