fusulinid

fu·su·li·nid

noun \ˌfyü-zə-ˈlī-nid, -ˈlē-, -ˈli-\

Definition of FUSULINID

: any of a family (Fusulinidae) of extinct marine foraminifers

Origin of FUSULINID

New Latin Fusulinidae, from Fusulina, a genus, from Latin fusus spindle + -ulus -ule + New Latin -ina, diminutive suffix

First Known Use: 1941

fusulinid

noun    (Concise Encyclopedia)

Any of a large group of extinct foraminiferans, single-celled organisms related to amoebas but having complex shells that are easily preserved as fossils. The fusulinids first appeared during the Carboniferous period, perhaps c. 320 million years ago, and persisted until the end of the Permian period, 248 million years ago. They have been extremely useful for correlating different rock units in widely separated regions and for dividing geologic time into smaller units. Petroleum geologists also use them to help locate economically valuable deposits of oil and natural gas.