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My trilobite of the week.


rew

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1 hour ago, Huntonia said:

What an incredible piece! I love the eyes! 

What's the size of it?

 

It's just average size, 5.8 cm.  But nicely preserved, it's not on my "to be upgraded" list.

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11 hours ago, rew said:

 

It's just average size, 5.8 cm.  But nicely preserved, it's not on my "to be upgraded" list.

Wow a whole list, I can probably save you some time and just take all those dusty old bugs off your hands for you :heartylaugh:

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It's time for another obscure little Proetid.  Trilobite of the week #99 is Proetina ihmadii from the Pragian stage of the Devonian and found in the Moroccan Lhandar Formation.

 

Proetina is given as a suborder of Proetida on Sam Gon's list of trilobite genera (https://www.trilobites.info/genera.htm).   That suborder includes the family Proetidae in which the Proetina genus is placed.  So here we have a trilobite with the same genus and suborder.  I think the suborder Proetina is simply a placeholder on Gon's site, I don't recall seeing it actually used.

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What an amazing thread!  Your collection is truly spectacular.

"There is no shortage of fossils. There is only a shortage of paleontologists to study them." - Larry Martin

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This week there is a midweek bonus trilobite -- #100, Modocia laevinucha, a Middle Cambrian bug from the Marjum Formation in the House Range of Utah.

 

This bug is both rarer and less spiny than M. typicalis.  The reddish color in the center of the head and the center of the thorax is apparently due to some guts squeezed beneath the carapace.

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It's time for #101, the official trilobite of the week.  This is a small but elegant new species of Acanthopyge from Jorf, Morocco, of Middle Devonian age, currently without a formal description. The rocks at Jorf are partially metamorphized, giving many of the trilobites there a smooth, plasticy appearance, including this one. I suspect that in life this was more pustular than its current preservation shows.

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Trilobite #102 is a mid-week bonus trilobite.  Sometimes I grab a not-too-expensive trilobite simply because it's in a family that has no other representation in my collection.  Thus we have Szechuanella granulata, in the family Leiostegiidae, order Corynexochida, an Ordovican bug from the Fenxiang Formation of Hunan Province, China.  (If most of your collection has American, European, and Moroccan trilobites, it's easy to find unrepresented families in China.)

 

 

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1 hour ago, rew said:

Trilobite #102 is a mid-week bonus trilobite.  Sometimes I grab a not-too-expensive trilobite simply because it's in a family that has no other representation in my collection.  Thus we have Szechuanella granulata, in the family Leiostegiidae, order Corynexochida, an Ordovican bug from the Fenxiang Formation of Hunan Province, China.  (If most of your collection has American, European, and Moroccan trilobites, it's easy to find unrepresented families in China.)

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Szechuanella granulata Lu 1975 was reclassified by Ghobadi Pour & Turvey 2009: Pseudocalymene granulata

 

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Ghobadi Pour, M., Turvey, S.T. 2009

Revision of some Lower to Middle Ordovician Leiostegiid and associated Trilobites from Iran and China.

Memoirs of the Association of Australasian Palaeontologists, 37:463-480  PDF LINK

 

Lu, Y. 1975

Ordovician Trilobite Faunas of Central and Southwestern China.

Palaeontologia Sinica, New Series B, Whole Number 152(11):1-463 

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7 hours ago, rew said:

I hate to think how much of my collection would be mislabeled without piranha.

Ha, you are not alone...……..

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17 hours ago, rew said:

I hate to think how much of my collection would be mislabeled without piranha.

 

10 hours ago, Ruger9a said:

Ha, you are not alone...……..

I had complete documents from him about the trilobites of my country !

 

A gvery nice surprise from @Kane, Greenops widderensis, from the Devonian of Arkona, Ontario.

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"On ne voit bien que par le coeur, l'essentiel est invisible pour les yeux." (Antoine de Saint-Exupéry)

"We only well see with the heart, the essential is invisible for the eyes."

