This trilobite is an extremely rare Chasmops tallinensis that was found inside a glacial erratic (Ordovician limestone) in northern Germany. Complete trilobites from the subfamily Chasmopinae are rarities in glacial erratics of northern Germany and generally very difficult to prepare. The shell is very delicate and the rock shows almost no separation.

The preparation proved to be extremely difficult here as well and could only be mastered by using fine air abrasives and a lot of patience. At the request of the collector, a drifted librigena was rearticulated and also missing shell parts, such as the tips of the genals, were restored or reconstructed. The entire preparation work on this piece was described in detail in an article published on steinkern.de (see below).

Fossil: Chasmops tallinnensis ÖPIK 1937

Locality: Kreuzfeld near Malente (Germany)

Formation: Ludibunduskalk (?), Upper Ordovician

Width of the cephalon: 3.4 cm (1.3 inches)

Work required: 59 hours

Collection: Jan Deppermann

The specimen and its preparation were published on steinkern.de in 2022:

FREITAG, P. (2022): Extremely rare and extremely challenging: a complete Chasmops from glacial erratics
Link to the article: https://www.steinkern.de/english-articles/1411-chasmops-preparation.html