If you disagree or feel that it is unfounded, a simple statement therein is fine, but the proposition that there's a possibility of common ancestry is not something so out of whack as to merit the level of "astonishment" that you appear to feel.
1. I'm more astonished that you even care for something so irrelevant. Then again, people haven't asked what kind of grandma underwear would Barenziah wear.
2. It's not a feeling. You have nothing substantial from any text or in game except based on physical resemblances. Have you heard of convergent evolution? Structures of two organisms from radically different lineages are similar. But, even that statement lacks any evidence from in-game that convergent evolution happened. Simply, not having any phylogenetic relationships mentioned is I don't know irrelevant.
Really now..