rotaliid

Rotaliid refers to a superfamily of single-celled organisms belonging to the order Rotaliida within the class Foraminifera. These are marine protists that construct shells, or tests, out of calcium carbonate. The tests of rotaliids are typically planispiral, coiled in a flat spiral, although some may exhibit trochospiral coiling, resembling a spiral staircase. They are characterized by a porous test through which they extend pseudopods for locomotion and feeding.

Rotaliids are abundant in marine sediments and water columns worldwide, particularly in tropical and subtropical regions. They play significant roles in marine ecosystems, contributing to the carbon cycle and serving as a food source for various organisms. Their fossilized tests are valuable in paleontology and stratigraphy, as they can be used to date rock layers and reconstruct past environmental conditions. The diversity within the Rotaliida superfamily is considerable, with numerous genera and species identified based on variations in test morphology, aperture structure, and internal features. Common examples include the genera Ammonia and Pseudonodosaria.