orbitoid

fossil foraminiferan

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July 21, 2026

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The term "orbitoid" refers to a member of the genus Orbitoides. This genus consists of fossil foraminiferans, which are single-celled organisms with complex shells that preserve well as fossils. Orbitoides lived from the Upper Cretaceous to the Miocene epochs. These foraminiferans are characterized by chambers arranged radially, with multiple layers of smaller chambers on both surfaces of the main chamber layer. They are similar in appearance to another genus of foraminiferans called Nummulites.123

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Cretaceous Period
Mass extinction
…benthos, the larger foraminiferans (orbitoids) died out, and the hermatypic corals were reduced to about one-fifth of their genera. Rudist bivalves disappeared, as did bivalves with a reclining life habit, such as Exogyra and Gryphaea. The stratigraphically important inoceramids also died out. Overall, approximately 80 percent of animal species…
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…benthos, the larger foraminiferans (orbitoids) died out, and the hermatypic corals were reduced to about one-fifth of their genera. Rudist bivalves disappeared, as did bivalves with a reclining life habit, such as Exogyra and Gryphaea. The stratigraphically important inoceramids also died out. Overall, approximately 80 percent of animal species…
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K–T extinction
…invertebrates, the larger foraminifers (orbitoids) died out, and the hermatypic corals were reduced to about one-fifth of their genera. Rudist bivalves also disappeared, as did bivalves with a reclining (or partially buried) life habit, such as Exogyra and Gryphaea. The
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…invertebrates, the larger foraminifers (orbitoids) died out, and the hermatypic corals were reduced to about one-fifth of their genera. Rudist bivalves also disappeared, as did bivalves with a reclining (or partially buried) life habit, such as Exogyra and Gryphaea. The
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