EA's lawsuit is the latest in a series of copycat accusations leveled against Zynga, a company that has shrugged off similar litigation in the past as it grew into the dominant publisher of games on Facebook.

In a 40-page filing, the Redwood City, California-based game publisher pointed out numerous game elements it claimed Zynga mimicked in "The Ville," from personality traits to avatars' actions, such as conversing and dancing.

In one instance, EA claimed "The Ville" characters included eight personality types, ranging from athlete to villain, that mirrored "The Sims" own jock-to-scoundrel lineup. EA also accused Zynga of using eight identical colors for its characters' skin-tone palette.

"Zynga's design choices, animations, visual arrangements and character motions and actions have been directly lifted from 'The Sims Social,'" Lucy Bradshaw, head of EA's Maxis label, said in a statement. "The copying was so comprehensive that the two games are, to an uninitiated observer, largely indistinguishable."

"The Sims Social," which allows players to create their own customizable characters and interact in a fictional town, was launched on Facebook in August last year.

Zynga announced its own Facebook offering "The Ville," which allows users to dress their avatars, build homes and interact, in June as part of its "Ville" franchise.

"It's unfortunate that EA thought that this was an appropriate response to our game, and clearly demonstrates a lack of understanding of basic copyright principles," Reginald Davis, Zynga's general counsel, said in a statement.

"We plan to defend our rights to the fullest extent possible," he added.

GAMING INDUSTRY LAWSUITS COMMON

Analysts say it is highly common for competitors in the cutthroat gaming industry to create similar offerings, and the sector has seen a large number of lawsuits in recent years, most of which have been settled out of court.

"There's a tremendous significance to this case," said J. Gregory Boyd, a partner at Frankfurt Kurnit Klein & Selz PC. "The issues of copying, particularly in the social space, have been bubbling for years. Now we have two behemoth companies that have the opportunity between the two of them to settle a lot of questions."

But even if EA-Zynga is settled without reaching a jury, which is likely, the court's decision to grant or deny EA's request for a preliminary injunction to stall "The Ville" could be telling, Boyd said.

Founded by CEO Mark Pincus in 2007, Zynga has been no stranger to copyright spats, but it has rarely faced an antagonist as large as EA in the courtroom.

"It's definitely a battle; it's going to be very costly and will take a lot of legal hours for EA to establish its claim," said Jovan Johnson, partner at Los Angeles-based law firm Johnson & Moo. "The problem that I see for Zynga is that EA is well capitalized, they can afford to maintain the lawsuit."

In 2011, Zynga settled with Digital Chocolate over a dispute about one of its early hits, "Mafia Wars," while that same year, The Learning Channel, maker of educational hit "Oregon Trail," slapped Zynga with a lawsuit over the name of a "FrontierVille" release also named "Oregon Trail." That case also settled.

But has Zynga not shied away from dishing out lawsuits of its own. The company reached a settlement in December with game developer Vostu after suing the smaller company for copying games like CityVille. And in May, Zynga sued a French developer for using the word "Ville" in a game title.

Zynga stockholders, who have punished the stock in recent days following a disastrous second-quarter earnings report last week, barely flinched at news of the lawsuit.

On Friday Zynga shares closed up 0.7 percent at $2.72 and EA shares were up 5.27 percent at $11.97 on the Nasdaq.

"It's not the first time Zynga has been sued and it's not going to be the last," said National Alliance Securities analyst Mike Hickey. "They have bigger issues to look at."

EA ALLEGES ZYNGA HAD "PRIVATE" INFORMATION

As part of its lawsuit, EA alleged that Zynga obtained "private" information about "The Sims Social" development plans after hiring three of EA's top employees shortly before the game's launch.

In 2011, Zynga hired EA's chief operating officer, John Schappert, to take on a similar role at Zynga at a time when "'The Sims Social' was in its final stages of development and EA was preparing its rollout," the lawsuit said.

It said other EA employees with knowledge of "The Sims Social" that followed Schappert to Zynga included Jeff Karp, now Zynga's top marketer, as well as Barry Cottle, a business development executive.

"By early 2012, Zynga had targeted and hired away three of EA's top executives who had access to the most sensitive design, development, and strategic information about 'The Sims Social,'" EA alleged.

The complaint was filed in the District Court for the Northern District of California.

(Reporting By Malathi Nayak and Gerry Shih; editing by Gerald E. McCormick, John Wallace, G Crosse)

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