Experienced lock Eben Etzebeth will captain the Springboks in the injury absence of Warren Whiteley, coach Allister Coetzee confirmed on Wednesday.
Loose forward Siya Kolisi was named as the Bok vice-captain.
Etzebeth led South Africa in the last Test of the three-match series against France in June, when Whiteley was ruled out of action because of a groin injury.
Whiteley missed the remainder of the Super Rugby campaign as a result of the injury, and he will be out of action for at least six more weeks, ruling him out for the opening part of the Rugby Championship.
“Eben did an excellent job against France in Johannesburg, when he had to step in at short notice after the late withdrawal of Warren. He enjoys the respect of his teammates, and also commands respect on and off the field,” said Springbok coach Coetzee.
“He is well supported by our strong leadership group, which consists of Siya, Tendai Mtawarira and Elton Jantjies.”
Etzebeth has played in 57 Tests since making his debut on 9 June 2012 against England in Durban, when he was 20 years old.
The Springboks start their campaign against the Pumas on 19 August in Port Elizabeth, and then travel to Argentina a week later for the return leg in Salta.
Meanwhile, the Boks continued with their preparations on Wednesday with two more training sessions in Port Elizabeth. The squad had a split session in the morning, which consisted of field drills and gym work.
Later in the afternoon, they staged a public training session at the Gelvandale Stadium on the outskirts of the city.