[MM] Hadrocodium wui
The Earliest-Known Stem Mammals
DESCRIBER Luo, Crompton & Sun, 2001
TIME Jurassic Early
ORDER Incertae Sedis
FAMILY Incertae Sedis
FOSSILSITE Lower Lufeng Formation, Upper Red Beds, Yunnan, China
A very small mammalthat represent a distinct, hitherto unrecoginized stem lineage. It is more related to the mammalian crown group (inclusive of eutriconodontans) than to docodontans, morganucodontans, or Sinoconodon. The holotype represents a subadult individual with a skull length of about 12 mm. and an estimated bodyweight of about 2 gr.