Jason Holder has replaced Dwayne Bravo as West Indies one-day international captain.
The 23-year-old all-rounder has won 21 ODI caps since making his debut against Australia in February 2013.
Chairman of selectors Clive Lloyd said: "He has a very good cricketing brain, and the makings of a very good leader."
The move comes just two months before the start of the World Cup, with West Indies beginning their campaign against Ireland on 16 February.
Holder, who has just one Test cap, will lead his nation for the first time in a five-match ODI series in South Africa, beginning on 16 January.
Bravo, Darren Sammy and Kieron Pollard have been dropped from the ODI squad for SA, which is also expected to travel to the World Cup in Australia and New Zealand.
As ODI captain, Bravo played a key role in the controversial aborted tour of India in October over a pay dispute.
"The selectors decided that now is the time to make the transition, and Jason will have people around him to help and guide him," added Lloyd.
"Some might say it's close to the time of next year's Cricket World Cup in Australia and New Zealand, but we know that we have a good one-day team which can do very well.