My trilobite of the week.

[rew]

I am happy to see the fossil forum back up.  But with Thanksgiving tomorrow I've decided to just take this week off.

 

Next week will be brought to you by the letter I.  There will be two bonus trilobites.  The three trilobites are in three different orders and from three different continents.

 

Have a good Thanksgiving.

[rew]

Trilobite of the week #324 is a bonus trilobite.

I is for Isocolus sjogreni of Ordovician age from the Laeptaena-Kalk Beds at Kallholn, Dalarne, Sweden.

 

These are tiny Ptychoparid bugs, the biggest is about 3.5 mm.   These are the only trilobites I have in the family Isocolidae.

 

Edited November 27, 2023 by rew

[rew]

Trilobite #325 is a bonus trilobite.

 

I is for Isotelus iowensis of Ordovician age from the Maquoketa Formation at Bowling Green, Missouri.  (Yes, despite the species name this specimen comes from Missouri.)

 

I don't know what the chemistry is that causes the silvery color but I like it.

 

 

[rew]

Trilobite of the week #326 is a main trilobite.

 

I is for Iberocoryphe sp. of Late Ordovician age from Agdez, Draa-Tafilalt, Morocco.

 

I believe this trilobite still lacks a formal description but the AMNH trilobite gallery has what appears to be the same or very similar species and they place it in the Iberocoryphe genus.

 

This trilobite is in the Homalonotidae, a family of large burrowing trilobites.  This trilobite is large (19 cm) and may have been a burrowing trilobite.  But with some pleural spines and some nodes along the center of the thorax, this is not as specialized or streamlined as later species in the family.

 

Edited December 1, 2023 by rew

[rew]

This week is brought to you by the letter J.

 

There will be one bonus trilobite.  Both it and the main trilobite will be humble bugs.

 

I don't have a lot of J trilobites and you probably don't either.

[rew]

Trilobite of the week #327 is a bonus trilobite.

 

J is for Jianheaspis jiaobangensis of Middle Cambrian age from the Balang formation at Balang, Jianhe County, Guizhou province, China.

 

This is an internal mold.  This little bug (9 mm long) is in the family Oryctocephalidae, which includes Oryctocephalus walcotti, which was Trilobite of the Week #156.

 

 

[piranha]

2 hours ago, rew said:

J is for Jianheaspis jiaobangensis of Middle Cambrian age from the Balang formation at Balang, Jianhe County, Guizhou province, China.

 

 

This genus is invalid: nomen nudum.  It exists only in two unpublished theses.

 

Du, G. 2019
Study on the Ontogeny and Biostratigraphy of the Oryctocephalid Trilobites from Balang Formation of Cambrian, Guizhou Province, China.

PhD Thesis, Guizhou University, 190 pp.

 

Shen, Z. 2016
The Oryctocephalid Trilobites and their Biostratigraphic Significance from Balang Formation of Cambrian, Guizhou Province, China.

MSc Thesis, Guizhou University, 96 pp.

[rew]

Well, let's hope I do better with the main trilobite.

 

So is this bug officially not named yet?

[piranha]

1 hour ago, rew said:

So is this bug officially not named yet?

 

 

Correct.

 

The theses by Du 2019 and Shen 2016 each introduce: "Jianheaspis jiaobangensis gen. et sp. nov." 

 

The systematic descriptions are similar in each and supervised by the same thesis advisor. Until a formal peer reviewed paper is published: Oryctocephalidae sp.

[crinus]

On 12/26/2021 at 12:45 PM, rew said:

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.

 

 

There is no Bobcaygeon in the Bowmanville Quarry.  Bowmanville is Lindsay Formation with some Verulam at the bottom of the quarry.

[Sjfriend]

Someone mentioned  before you need to have a museum. I would absolutely pay to visit..... though you had better search me before you let me leave

[rew]

Trilobite of the week #328 is a main trilobite and I better get the genus right or this project is a flaming wreckage.

 

J is for Jenkinsonia varga, of Middle Cambrian age, from the Wheeler Shale at the House Range in Millard County, Utah.

 

This tiny bug, 5 mm long in its stocking feet, is a grown up of its species.  Jenkinsonia varga is the smallest member of the Alokistocaridae I know of.  But it's big compared to those Isocolus trilobites.

 

 

[trilobites_are_awesome]

You have some great bugs!

[rew]

This week is brought to you by the letter K.  There will be two bonus trilobites.  The three trilobites come from three different orders.

[rew]

Trilobite of the week #329 is a bonus trilobite.

 

K is for Kayserops megaspina of Middle Devonian age from Boulashghal, Morocco.  There are no vertical spines on this bug but it's a showy trilobite nonetheless.  You may recognize this as the trilobite on the front cover of Levi-Setti's last trilobite book.

 

 

Edited December 11, 2023 by rew

[rew]

Trilobite of the week #330 is a bonus trilobite.

 

K is for Kootenia randolphi of Middle Cambrian age from the Wheeler Formation in Utah.

 

 

[rew]

Trilobite #331 is a main trilobite.

 

K is for Koneprusia sp. of Early Devonian age from Laatchana, Morocco.  Koneprusia dahmani has two thoracic segments with a pair of axial spines each followed by segments with a single axial spine.  This species, which I believe is still undescribed, has a pair of axial spines on each thoracic segment.

 

 

[rew]

This week is brought to you by the letter L.  There will be two bonus trilobites.  Each trilobite is in a different order and is from a different country, but all had lived in the Ordovician.

[rew]

Trilobite of the week #332 is a bonus trilobite.

 

L is for Liexiaspis zhengjiaensi of Early Ordovician age, from the Yinchufu Formation, Tremadoc layers at Liexi, Yongshun, Hunan, China.

 

This is a member of the family Pliomeridae.  It is 7.5 cm long and is the best example of this species I know of.

 

 

[piranha]

Very nice!  Here is a printable label for the original description of Liexiaspis zhengjiaensis.

 

 

Liu, Y. 1982. Trilobita. In: Li, S. (ed.) Palaeontological Atlas of Hunan.
People's Republic of China, Ministry of Geology and Mineral Resources.

Geological Memoirs: Series 2. Stratigraphy and Palaeontology Series 1.

Geological Publishing House, Beijing, 997 pp.  [Trilobita. pp. 290-347]

[rew]

Trilobite of the week #333 is a bonus trilobite.

 

L is for Lichas marocanus of Late Ordovician age (Katian stage) from the Upper Ktaoua Formation at Jbel Bou Degane, Morocco.  This is an uncommon trilobite.

 

Compare with the Silurian Dicranopeltis nereus.

 

 

Edited December 20, 2023 by rew

[rew]

Trilobite of the week #334 is a main trilobite.

 

L is for Lonchodomas volborthi of Early Ordovician age from Putilovo quarry, Asaphus lepidurus zone in the St. Petersburg region, Russia.

 

Like other members of the Trinucleoidea superfamily, it is blind, with no eyes.  This is a relative of the Moroccan Ampyx priscus, but since this bug is preserved in limestone it is fully 3D.

 

 

[rew]

I am taking Christmas week off.  The week after that will be for M trilobites.

[rew]

This week is brought to you by the letter M.  There will be two bonus trilobites.

 

The trilobites will be from three different orders and from three different countries.

 

[rew]

Trilobite of the week #335 is a bonus trilobite.

 

M is for Meteoraspis dis of Middle Cambrian age from the Weeks Formation in Millard County, Utah.

 

And Happy New Year to you all.

 

 

 

Edited January 1 by rew