Bright-field microscope image of trochophore of annelid ''Pomatoceros lamarckii | Bright-field microscope image of metatrochophore of annelid ''Pomatoceros lamarckii |
Many were long misidentified as the polychaete annelid Spirorbis until studies of shell microstructure and formation showed significant differences (Taylor and Vinn, 2006).
They discovered that the “Spirorbis” fossils found in sedimentary strata, including the Joggins and other Carboniferous coal measures, deposited from the Ordovician to Triassic periods are the remains of an extinct order of lophophorates (now called microconchids) unrelated to modern marine tube worms (Annelids) to which the genus Spirorbis belongs.
Polychaete annelid worms such as Rotularia and gastropods such as the cerithiid sea snail Cerithium have also been discovered in beds within the formation.
During a cave diving expedition to explore the Tunnel de la Atlantida, the world’s longest known submarine lava tube on Lanzarote in the Canary Islands, an international team of scientists and cave divers discovered the previously unknown species of crustacean, belonging to the remipede genus Speleonectes, along with two new species of annelid worms of the class Polychaeta.
The empty calcareous tubes of certain marine annelid tube worms, for example the Serpulidae, can sometimes be casually misidentified as empty vermetid shells, and vice versa.