Mesosauridae
Mesosaurus is an extinct genus of aquatic reptile from the late Early Permian of southern Africa and South America. It is the only member of the family Mesosauridae and order Mesosauria. Two other genera of mesosaurs, Brazilosaurus and Stereosternum, were formerly recognised, but are now considered synonyms of Mesosaurus. Mesosaurus contains a single valid species, M. tenuidens. Mesosaurus represents one of the earliest lineages of aquatically adapted reptiles. It had many adaptations to a fully aquatic lifestyle. Mesosaurus lived around the shorelines of the Irati–Whitehill sea, an epicontinental sea that covered parts of southern Pangaea during the late Early Permian, likely feeding on small prey such as pygocephalomorph crustaceans. Mesosaurs have often been considered parareptiles, though the validity of "Parareptilia" has recently been brought into question. Recent studies regardless place mesosaurs as basal, non-diapsid reptiles.

Kevmin · CC BY-SA 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
- MesosauriaPBDB
- Diet
- piscivorePBDB
- Life habit
- amphibiousPBDB
- Motility
- actively mobilePBDB
- Environment
- coastal,marine,brackishPBDB
Time the record covers
At least 199 million years on record.
The record covers at least 283.3 Mya to 83.6 Mya. No occurrence read is dated outside 290.1 Mya to 66 Mya.
62 occurrences of Mesosauridae on record, most of them in the Permian. 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
62 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
9 formations
- Irati Formation · Passa Dois Group40
- Whitehill Formation · Ecca Group7
- Huab Formation · "Ecca" Group4
- Melo Formation4
- Whitehill Formation · Ecca Group2
- ? San Miguel Formation · Independencia Group2
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The named rock units Mesosauridae has been recovered from, largest first. Drawn where the rock is now, not where it formed.
Mesosauridae and its relatives
PermianWhere Mesosauridae and its relatives were recorded in the Permian.
Found in the same rock
9 taxa- Mesosaurus tenuidens9 sites
- Mesosaurus5 sites
- Brasileosaurus pachecoi1 site
- Brazilosaurus sanpauloensis1 site
- Carnosauria1 site
- Coelurosauria1 site
- Crocodylia1 site
- Liocaris huenei1 site
- Stereosternum tumidum1 site
The Paleobiology Database records 18 sites for Mesosauridae, and this reads all of them. The number is how many of those sites it was catalogued from too.
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
21 references- Das Mesosaurier-Material in der Bayerischen Staatssammlung für Paläontologie und Historische Geologie: Übersicht und neue Erkenntnisse11
- Studien an Mesosauriern (Amniota inc sed: Mesosauridae): 2 Neue Erkenntnisse zur Anatomie, mit Berücksichtigung der Taxonomie von Mesosaurus pleurogaster (Seeley)7
- A taphonomic model for the Mesosauridae assemblage of the Irati Formation (Paraná Basin, Brazil)5
- A coluna vertebral de Brazilosaurus sanpauloensis Shikama e Ozaki, 1966 da Formação Irati, Permiano da Bacia do Paraná (Brasil) (Proganosauria, Mesosauridae)5
- Mesosaurid specimens in the collections of the Museum für Naturkunde Berlin4
- The Mesosauria in the collections of Göttingen and Clausthal: implications for a modified classification4
- Depositional environments and stratigraphic correlation of the Karoo Sequence in northwestern Damaraland4
- Lista de los vertebrados fosiles del Uruguay, I. Chondrichthyes, Osteichthyes, Reptilia, Aves [List of the fossil vertebrates of Uruguay, I. Chondrichthyes, Osteichthyes, Reptilia, Aves]4
- Studien an Mesosauriern (Amniota inc sed, Mesosauridae): 3 Neue Aspekte zur Anatomie, Erhaltung und Paläoökologie aufgrund der Exemplare im Paläontologischen Institut der Universität Zürich. [Studies on mesosaurs (Amniota inc sed, Mesosauridae): 3 New aspects on the anatomy, preservation and palaeoecology, based on the specimens from the Palaeontological Institute of the University of Zurich]2
- Noteosaurus africanus Broom is a nomen dubium2
- Sobre un Hallazgo de Fósiles Pérmicos en Villarrica (República del Paraguay)2
- Die ersten fossilen Reptilreste aus Deutsch-Südwestafrika und ihre geologische Bedeutung2
Each of the 62 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. 9 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 Mesosauridae
- Source
- Wikipedia/Commons
- Credit
- Kevmin
- Licence
- CC BY-SA 3.0
- Commercial use
- the licence allows it
No 3D scan of Mesosauridae 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
- Source
- Wikipedia, “Mesosaurus”
- 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 itMesosauria through timeFormations of the PermianThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Baur 1889