Scolecodont

Scolecodonts are common and diverse microfossils, which range from the Cambrian period (around half a billion years ago at the start of the Paleozoic era) to the present.

Since the other classes of annelids (specifically, the earthworms and leeches) lack hard parts, only the sea-dwelling polychaetes are frequently represented in the fossil record.

Polychaetes are commonly fossilized due to their chitinous teeth and their dwelling tubes made of durable calcite (a calcium carbonate), hardened mucus (a.k.a.

Segments of the fossil jaw of a polychaete worm were first reported from Silurian strata on the Estonian island of Saaremaa in 1854,[2] but they were misinterpreted as fish teeth.

[3] Subsequently, E. Ehlers, a specialist on recent polychaetes, recorded them from the Jurassic Solenhofen Stone of Bavaria, Germany, demonstrating their affinity and proposing the generic names Eunicites and Lumbriconereites.