| Fusulinida Temporal range: L Silurian - U Permian |
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| Scientific classification | |
| Kingdom: | Protista |
| Phylum: | Rhizaria |
| Class: | Foraminifera |
| Order: | Fusulinida |
| Superfamilies | |
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Archaediscacea |
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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, although in the Treatise, 1964, it is given from the Ordovician to the Triassic.
Contents |
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).
The term, "fusulinid" really applies to any of the Fusulinida. The Fusulinida are fusulinids ( sensu latu). However the term "fusulinid" is often applied just to the fusiform Fusulinacea, and not to the entire order.
Members, especially of the Fusulinacea, are excellent guide 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.