Geosaurus
Geosaurus is an extinct genus of marine crocodyliform within the family Metriorhynchidae, that lived during the Late Jurassic and the Early Cretaceous. Geosaurus was a carnivore that spent much, if not all, its life out at sea. No Geosaurus eggs or nests have been discovered, so little is known of the reptile's lifecycle, unlike other large marine reptiles of the Mesozoic, such as plesiosaurs or ichthyosaurs which are known to give birth to live young out at sea. Where Geosaurus mated, whether on land or at sea, is currently unknown. The name Geosaurus means "Mother of Giants lizard", and is derived from the Greek Ge- and σαῦρος -sauros ("lizard"). The name Geosaurus was established by the French naturalist Georges Cuvier in 1824.

LiterallyMiguel · 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
- GeosaurinaPBDB
- Diet
- carnivorePBDB, for Thalattosuchia
- Life habit
- nektonicPBDB, for Thalattosuchia
- Motility
- actively mobilePBDB, for Thalattosuchia
- Environment
- marinePBDB, for Thalattosuchia
Time the record covers
At least 150 million years on record.
The record covers at least 283.3 Mya to 132.6 Mya. No occurrence read is dated outside 298.9 Mya to 125.77 Mya.
18 occurrences of Geosaurus on record, most of them in the Late 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
18 occurrencesThese 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
6 formations
- Vaca Muerta Formation3
- Mörnsheim Formation · Weißjura Group3
- Jagua Formation2
- Solnhofen Formation1
- Kimmeridge Clay Formation1
- Mergelstetten Formation · Weißjura Group1
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The named rock units Geosaurus has been recovered from, largest first. Drawn where the rock is now, not where it formed. 7 occurrences have no formation on record, which is common for older literature.
Geosaurus and its relatives
Late JurassicWhere Geosaurus and its relatives were recorded in the Late Jurassic.
Found in the same rock
88 taxa- Neusticemys neuquina3 sites
- Ophthalmosaurus3 sites
- Caturus furcatus2 sites
- Cricosaurus2 sites
- Dakosaurus maximus2 sites
- Eurysternum neuquinum2 sites
- Ichthyosauria2 sites
- Lepidotus unguiculatus2 sites
- Notoemys laticentralis2 sites
- Aeolodon priscus1 site
- Altmuehlfuro boomerang1 site
- Anaethalion knorri1 site
- Araucarites1 site
- Archaeogracilidens macer1 site
- Archaeopteryx albersdoerferi1 site
- Ardeadactylus longicollum1 site
- Athrotaxites lycopodioides1 site
- Belonostomus sphyraenoides1 site
- Brachyphyllum1 site
- Callipurbeckia notopterus1 site
- Callitris1 site
- Caturus contractus1 site
- Caturus elongatus1 site
- Caturus macrurus1 site
The Paleobiology Database records 17 sites for Geosaurus, 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
10 references- The evolution of extreme hypercarnivory in Metriorhynchidae (Mesoeucrocodylia: Thalattosuchia) based on evidence from microscopic denticle morphology4
- Jurassic marine reptiles of the Neuquen Basin: records, faunas, and their palaeobiogeographic significance3
- Re-description of a putative Early Cretaceous "teleosaurid" from France, with implications for the survival of metriorhynchids and teleosaurids across the Jurassic-Cretaceous Boundary2
- What is Geosaurus? Redescription of Geosaurus giganteus (Thalattosuchia: Metriorhynchidae) from the Upper Jurassic of Bayern, Germany2
- Metriorhynchid crcodiles (Crocodyliformes) from the Oxfordian of Western Cuba2
- Evidence of the metriorhynchid crocodylomorph genus Geosaurus in the Lower Kimmeridge Clay Formation (Late Jurassic) of England1
- Solnhofen tetrapod taphonomy1
- Tithonian marine reptiles of the Eastern Pacific1
- Pelycosauria1
- Découverte d’un crocodilien dans le Néocomien de La Martre (Var) Dacosaurus lapparenti n. sp.1
Each of the 18 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. 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 Geosaurus
- Source
- Wikipedia/Commons
- Credit
- LiterallyMiguel
- Licence
- CC BY 4.0
- Commercial use
- the licence allows it
Laser scan
- Source
- MorphoSource
- Licence
- In Copyright
- Commercial use
- cannot be read from the licence given — check the record
- Specimen
- Geosaurus gigantea · NHMUK:PAL:PV R 1230
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
- Source
- Wikipedia, “Geosaurus”
- 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 itGeosaurina through timeFormations of the Late JurassicThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Cuvier 1824