Sphenodontia

Rhynchocephalia is an order of lizard-like reptiles that includes only one living species, the tuatara of New Zealand. Despite its current lack of diversity, during the Mesozoic rhynchocephalians were a speciose group with high morphological and ecological diversity. The oldest record of the group is dated to the Middle Triassic around 244 million years ago, and they had achieved global distribution by the Early Jurassic. Most rhynchocephalians belong to the suborder Sphenodontia ('wedge-teeth'). Their closest living relatives are lizards and snakes in the order Squamata, with the two orders being grouped together in the superorder Lepidosauria.

Sphenodontia

KeresH · CC BY 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
LepidosauriaPBDB
Motility
actively mobilePBDB, for Osteichthyes
Environment
terrestrialPBDB, for Amniota

Time the record covers

At least 155 million years on record.

The record covers at least 227.3 Mya to 72.2 Mya. No occurrence read is dated outside 237 Mya to 66 Mya.

Middle Triassic — about 0 of 178 occurrencesLate Triassic — about 79 of 178 occurrencesLate TriassicEarly Jurassic — about 31 of 178 occurrencesEarly JurassicMiddle Jurassic — about 5 of 178 occurrencesLate Jurassic — about 54 of 178 occurrencesLate JurassicEarly Cretaceous — about 8 of 178 occurrencesEarly CretaceousLate Cretaceous — about 1 of 178 occurrencesLate CretaceousPaleocene — about 0 of 178 occurrences240–234 Mya — about 12 occurrences234–229 Mya — about 28 occurrences229–223 Mya — about 10 occurrences223–217 Mya — about 5 occurrences217–211 Mya — about 8 occurrences211–205 Mya — about 7 occurrences205–199 Mya — about 19 occurrences199–193 Mya — about 5 occurrences193–187 Mya — about 7 occurrences187–181 Mya — about 8 occurrences181–175 Mya — about 2 occurrences175–169 Mya — about 0.8 occurrences169–163 Mya — about 4 occurrences157–152 Mya — about 7 occurrences152–146 Mya — about 35 occurrences146–140 Mya — about 17 occurrences140–134 Mya — about 2 occurrences134–128 Mya — about 0.1 occurrences116–110 Mya — about 0.0 occurrences110–104 Mya — about 0.6 occurrences104–98 Mya — about 0.4 occurrences74–69 Mya — about 0.6 occurrences69–63 Mya — about 0.4 occurrences227.3 Mya72.2 Mya240 Mya63 Mya

178 occurrences of Sphenodontia on record, most of them in the Late Triassic. 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

178 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

36 formations

Morrison — 40.42°N, 109.21°WMorrison — 41.89°N, 106.00°WMorrison — 39.24°N, 109.00°WMorrison — 38.54°N, 105.19°WMorrison — 39.17°N, 108.77°WMorrison — 44.49°N, 107.88°WMorrison — 40.44°N, 109.30°WMorrison — 41.88°N, 106.11°WMorrison — 40.50°N, 109.17°WMorrison — 41.98°N, 106.15°WMorrison — 39.15°N, 108.77°WMorrison — 44.46°N, 104.73°WMorrison — 39.01°N, 111.02°WMorrison — 40.30°N, 108.57°WLa Boca — 26.60°N, 99.52°WSolnhofen — 48.92°N, 11.12°ESolnhofen — 48.90°N, 11.19°ESolnhofen — 48.88°N, 10.95°EMcCoy Brook — 45.40°N, 64.22°WTecovas — 33.43°N, 101.16°WKsar Metlili — 32.70°N, 3.22°WMagnesian Conglomerate — 51.47°N, 2.62°WCaturrita — 29.56°S, 53.45°WCaturrita — 29.69°S, 52.85°WKlettgau — 47.71°N, 8.45°EKlettgau — 47.71°N, 8.45°EKlettgau — 47.51°N, 8.01°ELulworth — 50.60°N, 1.97°WForest Marble — 51.87°N, 1.27°WForest Marble — 50.71°N, 2.78°WForest Marble — 50.68°N, 2.66°WCooper Canyon — 33.52°N, 101.32°WCooper Canyon — 33.00°N, 101.15°WLufeng — 25.15°N, 101.98°ELufeng — 25.18°N, 102.09°EPosidonia Shale — 48.18°N, 8.75°EPosidonia Shale — 48.65°N, 9.53°EPosidonia Shale — 49.16°N, 11.40°EMörnsheim — 48.79°N, 10.90°EMörnsheim — 48.86°N, 10.97°EFleming Fjord — 71.48°N, 22.68°WVinita — 37.46°N, 77.67°WLossiemouth Sandstone — 57.72°N, 3.29°WKota — 19.27°N, 79.52°EKirkwood — 33.44°S, 25.45°EKirkwood — 33.46°S, 25.52°ENugget Sandstone — 40.45°N, 109.24°WKayenta — 35.76°N, 111.08°WChipping Norton Limestone — 51.99°N, 1.80°WChinle — 36.33°N, 106.47°W

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The named rock units Sphenodontia has been recovered from, largest first. Drawn where the rock is now, not where it formed. 12 further formations hold fewer occurrences each and are not listed. 63 occurrences have no formation on record, which is common for older literature.

Sphenodontia and its relatives

Late Triassic

Where Sphenodontia and its relatives were recorded in the Late Triassic.

Found in the same rock

997 taxa

The Paleobiology Database records 122 sites for Sphenodontia, 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

87 references

Each of the 178 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. 75 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 Sphenodontia

Credit
KeresH
Licence
CC BY 3.0
Commercial use
the licence allows it

No 3D scan of Sphenodontia 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 itLepidosauria through timeFormations of the Late TriassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. (Jaekel 1910)