Monotremata
Monotremes are mammals of the order Monotremata. They are the only mammals still in existence which lay eggs, rather than bearing live young. The five extant monotreme species are the platypus and the four species of echidnas. Monotremes are typified by structural differences in their brains, jaws, digestive tracts, reproductive tracts, and other body parts, compared to the more common mammalian types. Although they are different from other living mammals in that they lay eggs, female monotremes are like other mammals in that they nurse their young with milk.

Ypna · 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- Also called
- monotremePBDB
- Sits inside
- AustralosphenidaPBDB
- Diet
- insectivorePBDB, for Mammaliaformes
- Life habit
- scansorialPBDB, for Mammaliaformes
- Motility
- actively mobilePBDB, for Osteichthyes
- Environment
- terrestrialPBDB, for Mammalia
Time the record covers
At least 121 million years on record.
The record covers at least 121.4 Mya to 11.7 ka. No occurrence read is dated outside 125.77 Mya to 0 Mya.
42 occurrences of Monotremata on record, most of them in the Pleistocene. The Paleobiology Database records this as a living group. 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
42 occurrences- Early Cretaceous12%
- Late Cretaceous21%
- Paleocene2%
- Oligocene12%
- Miocene5%
- Pliocene5%
- Pleistocene38%
- Holocene5%
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
8 formations
- Griman Creek Formation · Rolling Downs Group7
- Namba Formation3
- Eumeralla Formation · Otway Group3
- "Wonthaggi" Formation · Strzelecki Group2
- Chorrillo Formation2
- Etadunna Formation1
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The named rock units Monotremata has been recovered from, largest first. Drawn where the rock is now, not where it formed. 22 occurrences have no formation on record, which is common for older literature.
Monotremata and its relatives
PleistoceneWhere Monotremata and its relatives were recorded in the Pleistocene.
Found in the same rock
394 taxa- Thylacoleo carnifex12 sites
- Macropus (Macropus) giganteus9 sites
- Pseudomys9 sites
- Simosthenurus occidentalis9 sites
- Thylacinus cynocephalus9 sites
- Rattus8 sites
- Chelidae7 sites
- Dasyurus viverrinus7 sites
- Macropus7 sites
- Mastacomys7 sites
- Bettongia6 sites
- Bettongia penicillata6 sites
- Cercartetus nanus6 sites
- Isoodon obesulus6 sites
- Macropus goliah6 sites
- Macropus rufogriseus6 sites
- Ornithopoda6 sites
- Perameles gunnii6 sites
- Plesiosauria6 sites
- Pseudocheirus peregrinus6 sites
- Simosthenurus maddocki6 sites
- Sthenurus andersoni6 sites
- Tachyglossus aculeatus6 sites
- Theropoda6 sites
The Paleobiology Database records 37 sites for Monotremata, 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
30 references- Terrestrial and Freshwater Turtles of Early Cretaceous Australia4
- Notes on the occurrence of monotreme remains in the Pliocene of New South Wales4
- First monotreme from the Late Cretaceous of South America2
- Rich and Vickers-Rich, 20202
- Pleistocene fossil vertebrate sites of the South East region of South Australia II2
- A review of the Tertiary fossil Cetacea (Mammalia) localities in Australia2
- Pleistocene fossil vertebrate sites of the South East region of South Australia2
- Tropical Rainforests of North Queensland: Their Conservation Significance2
- A New, Giant Platypus, Obdurodon tharalkooschild, sp. nov. (Monotremata, Ornithorhynchidae), from the Riversleigh World Heritage Area, Australia1
- In Situ Taphonomic Investigation of Pleistocene Large Mammal Bone Deposits from The Ossuaries, Victoria Fossil Cave, Naracoorte, South Australia1
- A tachyglossid-like humerus from the Early Cretaceous of south-eastern Australia1
- Systematics and evolution of the sthenurine kangaroos1
Each of the 42 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. 18 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 Monotremata
- Source
- Wikipedia/Commons
- Credit
- Ypna
- Licence
- CC BY-SA 4.0
- Commercial use
- the licence allows it
No 3D scan of Monotremata 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, “Monotreme”
- 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 itAustralosphenida through timeFormations of the PleistoceneThe world it lived on
Occurrence data from the Paleobiology Database, CC BY 4.0. (Bonaparte 1838)