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JOHANVAN

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Sonntag, 27. Juli 2014, 17:36

Agnostus agnostus? - solved: is Peronopsis interstricta...

Hello,
I am new so forgif me some mistakes.
I got a little trilobite from someone out of the USA
I should like to know something more about and thought it could be an Agnostus agnostus...?
Imag.1 is the real photograph
Imag.2 is a photograph set in a drawning using Akvis Sketch
Imag.3 is a photograph with some references to measurements.
Can someone help me about?
Thanks.
»JOHANVAN« hat folgende Bilder angehängt:
  • Agnostus agnostus 3-AFM.jpg
  • Agnostus agnostus1.jpg
  • Agnostus agnostus 2-Tek.jpg

Dieser Beitrag wurde bereits 2 mal editiert, zuletzt von »JOHANVAN« (14. August 2014, 15:30)


Jens

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Sonntag, 27. Juli 2014, 20:19

Hello Johanvan,

nice to see you here. We welcomed you recently in our new Welcome-section in the forum and I'm happy to see your contribution.

We will try to find a good determination for your trilobite. The pictures are good, keeping in mind that this is a very tiny trilobite. Unfortunately your pictures did not show any matrix around the trilobite. It would made it easier to get a solid determination, because the find locality is not known to you.

Agnostus agnostus sounds for me wrong and not after a species I have heard of, because Agnostus is a genus name and so far I know not used on species level. Please correct me if I'm wrong.

Anyway, the most logical assumption would be that your trilobite is a frequently found species. Most Cambrian trilobites on the market come from the Wheeler shales in Utah and there is Peronopsis interstrictus (White, 1874) the most common agnostid trilobite, which seems to show a lot of similarities with the photos you showed us.

http://research.amnh.org/paleontology/tr…s-interstrictus
http://www.trilobites.info/Utah.htm
http://commons.wikimedia.org/wiki/File:I…3.33%C2%B0W.jpg

In the Wiki Itagnostus is used for this species. I'm not sure if this is correct, but many pictures will pop out if you ask Google after this;-) Also Western Trilobites use Itagnostus.

http://www.westerntrilobites.com/trilobi…terstrictus.htm

Maybe made another photo of the whole piece, then it will be easier to confirm if its Wheeler shale or not.

Agnostids are not easy to determinate and Peronopsis and Itagnostus looks very close to Agnostus.

all the best,
Jens
Was wäre die Welt ohne Trilobiten.
:267: :240: :272:

Dieser Beitrag wurde bereits 1 mal editiert, zuletzt von »Jens« (28. Juli 2014, 17:00)


JOHANVAN

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Sonntag, 27. Juli 2014, 23:40

Agnostus

Hello Johanvan,

nice to see you here. We welcomed you recently in our new Welcome-section in the forum and I'm happy to see your contribution.

We will try to find a good determination for your trilobite. The pictures are good, keeping in mind that this is a very tiny trilobite. Unfortunately your pictures did not show any matrix around the trilobite. It would made it easier to get a solid determination, because the find locality is not known to you.

Agnostus agnostus sounds for me not after a species I have heard of, because Agnostus is a genus name and so far I know not used on species level. Please correct me if I'm wrong.

Anyway, the most locical assumption would be that your trilobite is a frequent found species. Most Cambrian trilobites on the market come from the Wheeler shales in Utah and there Peronopsis interstrictus (White, 1874) is the most common agnostid trilobite, which seems to show a lot of similarities with the photos you showed us.

http://research.amnh.org/paleontology/tr…s-interstrictus
http://www.trilobites.info/Utah.htm
http://commons.wikimedia.org/wiki/File:I…3.33%C2%B0W.jpg

In the Wiki Itagnostus is used for this species. I'm not sure if this is correct, but many pictures will pop out if you ask Google after this;-) Also Western Trilobites use Itagnostus.

http://www.westerntrilobites.com/trilobi…terstrictus.htm

Maybe made another photo of the whole piece, then it will be easier to confirm if its Wheeler shale or not.

Agnostids are not easy to determinate and Peronopsis and Itagnostus looks very close to Agnostus.

all the best,
Jens


Thanks so very much Jens, you are right I think...but there was no matrix around this little specimen so I can not send you an another picture.
However your indications must be right; I will study more in depht all you wrote. I also think this must be one of the most common species which came over.

Thanks for the nice welcome , I have still a lot of questions about identification...but as said: one by one and on easy.

Johanvan

Dieser Beitrag wurde bereits 1 mal editiert, zuletzt von »Jens« (28. Juli 2014, 18:24)


Jens

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Montag, 28. Juli 2014, 16:46

Hi Johanvan,

the others here in the forum appear a little sleepy but its also holiday-time, so small wonder that its relatively calm here.

