| Tritheledontidae | |
|---|---|
 | |
| Restoration ofPachygenelus monus | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Synapsida |
| Clade: | Therapsida |
| Clade: | Cynodontia |
| Clade: | Prozostrodontia |
| Family: | †Tritheledontidae Broom,1912 |
| Genera | |
Tritheledontidae, thetritheledontids orictidosaurs,[1] is anextinctfamily of small to medium-sized (about 10 to 20 cm long[1])cynodonts. They were highlymammal-like, specialized cynodonts, although they still retained a fewreptile-like anatomical traits. Tritheledontids were mainlycarnivorous orinsectivorous, though some species may have developedomnivory. Their skeletons show that they had a close relationship to mammals. Tritheledontids or their closest relatives may have given rise to themammaliaforms. The tritheledontids were one of the longest lived non-mammaliantherapsid lineages, living from the lateTriassic to theJurassic period. Tritheledontids became extinct in the Jurassic period, possibly due to competition withprehistoric mammals such as theeutriconodonts. They are known from finds inSouth America andSouth Africa, indicating that they may have lived only on thesupercontinent ofGondwana. The family Tritheledontidae was named by South African paleontologistRobert Broom in 1912.[2] The family is often misspelled "Trithelodontidae".
It is possible that tritheledontids hadvibrissae, according to thePBS documentary,Your Inner Fish.[3] A common ancestor of all therian mammals did so.[4] It is possible that the development of the whisker sensory system played an important role in mammalian development, more generally.[4]
Cladogram after Ruta, Botha-Brink, Mitchell and Benton (2013):[5]
