Arkarua
Arkarua adami is a small, Precambrian disk-like fossil with a raised center, a number of radial ridges on the rim, and a five-pointed central depression marked with radial lines of five small dots from the middle of the disk center. Fossils range from 3 to 10 mm in diameter.

Domenic Pennetta · CC BY-SA 4.0 · via Wikipedia/Commons. May be a photograph of a specimen, or an artist’s reconstruction — an interpretation of a skeleton, since colour and soft tissue are almost never preserved.
On record
Recorded, not inferred- Sits inside
- PentaradialomorphaPBDB
- Diet
- suspension feeder, osmotrophPBDB
- Life habit
- low-level epifaunalPBDB
- Motility
- stationary, attachedPBDB
- Environment
- coastal,inner shelf,marinePBDB
Time the record covers
At most 97 million years on record.
Every occurrence read is dated to somewhere between 635 Mya and 538.8 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.
5 occurrences of Arkarua on record. Bar height is expected occurrences, not a count: each fossil is spread across the span it is dated to, so a tall narrow bar means tight dating and a low wide one means loose.
When
5 occurrencesThese are dates about fossils, not the animal: the record can only begin after it arose and end before it died out, so either end may reach further. Shares are expected occurrences: a fossil dated to a span is counted partly in each period it straddles. More on what this infers.
Found in
1 formation
- Rawnsley Quartzite Formation · Wilpena Group5
Loading coastlines…
The named rock units Arkarua has been recovered from, largest first. Drawn where the rock is now, not where it formed.
Found in the same rock
17 taxa- Dickinsonia costata2 sites
- Phyllozoon hanseni2 sites
- Tribrachidium heraldicum2 sites
- <Disc>1 site
- <Frond>1 site
- Archaeaspinus1 site
- Aspidella1 site
- Aulozoon soliorum1 site
- Brachina delicata1 site
- Coronacollina acula1 site
- Inaria karli1 site
- Kimberella quadrata1 site
- Palaeophragmodictya reticulata1 site
- Parvancorina minchami1 site
- Problematica1 site
- Rugochonites sp.1 site
- Rugoconites enigmaticus1 site
The Paleobiology Database records 4 sites for Arkarua, and this reads all of them. The number is how many of those sites it was catalogued from too.
This is not a list of everything alive at the time. It is only what has come out of the same ground as this animal and been written down.
Entered from
4 references- Earliest known echinoderm - a new Ediacaran fossil from the Pound Subgroup of South Australia2
- Supplemental Data for Ediacaran Diversification Rates1
- The rise of animals: Evolution and diversification of the Kingdom Animalia1
- Assemblage palaeoecology of the Ediacara biota: The unabridged edition?1
Each of the 5 occurrences read was entered from one of these publications, ordered by how many each accounts for. This is not a search for papers mentioning the name. Entries link to doi.org where the Paleobiology Database holds an identifier, and to its own record where it does not. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.
Media and terms
Media content1
Picture of Arkarua
- Source
- Wikipedia/Commons
- Credit
- Domenic Pennetta
- Licence
- CC BY-SA 4.0
- Commercial use
- the licence allows it
No 3D scan of Arkarua was found in Sketchfab.
Smithsonian Open Access and MorphoSource were not reached for this taxon, so this list is what the others held rather than everything there is.
The description on this site
- Source
- Wikipedia, “Arkarua”
- Licence
- CC BY-SA 4.0
This is what the site found, which is not the same as what exists.
Keep going
What may have been alongside itPentaradialomorpha through time
Occurrence data from the Paleobiology Database, CC BY 4.0. Gehling 1987