fusulinid
noun
fu·su·li·nid ˌfyü-zə-ˈlī-nid 
-ˈlē-,
-ˈli-
: any of a family (Fusulinidae) of extinct marine foraminifers
Example Sentences
Recent Examples on the Web The traces of ancient invertebrates with astonishing names (crinoids, fusulinids, and so on) were just one of many signs that the landscape my coastal relatives used to mock for its monotony in fact harbored wonders. 
Ben Lerner, The New Yorker, 29 Mar. 2017
Ben Lerner, The New Yorker, 29 Mar. 2017 Word History
Etymology
New Latin Fusulinidae, from Fusulina, a genus, from Latin fusus spindle + -ulus -ule + New Latin -ina, diminutive suffix
First Known Use
1941, in the meaning defined above