Yuknessia

Yuknessia is an early pterobranch, known from the Burgess Shale and the Wheeler Shale. Long, unbranched fronds emerge from a central holdfast-like body covered in small conical plates. 23 specimens of Yuknessia are known from the Greater Phyllopod bed, where they comprise < 0.1% of the community. The genus contains two species: the type species Y. simplex and Y. stephenensis. It was originally interpreted as a green alga, and has since been reinterpreted it as a colonial pterobranch.

Yuknessia

瑞丽江的河水 · 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
PterobranchiaPBDB

Time the record covers

At least 21 million years on record.

The record covers at least 525.5 Mya to 504.5 Mya. No occurrence read is dated outside 538.8 Mya to 497 Mya.

Cambrian — about 17 of 17 occurrencesCambrian540–538 Mya — about 0.0 occurrences538–537 Mya — about 0.1 occurrences537–535 Mya — about 0.1 occurrences535–534 Mya — about 0.1 occurrences534–532 Mya — about 0.1 occurrences532–531 Mya — about 0.1 occurrences531–529 Mya — about 0.1 occurrences529–528 Mya — about 0.1 occurrences528–527 Mya — about 0.1 occurrences527–525 Mya — about 0.1 occurrences522–521 Mya — about 0.1 occurrences521–519 Mya — about 0.6 occurrences519–518 Mya — about 0.6 occurrences518–516 Mya — about 0.6 occurrences516–515 Mya — about 0.2 occurrences511–509 Mya — about 1 occurrence509–508 Mya — about 4 occurrences508–506 Mya — about 4 occurrences506–505 Mya — about 3 occurrences505–503 Mya — about 0.1 occurrences503–502 Mya — about 0.2 occurrences502–501 Mya — about 0.2 occurrences501–499 Mya — about 0.2 occurrences499–498 Mya — about 0.2 occurrences498–496 Mya — about 0.1 occurrences525.5 Mya504.5 Mya539.6 Mya496.2 Mya

17 occurrences of Yuknessia 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

17 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

6 formations

Burgess Shale — 51.44°N, 116.47°WBurgess Shale — 51.38°N, 116.43°WLead Bell Shale — 42.00°N, 112.00°WNiutitang — 27.60°N, 106.71°EYuanshan — 25.40°N, 103.38°EMarjum Limestone — 39.22°N, 113.40°WYanjiahe — 30.73°N, 111.08°E

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

Yuknessia and its relatives

Cambrian

Where Yuknessia and its relatives were recorded in the Cambrian.

Found in the same rock

192 taxa

The Paleobiology Database records 15 sites for Yuknessia, 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

7 references

Each of the 17 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 Yuknessia

Credit
瑞丽江的河水
Licence
CC BY-SA 4.0
Commercial use
the licence allows it

No 3D scan of Yuknessia 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 itPterobranchia through timeFormations of the CambrianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Walcott 1919