Paramacellodidae

Paramacellodidae is an extinct family of lizards that first appeared in the Middle Jurassic around 170 million years ago (Ma) and became extinct at the end of the Cretaceous around 66 Ma. It was one of the earliest groups of lizards to have undergone an evolutionary radiation, with members found across the supercontinent Laurasia. The phylogenetic relationships and constituent species of Paramacellodidae are uncertain. Many studies regard them to be scincomorphs, a large group that includes skinks and their closest extinct relatives, and possibly also to Cordyoidea, a group that includes spinytail lizards and relatives. Like modern skinks, paramacelloidids had rectangular bony plates called osteoderms covering most of their bodies, including their backs, undersides, and tails. They also had short and robust limbs. Paramacellodids are distinguished from other lizards by the combination two traits in their dentition, the teeth are labiolingually expanded at their bases, and the tooth apices are lingually concave.

Paramacellodidae

Chase D. Brownstein, Dalton L. Meyer, Matteo Fabbri, Bhart-Anjan S. Bhullar & Jacques A. Gauthier · CC BY 4.0 · 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
ScincoideaPBDB
Motility
actively mobilePBDB, for Osteichthyes
Environment
terrestrialPBDB, for Amniota

Time the record covers

At least 93 million years on record.

The record covers at least 165.3 Mya to 72.2 Mya. No occurrence read is dated outside 168.2 Mya to 66 Mya.

Middle Jurassic — about 3 of 76 occurrencesMiddle JurassicLate Jurassic — about 25 of 76 occurrencesLate JurassicEarly Cretaceous — about 41 of 76 occurrencesEarly CretaceousLate Cretaceous — about 7 of 76 occurrencesLate CretaceousPaleocene — about 0 of 76 occurrences170–167 Mya — about 2 occurrences167–163 Mya — about 1 occurrence163–160 Mya — about 0.3 occurrences160–156 Mya — about 0.7 occurrences156–153 Mya — about 4 occurrences153–149 Mya — about 8 occurrences149–145 Mya — about 7 occurrences145–142 Mya — about 7 occurrences142–138 Mya — about 11 occurrences138–135 Mya — about 0.9 occurrences135–131 Mya — about 0.5 occurrences128–124 Mya — about 4 occurrences124–121 Mya — about 7 occurrences121–117 Mya — about 4 occurrences117–114 Mya — about 4 occurrences114–110 Mya — about 3 occurrences110–106 Mya — about 2 occurrences106–103 Mya — about 2 occurrences103–99 Mya — about 2 occurrences99–96 Mya — about 1 occurrence96–92 Mya — about 0.7 occurrences85–82 Mya — about 0.3 occurrences82–78 Mya — about 0.6 occurrences78–75 Mya — about 0.6 occurrences75–71 Mya — about 1.0 occurrences71–67 Mya — about 2 occurrences67–64 Mya — about 0.7 occurrences165.3 Mya72.2 Mya170 Mya64 Mya

76 occurrences of Paramacellodidae on record, most of them in the Early 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

76 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

28 formations

Morrison — 41.89°N, 106.00°WMorrison — 44.46°N, 104.73°WMorrison — 39.15°N, 108.77°WMorrison — 39.15°N, 108.77°WMorrison — 40.50°N, 109.17°WLulworth — 50.60°N, 1.97°WLulworth — 50.58°N, 1.95°WCloverly — 45.20°N, 109.00°WCloverly — 45.10°N, 106.90°WCloverly — 44.51°N, 107.90°WCloverly — 44.50°N, 107.82°WAlcobaça — 39.70°N, 8.80°WIlek — 55.90°N, 87.96°EIlek — 56.53°N, 91.81°ELa Huérguina — 40.22°N, 1.98°WLourinhã — 39.22°N, 9.34°WAntlers — 34.15°N, 95.82°WForest Marble — 51.87°N, 1.27°WKsar Metlili — 32.70°N, 3.22°WPui Beds — 45.49°N, 23.09°ECamarillas — 40.64°N, 0.86°WDzunbain — 42.45°N, 102.42°EAguja — 29.10°N, 103.17°WAguja — 29.34°N, 103.59°WHolly Creek — 34.09°N, 93.88°WCedar Mountain — 38.66°N, 111.24°WKuwajima — 36.17°N, 136.63°EDöshuul — 45.40°N, 101.73°EBlesa — 40.95°N, 0.77°WArtoles — 40.82°N, 0.28°WMurtoi — 51.20°N, 106.27°EWessex — 50.64°N, 1.41°WQigu — 43.55°N, 87.26°EKarabastau — 42.90°N, 70.00°E

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The named rock units Paramacellodidae has been recovered from, largest first. Drawn where the rock is now, not where it formed. 4 further formations hold fewer occurrences each and are not listed. 3 occurrences have no formation on record, which is common for older literature.

Paramacellodidae and its relatives

Early Cretaceous

Where Paramacellodidae and its relatives were recorded in the Early Cretaceous.

Found in the same rock

891 taxa

The Paleobiology Database records 53 sites for Paramacellodidae, 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

41 references

Each of the 76 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. 29 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 Paramacellodidae

Credit
Chase D. Brownstein, Dalton L. Meyer, Matteo Fabbri, Bhart-Anjan S. Bhullar & Jacques A. Gauthier
Licence
CC BY 4.0
Commercial use
the licence allows it

CT scan

Licence
In Copyright
Commercial use
cannot be read from the licence given — check the record
Specimen
Squamata cf. Paramacellodidae indet. · nms:g:2019.34.11

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 itScincoidea through timeFormations of the Early CretaceousThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Estes 1983