There were no Sharks players included because of the franchise's involvement in the Super 14 competition.
The team will be led by World Cup-winning captain John Smit and also includes most of the team which won in France, including veterans Victor Matfield and Percy Montgomery, all of whom play their club rugby in Europe.
Speaking after the announcement, De Villiers was quick to point out that the team named was not his final Test squad.
"I want to congratulate all the players who were named and I look forward to working with them all next week," said the coach, who will meet the group at a camp in Stellenbosch and Somerset West on May 21.
"I want to emphasise that this is a training squad, not a Test squad.
"I have selected certain players to work with them in a squad environment alongside the country's finest players, and others because I felt I had not seen enough of them during the Super 14."
The new players named in the squad are Jongi Nokwe, Wian du Preez, Duane Vermeulen (all Cheetahs), Louis Ludik, Earl Rose, Gerhard Mostert (all Lions), Andries Bekker, Schalk Brits, Brian Mujati (all Stormers), Heini Adams, Zane Kirchner (both Bulls) and Isma-eel Dollie (Western Province).
De Villiers also believes that naming the uncapped players is just reward for hard work put in during the early part of the season.
He added: "All the players named, including the young ones, have been on form and showed what they can do in the Super 14.
"I think it is time for us to give back to them after they showed South Africa that they are able to put their bodies on the line for their country.
"We want to keep and build on what we've got in this country. With four years in mind, we want to bring the young blood and mix them with the older players and see what we can get at the end of the four year cycle.
"You can't buy the experience that the older guys bring. We need this experience to rub on to the younger guys."
The world champions take on Wales in the first Test in Bloemfontein on June 7 with the second a week later at Loftus Versfeld in Pretoria.
South Africa 42-man training squad:
Backs: Heini Adams, Gcobani Bobo, Meyer Bosman, Tonderai Chavhanga, Jean de Villiers, Isma-eel Dollie, Fourie du Preez, Jaque Fourie, Peter Grant, Bryan Habana, Butch James, Enrico Januarie, Conrad Jantjes, Zane Kirchner, Louis Ludik, Percy Montgomery, Akona Ndungane, Jongi Nokwe, Wynand Olivier, Earl Rose.
Forwards: Andries Bekker, Bakkies Botha, Schalk Brits, Schalk Burger, Wian du Preez, Kabamba Floors, Hilton Lobberts, Victor Matfield, Gerhard Mostert, Brian Mujati, Chiliboy Ralepelle, Danie Rossouw, John Smit (capt), Juan Smith, Pierre Spies, Gurthro Steenkamp, CJ van der Linde, Heinke van der Merwe, Wikus van Heerden, Joe van Niekerk, Luke Watson, Duane Vermeulen.