Chondrosteus

Chondrosteus is a genus of extinct marine actinopterygian belonging to the family Chondrosteidae. It lived during the Hettangian and Sinemurian in what is now England. Chondrosteus is related to sturgeons and paddlefishes as part of the clade Acipenseriformes, and is one of the earliest known definitive members of the group. Similar to sturgeons, the jaws of Chondrosteus were free from the rest of the skull. Its scale cover was reduced to the upper lobe of the caudal fin like in paddlefish. It is represented by a single species, C. acipenseroides.

Chondrosteus

Ghedoghedo · 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
ChondrosteidaePBDB
Diet
carnivorePBDB, for Acipenseriformes
Life habit
nektobenthicPBDB, for Acipenseriformes
Motility
actively mobilePBDB, for Acipenseriformes

Time the record covers

At least 107 million years on record.

The record covers at least 192.9 Mya to 85.7 Mya. No occurrence read is dated outside 199.5 Mya to 83.6 Mya.

Late Triassic — about 0 of 9 occurrencesEarly Jurassic — about 8 of 9 occurrencesEarly JurassicMiddle Jurassic — about 0 of 9 occurrencesLate Jurassic — about 0 of 9 occurrencesEarly Cretaceous — about 0 of 9 occurrencesLate Cretaceous — about 1 of 9 occurrencesLate Cretaceous202–198 Mya — about 2 occurrences198–194 Mya — about 5 occurrences194–190 Mya — about 1 occurrence89–85 Mya — about 0.2 occurrences85–81 Mya — about 0.8 occurrences192.9 Mya85.7 Mya202 Mya81 Mya

9 occurrences of Chondrosteus on record, most of them in the Early Jurassic. 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

9 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.

Chondrosteus and its relatives

Early Jurassic

Where Chondrosteus and its relatives were recorded in the Early Jurassic.

Found in the same rock

104 taxa

The Paleobiology Database records 5 sites for Chondrosteus, 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

4 references

Each of the 9 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 Chondrosteus

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

No 3D scan of Chondrosteus 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.

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 itChondrosteidae through timeFormations of the Early JurassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Agassiz 1843