Largest organisms photosynthetic unicellular and multicellular protists that are related to land plants. The thallus of the unicellular mermaid's wineglass, "Acetabularia", can grow to several inches (perhaps 0.1 to 0.2 m) in length. The fronds of the similarly unicellular, and invasive "Caulerpa taxifolia" can grow up to a foot (0.3 m) long. A member of the order Cetacea, the blue whale ("Balaenoptera musculus"), is thought to be the largest animal ever to have lived. The maximum recorded weight was 190 metric tonnes for a specimen measuring , whereas longer ones, up to , have been recorded but not weighed. The African bush
Largest prehistoric animals measured long. An extinct megatoothed shark, "C. megalodon" is by far the biggest shark known. This giant shark reached a total length of more than . "C. megalodon" may have approached a maximum of in total length and in mass. The largest-known symmoriid was "Stethacanthus" at long. The largest-known eugenedont is a yet unnamed species of "Helicoprion" discovered in Idaho. The specimens suggest an animal that possibly exceeded in length. Another fairly large eugenedont is Parahelicoprion. The specimens suggest an animal that grew to the same size (), but was much less slender and overall less heavy. The largest-known hydontiformid