My trilobite of the week.

[Danielb]

Love this thread can’t wait to see what else you have! 

Edited October 22, 2023 by Danielb

[rew]

Trilobite #312 is a bonus trilobite.

 

E is for Eccoptochile mariana of Middle Ordovician age from Jbel Tiskaouine, Morocco.

 

Ecocoptochile is commonly faked.  If you see a large, excellent Eccoptochile at a moderate price, is is very likely made in a mold, painted, and glued to a rock.  This one has a bit of restoration, but is real.

 

 

[rew]

Trilobite #313 is a bonus trilobite.

 

E for for Eoharpes cristatus of Early Ordovician age from the Fezouata Formation at Zagora, Morocco.

 

Good examples of this early harpetid don't come up very often.

 

 

[piranha]

On 10/24/2023 at 10:54 PM, rew said:

Eoharpes cristatus of Early Ordovician age from the Fezouata Formation at Zagora, Morocco.

 

 

Eoharpes cristatus is a Portuguese trilobite. E. cristatus has a maximum of six to seven pits across the anterior width of the brim, and the prolongation of the cephalic brim does not extend beyond the pygidium. Some of the recent literature has referred these Fezouata harpetids to Eoharpes sp. and still awaiting a formal description. Unfortunately, this is yet another case of widespread misinformation propagated by various online fossil dealers.

 

 

Romano, M. 1975
Harpid Trilobites from the Ordovician of North Portugal.
Comunicações dos Serviços Geológicos de Portugal, 59:27-36

 

Romano, M., Henry, J.L. 1982
The Trilobite Genus Eoharpes from the Ordovician of Brittany and Portugal.
Palaeontology, 25(3):623-633  PDF LINK

 

Tauber, E.H., Reis, M.J. 1994
The Trilobite Eoharpes cristatus Romano, 1975 from the Valongo Formation (Ordovician) of North Portugal.
Comunicações do Instituto Geológico e Mineiro, 80:35-49  PDF LINK

[rew]

Okay, it's Eoharpes sp. for now.  That's what the AMNH trilobite gallery calls it.  They do have a question mark beside the name.  So maybe this is an "E" trilobite, maybe it isn't.

 

https://www.amnh.org/research/paleontology/collections/fossil-invertebrate-collection/trilobite-website/gallery-of-trilobites/ordovician-period-trilobites/ordovician-trilobites-of-morocco-africa-alphabetized

Edited October 26, 2023 by rew

[rew]

Trilobite of the week #314 is a main trilobite.

E is for Erbenochile erbeni of Early Devonian age from Jbel Ou Driss, Morocco.

 

This is a better than average specimen.  The species is a member of the Acastidae with very large schizochroal eyes with readily visible lenses.

 

 

Edited October 27, 2023 by rew

[rew]

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

[rew]

Trilobite of the week #315 is a bonus trilobite.

F is for Flexicalymene cf. granulosa of Late Ordovician age from the Nicolet River Formation in LaPrarie, Quebec.

 

This bug is covered with tiny pustules.

 

Flexicalymene granulosa comes from the Pulaski Shale in Oswego County, New York.  This Canadian bug may or may not be the same species.

[rew]

Trilobite of the week #316 is a bonus trilobite.

 

F is for Foulonia sp. of Early Ordovician age from the Upper Fezouata Formation at the Zagora Area, Morocco.

 

This is a natural double.  The leading specimen is larger and the skinny pointy thing next to it is the rostrum of an ampyx trilobite.  The trailing specimen is a bit better preserved and is right on top of another trilobite (which seems to be some sort of asaphid).  Both bugs are prepped with all spines freed from the matrix.

 

 

 

Edited November 1, 2023 by rew

[rew]

Trilobite of the week #317 is a main trilobite.

 

F is for Fallotaspis cf. bondoni of Early Cambrian age from the Issafen Formation at Tazemourt, Morocco.  

 

 

[rew]

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

[rew]

Trilobite #318 is a bonus trilobite.

 

G is for Grandagnostus sp. of Late Middle Cambrian age from the Cassis or Agra Zone at Christmas Hills Road, Christmas Hills, Tasmania, Australia.

 

This agnostid is my only trilobite from Tasmania.

 

It is placed under the suborder Agnostina but not in any specific family because the head and pygidium are so effaced that has no features to place it into a family.  There is, however, a "rim" around the head.

 

 

Edited November 8, 2023 by rew

[rew]

Trilobite #319 is a bonus trilobite.

 

G is for Genevievella granulatus of Late Cambrian age from the Weeks Formation at Amasas Valley, Utah.

 

This is my only trilobite in the family Llanoaspididae.

 

 

[rew]

Trilobite of the week #320 is a main trilobite.

 

G is for Gabriceraurus mifflinensis of Ordovician age (Blackriveran Stage) from the Mifflin Formation in Grant County, Wisconsin.

