Alligator prenasalis

Alligator prenasalis is an extinct species of alligator from the Late Eocene period. It is well known, with many fossils having been collected from the Chadron and Brule Formations in South Dakota. The species was first named in 1904, but was originally classified as a crocodile in the genus Crocodilus. It was reassigned to the genus Alligator in 1918 on the basis of more complete material. It is the earliest known member of the genus Alligator.

Alligator prenasalis

Ghedoghedo · Public Domain · 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
AlligatorPBDB
Diet
carnivorePBDB, for Crocodylia
Motility
actively mobilePBDB, for Osteichthyes
Environment
marinePBDB, for Mesoeucrocodylia

Time the record covers

At most 5.8 million years on record.

Every occurrence read is dated to somewhere between 39.7 Mya and 33.9 Mya, and nothing in the dating separates them, so that window is what the record shows rather than a span.

Eocene — about 8 of 8 occurrencesEoceneOligocene — about 0 of 8 occurrences40–40 Mya — about 0.1 occurrences40–39 Mya — about 0.1 occurrences39–39 Mya — about 0.1 occurrences39–39 Mya — about 0.1 occurrences39–39 Mya — about 0.1 occurrences39–38 Mya — about 0.1 occurrences38–38 Mya — about 0.1 occurrences38–38 Mya — about 0.1 occurrences38–38 Mya — about 0.1 occurrences38–37 Mya — about 0.1 occurrences37–37 Mya — about 0.1 occurrences37–37 Mya — about 0.1 occurrences37–37 Mya — about 0.5 occurrences37–37 Mya — about 0.5 occurrences37–36 Mya — about 0.5 occurrences36–36 Mya — about 0.5 occurrences36–36 Mya — about 0.5 occurrences36–36 Mya — about 0.5 occurrences36–35 Mya — about 0.5 occurrences35–35 Mya — about 0.5 occurrences35–35 Mya — about 0.5 occurrences35–35 Mya — about 0.5 occurrences35–35 Mya — about 0.5 occurrences35–34 Mya — about 0.5 occurrences34–34 Mya — about 0.5 occurrences34–34 Mya — about 0.4 occurrences40.2 Mya33.4 Mya

8 occurrences of Alligator prenasalis on record, most of them in the Eocene. 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

2 formations

Chadron — 43.60°N, 102.45°WChadron — 43.68°N, 102.82°WChadron — 43.75°N, 102.77°WChadron — 43.78°N, 102.70°WChadron — 43.78°N, 102.55°WSlim Buttes — 45.62°N, 103.93°W

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

Alligator prenasalis and its relatives

Eocene

Where Alligator prenasalis and its relatives were recorded in the Eocene.

Found in the same rock

55 taxa

The Paleobiology Database records 8 sites for Alligator prenasalis, 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

6 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 content2

Picture of Alligator prenasalis

Credit
Ghedoghedo
Licence
Public Domain
Commercial use
the licence allows it

Laser scan

Licence
In Copyright
Commercial use
cannot be read from the licence given — check the record
Specimen
Alligator prenasalis · AMNH:FARB:4994

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 itAlligator through timeFormations of the EoceneThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. (Loomis 1904)