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Smithsonian National Museum of Natural History

Department of Paleobiology

What are Foraminifera?

Foraminifera are tiny single-celled organisms that construct shells. They inhabit a wide range of marine environments, from the intertidal zone to the deep sea in all regions. After death, their abundance in sediment samples can reach tens of thousands of individuals per cubic centimeter. The two major group of foraminifera are benthic, which live in sediments on the sea floor, and planktic, which live in the upper 300 feet or so of the ocean. Foraminiferal shells of both groups occur in a variety of shapes, and typically range from 0.1 mm to 1 mm in size. The shells of all planktic and most benthic species are composed of calcite, the same mineral larger sea shells are made of. Some benthic species construct their shells with other secreted minerals, such as aragonite or silica, while others consist of organic materials or cemented sediment particles.

The fossil record of benthic foraminifera is ancient, dating to more than 550 million years. Planktic species range to about 190 million years. The abundance of their shells in ancient sediments, their wide distribution and their sensitivity to changes in environmental conditions make them valuable indicators of past climate change. Because the length of time a foraminifera species exists is geologically brief (~5-15 million years), the shells are also very useful for determining the age of sediments in which they occur.

Planktic Foraminifer Dictionaries

The Planktic Foraminifer Dictionary is divided up into 3 main parts by age. Each dictionary is a separate document, with links to each other.

The planktic foraminifer species dictionary for the Cretaceous, Paleogene, and Neogene, was put together by Brian Huber, Paul Pearson, and Silvia Spezzaferri for the Ocean Drilling Program's JANUS computer database. It includes the most recent genus-species senior synonyms, names of the original species author(s) and dates of the original description. Parentheses around the author names indicate a different genus name was used when the species was originally defined. Not all of the species named in the dictionary are represented in the National Register (yet).

Suggestions, questions or comments can be directed to Brian Huber.