In Portugal, hereditary surnames were adopted according to fairly general rules and during the late Middle Ages, names that described a person's temperament or appearance were frequently used. Such nicknames sometimes became hereditary and were passed down as surnames onto further generations. The name Lopes is thought to be derived from the Latin word "lupus," meaning "wolf."
Spelling variations of this family name include: Lopez, Lopes, Lope, Llop, Lupus, Llopis and others.
In the United States, the name Lopes is the 2,275th most popular surname with an estimated 14,922 people with that name.  However, in France, the name Lopes is ranked the 371st most popular surname with an estimated 11,272 people with that name. 
^ Filby, P. William, Meyer, Mary K., Passenger and immigration lists index : a guide to published arrival records of about 500,000 passengers who came to the United States and Canada in the seventeenth, eighteenth, and nineteenth centuries. 1982-1985 Cumulated Supplements in Four Volumes Detroit, Mich. : Gale Research Co., 1985, Print (ISBN 0-8103-1795-8)