Really? Why should it be so? Why are chickens and bats more similar to each other than to mosquitos, especially since we're talking mitochodrial DNA, and not the genome of the organisms themselves?
"Why should it be so", is a metaphysical question. I don't know. But what causes the relationships between the mitrochondrial DNA that I have listed? Why should something about a bat be closer to a mosquito than that "same" something in a chicken compared to the mosquito? What is "closer" to a fish, a chicken or a bat?