Lepidosauromorpha
Lepidosauromorpha is a group of reptiles comprising all diapsids closer to lizards than to archosaurs. The only living sub-group is the Lepidosauria, which contains two subdivisions, Squamata, which contains lizards and snakes, and Rhynchocephalia, the only extant species of which is the tuatara.

Neil Pezzoni · 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
- SauriaPBDB
- Motility
- actively mobilePBDB, for Osteichthyes
- Environment
- terrestrialPBDB, for Amniota
Time the record covers
At least 250 million years on record.
The record covers at least 250.8 Mya to 11.7 ka. No occurrence read is dated outside 251.902 Mya to 0 Mya.
439 occurrences of Lepidosauromorpha on record, most of them in the Late Triassic. The Paleobiology Database records this as a living group. 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
439 occurrences- Early Triassic3%
- Middle Triassic4%
- Late Triassic37%
- Early Jurassic12%
- Middle Jurassic5%
- Late Jurassic21%
- Early Cretaceous8%
- Late Cretaceous6%
- Paleoceneunder 1%
- Eoceneunder 1%
- Mioceneunder 1%
- Plioceneunder 1%
- Pleistoceneunder 1%
- Holocene3%
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
94 formations
- Morrison Formation40
- Hell Creek Formation · Montana Group18
- La Boca Formation · Huizachal Group14
- Chinle Formation13
- Forest Marble Formation · Great Oolite Group12
- Tecovas Formation · Chinle Group10
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The named rock units Lepidosauromorpha has been recovered from, largest first. Drawn where the rock is now, not where it formed. 70 further formations hold fewer occurrences each and are not listed. 134 occurrences have no formation on record, which is common for older literature.
Lepidosauromorpha and its relatives
Late TriassicWhere Lepidosauromorpha and its relatives were recorded in the Late Triassic.
Found in the same rock
1,870 taxa- Lepidosauria51 sites
- Theropoda46 sites
- Mammalia31 sites
- Sphenodontia31 sites
- Pterosauria25 sites
- Caudata24 sites
- Testudines22 sites
- Crocodylomorpha21 sites
- Sphenodontidae21 sites
- Actinopterygii20 sites
- Archosauria20 sites
- Anura18 sites
- Goniopholis18 sites
- Ornithischia18 sites
- Ceratopsidae17 sites
- Squamata17 sites
- Trionychidae17 sites
- Borealosuchus sternbergii16 sites
- Clevosaurus16 sites
- Crocodylia16 sites
- Cyclurus fragosus15 sites
- Lepisosteus occidentalis15 sites
- Osteichthyes15 sites
- Rhynchocephalia15 sites
The Paleobiology Database records 285 sites for Lepidosauromorpha, and this reads 240 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
221 references- Assemblages of small tetrapods from British Late Triassic fissure deposits22
- The ecology of a Late Triassic reptile assemblage from Gloucestershire, England19
- Vertebrate biostratigraphy of the Hell Creek Formation in southwestern North Dakota and northwestern South Dakota16
- Paleoecological analysis of the vertebrate fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain region, U.S.A.14
- Les rhynchocephales et les pterosauriens a crete parietale du Kimeridgien superieur-Berriasien d'Europe occidentale: le gisement de Canjuers (Var-France) et ses abords14
- Quaternary fossil fauna of South Canterbury, South Island, New Zealand11
- Mesozoic lepidosauromorphs of Mexico: a review and discussion of taxonomic assignments10
- Late Triassic microvertebrates from the lower Chinle Group (Otischalkian-Adamanian: Carnian), southwestern U.S.A.8
- Middle Jurassic microvertebrate assemblages from the British Isles8
- Les Rhynchocéphales et les Sauriens des Calcaires lithographiques (Jurassique supérieur) d’Europe occidentale7
- The Late Triassic lepidosaur fauna from Hallau, North-Eastern Switzerland, and a new ‘basal’ rhynchocephalian Deltadectes elvetica gen. et sp. nov.6
- New Triassic sphenodontids from south-west England and a review of their classification6
Each of the 439 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. 209 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 Lepidosauromorpha
- Source
- Wikipedia/Commons
- Credit
- Neil Pezzoni
- Licence
- CC BY 3.0
- Commercial use
- the licence allows it
CT scan
- Source
- MorphoSource
- Licence
- In Copyright
- Commercial use
- cannot be read from the licence given — check the record
- Specimen
- Lepidosauromorpha species A · nms:g:2019.34.9
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 itSauria through timeFormations of the Late TriassicThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. (Benton 1983)