Fieldia (worm) explained

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]

It was originally interpreted as an arthropod; its trunk bears a dense covering of spines, and its proboscis is small. It fed on sea-floor mud, evidenced by the frequent presence of sediments preserved in its gut. 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. 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]

External links

Notes and References

  1. Web site: Fieldia lanceolata. Burgess Shale Fossil Gallery. Virtual Museum of Canada. 2011.
  2. Conway Morris . S.. The Burgess Shale (Middle Cambrian) Fauna. Annual Review of Ecology and Systematics. 10. 327–349. 1979. 10.1146/annurev.es.10.110179.001551.
  3. F. D.. Class Seticoronaria and Phylogeny of the Phylum Priapulida. Zoologica Scripta. Por. 12. 4. 267–272. 1983. 10.1111/j.1463-6409.1983.tb00510.x . 85091685.
  4. Anatomy and lifestyles of Early Cambrian priapulid worms exemplified by Corynetis and Anningvermis from the Maotianshan Shale (SW China) . 2004 . Lethaia . 21–33 . D. Y. . Vannier . J. . Chen . J.Y. . 10.1080/00241160410005088 . Huang . 37 . 2004Letha..37...21H .
  5. M. A. . Cambrian and Recent Disparity: the Picture from Priapulids . Paleobiology . 24 . 2. Wills . 177–199 . 1 April 1998 . 2401237 . 10.1666/0094-8373(1998)024[0177:CARDTP]2.3.CO;2 . 88647544 .
  6. Caron . Jean-Bernard. Jackson . Donald A.. Taphonomy of the Greater Phyllopod Bed community, Burgess Shale. PALAIOS . 21 . 5 . 451–65. October 2006. 10.2110/palo.2003.P05-070R. 20173022. 2006Palai..21..451C . 53646959 .

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