The Earliest-Known Stem  Mammals

DESCRIBER    Parrington, 1941
TIME    Triassic Late
?Norian
CLASS    Mammalia
SUBCLASS    Incertae Sedis
ORDER    Morganucodonta (Kermack, et al., 1973)
FAMILY    Morganucodontidae (Kühne, 1958)
FALL UNDER    Eozostrodon parvus
FOSSILSITE    Fissure fillings in Holwell Quarry, Oxford, England, Britain
INFO

Eozostrodon parvus (Parrington, 1941) > Eozostrodon problematicus (Parrington, 1941)

Eozostrodon differs from Morganucodon watsoni in having a better/developed labial cingulum on the upper premolar, a more gracile and posteriorly reclined cusp C, and more tapering distal end of theposterior root. (Parrington, 1971; Clemens, 1979). Eozostrodon watsoni and Eozostrodon heikuopengensis are now assigned to Morganucodon.