Tritheledontidae

Tritheledontidae, the tritheledontids or ictidosaurs, is an extinct family of small to medium-sized cynodonts. They were highly mammal-like, specialized cynodonts, although they still retained a few reptile-like anatomical traits. Tritheledontids were mainly carnivorous or insectivorous, though some species may have developed omnivory. Their skeletons show that they had a close relationship to mammals. Tritheledontids or their closest relatives may have given rise to the mammaliaforms. The tritheledontids were one of the longest lived non-mammalian therapsid lineages, living from the late Triassic to the Jurassic period. Tritheledontids became extinct in the Jurassic period, possibly due to competition with prehistoric mammals such as the eutriconodonts. They are known from finds in South America and South Africa, indicating that they may have lived only on the supercontinent of Gondwana. The family Tritheledontidae was named by South African paleontologist Robert Broom in 1912. The family is often misspelled "Trithelodontidae".

Tritheledontidae

Smokeybjb · 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
MammaliamorphaPBDB
Motility
actively mobilePBDB, for Osteichthyes
Environment
terrestrialPBDB, for Amniota

Time the record covers

At least 4.3 million years on record.

The record covers at least 205.7 Mya to 201.4 Mya. No occurrence read is dated outside 227.3 Mya to 192.9 Mya.

Late Triassic — about 13 of 29 occurrencesLate TriassicEarly Jurassic — about 16 of 29 occurrencesEarly Jurassic228–227 Mya — about 0.3 occurrences227–226 Mya — about 0.7 occurrences226–224 Mya — about 0.7 occurrences224–223 Mya — about 0.7 occurrences223–222 Mya — about 0.7 occurrences222–221 Mya — about 0.7 occurrences221–220 Mya — about 0.7 occurrences220–218 Mya — about 0.7 occurrences218–217 Mya — about 0.7 occurrences217–216 Mya — about 0.7 occurrences216–215 Mya — about 0.7 occurrences215–214 Mya — about 0.7 occurrences214–212 Mya — about 0.7 occurrences212–211 Mya — about 0.7 occurrences211–210 Mya — about 0.7 occurrences210–209 Mya — about 0.7 occurrences209–208 Mya — about 0.7 occurrences208–207 Mya — about 0.7 occurrences207–205 Mya — about 0.5 occurrences202–201 Mya — about 3 occurrences201–199 Mya — about 3 occurrences199–198 Mya — about 2 occurrences198–197 Mya — about 2 occurrences197–196 Mya — about 2 occurrences196–195 Mya — about 2 occurrences195–193 Mya — about 2 occurrences193–192 Mya — about 0.8 occurrences205.7 Mya – 201.4 Mya228 Mya192.2 Mya

29 occurrences of Tritheledontidae on record. 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

29 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

8 formations

Elliot — 28.98°S, 27.37°EElliot — 30.47°S, 27.43°EElliot — 29.13°S, 27.37°EElliot — 28.92°S, 27.57°EElliot — 31.15°S, 26.62°EElliot — 30.43°S, 28.52°EElliot — 28.55°S, 27.95°EElliot — 28.55°S, 28.42°EElliot — 28.97°S, 27.32°EElliot — 29.10°S, 27.33°ECaturrita — 29.63°S, 53.23°WCaturrita — 29.56°S, 53.45°WCaturrita — 29.69°S, 52.85°WMcCoy Brook — 45.40°N, 64.22°WQuebrada del Barro — 31.60°S, 67.29°WLos Colorados — 29.85°S, 68.03°WLos Colorados — 29.73°S, 68.22°WElliot — 29.85°S, 27.27°EElliot — 30.42°S, 27.75°ECooper Canyon — 33.52°N, 101.32°WTecovas — 33.45°N, 101.17°W

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The named rock units Tritheledontidae has been recovered from, largest first. Drawn where the rock is now, not where it formed.

Found in the same rock

115 taxa

The Paleobiology Database records 26 sites for Tritheledontidae, 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

17 references

Each of the 29 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. 5 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 Tritheledontidae

Credit
Smokeybjb
Licence
CC BY-SA 3.0
Commercial use
the licence allows it

No 3D scan of Tritheledontidae 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

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 itMammaliamorpha through timeThe world it lived on

Occurrence data from the Paleobiology Database, CC BY 4.0. (Broom 1912)