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My trilobite of the week.


rew

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

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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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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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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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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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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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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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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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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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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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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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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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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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To photograph the eye of the Ditomopyge producta I used my magnifying macro lens.  Well, it was still on my camera so I figured I should take more pictures of little bugs.  The ones that are 3/4" long or smaller.  So this week's trilobite of the week, #45, is the Late Ordovician trilobite Remopleurides elongatus, from the Kingisepp quarry in the St. Petersburg region of Russia.  This trilobite has a nice axial spine, but its main feature is its wrap around visor like eyes.  (Note that the right free cheek is pushed forward a little bit, a minor defect on a Russian bug with no restoration.)

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Each eye has close to a 180 degree field of vision.  This bug could see forwards, backwards, and to the sides all at the same time.  I suspect this was a free swimming trilobite that had to look out for predators coming from any direction.

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1 hour ago, DevonianDigger said:

This is one of my absolute favorite trilobites. Can't afford to own one, lol, but I love them!

 

Russia has more cool trilobites than anybody can afford.  I had to save up for that Remopleurides, but it was high on my want list because that genus doesn't look like any other kind of trilobite.  The fact that the eye facets are visible was a bonus, I didn't realize that until I photographed it.

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39 minutes ago, rew said:

 

Russia has more cool trilobites than anybody can afford.  I had to save up for that Remopleurides, but it was high on my want list because that genus doesn't look like any other kind of trilobite.  The fact that the eye facets are visible was a bonus, I didn't realize that until I photographed it.

I like the pelagic trilobtes, mostly because of the eyes. But yes, Russia has some of the coolest bugs out there.

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Jay A. Wollin

Lead Fossil Educator - Penn Dixie Fossil Park and Nature Reserve

Hamburg, New York, USA

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I'm still doing the small bugs thing so the bonus trilobites of the week are both small Silurian American proetids.  Trilobite #46 is Radnoria bretti from the Rochester Shale of Middleport, NY and trilobite #47 is Maurotarion christyi from the Waldron Shale of Shelby County, Indiana.  Neither bug is perfect but they're good enough to show what they're about.

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The trilobite of the week, #48, is a small Eifelian proetid from the El Otfal Formation in Oufaten, Morocco: Otarionella lkomalii.  It's only about 13 mm long, but has a lot of nice features in a small amount of space -- genal spines, an occipital spine, two axial spines, some stubby spikes on the glabella, and short spines all along the rim of the head.  My only complaint is that I can't pronounce the species name without sounding like I'm coughing.

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This week's bonus triloblite, #49, is Ptychagnostus germanus from the Middle Cambrian Marjum Formation in Millard County, Utah.  It is a fairly typical agnostid trilobite.  As is usual with these trilobites, I'm not sure if this picture is heads up or heads down.

 

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I'm new to the forum, you have some amazing trilobites! I recently acquired a Hallardrops and Scabriscutellum with excellent eyes 

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