Cephalocarida

The Cephalocarida are a class in the subphylum Crustacea comprising only 12 species. Both the nauplii and the adults are benthic. They were discovered in 1955 by Howard L. Sanders, and are commonly referred to as horseshoe shrimp. They have been grouped together with the Remipedia in the Xenocarida. Although a second family, Lightiellidae, is sometimes used, all cephalocaridans are generally considered to belong in just one family: Hutchinsoniellidae. Fossil records of cephalocaridans have been found in the Ordovician Castle Bank site.

Cephalocarida

Eric A. Lazo-Wasem · 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
AllotriocaridaPBDB
Diet
detritivorePBDB
Life habit
low-level epifaunalPBDB
Motility
slow-movingPBDB
Vision
blindPBDB

Time the record covers

At least 24 million years on record.

The record covers at least 493.6 Mya to 469.4 Mya. No occurrence read is dated outside 497 Mya to 458.2 Mya.

Cambrian — about 1 of 2 occurrencesCambrianOrdovician — about 1 of 2 occurrencesOrdovician498–496 Mya — about 0.2 occurrences496–495 Mya — about 0.4 occurrences495–494 Mya — about 0.4 occurrences494–492 Mya — about 0.0 occurrences470–468 Mya — about 0.1 occurrences468–467 Mya — about 0.1 occurrences467–465 Mya — about 0.1 occurrences465–464 Mya — about 0.1 occurrences464–463 Mya — about 0.1 occurrences463–461 Mya — about 0.1 occurrences461–460 Mya — about 0.1 occurrences460–459 Mya — about 0.1 occurrences459–457 Mya — about 0.1 occurrences493.6 Mya469.4 Mya497.8 Mya457.4 Mya

2 occurrences of Cephalocarida 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

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

2 formations

Alum Shale — 58.50°N, 13.17°EGilwern Volcanic — 52.24°N, 3.38°W

Loading coastlines…

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

Cephalocarida and its relatives

Cambrian

Where Cephalocarida and its relatives were recorded in the Cambrian.

Found in the same rock

47 taxa

The Paleobiology Database records 2 sites for Cephalocarida, 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

2 references

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 Cephalocarida

Credit
Eric A. Lazo-Wasem
Licence
CC0
Commercial use
the licence allows it

No 3D scan of Cephalocarida 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 itAllotriocarida through timeFormations of the CambrianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Sanders 1955