Jugatacaris agilis

Jugatacaris is an extinct genus of bivalved arthropod known from a single species, Jugatacaris agilis found in the Cambrian Stage 3 aged Chengjiang biota of Yunnan, China. The carapace is around 28 to 37 millimetres in length, with a pronounced ridge at the top of the carapace separating the two valves, which formed a fin-like structure raised above the carapace. The head has a pair of stalked eyes, as well as a dumbbell shaped medial eye between them. The head also bore a pair of mandibles as well as at least one and possibly two pairs of antennae. The trunk had up to 65 segments, each with biramous (two-branched) appendages. The appendages had thin endopods with 30 podomeres (segments), each bearing a spiny endite, with the endopods ending with a terminal claw. The appendages also had overlapping flap-like exopods which are elongated, being at maximum eight times as long as they are wide, which on their posterior edge are covered with setae. The trunk ended with a forked tail. It was likely an actively swimming filter feeder, using its constantly beating appendages to sift food from the water column, which was then passed forward along the U-shaped food groove between the appendage pairs towards the mouth. While initially placed as a crustaceanomorph, later studies considered to be a member of Hymenocarina, which contains numerous other similar bivalved Cambrian arthropods.

A picture published with the record for Jugatacaris agilis. What it shows has not been checked.

Qohelet12 · CC BY-SA 4.0 · 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.

Time the record covers

At most 33 million years on record.

Every occurrence read is dated to somewhere between 538.8 Mya and 506.5 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Cambrian — about 2 of 2 occurrencesCambrian539–538 Mya — about 0.0 occurrences538–537 Mya — about 0.1 occurrences537–536 Mya — about 0.1 occurrences536–535 Mya — about 0.1 occurrences535–534 Mya — about 0.1 occurrences534–533 Mya — about 0.1 occurrences533–532 Mya — about 0.1 occurrences532–530 Mya — about 0.1 occurrences530–529 Mya — about 0.1 occurrences529–528 Mya — about 0.1 occurrences528–527 Mya — about 0.1 occurrences527–526 Mya — about 0.1 occurrences526–525 Mya — about 0.1 occurrences525–524 Mya — about 0.1 occurrences524–523 Mya — about 0.1 occurrences523–522 Mya — about 0.1 occurrences522–520 Mya — about 0.1 occurrences520–519 Mya — about 0.1 occurrences519–518 Mya — about 0.1 occurrences518–517 Mya — about 0.1 occurrences517–516 Mya — about 0.1 occurrences516–515 Mya — about 0.1 occurrences515–514 Mya — about 0.1 occurrences514–513 Mya — about 0.1 occurrences513–511 Mya — about 0.1 occurrences511–510 Mya — about 0.1 occurrences510–509 Mya — about 0.1 occurrences509–508 Mya — about 0.1 occurrences508–507 Mya — about 0.1 occurrences507–506 Mya — about 0.0 occurrences539.4 Mya505.9 Mya

2 occurrences of Jugatacaris agilis 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

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

1 formation

Hongjingshao — 24.83°N, 102.83°E

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

Jugatacaris agilis and its relatives

Cambrian

Where Jugatacaris agilis and its relatives were recorded in the Cambrian.

Found in the same rock

14 taxa

The Paleobiology Database records 2 sites for Jugatacaris agilis, and this reads all of them. The number is how many of those sites it was catalogued from too.

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

1 reference

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 Jugatacaris agilis

Credit
Qohelet12
Licence
CC BY-SA 4.0
Commercial use
the licence allows it

No 3D scan of Jugatacaris agilis 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 itFormations of the CambrianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0.