Polycotylidae

Polycotylidae is a family of plesiosaurs from the Cretaceous. Polycotylids first appeared during the Albian stage of the Early Cretaceous, before becoming abundant and widespread during the early Late Cretaceous. Several species survived into the final stage of the Cretaceous, the Maastrichtian, around 72-66 million years ago. The possible latest surviving member Rarosaurus from the late Maastrichtian is more likely a crocodylomorph.

Polycotylidae

MCDinosaurhunter · 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
PlesiosauroideaPBDB
Diet
carnivorePBDB, for Plesiosauria
Life habit
aquatic, depth=surfacePBDB, for Plesiosauria
Motility
actively mobilePBDB, for Plesiosauria
Environment
marinePBDB, for Plesiosauria

Time the record covers

At least 77 million years on record.

The record covers at least 149.2 Mya to 72.2 Mya. No occurrence read is dated outside 152.21 Mya to 66 Mya.

Late Jurassic — about 1 of 100 occurrencesLate JurassicEarly Cretaceous — about 6 of 100 occurrencesEarly CretaceousLate Cretaceous — about 93 of 100 occurrencesLate CretaceousPaleocene — about 0 of 100 occurrences154–151 Mya — about 0.4 occurrences151–148 Mya — about 0.6 occurrences124–121 Mya — about 0.0 occurrences121–118 Mya — about 0.6 occurrences118–115 Mya — about 0.8 occurrences115–112 Mya — about 0.9 occurrences112–109 Mya — about 0.6 occurrences109–106 Mya — about 0.1 occurrences106–103 Mya — about 2 occurrences103–100 Mya — about 2 occurrences100–97 Mya — about 5 occurrences97–94 Mya — about 5 occurrences94–91 Mya — about 15 occurrences91–88 Mya — about 10 occurrences88–85 Mya — about 7 occurrences85–82 Mya — about 11 occurrences82–79 Mya — about 8 occurrences79–76 Mya — about 8 occurrences76–73 Mya — about 8 occurrences73–70 Mya — about 7 occurrences70–67 Mya — about 6 occurrences67–64 Mya — about 3 occurrences149.2 Mya72.2 Mya154 Mya64 Mya

100 occurrences of Polycotylidae on record, most of them in the Late Cretaceous. 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

100 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

37 formations

Niobrara — 38.91°N, 101.18°WNiobrara — 38.91°N, 101.49°WNiobrara — 38.91°N, 101.32°WNiobrara — 38.91°N, 101.59°WNiobrara — 38.95°N, 101.16°WNiobrara — 43.41°N, 103.31°WPierre Shale — 43.40°N, 104.17°WPierre Shale — 43.01°N, 103.30°WPierre Shale — 38.88°N, 101.20°WPierre Shale — 43.24°N, 104.29°WPierre Shale — 43.19°N, 103.61°WPierre Shale — 43.25°N, 104.26°WGreenhorn Limestone — 37.22°N, 103.60°WGreenhorn Limestone — 39.53°N, 97.66°WGreenhorn Limestone — 38.91°N, 98.53°WGreenhorn Limestone — 38.78°N, 99.22°WGreenhorn Limestone — 39.16°N, 98.33°WGreenhorn Limestone — 44.65°N, 103.58°WConway — 43.06°S, 172.58°EConway — 42.57°S, 173.52°EConway — 43.05°S, 172.58°ETropic Shale — 37.29°N, 112.69°WTropic Shale — 37.08°N, 111.66°WTropic Shale — 37.00°N, 111.67°WCarlile Shale — 39.38°N, 98.54°WCarlile Shale — 38.87°N, 99.18°WCarlile Shale — 38.91°N, 98.81°WCarlile Shale — 39.10°N, 99.04°WCarlile Shale — 38.88°N, 97.37°WLa Colonia — 43.01°S, 67.62°WLa Colonia — 42.96°S, 67.52°WPierre Shale — 49.22°N, 98.20°WPierre Shale — 53.30°N, 102.30°WMesaverde — 44.12°N, 107.76°WRybushka — 51.35°N, 45.04°ERybushka — 44.68°N, 39.08°EAkrabou — 31.85°N, 4.93°WSanta Marta — 63.83°S, 57.95°WSanta Marta — 63.82°S, 57.88°WAllen — 40.03°S, 66.82°WAllen — 40.06°S, 66.80°WAgua Nueva — 26.66°N, 100.04°WAgua Nueva — 26.75°N, 100.05°WSharon Springs — 43.28°N, 104.13°WSharon Springs — 43.41°N, 103.31°WFrontier — 42.83°N, 108.02°WBelle Fourche — 53.21°N, 103.52°WJudith River — 50.50°N, 107.83°WMooreville Chalk — 32.96°N, 88.13°WConway Siltstone — 42.55°S, 173.50°ELake Waco — 31.60°N, 97.22°WThermopolis Shale — 45.40°N, 108.77°WBearpaw Shale — 51.63°N, 108.36°WFavel — 49.74°N, 98.76°W

Loading coastlines…

The named rock units Polycotylidae has been recovered from, largest first. Drawn where the rock is now, not where it formed. 13 further formations hold fewer occurrences each and are not listed. 20 occurrences have no formation on record, which is common for older literature.

Polycotylidae and its relatives

Late Cretaceous

Where Polycotylidae and its relatives were recorded in the Late Cretaceous.

Found in the same rock

326 taxa

The Paleobiology Database records 96 sites for Polycotylidae, 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

65 references

Each of the 100 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. 53 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 content2

Picture of Polycotylidae

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

Laser scan

Licence
not stated by the source
Commercial use
cannot be read from the licence given — check the record
Specimen
Polycotylidae indet. · qm:f:18041

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 itPlesiosauroidea through timeFormations of the Late CretaceousThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Williston 1908