Trilobite species

[Bilmor]

Hi all, I have a question about this trilobite. It`s for sure real (buyer from a very good taxidermist i Morocco) As you see it`s little translucent (like some russians) and you can see a oar through it. But can someone tell me what kind of species it is? or family?

 

best wishes

[Fossildude19]

This looks to me, most like a Gerastos granulosus , with the integument (black layer) removed, either chemically, or abrasively.  

I've never seen this done before. 

The only thing I can assume is that it was badly damaged during prep/discovery, and they chose to remove the remaining black areas. 

Odd. Thanks for posting this.

 

[piranha]

3 hours ago, Fossildude19 said:

This looks to me, most like a Gerastos granulosus...

 

 

Gerastos granulosus is not a valid species in Morocco. 

 

 

The translucent preservation is similar to some of the trilobites coming from the Jorf locality.

This one looked unusual, so I sent the photos to a friend that is familiar with Moroccan proetids.

I have a couple additional proetid specialists to contact.  I will post any updates as I receive them.

 

 

Here are his comments:

 

Thanks for the photos.  I don’t think I have seen this one before.
It is unusual for several reasons.  It only has 9 thoracic segments.
It has small eyes placed far forward, unusual for Proetids.
The glabella has faint furrows; not the fiddle shape of Cornuproetids.
It has a large pygidial axis.

From the small photo I cannot tell if the genal angles are complete or if genal spines are broken off.
My suspicion is they are complete because both sides look the same.

Unfortunately, I don’t really know of any Proetid genera that fit this.

 

The trilobites in Morocco I know of with 9 segments are:

Proetidae - Cornuproetinae: 
Macroblepharum - has big eyes touching posterior border furrow.
Proetina ihmadii - clearly not that.
Sculptoproetus - has eyes touching posterior border furrow.

Tropidocoryphidae - Eremiproetinae
Eremiproetus - has large eyes placed near posterior border furrow; small pygidial axis.

 

So none of these fit.  That leaves things where we don’t know the number of segments.

 

One interesting possibility is Helmutia.  The number of segments is unknown.

The glabella has faint furrows, not fiddle shaped.  Very short genal spines.
The eyes are smaller, placed mid-glabella.  Large pygidial axis.  Found in Tafilalt.

 

One of them has small eyes placed forward.
Kegeliella bouregregus?, used to be called Proetus listei bouregregus

However, if this trilobite is Kegeliella, then it has 10 segments.

 

[piranha]

We might be narrowing this one to: Helmutia, a subgenus of Orbitoproetus.  

 

Here is the response from another proetid specialist:

 

"Thanks for the file.  Great stuff!  It very looks like O. (Helmutia), i.e., an orbitoproetine having a moderately vaulted glabella. O. (Orbitoproetus) differs further in having 10 thoracic segments (as far as known).  I think this difference might be a further argument to shift O. (Helmutia) to generic rank."

 

 

figures from:

 

Feist, R., & Orth, B. (2000)
Trilobites de la limite Eifélien/Givétien de la région stratotypique (Tafilalet, Maider, Maroc). 
Travaux de l'Institut Scientifique Rabat, série géologie & géographie physique, 20:78-91

 

[Bilmor]

Thank you all so much for comments. Yes it is from Jorf and from Aziz (Abdelaziz, Harapis trilobite) He had never seen this before. I`m not an expert on trilobites  but have some in my small fossil collection (I`m a meteorite expert, writer, author and collector)

[piranha]

We have a consensus as a third proetid specialist also agrees on Helmutia:

 

 

"The locality seems to be west of Jorf at the road to Tinejad, where Helmutia has been found associated with Akantharges and Struveaspis in beds probably early Eifelian in age. The low number of thoracic segments may be related to the small size of Helmutia, which is indeed somewhat smaller than Orbitoproetus."