Fusulinida

Fusulinida Temporal range: L Silurian - U Permian
File:Fusulinids Topeka Limestone Virgilian Greenwood County KS.jpg
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

File:Fusulinid limestone, Upper Pennsylvanian; Elk County KS.jpg

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. 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

• Ursula Leppig, Holger C. Forke, Michael Montenari and Beate Fohrer (2005): A three- and two-dimensional documentation of structural elements in schwagerinids (superfamily Fusulinoidea) exemplified by silicified material from the Upper Carboniferous of the Carnic Alps (Austria/Italy): a comparison with verbeekinoideans and alveolinids.- Facies, Volume 51: 541 - 553.
• Alfred R. Loeblich, Jr., Helen Tappan, 1964:Sarcodina Chiefly "Thecamoebians" and Foraminiferida; Treatise on Invertebrate Paleontology, part C Protista 2.
• Alfred R. Loeblich, Jr., Helen Tappan, 1988: Foraminiferal genera and their classification, E-Book published by Geological Survey of Iran, 2005, Online

Triticites sp. cross-section; Plattsmouth Chert; Red Oak, Iowa; Permian.