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rew

Here's the smaller trilobite and the right eye of the larger trilobite.

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rew

Time for midweek bonus trilobites.  #39 is a Middle Devonian proetid from the Timrhanrhart Formation in the Alnif Basin of Morocco, Cornuproetus cornutus.

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rew

Trilobite #40 is Diademaproetus antatlasius from Djebel Oufaten, Morocco, and is also of Middle Devonian age.  This is from the same family as the C. cornutus, Tropidocoryphidae, and if it were not for its small rostrum would be almost identical to that species.

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rew

Now for the official trilobite of the week, #41, Akantharges mbareki, of Middle Devonian age and from Jorf, Morocco.  This is a clear relative of Basseiarges mellishae but is somewhat larger and more ornate.

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Misha

All of these are absolutely stunning, do you buy them or dig them?

I wish I could have such a collection of these wonderful creatures.

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rew

These were bought.  I live in a near fossil free area, New Hampshire.

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rew

Here are two mid-week bonus trilobites.  Both are from the Chouteau Formation of Saline County, Missouri.  These are early Mississippian (Tournaisian) in age.  As I'm sure most of you know, after the mass extinctions towards the end of the Devonian the only trilobites still surviving were in four families of the order Proetida.  And the great majority of the survivors were in the single giant family, Proetidae.  It's as if every mammal went extinct except cats.  So you have tigers and lynxes and ocelots, but no mice, bats, kangaroos, seals, monkeys, deer, bison, armadillos, whales, elephants, bears, weasels, or opossums.  These bugs are no exception, both are in the Proetidae.  Trilobite #42 is Ameropiltonia lauradanae.  At just under 13 mm (1/2 inches) this is typical size for this bug.  Trilobite #43 is Comptonaspis swallowi, which at 23 mm is at the upper end of the size range for the species.  Ameropiltonia lauradanae has a pustulose glabella and Comptonaspis swallowi does not.

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Jackson g
7 hours ago, rew said:

Here are two mid-week bonus trilobites.  Both are from the Chouteau Formation of Saline County, Missouri.  These are early Mississippian (Tournaisian) in age.  As I'm sure most of you know, after the mass extinctions towards the end of the Devonian the only trilobites still surviving were in four families of the order Proetida.  And the great majority of the survivors were in the single giant family, Proetidae.  It's as if every mammal went extinct except cats.  So you have tigers and lynxes and ocelots, but no mice, bats, kangaroos, seals, monkeys, deer, bison, armadillos, whales, elephants, bears, weasels, or opossums.  These bugs are no exception, both are in the Proetidae.  Trilobite #42 is Ameropiltonia lauradanae.  At just under 13 mm (1/2 inches) this is typical size for this bug.  Trilobite #43 is Comptonaspis swallowi, which at 23 mm is at the upper end of the size range for the species.  Ameropiltonia lauradanae has a pustulose glabella and Comptonaspis swallowi does not.

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Two of my local favorite proetids, very nice! If you ever visit Missouri, let me know. I could take you to dig your own some day. 

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rew

This week's theme is Carboniferous proetids, so the trilobite of the week, #44, is Paladin transilis from Zhirnovsk, Volgograd region, Russia.  It is Pennsylvanian (late Carboniferous) in age.  At 38 mm it would be a respectable sized proetid for any period.  This is my nominee for "most beautiful post-Devonian trilobite".  This used to be called Griffithides productus but for some time now has been called Paladin transilis.  This same species is called Ditomopyge producta in the Trilobite Gallery of the American Museum of Natural History.

 

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rew

The facets of the holochroal eyes are just barely visible (under magnification).  This is the only proetid I have where they can be seen at all.

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piranha
12 hours ago, rew said:

This week's theme is Carboniferous proetids, so the trilobite of the week, #44, is Paladin transilis from Zhirnovsk, Volgograd region, Russia.  It is Pennsylvanian (late Carboniferous) in age.  At 38 mm it would be a respectable sized proetid for any period.  This is my nominee for "most beautiful post-Devonian trilobite".  This used to be called Griffithides productus but for some time now has been called Paladin transilis.  This same species is called Ditomopyge producta in the Trilobite Gallery of the American Museum of Natural History.

 

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AMNH has the correct name as Ditomopyge productaPaladin does not have a median preoccipital lobe (termed 'praeoccipital' by Weber) which is a key feature for Ditomopyge.  Additionally, the genal spines of Paladin transilis only extend to the 7th thoracic segment and for Ditomopyge producta the genal spines extend to the pygidium along with coarse granulation of the occipital ring.  Originally described as Cyphinium productum var. granulata, Weber 1933. 

 

Weber, V.N. 1933

ТРИЛОБИТЫ ДОНЕЦКОГО БАССЕЙНА. [Trilobites of the Donets Basin.]

ТРУДЫ: ВСЕСОЮЗНОГО ГЕОЛОГО-РАЗВЕ - ДОЧНОГО ОБЪЕДИНЕНИЯ НКТП СССР

[Transactions of the United Geological and Prospecting Service of USSR] 255:1-95

 

Congrats on an excellent textbook specimen. :fistbump:

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rew

So you're telling me that that Russian site has two similar species, the real Paladin transilis and this imposter with the long genal spines, Ditomopyge producta?

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piranha

The trilobite is not an 'imposter', it is simply misidentified.  The information on trilobite taxonomy on the internet and from commercial dealers is often unreliable. 

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rew

Just a joke.  I agree that sellers often misidentify what they're selling.  And worse, they often don't know that what they're selling is fake.

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