Brooksella alternata Walcott, 1896

Emended diagnosis: Brooksella showing variable number of radial lobes (typically 4–7; rarely 15 or more); radial lobes variably distinct, resulting in range of morphologic shapes (from top or bottom view) including rounded, astraeiform, tetraradial, regularly or irregularly lobate, or compound-lobate; terminal openings may be present at distal end of each radial lobe; lateral profile variable from single cupshaped structure to multiple, imbricate structures; siliceous, four-rayed, stauract spicules variably present; surface may show small, scattered, round, craterlike structures.