Dick Clark's full name at birth was Richard Augustus Wagstaff Clark, Jr. As with most people in radio and TV, he chose to use a shorter version of his name-- in this case, a nickname ("Dick"), rather than using either Augustus or Wagstaff.
Clark Joseph (sometimes Jerome) Kent. A link to the Wikipedia post is provided.
Dick Clark
Annie Clark (full name- Andrea Jannett Clark)
In Christmas Vacation, Clark's last name is Griswold.
His middle name is Muriel.
Clark
Eugenie Clark's middle name was "Clark."
There was no legal change that I know of, but why would he have to? Dick is a nickname for Richard. Going by first and last name like most of us, he would be...Dick Clark!
Dick Geary's birth name is Richard Clark Geary.
Ross
Herbert Hoover's middle name was Clark
William
Ross
Ryan
Clark Wilhem Griswold Jr. His middle name is revealed during the opening credits to Euorpean Vacation on his passport.
George
Paul Clark McDermott