Do you know what was on my dog?

I was outside with my chihuahua/bichon mix.She was sitting by my mother.I saw a red thing on her belly.I picked her up and held her like a baby.It was a brownish red color. It looked like a tiny crab.Was it a tick,or flea? My mother swipped it off with a newspaper and I threw it in te street. I gave her a bath to be safe.