 

In memory of Doren

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Offical trilobote of the week, #103, is Isotelus gigas of Late Ordovician age and from the Walcott Rust Quarry (Trenton Group Formation) at Russia, New York.  This is a modest sized specimen, about 5.5 cm long, well below the maximum size. 

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Trilobite #104 is a midweek bonus trilobite.  It is Delgadella lenaica, of Botomian age (4th stage Cambrian), from Lena river, Yakutia, Russia, in the Bergeroniellus gurarii zone.  Most of the agnostid trilobites are in the suborder Agnostina, and have two thoracic segments and no eyes.  This is from the more primitive suborder Eodiscina, and has three segments in its thorax.  The pygydium of this genus is smooth and featureless, and the head is too, aside from a prominent lip.  A different and more primitive genus within the Eodiscina, the Tsunyidiscus, has members with eyes.

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And now for #105, the official trilobite of the week.  This is Cernuolimbus ludvigseni, of late Cambrian age, from the McKay Group, near Cranbrook, British Columbia.  Here we see another good example of how photographing your bugs can show you things you didn't know were there (hopefully more interesting than dust).  I noticed that on the front lip of the head, just in front of the glabella, is a row of small dots.  These aren't really visible with the naked eye.  I suspect they served a sensory function, maybe they had hairs to detect vibrations.

 

 

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44 minutes ago, Huntonia said:

Awesome! Maybe @piranha knows something about those dots?

 

I suspect if anybody here knows, he does.

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4 hours ago, rew said:

And now for #105, the official trilobite of the week.  This is Cernuolimbus ludvigseni, of late Cambrian age, from the McKay Group, near Cranbrook, British Columbia.  Here we see another good example of how photographing your bugs can show you things you didn't know were there (hopefully more interesting than dust).  I noticed that on the front lip of the head, just in front of the glabella, is a row of small dots.  These aren't really visible with the naked eye.  I suspect they served a sensory function, maybe they had hairs to detect vibrations.

 

 

Interesting.... I need to get my specimen (self-collected) properly prepped to see if it has that feature.

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11 hours ago, rew said:

And now for #105, the official trilobite of the week.  This is Cernuolimbus ludvigseni, of late Cambrian age, from the McKay Group, near Cranbrook, British Columbia.  Here we see another good example of how photographing your bugs can show you things you didn't know were there (hopefully more interesting than dust).  I noticed that on the front lip of the head, just in front of the glabella, is a row of small dots.  These aren't really visible with the naked eye.  I suspect they served a sensory function, maybe they had hairs to detect vibrations.

head-cropped-small.jpg

 

On your specimen it appears to be small tubercles. 

Chatterton & Gibb 2016 describe it as 'pitted' without speculation on function:

 

"Anterior border furrow is firmly impressed, weakly convex forward, particularly in front of glabella, and pitted."

 

Chatterton, B.D.E., Gibb, S.L. 2016

Furongian (Upper Cambrian) Trilobites from the McKay Group, Bull River Valley, Southeastern British Columbia, Canada.

Palaeontographica Canadiana, 35:1-275

 

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According to the literature this feature is variable in Cernuolimbus: coarse pits or granules

 

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Hopkins, M.J. 2011

Species-Level Phylogenetic Analysis of Pterocephaliids (Trilobita, Cambrian) from the Great Basin, Western USA.

Journal of Paleontology, 85(6):1128-1153  PDF LINK

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I glad to hear my bug is *supposed* to have these little dots.  I'm sticking with the "vibration sensing hairs on dots" theory.

 

Anyhow, I was fortunate to get a fine example of this species.

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The photo is tricky to my eyes... eyepopping.gif ...if I change the viewing angle they also look like pits.  Are they granules or pits? mail?url=http%3A%2F%2Fmail.yimg.com%2Fok%2Fu%2Fassets%2Fimg%2Femoticons%2Femo20.gif&t=1583612390&ymreqid=23281213-8dc1-3cff-1cb9-fa0003013000&sig=DJEBukZooD3TZND9MU22Eg--~C

image.png.a84de26dad44fb03836a743755df237c.png

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