Isotemnidae
Isotemnidae is a paraphyletic extinct family of notoungulate mammals known from the Early Eocene (Itaboraian) to Middle Miocene of South America.

Ghedoghedo · 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
- ToxodontiaPBDB
- Diet
- herbivorePBDB, for Notoungulata
- Life habit
- scansorialPBDB, for Eutheria
- Motility
- actively mobilePBDB, for Osteichthyes
- Environment
- terrestrialPBDB, for Eutheria
Time the record covers
At least 27 million years on record.
The record covers at least 56 Mya to 29 Mya. No occurrence read is dated outside 57 Mya to 21 Mya.
150 occurrences of Isotemnidae on record, most of them in the Eocene. 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
150 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
- Sarmiento Formation60
- Las Flores Formation · Río Chico Group6
- Geste Formation · Pastos Grande Group3
- Casamayor Formation3
- Lumbrera Formation · Salta Group2
- Abanico Formation1
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The named rock units Isotemnidae has been recovered from, largest first. Drawn where the rock is now, not where it formed. 72 occurrences have no formation on record, which is common for older literature.
Isotemnidae and its relatives
EoceneWhere Isotemnidae and its relatives were recorded in the Eocene.
Found in the same rock
401 taxa- Archaeopithecus rogeri14 sites
- Henricosbornia lophodonta13 sites
- Notopithecus adapinus13 sites
- Pleurostylodon modicus13 sites
- Trigonostylops wortmani13 sites
- Antepithecus brachystephanus11 sites
- Notostylops11 sites
- Pleurostylodon similis11 sites
- Notostylops murinus10 sites
- Pleurostylodon10 sites
- Isotemnus primitivus9 sites
- Thomashuxleya externa9 sites
- Notoungulata8 sites
- Oldfieldthomasia debilitata8 sites
- Polydolops thomasi8 sites
- Maxschlosseria praeterita7 sites
- Notopithecidae7 sites
- Notostylops pendens7 sites
- Trigonostylops7 sites
- Anisotemnus distentus6 sites
- Didolodus multicuspis6 sites
- Isotemnus6 sites
- Othnielmarshia lacunifera6 sites
- Pseudhyrax eutrachytheroides6 sites
The Paleobiology Database records 55 sites for Isotemnidae, 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
24 references- The beginning of the age of mammals in South America. Part II60
- Biostratigraphy of the Casamayoran, Early Eocene of Patagonia33
- Mammiféres crétacés de l’Argentine (Deuxième contribution à la connaissance de la fauna mammalogique de couches à Pyrotherium) [Cretaceous mammals of Argentina (second contribution to the knowledge of the mammalian fauna of the Pyrotherium Beds)]7
- Vertebrate paleontology, geology, and geochronology of the Tapera de López and Scarritt Pocket, Chubut Province, Argentina6
- The Egidio Feruglio's collection in the Museum of Geology and Palaeontology of the University of Padova: its importance to the knowledge of Cenozoic mammals from South America5
- Nuevas especies de mamíferos, cretáceos y terciarios de la República Argentina [New species of mammals, Cretaceous and Tertiarty, from the Argentine Republic]5
- Noticias preliminares sobre nuevos mamíferos fósiles del Cretáceo superior y Terciario inferior de la Patagonia5
- Notoungulate faunas of north-western Argentina: new findings of early-diverging forms from the Eocene Geste Formation3
- Skeletal remains and restoration of Eocene Entelonychia from Patagonia3
- Notices préliminaires sur des mammifères nouveaux des terrains Crétacé de Patagonie {preliminary notes on new mammals from the Cretaceous terrains of Patagonia]3
- Notices préliminaires sur des ongulés nouveaux des terrains crétacés de Patagonie [Preliminary notes on new ungulates from the Cretaceous terrains of Patagonia]3
- New insights into the Kibenikhoria and Ernestokokenia faunas and the implications for the early Eocene of Patagonia, Argentina2
Each of the 150 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. 12 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 Isotemnidae
- Source
- Wikipedia/Commons
- Credit
- Ghedoghedo
- Licence
- CC BY-SA 3.0
- Commercial use
- the licence allows it
No 3D scan of Isotemnidae was found in MorphoSource and Sketchfab.
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, “Isotemnidae”
- 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 itToxodontia through timeFormations of the EoceneThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. Ameghino 1897