Swedish Illaenid

[Huntonia]

Hello all, I recently acquired this unidentified illaenid trilobite from the ordovician of Sweden. It's had some sloppy repair work (which I'm hopeful I can improve) but before I do I'm hoping someone can help me put a genus to it. It has a long, robust genal spine which doesn't seem to match any illaenus I've seen from Sweden. Any help is appreciated.

[Misha]

Possibly Dysplanus centrotus? I have seen some labeled as such which looked very similar

@Kane @piranha

[piranha]

@Misha

 

Here are 3 classic monographs on the Illaenidae of Sweden:

 

Holm, G. 1883
De Svenska arterna af Trilobitslägtet Illaenus (Dalman).
[The Swedish species of the Trilobite genus Illaenus (Dalman).]
Bihang Till Kungliga Svenska Vetenskaps-Akademiens Handlingar, 7(3):1-148  PDF LINK

 

Jaanusson, V. 1953
Zur Morphologie und Taxonomie der Illaeniden.

[On the Morphology and Taxonomy of the Illaenids.]
Archiv For Mineralogi och Geologi, 1(15):545-581  PDF LINK

 

Jaanusson, V. 1957
Unterordovizische Illaeniden aus Skandinavien, mit bemerkungen ueber die Korrelation des Unterordoviziums.
[Lower Ordovician Illaenids from Scandinavia, with remarks on the correlation of the Lower Ordovician.]
Bulletin of the Geological Institutions of the University of Uppsala, 37(1-2):79-165  PDF LINK

[Tidgy's Dad]

Nice trilo. 

And good call @Misha

[Huntonia]

Impressive work @Misha and @piranha!

Thanks once more for a quick ID. At times like these I'm always reminded how much more I have to learn, one of the many great things about this hobby 

 

[Paleome]

Misha and Piranha are probably correct, but I have a book with a picture that looks very close.  It is labeled Niobella laeviceps.  Is that related?

[Kane]

2 minutes ago, Paleome said:

Misha and Piranha are probably correct, but I have a book with a picture that looks very close.  It is labeled Niobella laeviceps.  Is that related?

No. Niobella is an asaphid. The specimen above is a corynexochid. Note the hallmark effacement of the features of the cephalon and pygidium, which is diagnostic for that Order. 

[Paleome]

Thank you, I like learning anything new.

[Paleome]

Just now, Paleome said:

Thank you, I like learning anything new.

Would you agree they look similar, or maybe my book had the wrong picture in it.

[Paleome]

Yeah, not a very good picture in my book.  Thanks for enlightening me.

[Kane]

11 minutes ago, Paleome said:

Would you agree they look similar, or maybe my book had the wrong picture in it.

Here are the two compared.

 

Images from Klikushin, V., Evdokimov, A. and P. Pilipyuk (2009). Ordovician Trilobites of the St. Petersburg Region, Russia. St. Petersburg: Griffon Enterprises.

[Paleome]

Oh, they are very different.  Which is which in the pictures you sent me?

[piranha]

14 minutes ago, Paleome said:

Would you agree they look similar, or maybe my book had the wrong picture in it.

 

Niobella has 8 thoracic segments ... Dysplanus has 9.

 

[Paleome]

I believe you all!  A big learning experience for me.  I am not used to looking at trilobites a lot of the time, so I am probably getting the wrong first impression, and not looking at the most important features for identification.  I need to study them more, and pay greater attention to the number of sections, etc. 

 

Please believe me, I wasn't doubting any of you.  I automatically defer to your knowledge in a heartbeat.  I finally counted the number of sections in my picture, and there were 8, just as you said.   Thank you all!  Now I have a better idea of what to look for.

[Huntonia]

2 hours ago, Paleome said:

A big learning experience for me.  I am not used to looking at trilobites a lot of the time, so I am probably getting the wrong first impression, and not looking at the most important features for identification.  I need to study them more, and pay greater attention to the number of sections, etc. 

@Paleome, if you want to learn more about trilobites and IDing them you should visit this website: http://trilobites.info/ordersoftrilobitesold.htm

It's an excellent guide to the 9 orders of trilobites. It outlines the main differences, as well as the various suborders and families, and their characteristics. I think you will find it very helpful.

 

[Paleome]

Thank you!  I appreciate the link.  

[Paleome]

Wow! I started looking at the link.  What an excellent resource!  

[Paleome]