Illaenurus
Searched as Illaenurus truncatus. The Paleobiology Database treats Illaenurus as the accepted name.

via iDigBio · CC0 · via iDigBio. 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
- IllaenuridaePBDB
- Diet
- carnivorePBDB, for Corynexochida
- Life habit
- nektobenthicPBDB, for Corynexochida
- Motility
- actively mobilePBDB, for Corynexochida
- Vision
- well-developedPBDB, for Illaenuridae
- Environment
- marinePBDB, for Trilobita
Time the record covers
At most 11 million years on record.
Every occurrence read is dated to somewhere between 497 Mya and 486.85 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.
4 occurrences of Illaenurus 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
4 occurrences- Cambrian100%
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
3 formations
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The named rock units Illaenurus has been recovered from, largest first. Drawn where the rock is now, not where it formed.
Illaenurus and its relatives
CambrianWhere Illaenurus and its relatives were recorded in the Cambrian.
Found in the same rock
71 taxa- Clelandia4 sites
- Dikelocephalus minnesotensis3 sites
- Idiomesus3 sites
- Monocheilus3 sites
- Plethopeltis3 sites
- Rasettia magna3 sites
- Saukiella3 sites
- Acheilops2 sites
- Bayfieldia2 sites
- Bayfieldia binodosa2 sites
- Briscoia angustilimba2 sites
- Eurekia2 sites
- Micragnostus insolitus2 sites
- Prosaukia pyrene2 sites
- Saukia2 sites
- Tellerina2 sites
- Aglaspis1 site
- Angulotreta catheta1 site
- Arcifimbrin pahasapaensis1 site
- Billingsella1 site
- Bowmania1 site
- Bowmania lassieae1 site
- Briscoia1 site
- Briscoia coloradoensis1 site
The Paleobiology Database records 17 sites for Illaenurus, 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
3 references- Faunas and stratigraphy of the Snowy Range formation (Upper Cambrian) in southwestern Montana and northwestern Wyoming2
- Trilobites from Minnesota and Wisconsin1
- Trilobites of the Franconia Formation, southeast Minnesota1
Each of the 4 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 Illaenurus
- Source
- iDigBio
- Credit
- via iDigBio
- Licence
- CC0
- Commercial use
- the licence allows it
No 3D scan of Illaenurus 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.
This is what the site found, which is not the same as what exists.
Keep going
What may have been alongside itIllaenuridae through timeFormations of the CambrianThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Hall 1863