Fine that my comments were helpful and I understand now why the Agnostid was presented in this way, because he was already isolated.

This is an uncommon condition, normally such small trilobites are discovered on bedding planes. But this isolated condition is another hint towards the Wheeler shale. Its a common situation to find calcite crusts ventrally on many specimens found in the dark-grey layers. Isolated Elrathia is not that rare and possible because of the stabilzing influence of the diagenetic calcite crust. If the shale is weathered such trilobites can plop out of the stone and become so completely isolated.
The same is for sure possible for Agnostids, but surely most of them would be lost when becoming loose.

All the best,
Jens
Was wäre die Welt ohne Trilobiten.
:267: :240: :272:

Dieser Beitrag wurde bereits 1 mal editiert, zuletzt von »Jens« (28. Juli 2014, 17:05)


Fred

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Montag, 28. Juli 2014, 17:00

Dag Johan,

Welkom! Knappe foto van een boeiende trilobiet!

Nice pic of an interesting trilobite! I think Jens has a valid point in thinking this one originates from the Wheeler shale. How does the ventral side of this trilobite look like? Any details visible?

Michael

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Dienstag, 29. Juli 2014, 08:06

Hello Johanvan,

sorry for answering so late, because of the hot weather I´m a little bit slowly in my head ;-)

Determination of agnostid trilobites is for me nearly impossible, they look all very similar (for me !)... But the widespread Peronopsis or Itagnostus (I hear this name first time) could be right. It´s interesting to see such a loose agnostid without any matrix. Nice and interesting bug, I look forward to see more trilobites from your collection ! :106:

best wishes,

Micha

JOHANVAN

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Dienstag, 29. Juli 2014, 09:56

Hello,
sorry for the late answer but just today I will see the person who gave me the little trilobite. He told me to bring some others for me. He stated they come from Millard County, Utah, USA and from a cambrium formation. As for me I will not discuss the answer of Jens for as long as I can see through my microscope he must be right in his statements.
This evening I can tell some more about. It seems very strange but yes indeed there was no matrix around only some little grey mass underneath the specimen.

Fred, sorry hoor maar de ventrale zijde is bedekt met een beetje grijze matrix. Ik had reeds de grootste moeite om deze wat te prepareren en heb schrik om hem helemaal stuk te prepareren. Bedankt voor het fijne welkomstwoord!

Michael, thanks for your kind words. My own collection exists out of some trilobites but the amazing news is: I have to photograph a collection of the Gent(ic) Nautilus collection which exists out of the late Delil collection and counts a 300 - 4OO specimen from allover the world. There are also very rare specimen among them.
The aim is to photograph and describe in full the entire collection with the aim to bring out a great exhibition in Gent (Belgium) with interactivity possibilities. It is in my thought to show them here on the site to check their names.

To all: thanks for helping because I am not a "connaissoir" of the item.
This evening I will tell some more?

(Sorry for my English...I learned it at my 18, now I am 66 years old....SO, and so what !!!!

Lugo

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Dienstag, 29. Juli 2014, 11:24

Hi Johan,

i wish you also a warm welcome on the forum. Thanks for starting this interesting topic, hopefully i will learn more about the Cambrian trilobites.
Your idea to start posting more pictures from the Nautilus collection sounds great, i look forward to see them; also because the quality of your pictures is fantastic.

Good luck

Luc
:026:

Jens

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Dienstag, 29. Juli 2014, 11:30

Hi Johan,

don't be shy, we understand your english well enough (and parts of the Dutch as well) and are happy to help;-)

After you mentioned that the material is from Millard Couty in Utah, we can now be pretty sure that your specimen is indeed from the Wheeler shales. Which means also Wheeler Formation, a Middle Cambrian age and the region is near Delta, Millard County;-)

See here for some informations about a quarry there, may be the U-dig quarry is the source of your bug: Der U-dig Fossil Quarry for trilobites, Utah, USA; Mittelkambrium, House Range

Anyway, you spoke about a grey mass underneath the specimen, this could be the calcite crust I mean. I tried to find a picture showing a isolated specimen of Elrathia in ventral position, but I failed to find a good one. But maybe this here might help to explain what I mean: http://jb.gayet.pagesperso-orange.fr/pag…rathiakingi.htm

This calcite cover is grey, a little amorph, but some crystalls might be visible.

all the best,
Jens
Was wäre die Welt ohne Trilobiten.
:267: :240: :272:

JOHANVAN

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Mittwoch, 30. Juli 2014, 11:28

At least and sorry but yesterday it was to late to photograph them at all but I will open a new thread under the name Perenopsis interstrictus or Itagnostus interstrictus.
I could get still 4 more of this common trilobites and Jens was right at full. Thanks for his hints and videos...now I know who digged or hammered them out also to.

