Arachnomorpha

Arachnomorpha is a proposed subdivision or clade of Arthropoda, comprising the group formed by the trilobites and their close relatives (Artiopoda), Megacheira and chelicerates. Under this proposed classification scheme, Arachnomorpha is considered the sister group to Mandibulata.

Arachnomorpha

Dwergenpaartje · 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
Also called
trilobite-likePBDB
Sits inside
ArthropodaPBDB
Motility
actively mobilePBDB, for Arthropoda

Time the record covers

At least 473 million years on record.

The record covers at least 497 Mya to 23.04 Mya. No occurrence read is dated outside 506.5 Mya to 15.98 Mya.

Cambrian — about 8 of 9 occurrencesOrdovician — about 0 of 9 occurrencesSilurian — about 0 of 9 occurrencesDevonian — about 0 of 9 occurrencesCarboniferous — about 0 of 9 occurrencesPermian — about 0 of 9 occurrencesEarly Triassic — about 0 of 9 occurrencesMiddle Triassic — about 0 of 9 occurrencesLate Triassic — about 0 of 9 occurrencesEarly Jurassic — about 0 of 9 occurrencesMiddle Jurassic — about 0 of 9 occurrencesLate Jurassic — about 0 of 9 occurrencesEarly Cretaceous — about 0 of 9 occurrencesLate Cretaceous — about 0 of 9 occurrencesPaleocene — about 0 of 9 occurrencesEocene — about 0 of 9 occurrencesOligocene — about 0 of 9 occurrencesMiocene — about 1 of 9 occurrences516–499 Mya — about 6 occurrences499–482 Mya — about 2 occurrences23–6.2 Mya — about 1 occurrence497 Mya23.04 Mya516 Mya6 Mya

9 occurrences of Arachnomorpha 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

9 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

3 formations

Marjum — 39.25°N, 113.36°WMarjum — 38.82°N, 113.23°WMarjum — 39.27°N, 113.31°WWheeler Shale — 39.31°N, 113.29°WWheeler — 39.40°N, 113.28°W

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The named rock units Arachnomorpha has been recovered from, largest first. Drawn where the rock is now, not where it formed. 1 occurrence has no formation on record, which is common for older literature.

Arachnomorpha and its relatives

Cambrian

Where Arachnomorpha and its relatives were recorded in the Cambrian.

Found in the same rock

169 taxa

The Paleobiology Database records 7 sites for Arachnomorpha, 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

3 references

Each of the 9 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 Arachnomorpha

Credit
Dwergenpaartje
Licence
CC BY-SA 3.0
Commercial use
the licence allows it

No 3D scan of Arachnomorpha 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 itArthropoda through timeFormations of the CambrianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Lameere 1890