MEXICO CITY, June 4 (Reuters) - Mexican President Enrique Pena Nieto has chosen Gustavo Hernandez as the new head of state oil giant Pemex's exploration and production arm, the company said on Wednesday.

Hernandez, a longtime Pemex employee, has been running the key unit since February 7, the statement said, when his predecessor, Carlos Morales, resigned from the post.

Pemex said Hernandez officially took charge on June 1.

(Reporting by Gabriel Stargardter; Editing by Simon Gardner)