Soft-bottom tube worms: from irregular to programmed shell growth

Like other secondary soft-bottom dwellers, serpulid and sabellid tube worms used particular strategies in order to cope with their earlier loss of mobility. This is expressed by the transition from irregular to genomically programmed morphologies of their calcareous shells that guarantee a stable horizontal resting position. In contrast to permanent recliners, however, this attitude was probably only the starting position for active resurrection after the muddy tail of storm sediments had settled on top of the displaced animal.