Acadagnostus

Acadagnostus is a genus of trilobite from the Middle Cambrian, with 7 species currently recognized.

The type species A. acadicus has the widest distribution known from any peronopsid (with Peronopsis integer and P. scutalis) and has been found in North America, Greenland, England, Western Europe, Eastern Europe, Central Asia, the Altai Mountains, the Siberian shield, China, and Australia.

[2] Like all Agnostida, Acadagnostus is diminutive, with the headshield (or cephalon) and tailshield (or pygidium) of approximately the same size (or isopygous) and outline.

The pygidium is subquadrate, has a flat border, that is sometimes posteriorly widened and has a weak bifurcation.

It is believed that Acadagnostus gave rise to Pseudoperonopsis, the earliest representative of the Diplagnostidae family.

Schematic showing the relationship between Acadagnostus (light green), other Peronopsid genera (darker green) and other families (other colors). ^{[

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