Sam is the man - Warburton back as Lions captain for 'toughest' tourSports | Apr 20, 2017
Having captained the combined side on their victorious 2013 tour of Australia, the 28-year-old Wales back-row becomes just the second man after England great Martin Johnson to lead the Lions on two tours.
In contrast, hooker Hartley is the biggest casualty and the third successive England skipper to miss out on Lions selection after Steve Borthwick and Chris Robshaw.
New Zealand-born Lions coach Warren Gatland - who called it "the toughest tour" - gave surprise call-ups to Ireland full-back Jared Payne, England wing Jack Nowell and Wales back-row Ross Moriarty.
Warburton stood down from the Wales captaincy this season and is currently out with a knee injury. But he is expected to be fit before the squad departs on May 29 for a tour that will feature a three-Test series against the All Blacks.
Warburton was the skipper and Gatland, again on secondment from his job as Wales boss, the coach when the Lions won 2-1 in Australia four years ago.
While Hartley was left out, rival England hooker Jamie George was included, along with Ireland captain Rory Best and Wales' Ken Owens.
Six Nations champions England had the largest contingent in an unusually large squad with 16 players. Wales had 12 players and Ireland 11, with Scotland represented by full-back Stuart Hogg and wing Tommy Seymour.
"There's been healthy debate about the squad and now that it's been announced we need to get behind it 100 percent and get excited about traveling to New Zealand," said Gatland.
"There's competition for places and there will be players fighting for Test spots with no clear No 1, No 2 or No 3 in certain positions."
He added: "We know how tough it will be - this is the toughest tour."
Gatland's squad will be aiming to become just the second Lions party to win a Test series in New Zealand, with the combined side's lone series success against the All Blacks coming in 1971.
They begin their 10-match tour against a Provincial Union side in Whangarei on June 3, with the first of three Tests against the All Blacks in Auckland on June 24.
"In previous tours the midweek games tended to be a little easier, but when you look at the quality of the opposition we're facing in midweek [which includes all five New Zealand Super Rugby franchises] it's going to be hugely challenging," said Gatland. "That's why we've taken a few extra players."