A clade is all the descendants of a common ancestor. Any clade I happen to belong to is of course the top clade - eukaryotes (I have nuclei), gnathostomates (I have a jaw), eutheria (I could make a placenta if I wanted to), etc. Whenever I post about an animal, I try to use the icon for a clade we both belong to.
no subject
(Love your UFO icon, btw. :-)