Most individuals are between 4 and 10 mm, but smaller individuals would presumably have decayed before they could fossilize. Other Aspidella take the form of ellipses, 3–8 cm long and 1–4 cm wide.
Individuals typically range from 4 to 10 millimeters in size, but smaller ones might have decomposed before fossilization. Other Aspidella exhibit elliptical shapes, with lengths between 3 and 8 centimeters and widths of 1 to 4 centimeters.