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My trilobite of the week.


rew

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2 hours ago, NoahW24 said:

One day this could make a truly spectacular book if you felt so inclined-  Levi-Setti would be proud! I feel very spoiled with our weekly visits to the trilobrary on this thread:horseshoecrab:

 

If I did that Piranha would have to be editor.

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Trilobite of the week #195 is Anataphrus vigilans, a member of the Asaphidae of Ordovician age from the Maquoketa Formation in Fayette County, Iowa.

 

The bug I bought a few years back is the only one I've ever seen for sale, so this appears to be a fairly rare trilobite.

 

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Trilobite of the week #196 is Illaenus tauricornis of Middle Ordovician age from the Aseri Stage of Vilpovitsy quarry, near St. Petersburg, Russia.  The curved genal spines give it its species name.  Like other members of its family, the domed head looks two sizes too big for the body.

 

 

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Trilobite of the week #197 is Glossopleura sp. of Middle Cambrian age from the Spence Shale of Utah.  This is a fairly new and undescribed species.  There are three axial spines on the last three thoracic segments, although in this specimen the most anterior spine is broken off near the base, while the other two spines are complete.  As is usually the case with Cambrian trilobites preserved in shale, the spines are flattened against the thorax and pygidium.

 

This is the only bug I've shown so far in the family Dolichometopidae.

 

 

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Trilobite of the week #198 is Liocalymene clintoni, of Silurian age and from the Rose Hill Formation at McVeyton, Pennsylvania.  At 3.6 cm this is good size for the species.  It comes from an old collection and appears to have been prepared with a pin.  Liocalymene is distinguished from other calymenids by the lack or ornamentation on the left and right lobes of the pygidium.

 

Fun fact:

I have 2 Cambrian trilobites from Pennsylvania,

and 1 Ordovician trilobite from Pennsylvania,

and 1 Silurian trilobite from Pennsylvania,

and 1 Devonian trilobite from Pennsylvania...

but no Pennsylvanian trilobites from Pennsylvania.

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Trilobite of the week #199 is Crassiproetus microgranulatus, of Devonian age and from the Thunder Bay Limestone of Alpena County, Michigan.  4.8 cm in length, this is a good sized Proetid.

 

 

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Trilobite of the week #200 should be special, given that this is the 200th trilobite in this thread.  So here I have one of the Moroccan trilobites that have made the Acastidae famous:

Psychopyge elegans, of Middle Devonian age, from the Tazoulait Formation at Issoumour, Morocco.  With flaring genal, pleural and pygidal spines, a large rostrum, a prominent occipital spine and numerous short vertical spines running in three rows down the thorax, there aren't too many features this trilobite doesn't have.

 

 

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Congrats on the 200th weekly trilobite!  :trilo:

I've been enjoying every one.

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“If fossils are not "boggling" your mind then you are simply not doing it right” -Ken (digit)

"No fossil is garbage, it´s just not completely preserved” -Franz (FranzBernhard)

"With hammer in hand, the open horizon of time, and dear friends by my side, what can we not accomplish together?" -Kane (Kane)

"We are in a way conquering time, reuniting members of a long lost family" -Quincy (Opabinia Blues)

"I loved reading the trip reports, I loved the sharing, I loved the educational aspect, I loved the humor. It felt like home. It still does" -Mike (Pagurus)

“The best deal I ever got was getting accepted as a member on The Fossil Forum. Not only got an invaluable pool of knowledge, but gained a loving family as well.” -Doren (caldigger)

"it really is nice, to visit the oasis that is TFF" -Tim (fossildude19)

"Life's Good! -Adam (Tidgy's Dad)

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Trilobite of the week #201 doesn't look radical, but its a very special trilobite.  Ditomopyge artinskiensis is of Early Permian (Artinskian Stage) age and from the Arti Formation at Krasnoufimsk, Middle Ural, Russia.  This is my only trilobite of Permian age, the last period of the Paleozoic.  It is my latest (and thus youngest) trilobite.  It is instructive to compare it to my earliest and oldest trilobite, Archaeaspis macropleuron.  Archaeaspis macropleuron is in the order Redlichiida, the first trilobite order to appear.  Ditomopyge artinskiensis is in the order Proetida, the only trilobite order to survive into the last last two periods of the Paleozoic.

 

When Archaeaspis macropleuron lived during the early Atdabanian (3rd stage of the Cambrian) trilobites were as advanced as any other living thing. With antennae, eyes, and legs, they could move about and sense the world in a way that what was then the state of the art for animals. Our own phylum, the chordates, was represented by at best very primitive jawless fish, one step up from chordate worms. They were no threat to adult trilobites and nobody would have bet on that phylum ever amounting to anything much. The most advanced land "plants" were lichens (symbiotic combinations of fungi and algae or cyanobacteria).

