''Charniodiscus'' is an
Ediacaran
The Ediacaran ( ) is a geological period of the Neoproterozoic geologic era, Era that spans 96 million years from the end of the Cryogenian Period at 635 Million years ago, Mya to the beginning of the Cambrian Period at 538.8 Mya. It is the last ...
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
that in life was probably a stationary
filter feeder
Filter feeders are aquatic animals that acquire nutrients by feeding on organic matters, food particles or smaller organisms (bacteria, microalgae and zooplanktons) suspended in water, typically by having the water pass over or through a s ...
that lived anchored to a sandy sea bed. The organism had a
holdfast, stalk and frond. The holdfast was bulbous shaped, and the stalk was flexible. The frond was segmented and had a pointed tip. There were two growth forms: one with a short stem and a wide frond, and another with a long stalk, elevating a smaller frond about above the holdfast. While the organism superficially resembles the
sea pen
Sea pens are marine cnidarians belonging to the superfamily Pennatuloidea, which are colony-forming benthic filter feeders within the order Scleralcyonacea. There are 14 families within the order and 35 extant genera, and it is estimated a ...
s (
cnidaria
Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...
), it is probably not a
crown-group
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...
animal.
''Charniodiscus'' was first found in
Charnwood Forest in England, and named by
Trevor D. Ford in 1958. The name is derived from the fact that Ford described a holdfast consisting only of a double concentric circle, his species being named ''Charniodiscus concentricus''. Later it was discovered that a frond (''Charnia masoni'') was part of a closely related organism. ''
Charnia'' differs in the branching structure in the frond.
''Charniodiscus'' specimens are known from across the globe dating to around .
Species are distinguished by the number of segments, the presence or absence of distal spines, and by shape ratios.
Other described species, ''C. arboreus'', ''C. longus'', ''C. oppositus'', and ''C. spinosus'' are considered to belong to their own genus ''
Arborea
Arborea is a town and ''comune'' in the province of Oristano, Sardinia, Italy, whose economy is largely based on agriculture and cattle breeding with production of vegetables, rice, fruit and milk (notably the local milk product Arborea).
Histo ...
'', which is sometimes considered a synonym of ''Charniodiscus''.
The status of ''C. yorgensis'' needs to be restudied.
See also
*
List of Ediacaran genera
The existence of life, especially that of animals, before the Cambrian had long been the subject of debate in paleontology. The apparent suddenness of the Cambrian explosion had no firm explanation, and Charles Darwin himself recognized the chal ...
References
*Glaessner, M. F., and Daily, B. (1959
"The Geology and Late Precambrian Fauna of the Ediacara Fossil Reserve" ''Records of the South Australian Museum'' 13: 369-407 retrieved 26 January 2008
External links
Mistaken Point
{{Taxonbar, from=Q2318754
Ediacaran life
Petalonamae
Ediacaran Europe
White Sea fossils