My first is part of your digestive system, but you sometimes use only half of me.
My second is sometimes called what people sometimes call the shark hanging in the Smithsonian.
My third is my mom, once removed from Matilda and re-moved again.
My fourth is a greeting to my friend who is named after the end.
My fifth is a really fast run.
My sixth is in the number three.
My seventh can replace my first and my last.
My eighth is the last 2 of my dad's essay topics.
What is my all?
Note: I edited some of the clues for clarification.
The answer is NOT punctuation marks. There is an actual obvious answer once you know the answers.
In the hint for my third, the re-moved again part has significance.
At least two of the clues are the same.
My second is made of parts...
My third is re-moved again.
My sixth is not in #3
My seventh requires the others.