Ceratonurus - a rearticulation

Cross-section 1: Ceratonurus from ventral side
- left: Pygidium hidden under the rock, right: thick spines of the Cephalon

Cross-section 1: Ceratonurus from ventral side
- left: Pygidium hidden under the rock,
right: thick spines of the Cephalon

Cross-section 2: right side of the pleuraes, cranidium on the left

Cross-section 2: right side of the pleuraes,
cranidium on the left

Getting started: the cranidium is deep inside the
rock and the left librigena is disarticulated

Getting started: the cranidium
is deep inside the rock
and the left librigena is
disarticulated

The right librigena lies close to the pygidium

The right librigena lies close to
the pygidium

The spine of the right librigena lies behind some pleural spines

The spine of the right librigena
lies behind some pleural spines

The left librigena will be carefully removed

The left librigena will be
carefully removed

The thorax shows very attractive long pleural spines

The thorax shows very attractive
long pleural spines

A removed spine showing excellent tubercles

A removed spine showing
excellent tubercles

The thorax was glued together and the cranidium removed

The thorax was glued together
and the cranidium removed

After the matrix had been formed, it was time to put all removed parts back in place

After the matrix had been formed,
it was time to put all removed parts back in place

The final result after about 60 hours of detailed and careful work

The final result after about 60 hours
of detailed and careful work

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The locality of Jorf offers up a lot of well preserved Devonian trilobites. Amongst which are extremely rare species, such as this Ceratonurus, which I received as a commissioned work piece. Complete specimens are virtually impossible to obtain and so I was delighted to be able to prepare this rarity.

The so called “glass limestone” from Jorf is a very though, nearly flint-like type of stone, which is almost exclusively workable with a sand blaster. Usually the matrix separation from the fossil is quite poor. Although, when carefully preparing the fossil, the shell details can still be secured. 

This specimen was an exuviae and was, as requested by the owner, rearticulated, which means that the dislocated shell pieces were removed from the matrix and replaced at their original spots. Considering the extreme rarity and according high worth of this trilobite this presents an entirely reasonable decision. The entire work progress was extensively documented.  

Fossil: Ceratonurus sp. 

Locality: Jorf (Morocco)

Formation: Devonian

Length of the trilobite: 3 cm

Work required: 60 hours