Magelona dakini is a small, thin, shovel-nosed burrowing worm with limited mobility.

[3] Magelonids build meandering burrows, usually below the top 20mm of sediment, in medium to fine sands.

This species is not especially susceptible to metal loading, meaning, excess iron and lead does not affect it much.

[6] Dannychaeta tucolus lived about 514 million years ago, putting it in the middle Cambrian.

Similar to M. dakini, D. tucolus is also characterized by two spindles that are located next to its mouth and lived in shallow borrows on the sea floor as indicated by trace fossils and intact trace fossils with D. tucolus inside of them.