My trilobite of the week.

[piranha]

1 hour ago, rew said:

Okay, I flipped a coin -- heads I go back to calling this Amecephalus laticaudum.  Heads it is.  (That's how I do science.)

 

 

A fortunate coin toss ... you are in good company following Robison, Babcock, etc.  Labels can always be changed easily ... that's science! 

[rew]

On 8/25/2019 at 5:29 PM, Scylla said:

Just saw this thread! Wow. I mean WOW! 

I hope you like it.  I post my bugs, and piranha keeps proving that he's knows more about my trilobite collection than I do.

[piranha]

On 1/13/2019 at 11:14 AM, rew said:

To start off, here is a plate of Primaspis crosotus trilobites from the Kope Formation.  These are itty bitty bugs, but show all the typical Ondotopleurid features -- pleural and pygidal spines all around, and fringes of short spines on the free cheeks.

 

I must have been asleep at the wheel somehow I missed the first one you posted.  In any event, better late than never!

 

In North America Primaspis is currently classified as Meadowtownella.  Conway & Botting 2012 has a thorough explanation:

 

Conway, T.M., Botting, J.P. 2012

Description and ecology of a new Middle Ordovician (Llanvirn) odontopleurid trilobite from the Builth Inlier of Mid-Wales, with a review of the genus Meadowtownella.

Geological Magazine, 149(3):397-411  PDF LINK

[Scylla]

6 hours ago, rew said:

I hope you like it.  I post my bugs, and piranha keeps proving that he's knows more about my trilobite collection than I do.

 

5 hours ago, piranha said:

 

I must have been asleep at the wheel somehow I missed the first one you posted.  In any event, better late than never!

 

In North America Primaspis is currently classified as Meadowtownella.  Conway & Botting 2012 has a thorough explanation:

 

Conway, T.M., Botting, J.P. 2012

Description and ecology of a new Middle Ordovician (Llanvirn) odontopleurid trilobite from the Builth Inlier of Mid-Wales, with a review of the genus Meadowtownella.

Geological Magazine, 149(3):397-411  PDF LINK

Yes, I see. 

[rew]

The AMNH trilobite gallery agrees that Primaspis crosotus in no longer valid, the bug is Meadowtownella crosotus now.  If I didn't post my bugs here a fifth of my collection would be misidentified.

[Wrangellian]

I think if you have a large enough collection of anything, you're going to be spending some time changing labels. I've done enough of that myself!

[rew]

Trilobite of the week #67 is Ceraurus plattinensis, a Middle Ordovician cheiruid from the Bobcaygeaon Formation in Ontario.  This is the Ceraurus that pumps iron, kicks sand in your face, and steals your girl friend.

[piranha]

9 minutes ago, rew said:

...This is the Ceraurus that pumps iron, kicks sand in your face, and steals your girl friend.

 

 

[rew]

Trilobite of the week #68 is Olenellus terminatus, an Early Cambrian (4th stage) bug from the Carrara Formation of Emigrant Pass, San Bernardino County, California. 

[rew]

Trilobite of the week #70 is Encrinurus macrourus, a Silurian trilobite from the Hemse beds of Sproge, Gotland, Sweden.

 

 

 

[rew]

Trilobite of the week #71 is a relative of last week's Encrinurus macrourus.  This is Encrinuroides capitonis, a Late Ordovician Encrinurid from the Poolville Member of the Bromide Formation in Criner Hills, Carter County, Oklahoma.  The trilobite lies on a bed of brachiopods.

 

 

[piranha]

6 hours ago, rew said:

Trilobite of the week #71 is a relative of last week's Encrinurus macrourus.  This is Encrinuroides capitonis, a Late Ordovician Encrinurid from the Poolville Member of the Bromide Formation in Criner Hills, Carter County, Oklahoma.  The trilobite lies on a bed of brachiopods.

 

 

Lespérance & Desbiens reclassified Encrinuroides capitonis as: Frencrinuroides capitonis

You can easily print the attached image instead of having to make a new label!  

 

 

Lespérance, P.J., Desbiens, S. 1995

Selected Ordovician trilobites from the Lake St.John District of Quebec and their bearing on systematics.

Journal of Paleontology Memoir, 42(S69):1-19

[Kil'Jaeden]

On 5/19/2019 at 10:43 PM, piranha said:

 

 

AMNH has the correct name as Ditomopyge producta.  Paladin 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.

Nowadays, all trilobites from Zhirnovsk (Province of Volgograd, Russian Federation) are described as Ditomopyge zhirnovskiensis Mychko

[piranha]

1 hour ago, Kil'Jaeden said:

Nowadays, all trilobites from Zhirnovsk (Province of Volgograd, Russian Federation) are described as Ditomopyge zhirnovskiensis Mychko

 

 

Ditomopyge zhirnovskiensis is not a valid name as it has not been formally published yet. 

It has been described in an unpublished thesis and only mentioned in a peer reviewed paper.

 

Mychko, E.V. 2016.

Trilobites of the Middle-Upper Carboniferous and Permian of Northern Eurasia.

Thesis, Moscow State University, 393 pp.

 

Mychko, E.V. & Alekseev, A.S. 2017

Locations of middle Carboniferous-Permian trilobites in Russia and neighboring countries.

Byulleten' Moskovskogo Obshchestva Ispytateley Prirody, Otdel Geologicheskiy, 92(3):40-83

[Kil'Jaeden]

5 minutes ago, piranha said:

 

 

Ditomopyge zhirnovskiensis is not a valid name as it has not been formally published yet. 

It has been described in an unpublished thesis and only mentioned in a peer reviewed paper.

 

Mychko, E.V. 2016.

Trilobites of the Middle-Upper Carboniferous and Permian of Northern Eurasia.

