The pair were included in a 26-man party on Thursday who will fly to Johannesburg on Friday ahead of the teams’ Aug. 20 tournament opener in Nelspruit.
Kremer has been promoted from the Pumitas side that finished third in the world under-20 championship in England in June when they beat the Baby Boks in the bronze medal match.
Centres Matias Moroni, who is with Argentina's Sevens team at the Rio Olympic Games, and Jeronimo de la Fuente, nursing a leg injury, are missing the trip.
Argentina, who beat South Africa for the first time in 22 meetings on their last trip across the south Atlantic in last year’s championship, host the Springboks a week later in Salta.
Squad
Forwards: Agustin Creevy (captain), Felipe Arregui, Julian Montoya, Nahuel Tetaz Chaparro, Lucas Noguera Paz, Ramiro Herrera, Enrique Pieretto, Matias Alemanno, Guido Petti, Tomas Lavanini, Marcos Kremer, Pablo Matera, Javier Ortega Desio, Juan Manuel Leguizamon, Facundo Isa
Backs: Tomas Cubelli, Martin Landajo, Nicolas Sanchez, Santiago Gonzalez Iglesias, Juan Martin Hernandez, Matias Orlando, Manuel Montero, Ramiro Moyano, Santiago Cordero, Lucas Gonzalez Amorosino, Joaquin Tuculet
(Writing by Rex Gowar; Editing by Toby Davis)
