Fieldia (worm)
Extinct genus of arthropods
From Wikipedia, the free encyclopedia
Fieldia (named after American businessman and financier Cyrus W. Field) [1] is a genus of worms known from the Cambrian Burgess Shale, and assigned to the priapulids.[2]
| Fieldia Temporal range: | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Stem group: | Priapulida (?) |
| Class: | †Archaeopriapulida |
| Family: | †Fieldiidae |
| Genus: | †Fieldia Walcott, 1912 |
| Species | |
| |
It was originally interpreted as an arthropod; its trunk bears a dense covering of spines, and its proboscis is small.[2] It fed on sea-floor mud, evidenced by the frequent presence of sediments preserved in its gut.[2] It reached 5 cm in length.
Along with the other Cambrian priapulids Ottoia, Selkirkia, Louisella, Ancalagon, Scolecofurca, and Lecythioscopa, the organism was originally classified into a clade termed the Archaeopriapulida, a stem group to the Priapulids proper.[3] However, the morphological similarity of these organisms to their modern cousins is remarkable, especially for the Burgess Shale,[4] and their similarity to the modern genus Maccabeus suggests that they are in the Seticoronaria stem group, and thus are true crown-group priapulids.[3] A phylogenetic analysis does not provide a great deal of resolution to the relationships between these basal worms.[5]
18 species of Fieldia are known from the Greater Phyllopod bed, where they comprise 0.03% of the community.[6]