Cyclomedusa is a circular fossil of the Ediacaran biota; it has a circular bump in the middle and as many as five circular growth ridges around it. Many specimens are small, but specimens in excess of 20 cm are known. The concentric disks are not necessarily circular, especially when adjacent individuals interfere with each other's growth. Many radial segment lines — somewhat pineapple-like — extend across the outer disks. A few specimens show what might be a stem extending from the center in some direction or other.
Charnia is an extinct genus of frond-like lifeforms belonging to the Ediacaran biota with segmented, leaf-like ridges branching alternately to the right and left from a zig-zag medial suture. The genus Charnia was named after Charnwood Forest in Leicestershire, England, where the first fossilised specimen was found; the species name after Roger Mason, a schoolboy who found it. Charnia is significant because it was the first Precambrian fossil to be recognized as such.
The rangeomorphs are a group of Ediacaran fossils. Ediacarans are the oldest large fossil organisms on earth, and many are not obviously related to anything else that has ever lived. However, some Ediacarans clearly resemble each other. Palentologists have not been able to agree on what else, if anything, is related to these organisms, so Ediacarans are usually classified into groups based on their appearance. These "form taxa" allow scientists to study and discuss Ediacarans when they cannot know what kind of living things they were, or how they were genetically related to each other. Rangeomorphs look roughly like fern fronds or feathers arranged around a central axis; the group is defined as Edicarans with a similar appearance and structure to the genus Rangea. Some researchers, such as Pflug and Narbonne, believe all rangeomorphs were more closely related to each other than to anything else. If true, this would make the group a natural taxon called Rangeomorpha.
Spriggina is a genus of early animals whose relationship to living animals is unclear. Fossils of Spriggina are known from the late Ediacaran period in what is now South Australia. Spriggina floundersi is the official fossil emblem of South Australia; it has been found nowhere else.
Hiemalora is a fossil of the Ediacaran biota, reaching around 3 cm in diameter, which superficially resembles a sea anemone. The genus has a sack-like body with faint radiating lines originally interpreted as tentacles, but discovery of a frond-like structure seemingly attached to some Heimalora has added weight to a competing interpretation: that it represents the holdfast of a larger organism.
Rangea is a frond-like Ediacaran fossil with six-fold radial symmetry. It is the type genus of the rangeomorphs.
Bradgatia linfordensis is a bush-like Ediacaran fossil. It consists of six or more fronds radiating from a central anchor point at the base. It superficially resembles a compressed cabbage in appearance, although in reality it had a more intricate, fractal mode of organisation. When multiple fossils are found together they are regularly spaced out rather than randomly distributed. It dominates the ecosystem at 8 to 22 cm above the mud surface at the bottom the sea where it grew. It was over-towered by Charnia and Charniodiscus which grew nearby.
Thectardis avalonensis is a triangular-shaped member of the Ediacaran biota, dating from 574 to 565 million years ago. The organism took the form of an elongated cone with a central depression, and its apex was anchored to the substrate.
Swartpuntia is a monospecific genus of erniettomorph from the terminal Ediacaran period, with at least three quilted, leaf-shaped petaloids — probably five or six. The petaloids comprise vertical sheets of tubes filled with sand. Swartpuntia specimens range in length from 12 to 19 cm, and in width from 11.5 to 140 cm. The margin is serrated, with a 1 mm wide groove. A 14 mm wide stem extends down the middle, tapering towards the top, and stopping 25 mm from the tip. The stem has a V-shaped ornamentation on it. The original fossils were found at, and named after, the Swartpunt farm between Aus and Rosh Pinah in Namibia. The generic name comes from Swartpunt, meaning black point in reference to the colour of the rocks. The specific name germsi honours Gerard Germs, who studied the Nama formation of geological beds.
Thaumaptilon is a fossil genus of animals from the middle Cambrian Burgess Shale which some authors have compared to members of the Ediacaran biota, generally believed to have disappeared at the start of the Cambrian, 539 million years ago. It was up to 20 cm long, and attached itself to the sea floor with a holdfast.
The Ediacaranbiota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period. These were enigmatic tubular and frond-shaped, mostly sessile, organisms. Trace fossils of these organisms have been found worldwide, and represent the earliest known complex multicellular organisms. The term "Ediacara biota" has received criticism from some scientists due to its alleged inconsistency, arbitrary exclusion of certain fossils, and inability to be precisely defined.
Roger Mason is an English geologist who is best known as the discoverer of the original type fossil, Charnia masoni, of a Precambrian organism that is part of the Ediacaran biota. He is now a professor at the China University of Geosciences in Wuhan, China.
Vendiamorpha is a class of extinct animals within the Ediacaran phylum Proarticulata.
The "ivesheadiomorphs" are a group of fossilised structures known from Ediacaran localities in England and Newfoundland. They are considered to be taphomorphs, representing the poorly preserved biological remains of various contemporary taxa such as Charnia, Charniodiscus, Bradgatia, Primocandelabrum, Pectinifrons and others, that were effaced by partial decay by micro-organisms following death on the seafloor before burial by sediment.
Arborea is a genus of petalonamid that was originally considered as being synonymous with Charniodiscus. It consisted of a frond-like body 3–4 inches (7.6–10.2 cm) long that was attached to the substrate via a holdfast that possessed many concentric rings on it. Species which were thought to have been within the genus Charniodiscus are now being interpreted as belonging to the genus Arborea with the latter of which being considered synonymous with Charniodiscus. A. arborea was first described from South Australia, and is the most abundant petalonamid in the Flinders Ranges. The genus currently contains 5 known species with 3 of them originally being species of Charniodiscus; the species include A. arborea, A. denticulata, A. longa, A. oppositus and A. spinosa.
Avalofractus abaculus is a frond-like rangeomorph fossil described from the Ediacaran of the Trepassey Formation, Spaniard's Bay, Newfoundland.
Noffkarkys is a genus of problematic fossil first found in the Ediacaran Grant Bluff Formation of Central Mount Stuart, Northern Territory, Australia, and another prostrate frond-like fossil. The genus was named in honor of Nora Noffke.
Trepassia is a 579 million-year-old fossil of Ediacaran rangeomorph. It was first discovered by Guy M. Narbonne, a professor at Queen's University in Ontario, Canada and colleagues in 2009. Three years later, Martin D. Brasier added additional description to Trepassia. The generic name is taken from the French word, trépassés, which translates to "those that have departed forever" and honors the Trepassey community in Newfoundland. It was originally described as Charnia wardi; it was referred under this synonym in a 2016 paper.
Hadrynichorde is a frondose organism from the Ediacaran period discovered in Newfoundland, Canada. It is a sessile, benthic marine organism. resembling modern sea whips.
Tina Negus is a British zoologist, painter and poet who is credited as the original discoverer of Charnia, the first ever known Precambrian fossil. A fossil enthusiast since childhood, she found the first specimen of frond-like fossil at Charnwood Forest in Leicestershire during a summer vacation in 1956. She studied zoology, botany and geography at the University of Reading. She took up zoology for her postgraduate degree and her dissertation research on mussel diversity and abundance, published in the Journal of Animal Ecology in 1966, became a fundamental information on the degree of pollution in the River Thames. In recognition of her pioneering work, the University of Reading commissioned the Tina Negus Prize to graduate students of biology since 2019.
