Pterygocephalus paradoxus Agassiz, 1839

I have only ever seen one other of this species.

I assume this is extremely rare?

Not really: According to a book written by Lorenzo Sorbini, Pterygocephalus seems to occur in the Pesciara "molto frequente" - quite often.

Interesting. I guess they just rarely appear on the open market then. Thanks.

Fossils from Monte Bolca - per se - are not common. In Italy, fossil collecting is forbidden. The pesciara is exploited by the Cerato family for more than 100 years (they own this quarry since 1787). Only this family is allowed to sell the more common fossils.

Thomas