Description

Middle Miocene (Mohnian)
Aguajito Shale Member, Monterey Fm.
Carmel, California, USA
High quality specimen with several pectinariid worm tubes. Longest is 54mm.

Worm, Annelid.

The Pectinariidae (trumpet worms) is a family within the Class Polychaeta (polychaete worms) Pectinariids date back perhaps to the Cretaceous and are still living today.

Worm tubes are formed from a secretion of the worm mixed with sand. The mixture hardens and the worm lives inside it. Occasionally, fossil worm tubes are found but only at a few localities as the tube is usually destroyed by soil compaction or erosion over time. 

It’s an odd kind of trace fossil some collectors look for because the worm itself is even more rarely preserved.