Jens

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Mittwoch, 30. Juli 2014, 11:49

Hi Johan,

hehe, fine, nice to hear that I was right;-) And no problem when it takes a while to made an update.

You can use this topic for the other specimens if you like, so we hold all together was belongs to Peronopsis or Itagnostus interstrictus. Its no problem to do a modification of the title of this thread.

If you like I can do that with the Edit-function or you can do it by yourself by clicking to the button Ändern in the first post of the thread and change then the title under Überschrift

But when you find the time to made images of the collection in Gent, then we should collect the images in an own thread and maybe every trilobite as an own posting within the thread. I can imagine that the trilobites collected in ancient times are not that easy to determinate. But we will see, its always cool to see what is in old collections. Sometimes there are surprises hidden for centuries.

all the best,
Jens
Was wäre die Welt ohne Trilobiten.
:267: :240: :272:

Dieser Beitrag wurde bereits 1 mal editiert, zuletzt von »Jens« (30. Juli 2014, 12:28)


JOHANVAN

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Mittwoch, 30. Juli 2014, 13:10

Hi jens,

I have no great experiences with fora and how to do...I think it should be best if you could help. I have to try and see how it works...
All the specimen of the Nautilus collection have an identification that starts with: "FAT" I think it stands for (FA?) of (T)rilobites.
I will start the collection after I have done the rectification about the "Agnostus agnostus"
JOHANVAN

JOHANVAN

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Mittwoch, 30. Juli 2014, 13:23

Agnostus agnostus is a Peronopsis interstrictus....

Hi to all,
thanks to Jens and all the friends I met into this topic I can close this issue by the following statement having photographed four new specimen.
With this I will show the four photographs (no preparations of the trilobites at yet !)
In a second thread I will show the same but enlarged with the appropriate dimensions.
It acts indeed about a trilobite as shown in the earlier remarks from Jens:

Perenopsis interstrictus or trivial name: Itagnostus interstrictus
Mid cambrium
Wheeler Shale Formation
House Range
Millard County
Utah
USA
»JOHANVAN« hat folgende Bilder angehängt:
  • Perenopsis 1T-25.jpg
  • Perenopsis 2T-25.jpg
  • Perenopsis 3T-25.jpg
  • Perenopsis 4T-25.jpg

JOHANVAN

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Mittwoch, 30. Juli 2014, 13:33

Peronopsis interstrictus or Itagnostus interstrictus enlargements and dimensions

And at least the last four photographs:
»JOHANVAN« hat folgende Bilder angehängt:
  • Perenopsis 1A-25.jpg
  • Perenopsis 2A-25.jpg
  • Perenopsis 4A-25.jpg
  • Perenopsis 3A-25.jpg

Jens

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Mittwoch, 30. Juli 2014, 14:39

Hi Johan,

I reunited all that topics made recently, they belong together and are together easier to find and the informations are not that widespread.

Hope its okay for you;-)

all the best,
Jens
Was wäre die Welt ohne Trilobiten.
:267: :240: :272:

Jens

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Mittwoch, 30. Juli 2014, 14:49

Hi,

again me. I looked for Itagnostus Öpik, 1979 to get some ideas what is it about. Jelll & Adrain listed this genus as a junior synonym of Peronopsis, after Robison 1988.
If its a correct statement, then Peronopsis Hawle & Corda, 1847 remained as valid genus for that species here.

"Battus" integer Beyrich, 1845 (or Peronopsis integra) is the type species of the genus Peronopsis and wellknown from the Middle Cambrian Jince Formation of the Czech Republic.

see here for a nice image: http://www.biolib.cz/en/image/id197747/

all the best,
Jens
Was wäre die Welt ohne Trilobiten.
:267: :240: :272:

JOHANVAN

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Mittwoch, 30. Juli 2014, 16:03

Hi jens,

of course it's OK to bring all this stuff together.
I am asking myself if it were not good to make drawings which could better expose the anatomical structures...or they exist already?
If yes than I will do my allmost best to do so.
Thanks a lot,
JOHANVAN

Jens

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Mittwoch, 30. Juli 2014, 16:10

Hi Johan,

feel free to prepare a drawing;-) Its the best way to understand a fossil.

Ideas how a drawing might look like you will find here: http://www.trilobites.info/galagnostida.htm

Somewhat simplified but in a good way done by Sam Gon III.

And see also here, Crozo did some nice drawings: http://www.trilobita.de/wbb2/thread.php?threadid=1113

all the best,
Jens
Was wäre die Welt ohne Trilobiten.
:267: :240: :272: