I do not believe the keys of apostolic authority were removed from the earth with the death of the last apostle, St. John. Paul and Barnabas, for example, were commissioned as apostles to the Gentiles by members of the original twelve, and they were not of the original twelve: Galatians 2:9 And when James, Cephas, and John, who seemed to be pillars, perceived the grace that was given unto me, they gave to me and Barnabas the right hands of fellowship; that we should go unto the heathen, and they unto the circumcision.