Fionna meets an Uncle and a great great Uncle?

You can see Fionna in the back with the other pups. My questions is who is the other dog? I am not sure what was going on but there was only 3 dogs and it looks like there was one more. Sort of odd. Fionna had a wonderful afternoon with her Uncles. We figured that Merlin was probably an Uncle several times removed and the other was Fionna's mothers brother.