Roan Resources Inc. said April 15 that CEO Tony Maranto had resigned after less than two years with the Oklahoma City-based company.

In the meantime, Joseph A. Mills, currently a Roan board member and head of another oil and gas company Samson Resources II LLC, has been appointed executive chairman of the board and will assume the duties and responsibilities of the principal executive officer of the company. Roan said these appointments are both on an interim basis until the company’s search for a new CEO is complete.

Maranto had been named as Roan president, CEO and board chairman in November 2017. Throughout his more than 35-year career, he has also held leadership positions with EOG Resources Inc., Continental Resources Inc. and EnerVest Operating Co.

During his time with Roan, he led the company through a reorganization between Roan and predecessor Linn Energy Inc. that resulted in Roan becoming a fully separate, new publicly traded pure-play operator with assets in the Anadarko Basin’s Merge, Scoop and Stack plays.

Roan said Maranto resignation, effective April 12, was due to personal reasons. His departure joins a growing list of leadership personnel shakeups occurring as U.S. shale producers face growing pressure from shareholder activists.

Mills joined Roan’s board of directors since November 2018. He currently serves as president and CEO of Samson Resources II.

All of the senior management of Roan remains in place and will report to Mills. The company doesn’t expect any disruptions in the operations of Roan’s assets.

“I know the company well from my service on its board and am excited to assume the role of executive chairman,” Mills said in a statement on April 15. “Roan has a premier and unique asset with over 170,000 acres in the core of the Anadarko Basin, offset by best in class operators such as EOG, Cimarex, Continental, Marathon and Encana. ... I look forward to working closely with all the talented employees of Roan to help capitalize on the opportunities ahead.”