Rhomaleosauridae

Rhomaleosauridae is a family of plesiosaurs from the Earliest Jurassic to the latest Middle Jurassic of Europe, North America, South America and possibly Asia. Most rhomaleosaurids are known from England, many specifically from lower Blue Lias deposits that date back to the earliest Jurassic, just at the boundary with the Triassic. In fact, to date only two undisputed rhomaleosaurids were named from outside Europe - the closely related Borealonectes russelli and Maresaurus coccai from Canada and Argentina, respectively. These two species are also the only Middle Jurassic representatives of the family. Rhomaleosauridae was formally named by Kuhn in 1961, originally proposed to include Rhomaleosaurus cramptoni and its relatives, which have short necks and large heads relatively to plesiosauroids like Elasmosaurus and Plesiosaurus, but longer necks and smaller heads relatively to advanced pliosaurids like Pliosaurus and Kronosaurus.

Rhomaleosauridae

MEHJones · CC BY-SA 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
PlesiosauriaPBDB
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 34 million years on record.

The record covers at least 199.5 Mya to 165.3 Mya. No occurrence read is dated outside 201.4 Mya to 154.8 Mya.

Late Triassic — about 0 of 33 occurrencesEarly Jurassic — about 26 of 33 occurrencesEarly JurassicMiddle Jurassic — about 7 of 33 occurrencesMiddle JurassicLate Jurassic — about 0 of 33 occurrencesLate Jurassic202–201 Mya — about 3 occurrences201–199 Mya — about 5 occurrences199–197 Mya — about 0.8 occurrences197–196 Mya — about 0.8 occurrences196–194 Mya — about 0.8 occurrences194–193 Mya — about 0.7 occurrences193–191 Mya — about 0.6 occurrences191–189 Mya — about 0.6 occurrences189–188 Mya — about 0.6 occurrences188–186 Mya — about 0.6 occurrences186–185 Mya — about 0.6 occurrences185–183 Mya — about 5 occurrences183–181 Mya — about 2 occurrences181–180 Mya — about 1 occurrence180–178 Mya — about 1 occurrence178–176 Mya — about 1 occurrence176–175 Mya — about 1 occurrence175–173 Mya — about 0.4 occurrences173–172 Mya — about 0.2 occurrences172–170 Mya — about 1 occurrence170–168 Mya — about 2 occurrences168–167 Mya — about 0.4 occurrences167–165 Mya — about 0.4 occurrences165–164 Mya — about 1 occurrence164–162 Mya — about 1 occurrence162–160 Mya — about 0.4 occurrences160–159 Mya — about 0.1 occurrences159–157 Mya — about 0.1 occurrences157–155 Mya — about 0.1 occurrences155–154 Mya — about 0.0 occurrences199.5 Mya165.3 Mya202.3 Mya153.9 Mya

33 occurrences of Rhomaleosauridae on record, most of them in the Early Jurassic. 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

33 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

12 formations

Blue Lias — 52.24°N, 1.46°WBlue Lias — 51.13°N, 2.73°WBlue Lias — 52.75°N, 1.15°WBlue Lias — 51.14°N, 2.55°WWhitby Mudstone — 54.53°N, 0.70°WWhitby Mudstone — 52.26°N, 0.90°WAlum Shale — 54.55°N, 0.88°WAlum Shale — 54.48°N, 0.60°WShaximiao — 29.34°N, 104.78°EShaximiao — 29.41°N, 104.85°EShaximiao — 29.61°N, 104.19°EHasle — 55.18°N, 14.72°EWestbury — 52.22°N, 1.75°WZiliujing — 31.37°N, 108.24°ELos Molles — 39.25°S, 70.30°WHiccles Cove — 76.15°N, 113.50°WPosidonia Shale — 48.63°N, 9.52°EMarlstone Rock — 52.21°N, 1.01°WHlebovskya Suite — 50.80°N, 45.15°E

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The named rock units Rhomaleosauridae has been recovered from, largest first. Drawn where the rock is now, not where it formed. 9 occurrences have no formation on record, which is common for older literature.

Rhomaleosauridae and its relatives

Early Jurassic

Where Rhomaleosauridae and its relatives were recorded in the Early Jurassic.

Found in the same rock

146 taxa

The Paleobiology Database records 26 sites for Rhomaleosauridae, 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

25 references

Each of the 33 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. 13 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 Rhomaleosauridae

Credit
MEHJones
Licence
CC BY-SA 4.0
Commercial use
the licence allows it

3D model

Source
Sketchfab
Licence
CC Attribution
Commercial use
cannot be read from the licence given — check the record

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 itPlesiosauria through timeFormations of the Early JurassicThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. Nopcsa 1928