Alalcomenaeus

Alalcomenaeus is one of the most widespread and longest-surviving arthropod genera of the Early and Middle Cambrian. Known from over 300 specimens in the Burgess Shale and the Chengjiang biota. It is a member of the family Leanchoiliidae in the group Megacheira.

Alalcomenaeus

Jean-Bernard Caron · CC0 · 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
LeanchoiliidaePBDB
Diet
carnivorePBDB
Life habit
nektobenthicPBDB
Motility
actively mobilePBDB

Time the record covers

At most 18 million years on record.

Every occurrence read is dated to somewhere between 514.5 Mya and 497 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Cambrian — about 12 of 12 occurrencesCambrian515–514 Mya — about 0.0 occurrences514–514 Mya — about 0.1 occurrences514–513 Mya — about 0.1 occurrences513–513 Mya — about 0.1 occurrences513–512 Mya — about 0.1 occurrences512–511 Mya — about 0.1 occurrences511–511 Mya — about 0.1 occurrences511–510 Mya — about 0.1 occurrences510–509 Mya — about 0.6 occurrences509–509 Mya — about 1 occurrence509–508 Mya — about 1 occurrence508–508 Mya — about 1 occurrence508–507 Mya — about 1 occurrence507–506 Mya — about 1 occurrence506–506 Mya — about 1 occurrence506–505 Mya — about 1 occurrence505–505 Mya — about 0.1 occurrences505–504 Mya — about 0.1 occurrences504–503 Mya — about 0.1 occurrences503–503 Mya — about 0.1 occurrences503–502 Mya — about 0.1 occurrences502–501 Mya — about 0.1 occurrences501–501 Mya — about 0.1 occurrences501–500 Mya — about 0.1 occurrences500–500 Mya — about 0.1 occurrences500–499 Mya — about 0.1 occurrences499–498 Mya — about 0.1 occurrences498–498 Mya — about 0.1 occurrences498–497 Mya — about 0.1 occurrences497–497 Mya — about 0.0 occurrences515 Mya496.5 Mya

12 occurrences of Alalcomenaeus on record, most of them in the Cambrian. 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

12 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

2 formations

Burgess Shale — 51.44°N, 116.47°WBurgess Shale — 51.39°N, 116.43°WBalang — 28.42°N, 109.42°E

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

Alalcomenaeus and its relatives

Cambrian

Where Alalcomenaeus and its relatives were recorded in the Cambrian.

Found in the same rock

229 taxa

The Paleobiology Database records 11 sites for Alalcomenaeus, 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

4 references

Each of the 12 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 Alalcomenaeus

Credit
Jean-Bernard Caron
Licence
CC0
Commercial use
the licence allows it

No 3D scan of Alalcomenaeus was found in MorphoSource and Sketchfab.

Smithsonian Open Access was 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 itLeanchoiliidae through timeFormations of the CambrianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Simonetta 1970