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My trilobite of the week.


rew

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Trilobite of the week #184 is Placoparia sp. of Ordovician age from the Ktaoua Formation of Morocco.  This is another trilobite in the Pliomeridae.  I don't know which species of Placoparia it is.

 

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Trilobite of the week 185 is Kettneraspis prescheri of Early Devonian (Pragian) age, from the Ihander Formation of Jbel Issoumour, Morocco.  This has a stout occipital spine and tiny vertical spines running along each side of the thorax.

 

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Two days ago, I said I was done with Moroccan Trilobites. I think the reality is if I desired, the collection will never be done. I am seriously thinking of clearing the junk room in my basement and setting 2 tables for this renewed hobby. I intend to go break rocks in September near Kindcardine. I will need a place to put them. The rest of my house is full of 3D printers !! 

 

BTW, very nice things you have !!!

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If you collect Moroccan trilobites, you will never be done.  If you collect American or Canadian trilobites, you'll never be done.  If you collect Russian trilobites, you'll be bankrupt before you are done.

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Trilobite of the week #186 is Pterygometopus sp. of Early Ordovician age from the Kunda horizon of Voibokalo quarry in the St. Petersburg region of Russia.  You will not be surprised to learn that this is in the family Pterygometopidae, the same family that includes the earlier shown Calyptaulax callicephalus.  That family is a sister group of the Phacopidae, so the similarity of trilobites in these two families is not surprising.

 

 

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Trilobite of the week #187 is Triarthrus becki of Late Ordovician age from the Utica shale at Little Falls, New York.  The shell of this bug has the same black color as the rock, so while this is a good specimen and of decent size, is is not terribly displayable.  Note the axial nodes.

 

 

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As you say, the same color as the matrix, it does not help to highlight the trilobite, but it looks a good piece. :Smiling:
Thanks for continuing to share.

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Trilobite of the week #188 is Myopsolenites boutiouiti of Middle Cambrian age from Toughach, Tassmant, Morocco.

 

 

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12 hours ago, rew said:

Trilobite of the week #188 is Myopsolenites boutiouiti of Middle Cambrian age from Toughach, Tassmant, Morocco.

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This trilobite has a recent tangled taxonomic tale to tell. Dies Álvarez et al. 2007 listed Myopsolenites a junior synonym of Onaraspis. Geyer 2016 listed Myopsolenites a junior synonym of Conomicmacca and retained Onaraspis as a separate genus. Álvaro et al. 2019 again listed Myopsolenites a junior synonym of Onaraspis. Nowicki & Żylińska 2019 recognize Conomicmacca, and most recently Bayet-Goll et al. 2021 continue to retain the name Conomicmacca.

 

In any event....Myopsolenites is discarded!  emo73.gif mail?url=http%3A%2F%2Fmail.yimg.com%2Fok%2Fu%2Fassets%2Fimg%2Femoticons%2Femo11.gif&t=1628356957&ymreqid=23281213-8dc1-3cff-1c28-350004017300&sig=c7U.rJanI4JIaItIT77J8w--~D mail?url=http%3A%2F%2Fmail.yimg.com%2Fok%2Fu%2Fassets%2Fimg%2Femoticons%2Femo31.gif&t=1628356957&ymreqid=23281213-8dc1-3cff-1c28-350004017300&sig=._4WSLGdqiZcQYjC6cn2DA--~D

 

 

Bayet-Goll, A., Daraei, M., Geyer, G., Bahrami, N., Bagheri, F. 2021
Environmental Constraints on the Distribution of Matground and Mixground Ecosystems across the Cambrian

Series 2–Miaolingian Boundary Interval in Iran: A Case Study for the Central Sector of Northern Gondwana.

Journal of African Earth Sciences, 176(104120):1-22

 

Geyer, G. 2016

Taxonomy of the 'Micmacca' Group, New Cambrian Chengkouiidae (Trilobita) from Morocco, and their Bearing on Intercontinental Correlation.

Memoirs of the Association of Australasian Palaeontologists, (49):329-393


Nowicki, J., Żylińska, A. 2019

The First Occurrence of the Earliest Species of Acadoparadoxides outside West Gondwana (Cambrian; Holy Cross Mountains, Poland).

Geological Magazine, 156(6):1027-1051

 

 

 

Álvaro, J.J., Esteve, J., Gracia, F., Zamora, S. 2019
Cambrian Trilobites from the Huérmeda Formation (Iberian Chains, north‐east Spain) and the inadequacy of the Marianian Stage.

Papers in Palaeontology, 5(2):299-321


Dies Álvarez, M.E., Liñan, E., Gozalo, R. 2007
The Cambrian Genus Onaraspis Öpik, 1968 (Trilobita, Cambrian) in Spain.
Memoirs of the Association of Australasian Palaeontologists, 34:419-429

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8 minutes ago, rew said:

Okay, which do I have -- Onaraspis or Conomicmacca?

 

 

"...and most recently Bayet-Goll et al. 2021 continue to retain the name Conomicmacca."

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Trilobite of the week #189 is Asaphiscus wheeleri of Middle Cambrian age from the Wheeler Shale from the Drum Mountains in Millard County, Utah.  This is a classic and fairly common Wheeler Shale bug.

 

 

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  • 2 weeks later...

Trilobite of the week #190 is Isotelus maximus, of Late Ordovician age, from the Arnheim Formation at Mt. Orab, Ohio.  This is a modest sized specimen, only 7 cm long, but is of good quality, with no restoration.  As you would guess with a species name of "maximus", this bug could get a lot bigger.  I believe there are one or two diggers right here on these forums who have dug up bigger specimens, so if you have a big one, post it here and get some bragging rights.

 

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Another beauty!  And one I do own, but not bigger or better than this one, so you clearly have bragging rights. I do have a fond memory of one of my early fossil hunting trips to Caesar’s Creek Reservoir in SW Ohio only a few years after it opened and there on the floor of the spillway was a perfect outline/imprint of the head and part of the body of probably close to a 12” Isotelus. I assume it had eroded or been scraped away during construction. So close......

 

As always, a wonderful collection, keep em coming,

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Trilobite of the week #191 is Tropidocoryphe amuri of Early Devonian age from the Timrhanrhart Formation at Foum Zguid, Morocco.  You won't be shocked to learn that this is in the Tropidocoryphidae family of the Proetida.

 

 

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Trilobite of the week #192 is Ditomopyge scitula, of Pennsylvanian age (late Carboniferous) and from the Wolfmountain Shale formation at Bridgeport, Wise County, Texas.  This trilobite was found in a concretion so the rock it's on is no bigger than the trilobite itself.  There is a dent in the edge of the front left part of the head, and the head overall is somewhat disarticulated from the thorax, but still this fossil provides a good idea of what this trilobite was about.

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Trilobite of the week #193 is Bristolia bristolensis, of Early Cambrian age and from the Pioche Shale of Nevada.  This has obvious imperfections, in particular, a large chunk of shell is missing from the left side of the head.  Still, you have no trouble understanding what the living bug looked like.

 

 

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Trilobite of the week #194 is Pseudogygites latimarginatus, a member of the Asaphidae of Late Ordovician age from the Whitby Shale of Bowmanville, Ontario.  The head is a bit crunched in on the right side but overall this is a good example of the species.  This is a dark trilobite on a dark rock, not my favorite color scheme, but nature picks this, not me.

 

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On 9/12/2021 at 2:03 AM, Diplocaulus said:

I hope one day to have a collection as vast as yours! :envy:

Haha, I gave up that hope 52 trilobites of the week ago! :popcorn:

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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:

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