Complex sentence: In the early 1950s, he succeeded Bob Lubbers as illustrator of the "Tarzan" comic strip, which he continued drawing until Russ Manning took it over in the 1960s.
Split into simpler sentences: In the early 1950s, he succeeded Bob Lubbers as illustrator of the "Tarzan" comic strip. He continued on "Tarzan" until Russ Manning took it over in the 1960s.