| image =Pantelosaurus.jpg | image_width = 230px | image_caption = Pantelosaurus | regnum = Animalia | phylum = Chordata | classis = Synapsida | ordo = Pelycosauria | suborder = Eupelycosauria | infraorder = Spenacodontia | subdivision_ranks = Genera and Clades | subdivision = See taxonomy}} Sphenacodontia's the name given to the clade that includes the Sphenacodontidae and all their descendants (including mammals). They first appear during the Late Pennsylvanian epoch. The defining characteris… (More on Sphenacodontia)