Is there a group noun which includes cousins, uncles, and aunts? Is an uncle or an aunt just a special case of a cousin? Then there are nephews and nieces. Is a male sibling a special case of nephew?
They are relatives -- but you are not their descendant, and they are not your ancestors. The term "direct ancestor" is redundant, there are no "indirect ancestors". That's all I'm saying.
collateral descendant
n. a relative descended from a brother or sister of an ancestor, and thus a cousin, niece, nephew, aunt or uncle.