9.B.303.  The Asgard Archaeal 9/10 TMS Protein (AsAr9/10Pr) Family 

Members of this family are found only in the 4 Asgard phyla.  There may be more than one in any one of these organisms.  Recognizable homologues are not found outside of these proteins. Possibly they are distantly related to the DMT superfamily (TC# 2.A.7), but this has not been proven.