Cullen is seen as arguably the best young spinner in Australia

The 21-year-old replaces seamer Michael Lewis as the only change to the squad beaten 3-2 in South Africa.

Lewis conceded 113 from 10 overs as South Africa made 438-9 to win the deciding game in Johannesburg.

The Australian selectors, meanwhile, have named an unchanged Test squad for two matches in Bangladesh with seam bowler Glenn McGrath again absent.

McGrath is taking time off from cricket to help care for his wife, who is suffering from cancer.

Next month's tour will be the first time Australia have played Test cricket in Bangladesh, who were only awarded full membership of the International Cricket Council five years ago.

They beat them 2-0 on home soil in 2003 - both of them innings victories - and will be looking for an equally convincing victory this time, having named a full strength squad, with the exception of McGrath.

But they will be taking nothing for granted in the three one-dayers after an embarrassing defeat in Cardiff during last summer's tri-series in England.

Cullen's inclusion follows a successful winter in which he took 27 wickets for South Australia in the first-class Pura Cup competition, albeit at a cost of more than 47 runs each.

And it means he will not be able to travel to England to take up a county contract with Somerset until the beginning of May.

"This is a great testament to our judgement that we have signed a player who has now been selected by his country.

"Before this announcement some people may have wondered who Dan was, but now they will not be left in any doubt.�

"All of the information that we received before we signed him told us that he was a really good prospect and this selection just goes to prove that this was right," said Somerset Director of Cricket Brian Rose.

Australia Test squad: R Ponting (capt), A Gilchrist (vice-capt), S Clark, M Clarke, M Hayden, M Hussey, M Kasprowicz, J Langer, B Lee, S MacGill, D Martyn, A Symonds, S Tait, S Warne.

Australia one-day squad: R Ponting (capt), A Gilchrist (vice-capt), N Bracken, S Clark, M Clarke, D Cullen, B Hogg, M Hussey, M Johnson, S Katich, B Lee, D Martyn, S Watson, A Symonds.