Acmarhachis

Acmarhachis is a genus of trilobites in the order Agnostida, which lived in what are now Australia, Canada, China (Anhui), Kazakhstan, Russia (Kharaulakh), and the US. It was described by Resser in 1938, and the type species is Acmarhachis typicalis.

Acmarhachis

我是一隻北極熊 · CC BY-SA 4.0 · via Wikidata/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
AgnostidaePBDB
Diet
detritivorePBDB, for Agnostida
Life habit
epifaunalPBDB, for Agnostida
Motility
slow-movingPBDB, for Agnostida
Vision
blindPBDB, for Agnostidae

Time the record covers

At least 6 million years on record.

The record covers at least 497 Mya to 491 Mya. No occurrence read is dated outside 504.5 Mya to 477.1 Mya.

Cambrian — about 78 of 79 occurrencesCambrianOrdovician — about 1 of 79 occurrencesOrdovician505–504 Mya — about 0.1 occurrences504–503 Mya — about 0.1 occurrences503–502 Mya — about 0.1 occurrences502–501 Mya — about 0.1 occurrences501–500 Mya — about 0.9 occurrences500–499 Mya — about 5 occurrences499–498 Mya — about 11 occurrences498–497 Mya — about 12 occurrences497–496 Mya — about 8 occurrences496–496 Mya — about 4 occurrences496–495 Mya — about 4 occurrences495–494 Mya — about 5 occurrences494–493 Mya — about 4 occurrences493–492 Mya — about 8 occurrences492–491 Mya — about 4 occurrences491–490 Mya — about 3 occurrences490–489 Mya — about 3 occurrences489–488 Mya — about 3 occurrences488–487 Mya — about 3 occurrences487–486 Mya — about 0.5 occurrences486–485 Mya — about 0.1 occurrences485–484 Mya — about 0.1 occurrences484–483 Mya — about 0.1 occurrences483–482 Mya — about 0.1 occurrences482–481 Mya — about 0.1 occurrences481–480 Mya — about 0.1 occurrences480–479 Mya — about 0.1 occurrences479–478 Mya — about 0.1 occurrences478–478 Mya — about 0.1 occurrences478–477 Mya — about 0.0 occurrences497 Mya491 Mya505 Mya476.6 Mya

79 occurrences of Acmarhachis 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

79 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

Zhumabai — 43.53°N, 69.95°ERabbitkettle — 62.70°N, 128.38°WRabbitkettle — 63.37°N, 128.60°WHuaqiao — 28.39°N, 109.53°EHuaqiao — 28.72°N, 109.97°EHuaqiao — 29.10°N, 110.92°EMachari — 37.31°N, 128.44°EShallow Bay — 49.92°N, 57.83°WShallow Bay — 49.83°N, 57.85°WShallow Bay — 49.92°N, 57.90°WSpurs — 71.34°S, 163.21°EBestogai — 43.53°N, 69.95°EFrederick Limestone — 39.41°N, 77.41°WHuayansi — 28.82°N, 118.60°EChatsworth — 21.94°S, 140.33°ERaiff Limestone — 39.40°N, 114.78°WVal d'Homs — 43.00°N, 3.00°ENopah — 39.00°N, 116.00°WOgon'or — 71.28°N, 127.63°EWeeks — 39.22°N, 113.40°W

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

Acmarhachis and its relatives

Cambrian

Where Acmarhachis and its relatives were recorded in the Cambrian.

Found in the same rock

232 taxa

The Paleobiology Database records 32 sites for Acmarhachis, 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

16 references

Each of the 79 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. 4 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 Acmarhachis

Credit
我是一隻北極熊
Licence
CC BY-SA 4.0
Commercial use
the licence allows it

No 3D scan of Acmarhachis 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 itAgnostidae through timeFormations of the CambrianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Resser 1938