Sinoconodon is an ancestor of this clade with many of its synapomorphies. Revising George Gaylord Simpson's 1945 classification, Malcolm McKenna and Susan Bell produced a comprehensive higher-level classification of this clade, which contains the only extant synapsids. In this clade, the dentary and squamosal bone form the jaw joint, while the articular and the quadrate moved up to the (*) middle ear. The vast majority of this class has seven cervical vertebrae. This class is also distinguished by the presence of a neocortex, and its extant members are all therians or 
Sinoconodon is an ancestor of this clade with many of its synapomorphies. Revising George Gaylord Simpson's 1945 classification, Malcolm McKenna and Susan Bell produced a comprehensive higher-level classification of this clade, which contains the only extant synapsids. In this clade, the dentary and squamosal bone form the jaw joint, while the articular and the quadrate moved up to the (*) middle ear. The vast majority of this class has seven cervical vertebrae. This class is also distinguished by the presence of a neocortex, and its extant members are all therians or monotremes. It evolved endothermy independently from birds, and mothers in this class nurse their young with milk from namesake glands. For 10 points, name this class of hairy vertebrates whose orders include Rodentia and Primates.
Sinoconodon is an ancestor of this clade with many of its synapomorphies.
mammals [or Mammalia]