Sam Warburton will become Wales' youngest World Cup captain when he leads the squad in New Zealand next month.
The 22-year-old Cardiff Blues flanker fills a vacancy created by a neck injury to Matthew Rees.
Warren Gatland's 30-man World Cup squad contains one uncapped player - Ken Owens, the Scarlets hooker - who received an 11th-hour call to replace Richard Hibbard, who was hurt during Saturday's World Cup warm-up victory over Argentina in his comeback match after undergoing summer shoulder surgery.
Owens joins fellow squad hookers Huw Bennett and Lloyd Burns in the absence of Rees and Hibbard.
There are few surprises in the squad, although the 99 time-capped Cardiff Blues flanker Martyn Williams misses out on playing in his fourth World Cup.
Gatland, the coach, has opted for a split of 16 forwards and 14 backs, with the Sale Sharks' Andy Powell gaining one of the back-row slots,
Assessing his squad and the 16-14 split, Gatland said: "We've had a few injuries in the back three, and we wanted to make we had cover there.
"It needed bolstering up, so we went for 16-14.
"We told Andy Powell before the Argentina game, his game had to be error-free and he needed to take his opportunities, and he delivered. He played his way into the squad."
On being appointed captain, Warburton said: "To be a World Cup captain is one of the biggest achievements a rugby player could achieve."
Elsewhere, Andy Robinson, the Scotland head coach, confirmed Alastair Kellock as captain of his squad.
The Glasgow Warriors second row led his country during this year's Six Nations tournament and he retains the armband for the Scots' World Cup campaign, which kicks off on September 10 against Romania in Invercargill, with further group games against Georgia, Argentina and England.
Kellock, who missed out on selection for the 2007 tournament, said: "Today is not a time for looking back. It's about reflecting on the huge honour of being selected for the squad, which is magnified by being asked to captain the squad."
Kellock's club colleague Johnnie Beattie, who was among the most impressive performers in the 2010 Six Nations before suffering a shoulder problem, has been omitted from Robinson's squad.
Chris Paterson is set to become the first Scot to appear in four Rugby World Cups after he was named in the squad.
Paterson made his debut in the 1999 tournament and is Scotland's most-capped player and record points scorer, with 105 appearances and 786 points.
"It was a huge goal of mine to make this World Cup," the full-back said. "I'm delighted to do that, but the hard work starts again tomorrow when we get back to training and fight for that starting place."
Conor Murray has been included in Ireland's squad at the expense of Munster teammate Tomas O'Leary.
Murray, who made his only Test appearance against France in Bordeaux nine days ago, travels with fellow scrum-halves Eoin Reddan and Isaac Boss.
O'Leary was thought to be Declan Kidney's first choice in the position but has paid the price for his poor display in Saturday's 26-22 defeat by Les Bleus.
Geordan Murphy, the Leicester full-back, travels to New Zealand, as does the Leinster utility back Fergus McFadden, but there is no place among the 30 for the winger Luke Fitzgerald.
Murphy's hopes of inclusion looked dashed after he started in the second string's victory over Connacht last Thursday.
At 33, Murphy's Test career seemed over only for a foot injury to Felix Jones, sustained against France on Saturday, to narrow the option available to Kidney, the Ireland coach.
Brian O'Driscoll will lead the squad, which has a 16-14 split between forwards and backs.
Ireland's group includes Australia, Italy, Russia and the United States.