Jon 'Bones' Jones -- My Newborn Baby's a Pro Boob Sucker

UFC light heavyweight champ Jon "Bones" Jones couldn't be more proud of his newborn baby daughter ... at least in the nipple-sucking department.

Jones -- whose baby daughter Olivia was born today at 6 pounds 10 ounces -- just tweeted, "Guys Liv is so pretty! She has a head full of hair and is sucking on this t*t like a champ."

Aahh ... nothing like a father's love.

Jones added, "Careful Ronda Rousey, we might have a new challenger for your belt."