Champions Cris Cyborg and Amanda Nunes have been sent bout agreements for a Dec. 29 UFC super-fight

The UFC has issued bout agreements to women’s featherweight champion Cris Cyborg and bantamweight champion Amanda Nunes for a planned Dec. 29 featherweight-title mega-fight at T-Mobile Arena in Las Vegas.

Brazil’s Nunes (16-4) is believed to have already signed and returned her agreement to meet her countrywoman, according to an official familiar with the talks but unauthorized to speak about them publicly.

Cyborg (20-1), who trains in Costa Mesa, might be posturing for further discussion on the topic after announcing earlier Wednesday that the paperwork was linked for her to fight Nunes at UFC 228 in Dallas on Sept. 8.

An official familiar with the paperwork sent to Cyborg made it clear Wednesday that the timing is best for Nunes and Cyborg to fight in December.

Cyborg told the Los Angeles Times on Wednesday night that she was under the impression as recently as Friday that Nunes would fight her Sept. 8, only to receive the agreement with the Dec. 29 date on it this week.

Cyborg has only two fights remaining in her current UFC deal. She says waiting until December for the first of those will make it a difficult turnaround to take a second fight before the end of her contract in March.

“I was told they didn’t have anyone to fight me, and I responded, ‘Fine, you have to release me,’” Cyborg said. “Amanda wouldn’t agree to fight me in July … she says her leg is hurting, ‘Oh, I need six months … .’

“I’ve accepted the fight with Amanda three times — before July, July and Sept. 8. I don’t need to wait for her when I’m ready to fight. I asked the UFC to bring Amanda to a Las Vegas doctor to see if this injury is true. They never did.”

Cyborg fought in late December and early March, first defeating former bantamweight champion Holly Holm by unanimous decision, then returning to replace injured men’s featherweight champion March 3 to knock out Yana Kunitskaya in the first round.

Nunes, 30, has been similarly dominant since winning the belt from Miesha Tate in 2016, then knocking out former champion Ronda Rousey in the first round later that year. She successfully defended her belt for a third time in May with a fifth-round stoppage of Raquel Pennington in Brazil.

While Cyborg was initially reluctant to fight a fellow Brazilian, she said Nunes’ continued push for the fight convinced her to take on the challenge in a division that is so thin the UFC has yet to post top-10 rankings as it does in other divisions.

Although the scope of the fight is significant, Cyborg is concerned by Nunes’ drawing power, saying she believes Nunes had less than 100,000 pay-per-view buys in a May main-event victory in Brazil.

“She don’t sell pay-per-views … I do. I already proved this,” Cyborg said. “I know they want to make this fight cool, but I don’t need to fight anybody and I don’t need to wait. I don’t have any injury. I haven’t fought since March, and waiting five more months is a long time.”

The bout is a compelling match between two superb strikers whose endurance and toughness easily rank them 1-2 in any pound-for-pound ranking of female MMA fighters.

Cyborg said a new crop of “The Ultimate Fighter” female fighters could be sought for an interim bout in September, or “anyone else.”

Asked if she’ll sign the bout agreement to fight Nunes in December, Cyborg said, “I’ve already agreed to fight Amanda three times. My word is more important than a signed paper.

“I’m ready … five months is a long time. But I’m ready.”

A second super-fight this year comes after the success of Saturday’s UFC 226 card in Las Vegas, when light-heavyweight champion Daniel Cormier knocked out heavyweight champion Stipe Miocic to join Conor McGregor as the only simultaneous two-belt champion in organization history.

An industry source reported the card drew nearly 400,000 pay-per-view buys despite the loss of the featherweight title fight between unbeaten Southland challenger Brian Ortega and champion Holloway, who withdrew with concussion effects.

The UFC is eyeing a Nov. 3 card at Madison Square Garden for Cormier in an expected meeting with former two-time light-heavyweight title challenger Alexander Gustafsson should Gustafsson prevail over Volkan Oezdemir on the UFC 227 card at Staples Center Aug. 4.

And the organization is awaiting for a McGregor return pending the announcement of a likely plea bargain on July 26 following his hand truck attack of a bus carrying UFC fighters in April in Brooklyn.

“I am ready, able, and willing to fight ANY opponent now,” said Cyborg. “I am willing to fight Amanda Nunes on the September 8 date that was discussed. I am not willing to wait until December for a bout.”

lance.pugmire@latimes.com