Charnia

Charnia is a genus of frond-like Ediacaran lifeforms with segmented, leaf-like ridges branching alternately to the right and left from a zig-zag medial suture (thus exhibiting glide reflection, or opposite isometry). The genus Charnia was named after Charnwood Forest in Leicestershire, England, where the first fossilised specimen was found. Charnia is significant because it was the first Precambrian fossil to be recognized as such. The living organism was a type of life form that grew on the sea floor and is believed to have fed on nutrients in the water. Despite Charnia's fern-like appearance, it is not a photosynthetic plant or alga because the nature of the fossilbeds where specimens have been found implies that it originally lived in deep water, well below the photic zone where photosynthesis can occur. Several Charnia species were described but only the type species C. masoni is considered valid. Some specimens of C. masoni were described as members of genus Rangea or a separate genus Glaessnerina: Two other described Charnia species have been transferred to two separate genera A number of Ediacaran form taxa are thought to represent Charnia (or Charniodiscus) at varying levels of decay; these include the Ivesheadiomorphs Ivesheadia, Blackbrookia, Pseudovendia and Shepshedia. Charnia masoni was first described from Charnwood Forest in England and subsequently was found in Ediacara Hills in Australia, Siberia and White Sea area in Russia and Precambrian deposits in Newfoundland, Canada. It lived around 550–570 million years ago. Charnia masoni was brought to the attention of scientists by Roger Mason, a schoolboy who later became a professor of metamorphic petrology. In 1957 Mason and his friends were rock-climbing in Charnwood Forest, in what is now a protected fossil site in Central England. They noticed this unusual fossil, and Mason took a rubbing of the rock. He showed the rubbing to his father, the minister of Leicester's Great Meeting Unitarian Chapel, who also taught at the local university and knew Trevor Ford, a local geologist. Mason took Ford to the site; Ford wrote up the discovery in the Journal of the Yorkshire Geological Society.