All animals share a common ancestor.
Explanation:
According to various phylogenetic gene sequence analysis, there are various evidences that proved all animals originated from a common ancestor.
Initially, it was stated that all organisms descended from a single cell which then gave rise to multicellular organisms. Organisms that descend from a common ancestor are closely related and grouped.
The lineage of the common ancestor can be traced in the neoproterozoic era.
The last common ancestor or the basal animal was sea sponge according to some researchers. The last universal common ancestor is called as the concestor.