A bit of shell in front of the right eye is missing, but there is no restoration.

 

 

[rew]

This week is brought to you by the letter H.

 

There will be two bonus trilobites.  The three bugs are of three different orders and from three different continents.

[rew]

Trilobite of the week #321 is a bonus trilobite.

 

H is for Hesslerides bufo of Mississippian age from the Edwardsville Formation in Montgomery County, Indiana.

 

The Edwardsville Formation is famous for the variety, size, completeness, and excellence of its crinoid fossils.  There are probably few serious crinoid collectors without some specimens from that formation.  This plate does not disappoint -- there are four crinoid species here.  The leftmost crinoid is Platycrinites hemisphericus, the upper right crinoid is the crown of a Scytalocrinus robustus, in the lower left of the plate to the right of the Platycrinites there is a Scytalocrinus decadactylus, and in the lower right is a Cyathocrinites multibrachiatus.  There is also a small Cladochonus beecheri coral.

 

But the stars of the show are the Hesslerides bufo trilobites, the only species of trilobite I know of from the Edswardsville Formation.  There are five specimens here.  Three are train wrecks -- two partials with heads and one enrolled and crushed specimen.  One prone specimen, next to the coral, is near perfect and another is of good quality, with its head bent down and slight disarticulation of the free cheeks.  These trilobites lived at time when crinoids were at their peak of diversity, but trilobites were on their way out.

 

Compare with its cousin, Hesslerides arcentensis, which was trilobite of the week #226 posted May 1, 2022.

 

Edited November 13, 2023 by rew

[piranha]

4 hours ago, rew said:

Hesslerides bufo trilobites, the only species of trilobite I know of from the Edswardsville Formation.

 

 

Congrats on this spectacular association plate from one of the preeminent collectors of Indiana trilobites.

 

These are the other Edwardsville Formation trilobites. The name "Basidechenella" needs to be updated as it is not a valid genus for North America.

 

 

Brezinski, D.K. 2007
Lower Mississippian Trilobite Biostratigraphy of the Central United States, and some New Osagean Species.
Journal of Paleontology 81(4):737-745

 

White, R.D., Lieberman, B.S. 1998
A Type Catalog of Fossil Invertebrates (Arthropoda: Trilobita) in the Yale Peabody Museum.
Postilla, 214:1-152

[rew]

Well, I always learn something new from piranha.  There are more different species of Edwardsville trilobites than I thought.  I'd love to have one of  those Brachymetopus spinosus trilobites, but I doubt I ever will.

 

 

 

 

[rew]

Trilobite of the week #322 is a bonus trilobite.

 

H is for Hoplolichoides furcifer, of Middle Ordovician age, from the Asery level of Vilpovitsy quarry, in the St. Petersburg region of Russia.

 

There is a fair amount of variation in this species.  The size of the axial spines and the thoracic segments they are on varies.  The occipital spine can be bifurcated into "goat's horns", as it is here, or there can be a single central occipital spine.

 

Everybody likes this bug.

[Coco]

Hi,

 

Is it normal for her eyes to be like this ?

 

Coco

[rew]

34 minutes ago, Coco said:

Hi,

 

Is it normal for her eyes to be like this ?

 

Coco

 

Yes.  With Russian bugs it is common for the optical surfaces of the holochroal eyes of lichids to not be preserved at all.  So what you see is rock.

[Isotelus2883]

The schizochroal eyes on the reconstructed specimens are all faked. Lichids do not have schizochroal eyes. This style of reconstruction is very common among this species.

3 hours ago, Coco said:

Is it normal for her eyes to be like this ?

 

[rew]

Trilobite of the week #323 is a main trilobite.

 

H is for Heliopeltis johnsoni, at the age of the Early to Middle Devonian transition (Emsian/Eifelian stage), from Jebel Ofaten, Morocco.

 

This ball of spines is a scutellid trilobite, from the same group that has Paralejurus.  To see where it came from, start with a Kolihapeltis.  That scutellid is already a strange looking trilobite, in large part because the left and right pleural lobes are thinned out to the point where they are spines, so only the central lobe is contiguous.  Now thin out the pygidium of the Kolihapeltis until it becomes a spine itself, make all the spines a little longer, and you have a Heliopeltis.   If you want to see the lenses of a holochroal eye, your best bet is to get a well preserved and prepared scutellid trilobite.  My Paralejurus trilobite has well preserved lenses, and so does this bug.

 

I suspect this bug had trouble hauling around all those spines.   It any case I don't believe there are any species descended from it. 

 

[Top Trilo]

What a stunning trilobite!

[rew]

15 hours ago, Top Trilo said:

What a stunning trilobite!

 

I certainly thought so.  It's one of those extreme endpoints of evolution, taking a body plan as far as it can go.