missing link

missing link (plural missing links)

1. (colloquial) A hypothetical primate once thought necessary to explain a perceived evolutionary gap between apes and humans.
   • 1912, Arthur Conan Doyle, The Lost World […], London, New York, N.Y.: Hodder and Stoughton, →OCLC:

     "In the latter case, he may well approximate to what the vulgar have called the 'missing link'."

2. (figuratively) Any sought-after or valuable intermediary figure or position.
   • 2010 February 4, Jonathan Jones, “Art v science – at last, the missing link”, in The Guardian‎:

     What we need is an artist who is also a scientist; or a scientist who thinks like an artist. And at last I can unveil that missing link of art and science!

   • 2020 August 3, Simon Hill, “Football looks to digital revolution to find missing link between base and elite”, in The Guardian‎:

     It is hoped this can finally solve the conundrum of how to connect the base to the elite, for so long the game’s missing link.

   • 2022 February 23, “Network News: MP urges link between Midlands cities to be 'reforged'”, in RAIL, number 951, page 24:

     "For too long, there has been a missing link between the East and West Midlands, and this is our opportunity to reforge it," said Webbe.