December marked the end of several eras in mixed martial arts.

The UFC is moving on from its relationship with Spike TV, with the Dec. 30 UFC 141 Spike Prelims marking the last broadcast on the cable partner that helped create the UFC we know today through its willingness to air The Ultimate Fighter.

It also marked the last time Brock Lesnar will step inside the Octagon to compete. While reports from The MMA Corner in August suggested that Lesnar was seriously contemplating retirement, everyone was quick to dismiss those reports based on denials from Lesnar and UFC president Dana White. In the end, however, despite apparent surprise at the announcement from many, White included, we can’t help but say we saw it coming.

Lesnar’s run in the sport was relatively short, lasting only eight fights with five wins, but he undoubtedly made a huge impact. The NCAA wrestling champion and former WWE superstar quickly became a top pay-per-view draw for the UFC, and only faced elite heavyweights upon his arrival in the Octagon. There’s no question that both the UFC and many fans will miss the outspoken, but recently more humble big man.

Lesnar’s departure also signaled the arrival of another top heavyweight to the Octagon after years of anticipation. Alistair Overeem debuted in a headlining bout with the organization and effectively sent Lesnar into retirement via some well-placed knees and a kick to the body.

UFC 141 and its headliner brought to a close a month in which the UFC also crowned two new TUF champions and showcased light heavyweight champion Jon Jones. Meanwhile, a return to Japan gave formerly invincible Fedor Emelianenko a chance to build a new winning streak and Strikeforce hosted an event in which two of its small group of remaining champions were able to remind the MMA world of their dominance.

So, who moved the needle on The Gauge the most in December? Read on to find out…

1. Jon Jones

It was supposed to be the toughest test yet for Jon Jones. How many times has that line been put to (electronic) paper by MMA journalists this year? The answer must at least hit triple digits, as “Bones” defeated Ryan Bader to earn a title shot, destroyed Mauricio “Shogun” Rua to claim the UFC light heavyweight belt and successfully defended it against Quinton “Rampage” Jackson. And yet it would be written again as he headed into a December title defense at UFC 140 against Lyoto Machida.

The phenom would emerge from the test with his now routine ease. Jones remained calm after getting rocked and just a short time later locked in a standing guillotine choke to finish Machida. The sight of Jones releasing the hold and Machida’s limp body falling to the canvas put an exclamation point on the year of 2011 for Jones. The champ is starting to put himself in the same category as Anderson Silva and Georges St-Pierre as one of the UFC’s seemingly invincible champions.

2. Alistair Overeem

The “Demolition Man’s” arrival in the Octagon has been highly anticipated for several years now. He’s held the Strikeforce heavyweight championship and stepped into the kickboxing ring to claim the 2010 K-1 World Grand Prix championship, but now it’s time for the vaunted striker to test his skills against the best the UFC has to offer.

He kicked things off with an end-of-year battle with UFC star Brock Lesnar at UFC 141. A few knees and one kick to the body later and Overeem’s hand was raised while Lesnar prepared to announce his retirement. It was an impressive debut performance, and competing against Lesnar assured him of plenty of eyes. Those fans who didn’t know his name before definitely know it now.

Next up for ‘Reem will be a title tilt against recently crowned UFC heavyweight kingpin Junior dos Santos.

3. Cristiane “Cyborg” Santos

Sixteen seconds.

That’s all it took for Strikeforce female featherweight champion Cristiane “Cyborg” Santos to remind fans of her utter domination of the women’s 145-pound division. At Strikeforce: Melendez vs. Masvidal, Santos returned from a near year-and-a-half absence from the Strikeforce cage and demolished Hiroko Yamanaka.

4. Gilbert Melendez

Melendez defended his Strikeforce lightweight crown on Dec. 17 against Jorge Masvidal, taking the win via unanimous decision. Masvidal spelled the last true challenger for Melendez under the Strikeforce banner, but Zuffa intends to keep all current Strikeforce fighters in place rather than allowing them to migrate to the UFC. This likely means a slim list of challengers for Melendez in 2012.

