Middle Ordovician (Llandeilian)

Northern France, Guichen (35), France

Fine 2.3cm Carpoid in 5.5cm concretion

Carpoid.

Mitrocystella is a genus of carpoid known from the Ordovician of various parts of Europe.

Carpoids are an extinct group that most paleontologists consider to be early echinoderms while others argue they could be primitive chordates.