 

When this trilobite lived the marine ecological niches formerly held by trilobites were largely taken over by crustaceans. Jawed fish had become the dominant type of fish during the Devonian and by the Permian the Actinopterygian (ray finned) fish were already the dominant type of fish (they have become more dominant since). On land vascular plants grew everywhere the ground was wet enough and there were great forests over much of the land. There were early conifers and tree ferns, although flowering plants were still far into the future. Tetrapods had evolved during the Devonian, and by the Permian large Temnospondyl amphibians haunted the swamps, and on dryer land there were early reptiles. When this trilobite lived the peak of trilobite diversity, at the end of the Cambrian and beginning of the Ordovician, was 200 million years in the past. The last time of significant trilobite diversity, the Middle Devonian, was 100 million years in the past. The world was becoming modern and this trilobite was a relic of an ancient past. 30 million years after it lived trilobites winked out of existence entirely during the great mass extinction that ended the Permian.

 

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What a wonderful synopsis of the Paleozoic!  That can be in the introduction of your forthcoming picture book of trilobites - haha!!  Keep em coming!!

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Trilobite of the week #202 is Chattiaspis sp., of Ordovician age and from Tazzarine, Morocco.  There is some missing shell on the head below both eyes but there are some preserved lenses in both eyes, particularly in the right eye.

 

This is a member of the Dalmanitidae, a reminder that families familiar from the Devonian (think Huntoniatonia huntonensis) generally started in the Ordovician or the Cambrian.  Perhaps Piranha can think of some exceptions.

 

 

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Trilobite of the week #203 Treveropyge berbera of early Devonian age from Jebel Boulachral, Morocco.

 

This is similar to Coltraneia but has a small pointed rostrum.

 

Will I ever run out of Acastid trilobites?  Probably not.

 

 

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Trilobite of the week #204 is an American species of Ceratonurus of Early Devonian age from the Haragan Formation of Clarita, Oklahoma.  The two occipital spines are both repaired.

 

 

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Trilobite of the week #205 is Kochina vestita of Middle Cambrian age from the Spence Shale of Utah.  This is a rare Ptychoparid trilobite, so even though a bit of the rear is missing (including the tiny pygidium) I'm happy to have this example.

 

 

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Trilobite of the week #206 is Baniaspis sp. of Late Ordovician age from the Lower Ktaoua Formation at Tazzarine, Morocco.  This is an early member of the Acastidae that is similar to Sokhretia, the main difference being in the tail spine.  This trilobite had schizochroal eyes like all acastids but the lenses are not well preserved in this specimen.  The last picture shows the tail spine of a Baniaspis on the left and a Sokhretia on the right.

 

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Trilobite of the week #207 is Attractopyge xipheres of Late Ordovician age from the Kukruse Horizon in the St. Petersburg region of Russia.  This is in the family Encrinuridae.

 

 

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Trilobite of the week #208 is Ceraurinus marginatus, of Middle Ordovician age, from the Bobcaygeon Formation of Bowmanville, Ontario.  This specimen has some erosion of the posterior left pleural spines so it's not the best specimen out there, but it's what I have.

 

 

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It's a new year so it's time for one of the special bugs.

 

Trilobite #209 is Dicranurus monstrosus of Early Devonian (Pragian) age, from the Lhander Formation in Atchana, Morocco.  This is a famous Odontopleurid trilobite.  How famous?  Famous enough to be the fossil used in the masthead of these forums.  This is an exceptional specimen, of above average size and with all spines freed from the matrix, including the down spines that are often left buried in the rock.  The color variation is natural.

 

 

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1 hour ago, rew said:

It's a new year so it's time for one of the special bugs.

 

Trilobite #209 is Dicranurus monstrosus of Early Devonian (Pragian) age, from the Lhander Formation in Atchana, Morocco.  This is a famous Odontopleurid trilobite.  How famous?  Famous enough to be the fossil used in the masthead of these forums.  This is an exceptional specimen, of above average size and with all spines freed from the matrix, including the down spines that are often left buried in the rock.  The color variation is natural.

 

 

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Awesome bug! :drool:

 

-@fossilhunter21

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What a great way to start the year, I have a soft spot for these spiny trilos.

“If fossils are not "boggling" your mind then you are simply not doing it right” -Ken (digit)

"No fossil is garbage, it´s just not completely preserved” -Franz (FranzBernhard)

"With hammer in hand, the open horizon of time, and dear friends by my side, what can we not accomplish together?" -Kane (Kane)

"We are in a way conquering time, reuniting members of a long lost family" -Quincy (Opabinia Blues)

"I loved reading the trip reports, I loved the sharing, I loved the educational aspect, I loved the humor. It felt like home. It still does" -Mike (Pagurus)

“The best deal I ever got was getting accepted as a member on The Fossil Forum. Not only got an invaluable pool of knowledge, but gained a loving family as well.” -Doren (caldigger)

"it really is nice, to visit the oasis that is TFF" -Tim (fossildude19)

"Life's Good! -Adam (Tidgy's Dad)

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2 hours ago, rew said:

Trilobite #209 is Dicranurus monstrosus of Early Devonian (Pragian) age, from the Lhander Formation in Atchana, Morocco.

 

Man! That must've been one heckuva prep and restore job!!!

 

Greetings from the Lake of Constance. Roger

http://www.steinkern.de/

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Wow!!  I'm not going to say this is my favorite one so far of yours, (because then I would have to go back through all of them and I'd be left envious and sitting in a puddle of drool) but it is right up there in the top!  And I agree with @Ludwigia, that prep job is just amazing!!  Thanks again for sharing.

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