5. Michael Bisping

After a season of tension and pranks while Bisping and Jason “Mayhem” Miller coached on The Ultimate Fighter 14, the two finally got to settle the score at the show’s finale event in Las Vegas on Dec. 3. Bisping proved to be, by far, the superior fighter that night, as Miller quickly gassed. The win puts Bisping close to the front of the line of middleweight contenders in the UFC.

6. Diego Brandao and John Dodson

The Ultimate Fighter 14 marked the last season of the reality series on Spike TV, as future editions will air on FX under the UFC’s new deal with the Fox Networks. It also marked the first season featuring the UFC’s (at the time) two lightest weight classes, bantamweight and featherweight.

Brandao impressed in working his way to the finals of the show’s featherweight bracket. The finals pitted him against Dennis Bermudez, and it would be Brandao impressing once again. The Jackson’s MMA product locked in an armbar just seconds before the end of the first stanza to claim the win and the TUF championship.

Meanwhile, the bantamweight division’s first appearance on the reality show actually prompted the long-awaited creation by the UFC of a flyweight division. Talk of 125-pounders in the Octagon was surely sparked by John Dodson’s run through the 135-pound bracket on the show. Typically fighting at 125, Dodson moved up in weight to compete on the show and emerged as the Ultimate Fighter champion following a TKO win over T.J. Dillashaw at the show’s finale.

7. Frank Mir

Making the UFC’s highlight reel for one gruesome appendage-snapping submission is noteworthy, but how about doing it twice? Frank Mir, who once snapped Tim Sylvia’s arm in half in cringe-worthy fashion, did just that at UFC 140.

In a rematch against Antonio Rodrigo Nogueira, whom Mir had previously defeated via TKO, Mir snagged one of Big Nog’s arms and applied a kimura. The former heavyweight champion continued to crank the arm until the visible pop of a broken bone forced the stoppage.

8. Chan Sung Jung, Nate Diaz and Johny Hendricks

December was also a month of surprise performances. Jung, Diaz and Hendricks are all good fighters, but none were expected to do what they did this month.

At UFC 140, Jung needed a mere seven seconds to knock out Mark Hominick. The win is especially significant for “The Korean Zombie,” as Hominick had previously taken UFC featherweight kingpin the distance in a title bout. Jung is now 2-0 in the UFC following an 0-2 run in the WEC. Could a zombie soon be challenging for a title?

Meanwhile, at UFC 141, two fighters impressed beyond expectations. Hendricks took out perennial welterweight contender Jon Fitch with just one punch, while Nate Diaz out-struck rising contender Donald Cerrone in a lightweight match-up.

9. Fedor Emelianenko

If there’s one place Fedor is comfortable, it’s in a roped ring in a Japanese arena on New Year’s Eve. The Russian heavyweight has been there plenty of times against a wide variety of opponents, from legitimate top heavyweights to more questionable foes. His victim on this particular New Year’s Eve at Dream’s marathon-length event was Olympic gold medalist judoka Satoshi Ishii.

Ishii’s lack of experience in the realm of mixed martial arts allowed Fedor to score an easy knockout win in the first round of their contest. The victory puts Emelianenko on a two-fight winning streak following a disappointing three-fight skid under the Strikeforce banner.

10. Brock Lesnar

Lesnar might have been on the losing end of his UFC 141 bout with Alistair Overeem, but it was his retirement that received a large amount of post-fight buzz. Lesnar’s has struggled to return to the Octagon following recurring bouts of diverticulitis. Doctors had advised Lesnar to stop, but he decided to push forward and compete again. However, it was clear from his post-fight interview that he had already planned to retire after, at most, two more fights.

Lesnar might have only compiled a 5-3 mark in the sport, but his impact definitely goes beyond wins and losses. As a WWE star and an out-spoken and cocky fighter, Lesnar likely introduced new fans to the sport and provided the UFC with a reliable pay-per-view draw.

Photo: Jon Jones (Phil Lambert/The MMA Corner)