Friday, September 13, 2013

Asaphus lepidurus trilobite from St. Petersburg, Russia

The Ordovician rocks found in the St. Petersburg region of Russia have long been a source for excellent trilobites. There are a great many quarries, pits and excavations, both active and overgrown, that are exploited by local collectors for the well preserved fossils within. One of the most commonly available species is Asaphus lepidurus and I have a couple of specimens in my collection.

Specimen #1 is a partially prone example of the species. Part of the thorax and the pygidium are folded at a 90 degree angle. I have to wonder if this position is one of a predatory nature or is it just a molt that stayed in that position? As I don't have any information as to what the original bedding plane was prior to this fossil being prepped I doubt I will ever know.

Specimen #2 is an older specimen that I bought years ago. It's not the best quality and shows evidence of repair but it's a nice example.

A face only a mother could love.
You can see that the fossil was preserved on a fractured piece of rock. The person who prepared this specimen did a good job keeping the matrix together and repairing the fossil.

Specimen #3 is an enrolled example of the species.

All three specimens are from the Voybokalo quarry near St. Petersburg which quarries rocks that are part of the Kunda stage (Darriwillian stage of the ICS) of the Ordovician.

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