Acoela

Acoela, or the acoels, is an order of small and simple invertebrates in the subphylum Acoelomorpha of phylum Xenacoelomorpha, a deep-branching bilaterian group of animals, which resemble flatworms. Historically, they were treated as an order of turbellarian flatworms. About 400 species are known, but probably many more are not yet described.

Acoela

Samuel Chow · CC BY 2.0 · 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
AcoelomorphaPBDB

Time the record covers

At most 2 million years on record.

Every occurrence read is dated to somewhere between 243.43 Mya and 241.464 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Middle Triassic — about 2 of 2 occurrencesMiddle Triassic243–243 Mya — about 0.1 occurrences243–243 Mya — about 0.1 occurrences243–243 Mya — about 0.1 occurrences243–243 Mya — about 0.1 occurrences243–243 Mya — about 0.1 occurrences243–243 Mya — about 0.1 occurrences243–243 Mya — about 0.1 occurrences243–243 Mya — about 0.1 occurrences243–243 Mya — about 0.1 occurrences243–242 Mya — about 0.1 occurrences242–242 Mya — about 0.1 occurrences242–242 Mya — about 0.1 occurrences242–242 Mya — about 0.1 occurrences242–242 Mya — about 0.1 occurrences242–242 Mya — about 0.1 occurrences242–242 Mya — about 0.1 occurrences242–242 Mya — about 0.1 occurrences242–242 Mya — about 0.1 occurrences242–242 Mya — about 0.1 occurrences242–241 Mya — about 0.1 occurrences243.93 Mya240.96 Mya

2 occurrences of Acoela on record, most of them in the Middle Triassic. The Paleobiology Database records this as a living group, and the chart stops with its fossils rather than at the present. 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

2 occurrences

These 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

Meissner — 50.94°N, 11.25°E

Loading coastlines…

The named rock units Acoela has been recovered from, largest first. Drawn where the rock is now, not where it formed.

Acoela and its relatives

Middle Triassic

Where Acoela and its relatives were recorded in the Middle Triassic.

Found in the same rock

15 taxa

The Paleobiology Database records 1 site for Acoela, 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

1 reference

Each of the 2 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. Each entry links to doi.org. Relayed as the Paleobiology Database holds them, not checked against what they resolve to.

Media and terms

Media content1

Picture of Acoela

Credit
Samuel Chow
Licence
CC BY 2.0
Commercial use
the licence allows it

No 3D scan of Acoela 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

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 itAcoelomorpha through timeFormations of the Middle TriassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0.