This is a rare cheirurid trilobite of the species Ceraurinus marginatus, originating from the Cobourg Formation in Canada.
The Trilobite itself ist about 49 mm long.

The genus Ceraurinus features a square-shaped, smooth glabella with no prominent pustules, and bears three pairs of marginal pygidial spines. The front pair is distinctly elongated and marked by a longitudinal groove.

In contrast, Ceraurus displays a semi-elliptical glabella with pronounced pustules and long, grooved pygidial spines, though lacking a clearly segmented three-pair arrangement.

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