Arkarua adami (lat.) Is a small Precambrian disk-shaped fossil with a raised center, with radial ridges along the rim and a five-pointed recess in the center, where each of the five radial lines has five point recesses from the middle of the disk to the center. Fossils have a diameter of 3 to 10 mm.
| † Arkarua adami |
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| Scientific classification |
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| No rank : | † Pentaradialomorpha |
| Gender: | † Arkarua Gehling, 1987 |
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| International scientific name |
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Arkarua adami Gehling, 1987 |
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Arkarua are only known in the Ediacar Flinders sediments in South Australia . The generic name comes from Arkaru, the mythical giant snake of the local Aboriginal people.
All known Arkarua samples are casts that do not provide information on the internal structure, which makes taxonomy problematic. Due to five-beam symmetry, Arkarua is preliminarily placed in the echinoderm type. By flattened form in the form of a disk or a button in combination with its five-beam symmetry, some researchers attribute it to the class of edrioasteroids (Edrioasteroidea).
This identification remains doubtful, since it is impossible to detect either a madrepore plate or a characteristic mineralized skeleton of calcium carbonate (stereoma) in fossils. The listed two signs are classification signs of echinoderms, and at least one of them is present in all echinoderms.