The big field of Republicans seeking 4th Congressional District nomination is a little less crowded.

Rob Russo, a former state senator from Bridgeport/Trumbull and aide to former U.S. Rep. Christopher Shays, confirmed Thursday that he has abandoned his bid for the GOP nod to take on U.S. Rep. Jim Himes, the freshman Democrat.

Russo, in a brief press conference in Fairfield, then endorsed his longtime friend, state Sen. Dan Debicella of Shelton, for the nomination. He made the announcement at the Metro Center site after Gov. M. Jodi Rell and town officials held a press conference announcing that financing is in place to finish the town's third railroad station.'

Russo's withdrawal leaves four other Republicans in the race in addition to Debicella.

They include: Rick Torres, the Bridgeport businessman who lost the 2003 mayoral election; Tom Herrmann, Easton's second-term first selectman; Will Gregory, 24, of New Canaan, and Rob Merkle, an executive recruiter from Norwalk.

Russo, a real estate lawyer who headed Rell's southwestern district office, and Debicella, a Harvard-educated marketer, were considered early favorites in the race with the most funding and the highest name recognition in the 17-town district.

Debicella has lined up many endorsements from leaders in 15 district towns, including the Republican Town Committee chairmen from Darien, Greenwich, Monroe, New Canaan, Norwalk, Redding, Shelton and Weston.

The contest for the Republican nomination is expected to continue beyond the party's May 21 convention to a primary election.

There are two ways hopefuls can get on the primary ballot: With 15 percent of the delegates at the May convention or with about 2,500 petition signatures from registered Republicans.