UPDATE 1-Talos Energy CEO Tim Duncan steps down, Mills named interim chief

Adds shares in paragraph 2, details and background from paragraph 3 onwards

Aug 30 (Reuters) - Talos Energy TALO.N said on Friday its CEO Tim Duncan had stepped down on Aug. 29 after serving more than 12 years as the U.S. oil and gas firm's top boss.

Shares of the company fell 2.7% in premarket trade.

The company board member Joseph Mills, who has more than four decades of experience in the oil and gas industry, as its interim chief.

Talos did immediately respond to Reuters' questions about Duncan's departure.

Duncan had joined Talos as its chief executive in January 2012 and also serves as board member at gas producer Chesapeake Energy CHK.O, according to his LinkedIn profile.

Under Duncan, Talos had been part of a handful of companies to have made significant discoveries in oil and gas exploration areas in offshore Mexico.

Talos said its board has initiated a search for a successor in partnership with a leading executive search firm.

(Reporting by Sourasis Bose in Bengaluru; Editing by Krishna Chandra Eluri)

((Sourasis.Bose@thomsonreuters.com;))