Agnatha

Agnatha or jawless fish is a paraphyletic infraphylum of animals in the subphylum Vertebrata of the phylum Chordata, characterized by the lack of jaws. The group consists of both living and extinct clades. They are sister to vertebrates with jaws known as gnathostomes, who evolved from jawless ancestors during the early Silurian by developing folding articulations in the first pairs of gill arches.

Agnatha

Geomyces.destructans · 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
Also called
jawless fishPBDB
Sits inside
VertebrataPBDB
Motility
actively mobilePBDB, for Chordata

Time the record covers

At least 63 million years on record.

The record covers at least 473.8 Mya to 410.62 Mya. No occurrence read is dated outside 477.1 Mya to 393.47 Mya.

Ordovician — about 2 of 8 occurrencesOrdovicianSilurian — about 3 of 8 occurrencesSilurianDevonian — about 3 of 8 occurrencesDevonian479–476 Mya — about 0.4 occurrences476–473 Mya — about 0.6 occurrences447–444 Mya — about 0.6 occurrences444–441 Mya — about 0.4 occurrences429–427 Mya — about 1 occurrence427–424 Mya — about 2 occurrences424–421 Mya — about 0.4 occurrences421–418 Mya — about 0.1 occurrences418–415 Mya — about 0.1 occurrences415–412 Mya — about 0.1 occurrences412–409 Mya — about 0.3 occurrences409–406 Mya — about 0.4 occurrences406–403 Mya — about 0.4 occurrences403–400 Mya — about 0.4 occurrences400–398 Mya — about 0.4 occurrences398–395 Mya — about 0.4 occurrences395–392 Mya — about 0.2 occurrences473.8 Mya410.62 Mya479 Mya392 Mya

8 occurrences of Agnatha on record, most of them in the Silurian. The Paleobiology Database records this as a living group, and the chart stops with its fossils rather than at the present. 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

8 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

7 formations

Nanook — 69.52°N, 145.63°WVesiku Beds — 59.07°N, 24.79°ESauvere — 59.07°N, 24.79°EHimmiste — 59.07°N, 24.79°EPircancha — 21.17°S, 65.08°WCedarburg — 32.30°S, 18.97°EWahnbach Shale — 50.95°N, 7.30°E

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

Agnatha and its relatives

Silurian

Where Agnatha and its relatives were recorded in the Silurian.

Found in the same rock

56 taxa

The Paleobiology Database records 8 sites for Agnatha, 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

5 references

Each of the 8 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 Agnatha

Credit
Geomyces.destructans
Licence
CC BY-SA 3.0
Commercial use
the licence allows it

No 3D scan of Agnatha 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 itVertebrata through timeFormations of the SilurianThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. (Cope 1889)