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Russian Trilobite Id


Han.T

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Hi all, I recently acquired this plate with a couple of Russian trilobites and a cystoid. Seller said it was from an old estate, and does not have the exact species for each type of bug. I have my own amateur suspicions on their IDs but I would be grateful if someone could help me confirm.

Larger trilobite is around 4 inches in length, could it be a Pseudoasaphus(Pseudoasaphinus)? Would like to pinpoint the exact species for this one if possible.

Ventral trilobite is about 3 inches, pity it came without the hypostome! My guess is an Asaphus cornutus or lepidurus?

Lastly the cystoid, Echinosphaerites? seems to be one of the more common types associated with Russian trilobites.

Please let me know what you think! :)

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Hi Han,

Pseudoasaphinus typically has more of an elongate pygidium compared to Pseudoasaphus. There are numerous species and sub-species that have characters that mimic each other so additional research is required to attempt a confident species classification. The ventral Asaphus is difficult to ID because the features of the cephalon (eyes & sutures) are obscured and distorted.

 

IMG1.jpg

 

Klikushin, V., Evdokimov, A., & Pilipyuk, A. (2009)
Ordovician Trilobites of the St. Petersburg Region, Russia.

Petersburg Paleontological Laboratory, Russian Federation, 544 pp.

 

 

 

image.png.a84de26dad44fb03836a743755df237c.png

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The Echinosphaerites looks to be authentic, but they are almost always added to plates such as yours to make them more "valuable".

Don

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Thank you both for the insight, especially the great reference diagram you made Piranha! Pseudoasaphus seems to have at least 4 species with not much available data to show which one mine confers to, I will have to label it as sp.

As for the ventral trilobite, would these close-ups help?

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The Singaporean Fossil Collectors Group, come join us here today!

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Attached are 5 species of Pseudoasaphus recorded in the St. Petersburg region. With the trilobite in hand you can determine which one has the most similar cephalic / glabellar features. Unfortunately the ventral trilobite doesn't show the entire course of the facial suture making it difficult to ID. Please send me a PM with your email address and I will forward some additional information to assist you.

 

 

IMG1.jpg

 

Klikushin, V., Evdokimov, A., & Pilipyuk, A. (2009)
Ordovician Trilobites of the St. Petersburg Region, Russia.

Petersburg Paleontological Laboratory, Russian Federation, 544 pp.

 

 

 

image.png.a84de26dad44fb03836a743755df237c.png

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