Aspidella

Aspidella is an Ediacaran disk-shaped fossil. It was most likely the imprint of the holdfast of a stalked organism, such as an erniettomorph or rangeomorph.

Morphology
Aspidella consists of disk-shaped fossils, with concentric rings and/or centripetal rays. The diameter of circular Aspidella varies from 1 to 180 mm.[1] Most individuals are between 4 and 10 mm, but smaller animals would presumably have decayed before they could fossilize. Other Aspidella take the form of ellipses, 3–8 cm long and 1–4 cm wide. Most have a central pimple. The rim of all specimens is made up by ridge-edged rays and/or concentric rings.

Ecology
The rarity of large individuals probably indicates that Aspidella were r-strategists, producing numerous offspring of which most died young. It is most common in deep-water sediments, but is a constituent of most Ediacaran fossil assemblages, including those deposited above storm wave-base.[2] The organisms can reach densities of 3000 m−2.