Domain Eukaryota Scientific name Fusulinida Higher classification Forams | Rank Order | |
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Similar Forams, Schwagerina, Conodont, Brachiopod, Crinoid | ||
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.
Contents
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.