"Direct predecessor" refers to something that came before or preceded something else in a straightforward and immediate manner, without any other intervening steps or elements in between. Full definition
Discoveries in Morocco convinced one research team that direct predecessors of H. sapiens lived there about 300,000 years ago (SN: 7/8/17, p. 6). (sciencenews.org)
Heseltine and Rab Butler were Prescott's direct predecessors in that they both combined the title of First Sec of State and deputy PM. (nextleft.org)
The international Infrared Astronomical Satellite, the most direct predecessor to the $ 320 - million WISE, was launched more than 25 years ago. (scientificamerican.com)