Fascinating Insight: ventral-side preparation

Fossil as found: two Calymene trilobites are
hidden inside a living chamber of a cephalopod.

Fossil as found: two Calymene trilobites are hidden inside a living chamber of a cephalopod.

Starting the preparation: outlines are now clearly visible

Starting the preparation:
outlines are now clearly visible

Using fine air abrasives, the inside of the trilobites can be cleaned carefully

Using fine air abrasives, the inside
of the trilobites can be cleaned carefully

The final result after 8 hours of painstaking preparation

The final result after 8 hours
of painstaking preparation

Cephalon of Hyrokybe sp. (?) showing a very fine tuberculation

Cephalon of Hyrokybe sp. (?)
showing a very fine tuberculation

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This piece was a steinkern of a cephalopode-living chamber, inside which were two complete calymenas, as well as a rare cephalon of a Hyrokybe sp. (?). It is not unusual to find trilobites inside of living chambers. They potentially used them as some sort of retreat, for example after moulting. 

The preparation was mostly done by gentle sand blasting to carefully expose the ventral sides of the trilobites. For both specimen the hypostome could be spotted. 

Fossil: Calymene sp. 

Locality: Beach near Blåhäll, Gotland (Sweden)

Formation: Silurian

Length of the trilobite: 3.3 cm

Collection: Karin and Wilfried Amelang

Work required: 8 hours

This specimen and its preparation were published in the Steinkern magazine, issue 29 in 2017:

FREITAG, P. (2017): Ungewohnte Perspektive: Ventralpräparate silurischer Trilobiten in der Wohnkammer eines Kopffüßers, in: DER STEINKERN, Heft 29, S. 37-41. Link zum Heft: https://www.steinkern.de/inhaltsangaben/1211-heft29.html