Xandarella

Xandarella is an extinct genus of xandarellid artiopodan known from the Cambrian of China, the type species Xandarella spectaculum was described in 1991 from the Cambrian Stage 3 aged Chengjiang Biota in China. Although an additional species Xandarella mauretanica was described from the Cambrian Stage 5 Tatelt Formation in Morocco in 2017, which preserved only the ventral anatomy, it is later found that is a species of trilobite Gigoutella instead. Like other xandarellids, the exoskeleton is unmineralised. The cephalon has pronounced eye slits, presumably derived from ancestral ventral stalked eyes.

Xandarella

Woudloper · 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.

On record

Recorded, not inferred
Sits inside
PetalopleuraPBDB
Life habit
epifaunalPBDB
Motility
actively mobilePBDB, for Arthropoda
Vision
well-developedPBDB

Time the record covers

At most 8.9 million years on record.

Every occurrence read is dated to somewhere between 521 Mya and 512.1 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Cambrian — about 15 of 15 occurrencesCambrian521–521 Mya — about 0.4 occurrences521–521 Mya — about 0.8 occurrences521–520 Mya — about 0.8 occurrences520–520 Mya — about 0.8 occurrences520–520 Mya — about 0.8 occurrences520–519 Mya — about 0.8 occurrences519–519 Mya — about 0.8 occurrences519–519 Mya — about 0.8 occurrences519–518 Mya — about 0.8 occurrences518–518 Mya — about 0.8 occurrences518–518 Mya — about 0.8 occurrences518–517 Mya — about 0.8 occurrences517–517 Mya — about 0.8 occurrences517–517 Mya — about 0.8 occurrences517–516 Mya — about 0.8 occurrences516–516 Mya — about 0.7 occurrences516–516 Mya — about 0.4 occurrences516–515 Mya — about 0.4 occurrences515–515 Mya — about 0.4 occurrences515–515 Mya — about 0.4 occurrences515–514 Mya — about 0.1 occurrences514–514 Mya — about 0.1 occurrences514–514 Mya — about 0.1 occurrences514–513 Mya — about 0.1 occurrences513–513 Mya — about 0.1 occurrences513–513 Mya — about 0.1 occurrences513–512 Mya — about 0.1 occurrences512–512 Mya — about 0.0 occurrences521.5 Mya511.6 Mya

15 occurrences of Xandarella 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

15 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

4 formations

Yuanshan — 24.81°N, 102.58°EYuanshan — 24.84°N, 102.41°EYu'anshan — 25.33°N, 103.50°EYu'anshan — 24.77°N, 102.58°EQiongzhusi — 24.65°N, 102.97°EQiongzhusi — 24.63°N, 102.95°EMarsden Sandstone — 35.58°S, 137.50°E

Loading coastlines…

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

Xandarella and its relatives

Cambrian

Where Xandarella and its relatives were recorded in the Cambrian.

Found in the same rock

259 taxa

The Paleobiology Database records 13 sites for Xandarella, 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

8 references

Each of the 15 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 Xandarella

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

No 3D scan of Xandarella 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 itPetalopleura through timeFormations of the CambrianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Hou et al. 1991