Enteropneusta

The acorn worms or Enteropneusta are a hemichordate class of invertebrates. The closest non-hemichordate relatives of the Enteropneusta are the echinoderms. There are 111 known species of acorn worm in the world, the main species for research being Saccoglossus kowalevskii. Two families—Harrimaniidae and Ptychoderidae—separated at least 370 million years ago.

Enteropneusta

Spengel, Johann Wilhelm · Public Domain · 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
HemichordataPBDB

Time the record covers

At least 310 million years on record.

The record covers at least 509.7 Mya to 199.5 Mya. No occurrence read is dated outside 516 Mya to 192.9 Mya.

Cambrian — about 42 of 46 occurrencesCambrianOrdovician — about 0 of 46 occurrencesSilurian — about 0 of 46 occurrencesDevonian — about 0 of 46 occurrencesCarboniferous — about 3 of 46 occurrencesCarboniferousPermian — about 0 of 46 occurrencesEarly Triassic — about 0 of 46 occurrencesMiddle Triassic — about 0 of 46 occurrencesLate Triassic — about 0 of 46 occurrencesEarly Jurassic — about 1 of 46 occurrences522–511 Mya — about 6 occurrences511–500 Mya — about 33 occurrences500–489 Mya — about 4 occurrences321–310 Mya — about 0.2 occurrences310–298 Mya — about 3 occurrences209–198 Mya — about 0.3 occurrences198–186 Mya — about 0.7 occurrences509.7 Mya199.5 Mya522 Mya186 Mya

46 occurrences of Enteropneusta on record, most of them in the Cambrian. 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

46 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

15 formations

Burgess Shale — 51.44°N, 116.47°WBurgess Shale — 51.03°N, 115.83°WKinzers — 40.08°N, 76.35°WKinzers — 40.04°N, 76.31°WKinzers — 40.07°N, 76.37°WWheeler Shale — 39.20°N, 113.30°WWheeler Shale — 39.29°N, 113.31°WCarbondale — 41.22°N, 88.21°WCarbondale — 41.34°N, 88.39°WStephen — 51.17°N, 116.08°WBalang — 28.42°N, 109.42°EKutorgina — 61.13°N, 126.80°ELead Bell Shale — 42.00°N, 112.00°WLower Wheeler Shale — 40.00°N, 113.00°WLombardische Kieselkalk — 46.00°N, 9.08°EMarjum Limestone — 39.22°N, 113.40°WDuchesnay — 50.63°N, 115.60°WRennie Shale — 47.98°N, 116.35°WLatham — 34.59°N, 115.52°WMarjum — 39.27°N, 113.31°W

Loading coastlines…

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

Enteropneusta and its relatives

Cambrian

Where Enteropneusta and its relatives were recorded in the Cambrian.

Found in the same rock

539 taxa

The Paleobiology Database records 39 sites for Enteropneusta, 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

Each of the 46 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 content1

Picture of Enteropneusta

Credit
Spengel, Johann Wilhelm
Licence
Public Domain
Commercial use
the licence allows it

No 3D scan was found. Smithsonian Open Access, MorphoSource and Sketchfab were all searched.

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 itHemichordata through timeFormations of the CambrianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0.