''Peraiocynodon'' is an extinct

mammaliaform Mammaliaformes ("mammalian forms") is a clade of synapsid tetrapods that includes the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts during the Late Triassic. It is defined a ...

from the order

Docodonta Docodonta is an Order (biology), order of extinct Mesozoic Mammaliaformes, mammaliaforms (advanced cynodonts closely related to true Crown group, crown-group mammals). They were among the most common mammaliaforms of their time, persisting from t ...

, found in the Middle Jurassic rocks of the United Kingdom. It is only known from isolated molar teeth found in the mammal bed at

Kirtlington Kirtlington is a village and Civil parishes in England, civil parish in Oxfordshire about west of Bicester. The parish includes the Hamlet (place), hamlet of Northbrook. The United Kingdom Census 2011, 2011 Census recorded the parish's popula ...

cement quarry in Oxfordshire, England ( Forest Marble Formation). ''Peraiocynodon'' was originally erected in 1929 with a single species named,Simpson GG. 1928. A Catalogue of the Mesozoic Mammalia in the Geological Department of the British Museum. British Museum. but it was later considered to be a synonym of '' Docodon''.Butler PM. 1939
The teeth of the Jurassic mammals
In Proceedings of the Zoological Society of London, 109:329-356). Oxford, UK: Blackwell Publishing Ltd. However, in 2003, the genus was resurrected and a new species, ''P. major'', was described based on new teeth found at Kirtington Cement Quarry in Oxfordshire.Sigogneau-Russell D. 2003
Docodonts from the British Mesozoic
Acta Palaeontologica Polonica, 48(3) It remains uncertain whether one or both of these species of ''Peraiocynodon'' may be the

deciduous teeth Deciduous teeth or primary teeth, also informally known as baby teeth, milk teeth, or temporary teeth,Fehrenbach, MJ and Popowics, T. (2026). ''Illustrated Dental Embryology, Histology, and Anatomy'', 6th edition, Elsevier, page 287–296. are ...

of another genus of docodontan, or whether they truly are separate species.

References

Docodonta Middle Jurassic synapsids of Europe Fossil taxa described in 1929 Taxa named by George Gaylord Simpson {{paleo-cynodont-stub