Retiolitid graptolite, Pseudoplegmatograptus, Llandovery, Poland

[TqB]

I was browsing some photos of monograptids for sale and noticed in the corner of one of them a ghostly patch with some faintly marked bristles . Thinking it was probably a retiolitid , I bought it and it arrived yesterday. So it turned out to be which was pleasing as they're very interesting and beautiful and I haven't found any in the field yet.

 

After wading through a fair bit of literature, I think it's probably Pseudoplegmatograptus obesus (Lapworth 1877), or something close (graptolites being frustratingly impossible to ID for non-specialists). (Mrs. @Spongy Joe ?)

From Zdanow, Bardzkie Mountains, Poland. Sold as Wenlockian but I believe that should probably be Telychian (Upper Llandovery).

 

Really tricky to photograph, the light has to be just right or it's near invisible, as in the first photo...

 

 

The next three are taken with near overhead light and some digital tweaking. Scale bar is 1cm.

 

 

 

 

 

[TqB]

A few images from literature:

 

Treatise, various retiolitids including Pseudoplegmatograptus:

 

One of many amazing etched out and SEM photographed specimens from the Canadian Arctic, from this free access paper

https://www.cambridge.org/core/journals/journal-of-paleontology/article/retiolitine-graptolites-from-the-aeronian-and-lower-telychian-llandovery-silurian-of-arctic-canada/A81F644E7C4ACC85665F2850794236E3/core-reader

 

And from the classic and beautifully drawn and printed Elles & Wood (1901 - 1918) Monograph of British Graptolites:

[Tidgy's Dad]

Nice spot! 

I'm pretty certain it's a retiolitid and your id seems to fit pretty well. 

Excellent, Tarquin, i am very happy for you. 

Just sorting my Llandovery graptolites, as it happens.  

[Kosmoceras]

Outstanding - that was a lucky spot.

[Fossildude19]

Well spotted, Tarquin!
Great addition to your collection!

Congratulations.

[doushantuo]

Nice one ,Tarq!!!

Well done 

fun fact/

the best monograph on retiolitids around:

Bates, D.E.B. and Kirk, N.H. 1992. The ultrastructure, mode of construction
and functioning of a number of Llandovery ancorate and retiolitid
graptolites. Modern Geology 17: 1–270.It's even got colour pix,a bit of a rarity for 1992

A lot of standard terms like "ancora sleeve" are explained in that one

 

[TqB]

2 hours ago, Tidgy's Dad said:

Nice spot! 

I'm pretty certain it's a retiolitid and your id seems to fit pretty well. 

Excellent, Tarquin, i am very happy for you. 

Just sorting my Llandovery graptolites, as it happens.  

 

52 minutes ago, Kosmoceras said:

Outstanding - that was a lucky spot.

 

47 minutes ago, Fossildude19 said:

Well spotted, Tarquin!
Great addition to your collection!

Congratulations.

 

32 minutes ago, doushantuo said:

Nice one ,Tarq!!!

Well done 

fun fact/

the best monograph on retiolitids around:

Bates, D.E.B. and Kirk, N.H. 1992. The ultrastructure, mode of construction
and functioning of a number of Llandovery ancorate and retiolitid
graptolites. Modern Geology 17: 1–270.It's even got colour pix,a bit of a rarity for 1992

A lot of standard terms like "ancora sleeve" are explained in that one

 

 

Thank you, everyone! There are potential locations not that far from me so I'll try and find my own soon.

 

@doushantuo That looks excellent, Ben, there are a few for sale but I'll see if I can borrow it  - I also came across this 2005 free access paper with Bates as co-author, also with colour pics that made some confusing details clear.

Silurian retiolitid graptolites: Morphology and evolution

 

[doushantuo]

 

the number of graptolite papers I've read number into the hundreds,can you tell or not?

 

 

[Bobby Rico]

Fantastic spot Tarquin It is a good job you have an eye for the details. Very interesting specimens and nice photo too. Thank you

[ynot]

Nice catch and acquisition!

[TqB]

17 hours ago, Bobby Rico said:

Fantastic spot Tarquin It is a good job you have an eye for the details. Very interesting specimens and nice photo too. Thank you

Thanks, Bobby. A big screen helps a lot.

15 hours ago, ynot said:

Nice catch and acquisition!

Thank you!

[Manticocerasman]

nice  it is rare to see graptolites on the forum. thanks for sharing 

[Spongy Joe]

Oh, that is lovely!

 

It's amazingly hard to find these in the field, unless you have a lot of contrast with the rock. We normally find them accidentally under the microscope, but occasionally do see them in the wild... and it's surprising how rare they are, in general. In the Llanfawr Quarries, after going there for 20 years, I've seen one Reteograptus. That's it. And last year, Mrs. Spongy found a slab with several on, in the late Llandovery. We spent the next hour looking for more in vain.

 

Is this one Pseudoplegmatograptus obesus? It certainly looks good to me, at first appearances... but she'll need to get her books out to check for other similar species. Most retiolitid taxonomy is really hard in flattened material, but this might just be a distinctive one.

[TqB]

On 28/05/2018 at 5:35 PM, Manticocerasman said:

nice  it is rare to see graptolites on the forum. thanks for sharing 

Thank you! 

3 hours ago, Spongy Joe said:

Oh, that is lovely!

 

It's amazingly hard to find these in the field, unless you have a lot of contrast with the rock. We normally find them accidentally under the microscope, but occasionally do see them in the wild... and it's surprising how rare they are, in general. In the Llanfawr Quarries, after going there for 20 years, I've seen one Reteograptus. That's it. And last year, Mrs. Spongy found a slab with several on, in the late Llandovery. We spent the next hour looking for more in vain.

 

Is this one Pseudoplegmatograptus obesus? It certainly looks good to me, at first appearances... but she'll need to get her books out to check for other similar species. Most retiolitid taxonomy is really hard in flattened material, but this might just be a distinctive one.

Thanks, Joe! It's sort of good to know how hard they are to look for, and that from someone with a penchant for spotting invisible sponges.  I'm off to a couple of locations soon where they're theoretically possible, including Retiolites geinitzianus  which I hope shouldn't be too hard to see, being a lot more dense.

 

Here's an R. geinitzianus (probably?) from the same Polish locality as the other (haven't been able to get into the field lately so slaking my cravings on auction sites ):

(And talking of Retiograptus, I see that has a geinitzianus too - how confusing...)

 

 

 

 

[Tidgy's Dad]

On 5/28/2018 at 5:35 PM, Manticocerasman said:

nice  it is rare to see graptolites on the forum. thanks for sharing 

I have posted a few recently, if you'd like to look. 

Here are a few :

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

And more half way down the page : 

http://www.thefossilforum.com/index.php?/topic/84678-adams-silurian/&page=2