Thesis, Moscow State University, 393 pp.

 

Mychko, E.V. & Alekseev, A.S. 2017

Locations of middle Carboniferous-Permian trilobites in Russia and neighboring countries.

Byulleten' Moskovskogo Obshchestva Ispytateley Prirody, Otdel Geologicheskiy, 92(3):40-83

May be you're right...honestly, I don't know how to check the validity of a scientific name

 

Eduard Mychko is the only scientist who studies Permian and Carboniferous trilobites in Russia. Hope, he'll publish his descriptions in a proper way

[piranha]

24 minutes ago, Kil'Jaeden said:

May be you're right...honestly, I don't know how to check the validity of a scientific name

 

Eduard Mychko is the only scientist who studies Permian and Carboniferous trilobites in Russia. Hope, he'll publish his descriptions in a proper way

 

 

Yes, I agree his work is exceptional and hopefully he will publish all the new species from his thesis in the near future. 

 

Mychko & Alekseev 2017:  D. zhirnovskiensis is only mentioned as having been described from the thesis:

 

"These trilobites are described in the dissertation of E.V. Mychko (2017) as Ditomopyge (Ditomopyge) zhirnovskiensis sp. nov."

"Эти трилобиты описаны в диссертации Э.В. Мычко (2017) как Ditomopyge (Ditomopyge) zhirnovskiensis sp. nov."  PDF LINK

[Kil'Jaeden]

9 minutes ago, piranha said:

 

 

Yes, I agree his work is exceptional and hopefully he will publish all the new species from his thesis in the near future. 

 

Mychko & Alekseev 2017:  D. zhirnovskiensis is only mentioned as having been described from the thesis:

 

"These trilobites are described in the dissertation of E.V. Mychko (2017) as Ditomopyge (Ditomopyge) zhirnovskiensis sp. nov."

"Эти трилобиты описаны в диссертации Э.В. Мычко (2017) как Ditomopyge (Ditomopyge) zhirnovskiensis sp. nov."  PDF LINK

Thanks, I have all his papers in my library

 

By the way, I'm only a couple of hours on this forum, but I found only several photos of Carboniferous trilobites, pygidiums mostly...are they so rare in the US or just nobody pays attention to them?

[rew]

Well, in this thread alone I have three complete Carboniferous trilobites (Ameropiltonia lauradanae and Comptonaspis swallowi in addition to the above Ditomopyge producta).  I have a few more American Carboniferous bugs coming along.

[rew]

Here's the third member of the Encrinuridae in a row.  Trilobite of the week #72 is Coronocephalus rex, an Early Silurian bug from the Sintan Shale of China.  This is one of my favorite Silurian trilobites, with the crenulations on the high free cheeks that give the genus its name.  There are long genal spines and a pair of macropleural spines, although only the left macropleural spine is clearly visible.  Isolated pygidia and molts of this species are commonly available on our favorite auction site, but this bug is all about its free cheeks so you really want a complete specimen, which seem uncommon.

[piranha]

3 hours ago, rew said:

Here's the third member of the Encrinuridae in a row.  Trilobite of the week #72 is Coronocephalus rex, an Early Silurian bug from the Sintan Shale of China.  This is one of my favorite Silurian trilobites, with the crenulations on the high free cheeks that give the genus its name.  There are long genal spines and a pair of macropleural spines, although only the left macropleural spine is clearly visible.  Isolated pygidia and molts of this species are commonly available on our favorite auction site, but this bug is all about its free cheeks so you really want a complete specimen, which seem uncommon.

 

 

This one is Coronocephalus gaoluoensis.  The glabella of C. rex is more tuberculate compared to the anteriorly smooth glabella of C. gaoluoensis.

 

Chen, G., Han, N., Luo, R. 2012. Restudy of Coronocephalus gaoluoensis Wu, 1979. Acta Palaeontologica Sinica, 50(3):284-303

 

Wu, H.J. 1990. On genus Coronocephalus Grabau, 1924 (Silurian Trilobite). Acta Palaeontologica Sinica, 29(5):527-547

[rew]

Do you have images of C. rex?  I'd like to see just how much more tuberculate its glabella is.

[piranha]

On 9/30/2019 at 8:56 AM, rew said:

Do you have images of C. rex?  I'd like to see just how much more tuberculate its glabella is.

 

 

Yes, look again as there are 5 images of the glabella of Coronocephalus rex that I already posted above.  Beside being more tuberculate, the tubercles are also considerably larger on Coronocephalus rex.  Here is another example showing the difference in the larger tubercles of Coronocephalus rex.  This is a typical mistake in taxonomy incorrectly sourced from the literature.  The seller that you purchased it from simply misidentified the species.

 

Zhang, W.T. 1983

On the Subfamily Coronocephalinae (Trilobita).

Palaeontologia Cathayana, 1:195-258

[rew]

Okay, it looks like I have C. gaoluoensis.  I'm going to run out of blank labels.

[Jackson g]

On 9/24/2019 at 4:25 PM, Kil'Jaeden said:

Thanks, I have all his papers in my library

 

By the way, I'm only a couple of hours on this forum, but I found only several photos of Carboniferous trilobites, pygidiums mostly...are they so rare in the US or just nobody pays attention to them?

They are rare, at least here in Missouri. 2 of the 3 species Rew named are Carboniferous proetid trilobites of Missouri. In the 4 months of searching just for trilo sweet spots around my state, I've only found 2 complete Ameropiltonia along with 4 pygidiums, 0 of any Comptonaspis, and 2 Ameura pygidiums. Of course I could just be unlucky, but I think the main census would be they are in general rare.

[rew]

Yup.  I don't know of any Carboniferous trilobites that would rate as common.  They tend to be pretty rare, rare, really rare, or forget-about-ever-finding-one rare.