Fusulinida

Fusulinida
Temporal range: L Silurian - U Permian
Scientific classification
Domain: Eukaryota
(unranked): SAR
(unranked): Rhizaria
Phylum: Retaria
Subphylum: Foraminifera
Order: Fusulinida
Superfamilies

Archaediscacea
Colaniellacea
Earlandiacea
Endothyracea
Fusulinacea
Geinitzinacea
Moravamminacea
Nodosinellacea
Palaeotextulariacea
Parathuraminacea
Ptychocladiacea
Tetrataxacea
Tournayellacea

Fusulinid limestone, Upper Pennsylvanian; Elk County, Kansas. Field of view is 3.9 cm wide. Link at source to view of entire slab.

The Fusulinida is an extinct order within the Foraminifera in which the tests (shells) are composed of tightly packed, secreted microgranular calcite. Like all Forams, they are single-celled organisms. In advanced forms the test wall is differentiated into two or more layers. Loeblich and Tappan, 1988, gives a range from the Lower Silurian to the Upper Permian, with the fusulinid foraminifera going extinct with the Permian–Triassic extinction event.

Taxonomy

Thirteen superfamilies are presently recognised, based on taxa (families) included in the three superfamilies given in the Treatise. Three are based on families in the Parathuramminacea, 1964, and nine on families in the Endothyracea, 1964. The Fusulinacea remains the same in both sources (Treatise 1964 and Loeblich and Tappan, 1988).

Terminology

The term "fusulinid" applies to any of the Fusulinida. The Fusulinida are fusulinids (sensu lato). However, the term "fusulinid" is often applied just to the fusiform Fusulinacea and not to the entire order.

Application

Members, especially of the Fusulinacea, are excellent index fossils for determining ages and correlating Upper Mississippian to Permian strata. In some places fusulinaceans may be so abundant as to be a significant component of limestone.

Further Reading

Triticites sp. cross-section; Plattsmouth Chert; Red Oak, Iowa; Permian.
Wikimedia Commons has media related to Fusulinida.
This article is issued from Wikipedia - version of the Monday, February 15, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.