rangeomorph

noun

1. Any organism of the clade Rangeomorpha, Precambrian (Ediacaran) sessile organisms resembling ferns, possibly descended from sponges and among the oldest known complex lifeforms.

   “Previous comparisons of rangeomorphs with cnidarians or ctenophores now seem unlikely. The fact that both sides of the rangeomorph structure are essentially identical, is not consistent with the rangeomorph frondlet "representing the bases of an array of open tubes that housed polyps or other filter feeding organisms."”

   “Although the possibility that they were passive “mattresses” holding symbiotic algae is plausible for the shallow-marine specimens of Australia, the oldest Ediacarans are the branching, frond-shaped rangeomorphs from Mistaken Point, Newfoundland, which lived without light in deep water (Narbonne, 1998).”

   “Rangeomorphs became extinct at the end of the Ediacaran, at or before 541 Ma,[…].”