Archimedes (bryozoan)

Archimedes is a genus of bryozoans belonging to the family Fenestellidae. The first use of the term "Archimedes" in relation to this genus was in 1838.[2]

Archimedes
Temporal range: Carboniferous - Permian
Fossil stalks of Archimedes from Illinois, on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification
Kingdom:
Animalia
Phylum:
Bryozoa
Class:
Stenolaemata
Order:
Fenestrida
Family:
Fenestellidae
Genus:
Archimedes[1]

Owen, 1838
species
  • A. wortheni (Hall, 1856) type = Fenestella wortheni
Synonyms

Archimedipora d'Orbigny, 1849

Etymology

This genus of bryozoans is named Archimedes because of its corkscrew shape, in analogy to the Archimedes' screw, a type of water pump which inspired modern ship propellers. These forms are common as fossils but they have been extinct since the Permian.

Species
  • Archimedes orientalis Schulga-Nesterenko 1936
  • Archimedes regina Crockford 1947
  • Archimedes stuckenbergi Nikiforova 1938

[3]

Fossil range

These bryozoans lived from the Carboniferous period (Tournaisian age) to the Permian period (Leonard age) (345.3 to 268.0 Ma), when this genus became extinct.[3][4]

Description
Stereo image
Right frame 
Fossilized skeleton of Archimedes Bryozoan.

Archimedes is a genus of fenestrate bryozoans with a calcified skeleton of a delicate spiral-shaped mesh that was thickened near the axis into a massive corkscrew-shaped central structure. The most common remains are fragments of the mesh that are detached from the central structure, and these may not be identified other than by association with the "corkscrews", that are fairly common. Specimens in which the mesh remains attached to the central structure are rare.[5] Like other bryozoans, Archimedes forms colonies, and like other fenestrates, the individuals (or zooids) lived on one side of the mesh, and can be recognized for the two rows of equally distanced rimmed pores. Inside the branches, neighbouring individuals were in contact through small canals. Bryozoans are stationary epifaunal suspension feeders.[3]

Distribution

The majority of fossils of this genus are distributed throughout Europe and North America, but they have also been found in sediments of Afghanistan, Canada, Russia, and Australia.[3]

References
  1. Col, Jeananda, 'Archimedes', Dinosaur and Paleontology Dictionary, 1996, accessed March 8, 2011
  2. Duncan, Helen M. and W.H. Easton. "Archimedes and its Genotype." Journal of Paleontology. SEPM Society for Sedimentary Geology. Vol. 27, No. 5 (Sep., 1953), pp. 737–741.
  3. The Paleobiology Database
  4. Sepkoski, Jack Sepkoski's Online Genus Database - Bryozoa
  5. Mckinney, Frank, K.; Burrdick, Dennis W. (2001). "A rare, larval-founded colony of the bryozoan Archimedes from the Carboniferous of Alabama". Palaeontology. 44 (5): 855–859. doi:10.1111/1475-4983.00204.
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