Complex sentence: This unusual ant remained unknown to scientists, but caused intense scientific interest in the early 1950s, but over three decades, teams of Australian and American collectors failed to re-find it after they initiated a series of searches.
Split into simpler sentences: This unusual ant remained unknown to scientists, causing intense scientific interest in the early 1950s. Over three decades, however, teams of Australian and American collectors failed to re-find it after they initiated a series of searches.