Danbury Mayor Mark Boughton and Senate Minority Leader John P. McKinney of Fairfield, the runners up to Tom Foley in balloting for governor at the GOP state convention Saturday, filed papers Thursday that place them on the ballot for a Republican primary on Aug. 14.

But Boughton lost his running mate, Heather Bond Somers, a significant blow to his ability to qualify for an initial public financing grant of $1.35 million. A new alliance is expected, most likely with Shelton Mayor Mark Lauretti, whose lawyer made inquiries about getting on the primary ballot for lieutenant governor.

“We have an alternate strategy we’ve been working on for a couple of days,” Boughton said, declining to be specific. Asked about Lauretti, Boughton said, “I think Mark would be an interesting candidate for lieutenant governor.”

(Update: Boughton later confirmed during a taping of WFSB’s “Face the State,” to be aired Sunday, that Lauretti will be his running mate.)

Lauretti, a gubernatorial candidate who won only one percent of the convention vote, said earlier Thursday that his official stance “at this point” is that he is pursuing an alternate route to a gubernatorial primary: collecting 8,190 petition signatures. A fifth gubernatorial candidate, Joe Visconti of West Hartford, already is collecting signatures.

Somers, one of three candidates for lieutenant governor, announced she was ending her alliance with Boughton and would continue as an unattached candidate in the primary.

“Obviously, we’re disappointed, but it was not unexpected,” Boughton said. “This doesn’t mean our train stops. It wasn’t like we didn’t see it coming.”

The Somers campaign gave no reason for the dissolution of the partnership, other than alluding to her stronger showing at the convention.

“There’s been a number of Heather supporters who have expressed deep personal concern over the last five days and before the convention — clearly more after — regarding the linkage of the two candidates,” said Richard Foley, a campaign spokesman.

Somers, a businesswoman and former part-time mayor of Groton town,  finished second to Bacchiochi in the lieutenant governor voting, finishing with 35.6 percent. Boughton finished second to Foley, with 22.2 percent.

Did Somers renege on a deal to run with Boughton and jointly qualify for public financing?

“I don’t believe so. The reason I don’t believe so was everybody understood that there’s not a legal merger until the form had been signed by both parties,” Foley said, referring to a joint application for public financing. “That’s something both sides were keenly aware of.”

Boughton pointedly noted that in 2010 he honored his deal to jointly raise money as the running mate of Michael C. Fedele, even though Boughton polled more strongly at the convention than did Fedele.

“Our business is based on a handshake and keeping your bond,” Boughton said.

Foley, the 2010 nominee and the GOP’s 2014 front runner in two Quinnipiac University polls this spring, won the convention endorsement on the first ballot. Boughton and McKinney each qualified for a primary with more than 15 percent of the convention vote.

Lauretti left open the possibility of ending his campaign Saturday, but he said Thursday his campaign was out collecting signatures to qualify for a gubernatorial primary.

“That may change. And if it does, it would have to be soon, obviously,” Lauretti said.

The secretary of the state’s office said Lauretti’s lawyer had informed its election division he wished to withdraw his gubernatorial petitions and instead try to petition his way on the GOP ballot for lieutenant governor. Lauretti denied that was the case, though he said he has been urged to consider a run for lieutenant governor.

He could not be reached after Somers’ announcement to say if he had discussed an alliance with Boughton. Lauretti has proven to be a strong fundraiser, taking in $106,735 in qualifying donations of no more than $100 each in little more than three months.

If Lauretti were to switch to the race for lieutenant governor, he would have to return those funds and begin anew.

McKinney, meanwhile, announced he filed his papers.

“I’m officially on the ballot and ready to take Connecticut in a positive new direction,” McKinney said in a statement.

Boughton made no announcement and was not available for comment, but the secretary of the state’s office said he filed his paperwork. Visconti already was collecting signatures. To qualify for the ballot, he needs to collect sufficient signatures by June 10.

Penny Bacchiochi won the endorsement for lieutenant governor, but Somers and David M. Walker each qualified for a primary. None had filed their papers by late Thursday afternoon.

Somers’ announcement is a blow to Boughton, primarily for financial reasons.

Alone, Boughton had raised less than $150,000 as of the April report. He needs $250,000 to qualify. By herself, Somers needs just $75,000 to qualify a public grant for the primary for lieutenant governor.

McKinney and Walker formed a ticket at the convention, but they intend to separately seek public financing grants. Foley and Bacchiochi each are unattached, and neither needs an alliance to qualify for public financing.

Candidates for governor and lieutenant governor appear separately on a primary ballot, and voters have mixed and matched in other years. In 2010, Boughton shifted from being Fedele’s running mate in the primary to Foley’s in the general election after Boughton won the primary for lieutenant governor, while Foley won the primary for governor.