Sphaeragnostus

Sphaeragnostus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It can be recognized by having two thorax segments, a totally effaced headshield, while the tailshield although effaced, has a clear furrow parallel to its border, and a short, convex, subcircular axis. It lived during the Ordovician.

Sphaeragnostus

Dwergenpaartje · CC BY-SA 3.0 · 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
PeronopsidaePBDB
Diet
suspension feederPBDB, for Agnostoidea
Life habit
nektonicPBDB, for Agnostoidea
Motility
actively mobilePBDB, for Agnostoidea
Vision
blindPBDB, for Peronopsidae
Environment
marinePBDB, for Agnostoidea

Time the record covers

At least 14 million years on record.

The record covers at least 463.3 Mya to 448.8 Mya. No occurrence read is dated outside 469.4 Mya to 443.1 Mya.

Ordovician — about 22 of 22 occurrencesOrdovicianSilurian — about 0 of 22 occurrences470–469 Mya — about 0.1 occurrences469–468 Mya — about 0.1 occurrences468–467 Mya — about 0.1 occurrences467–466 Mya — about 0.1 occurrences466–465 Mya — about 0.1 occurrences465–464 Mya — about 0.1 occurrences464–464 Mya — about 0.1 occurrences464–463 Mya — about 0.0 occurrences462–461 Mya — about 0.2 occurrences461–460 Mya — about 1 occurrence460–459 Mya — about 0.5 occurrences459–458 Mya — about 0.3 occurrences458–457 Mya — about 0.5 occurrences457–456 Mya — about 0.5 occurrences456–455 Mya — about 0.5 occurrences455–454 Mya — about 0.5 occurrences454–454 Mya — about 0.8 occurrences454–453 Mya — about 1 occurrence453–452 Mya — about 0.7 occurrences452–451 Mya — about 0.7 occurrences451–450 Mya — about 0.8 occurrences450–449 Mya — about 2 occurrences449–448 Mya — about 2 occurrences448–447 Mya — about 2 occurrences447–446 Mya — about 2 occurrences446–445 Mya — about 2 occurrences445–444 Mya — about 0.6 occurrences444–443 Mya — about 0.4 occurrences443–443 Mya — about 0.2 occurrences463.3 Mya448.8 Mya469.9 Mya442.6 Mya

22 occurrences of Sphaeragnostus on record, most of them in the Ordovician. 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

22 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

13 formations

Tangtou — 32.00°N, 118.00°ETangtou — 32.00°N, 119.00°ETangtou — 32.07°N, 119.26°ESaergan — 40.64°N, 79.50°EGrande Coupe — 48.54°N, 64.25°WJerrestad — 55.71°N, 13.28°EJerrestad — 55.43°N, 13.30°EJerrestad Shale — 55.54°N, 14.29°EDwyfor Mudstone — 53.00°N, 4.00°WSarka — 50.00°N, 14.00°EDobrotiva — 50.00°N, 14.00°EHuangnigang — 29.00°N, 119.00°EJerrestad — 55.06°N, 14.89°EWolka — 50.77°N, 20.57°EPyle Mountain Argillite — 46.68°N, 68.22°WDomusnovas — 39.33°N, 8.67°E

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The named rock units Sphaeragnostus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 3 occurrences have no formation on record, which is common for older literature.

Sphaeragnostus and its relatives

Ordovician

Where Sphaeragnostus and its relatives were recorded in the Ordovician.

Found in the same rock

468 taxa

The Paleobiology Database records 22 sites for Sphaeragnostus, 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

15 references

Each of the 22 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. 3 further references are not listed. 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 Sphaeragnostus

Credit
Dwergenpaartje
Licence
CC BY-SA 3.0
Commercial use
the licence allows it

No 3D scan of Sphaeragnostus 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 itPeronopsidae through timeFormations of the OrdovicianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Cooper and Kindle 1936