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Phacops Trilobite Fossil, Morocco a.jpg


Phacops Trilobite Fossil

Middle Devonian 393-383 million years ago
Phacops is a genus of trilobites in the order Phacopida, family Phacopidae, that lived in Europe, northwestern Africa, North and South America and China from the Early until the very end of the Devonian, with a broader time range described from the Late Ordovician. It was a rounded animal, with a globose head and large eyes, and probably fed on detritus. Phacops is often found rolled up, a biological defense mechanism that is widespread among smaller trilobites but further perfected in this genus. Like in all sighted Phacopina, the eyes of Phacops are compounded of very large, separately set lenses without a common cornea (so called schizochroal eyes), and like almost all other Phacopina, the articulate mid-length part of the body (or thorax) in Phacops has 11 segments.
Kingdom: Animalia
Phylum: Arthropoda
Class: †Trilobita
Order: †Phacopida
Family: †Phacopidae
Genus: †Phacops

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MY FOSSIL Collection - Dpaul7

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Unfortunately, this trilobite is not from the Genus Phacops. It's actually a proetid - Gerastos sp.


As a side note, the trilobites you have listed as Calymene tristani aren't from that species either - they're examples of Flexicalymene ouzregui.

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:drool:  That's what I get for trusting the dealer to "get it right" - I took a good look at the "Phacops" :trilo:.

Indeed, it is NOT Phacops; the genal spine shows that!


On the other trilobites - I THINK I can see your reasoning - based on the posterior margin?

And this image? Also flexicalymene?  MANY THANKS for your input!  It is truly appreciated!


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I looked at the seller's information - They call the three trilobites "Calymene" but state: These trilobites have often been referred to as Flexicalymene ouzregui but the genus/species names are been continuously in flux. Many of these specimens have some minor repair, usually just to glue them back together as they are often found in pieces.

I will be changing the name for these three!  Hopefully the SINGLE specimen is Calymene! 

You have a good eye for Trilobites, Douvilleiceras! :trilo:

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You're welcome! Sadly, the single trilobite is also F. ouzregui :(. The dealer's location info is wrong though. Jbel Issoumour is a Devonian site, not Upper Ordovician. The locality that F. ouzregui are extracted from is the Upper Ktaoua Formation, in the Maïder region of Morocco.

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