The Earliest-Known Stem  Mammals

DESCRIBER    Clemens,1980
TIME    Triassic Late
Rhaetian
CLASS    Mammalia
SUBCLASS    Incertae Sedis
ORDER    Morganucodonta (Kermack, et al., 1973)
FAMILY    Morganucodontidae (Kühne, 1958)
FOSSILSITE    Hallau bonebed , Kanton Schaffhausen, Switserland
INFO
Type species by monotype. Based on an isolated tooth. The main cusp A differs frome those of Morganucodon in having wrinkled enamel. In this feature Helvetiodon is similar to Brachyzostrodon and Wareolestes