Tribrachidium
Tribrachidium is a tri-radially symmetric fossil animal that lived in the late Ediacaran (Vendian) seas. In life, it was hemispherical in form. T. heraldicum is the best known member of the extinct group Trilobozoa.

Aleksey Nagovitsyn ( User:Alnagov ) · CC BY-SA 3.0 · 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
- TriradialomorphaPBDB
- Diet
- osmotrophPBDB
- Life habit
- low-level epifaunalPBDB
- Motility
- stationary, attachedPBDB
- Environment
- 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.
30 occurrences of Tribrachidium 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
30 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
8 formations
- Rawnsley Quartzite Formation · Wilpena Group17
- Verkhovka Formation5
- Zimnie Gory Formation · Ust-Pinega Group2
- Yorga Formation2
- Mezen' Formation1
- Ust-Pinega Formation1
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The named rock units Tribrachidium has been recovered from, largest first. Drawn where the rock is now, not where it formed.
Found in the same rock
120 taxa- Aspidella17 sites
- Dickinsonia costata11 sites
- Parvancorina minchami11 sites
- Dickinsonia tenuis10 sites
- Kimberella quadrata10 sites
- Palaeopascichnus8 sites
- Charniodiscus7 sites
- Yorgia waggoneri7 sites
- Cyanorus singularis6 sites
- Palaeophragmodictya6 sites
- Cephalonega stepanovi5 sites
- Dickinsonia5 sites
- Kimberella5 sites
- Rugoconites5 sites
- Albumares4 sites
- Coronacollina acula4 sites
- Ediacaria4 sites
- Intrites4 sites
- Parvancorina4 sites
- Rugoconites enigmaticus4 sites
- Anfesta3 sites
- Animalia3 sites
- Armillifera3 sites
- Charnia3 sites
The Paleobiology Database records 30 sites for Tribrachidium, and this reads all of them. The number is how many of those sites it was catalogued from too. The 24 sharing the most are listed.
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
18 references- Supplemental Data for Ediacaran Diversification Rates3
- Phyllozoon and Aulozoon : key components of a novel Ediacaran death assemblage in Bathtub Gorge, Heysen Range, South Australia3
- Paleoecological reconstruction of the Ediacaran benthic macroscopic communities of the White Sea (Russia)3
- How well do fossil assemblages of the Ediacara Biota tell time?3
- How diverse were early animal communities? An example from Ediacara Conservation Park, Flinders Ranges, South Australia2
- Patterns of evolution of the Ediacaran soft-bodied biota2
- Assemblage palaeoecology of the Ediacara biota: The unabridged edition?2
- Age of Neoproterozoic bilatarian body and trace fossils, White Sea, Russia: implications for metazoan evolution2
- A new species of the iconic triradial Ediacaran genus Tribrachidium from Nilpena Ediacara National Park, Flinders Ranges (South Australia)1
- Trilobozoan (Tribrachidium and Albumares) Ediacaran organisms from Marwar Supergroup, Western India1
- Piecing together the puzzle of the Ediacara Biota: Excavation and reconstruction at the Ediacara National Heritage site Nilpena (South Australia)1
- The advent of animals: The view from the Ediacaran1
Each of the 30 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. 6 further references are not listed. 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 content2
Picture of Tribrachidium
- Source
- Wikipedia/Commons
- Credit
- Aleksey Nagovitsyn ( User:Alnagov )
- Licence
- CC BY-SA 3.0
- Commercial use
- the licence allows it
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
- 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 itTriradialomorpha through time
Occurrence data from the Paleobiology Database, CC BY 4.0. Glaessner 1959