Middle Cambrian, Jince formation. What's on the left?

[Wanda8]

Middle Cambrian, Jince (Czech Republic).
There are three different fossils on the rock:
trilobite Ellipsocephalus hoffi (whole),
trilobite Ellipsocephalus hoffi (side fragment)
and on the left side...

What's on the left?

 

 

[Kane]

Quite possibly a shed cephalic part of a Hydrocephalus minor. My second guess would be Paradoxides gracilis, but that would be a poorer match. 

[Wanda8]

Thank you for your answer.

I asked the paleontology professor. This is not a trilobite. Certainly a carapace, but not a trilobite.

 

Edited February 28 by Wanda8

[Wanda8]

[piranha]

1 hour ago, Wanda8 said:

I asked the paleontology professor. This is not a trilobite. Certainly a carapace, but not a trilobite.

 

 

That professor is not very well versed with the morphology of paradoxidid trilobites. 

 

Kane has already suggested:  Hydrocephalus appears to be a very good match.

 

[Wanda8]

Kane and piranha: Thank you very much, you convinced me. It's nice that sometimes forum members are better than professors! Congratulation on your knowledge!