San Francisco, Calif. — Vostu is fighting back against the lawsuit social game developer Zynga filed in June accusing it of copyright infringement. Vosta’s response was to file Wednesday an extensive counterclaim questioning Zynga’s claim to own the rights in the first place.

The original suit asserted that Vostu had stolen Zynga’s ideas, game designs, mechanics, objectives and storylines. Vostu avers that Zynga has copied designs from other gaming platforms in the past, and that it has no rights over the design of everyday things like farms, barns and chairs. Vostu further claims that the lawsuit’s “deceptive allegations are at their foundation a vicious effort to malign Vostu for competing with Zynga.”

Both companies have a lot at stake, since Vostu is the largest social game company in Brazil and other territories.

“It is one thing to be inspired by Zynga games, but it is entirely different to copy all of our key product features, product strategy, branding, mission statement and employee benefits lock, stock and barre,” Reggie Davis, general counsel of Zynga said in a statement

The lawsuit was filed in the United States District court in the Northern District of California.

Related Links: (New York Times) (Wall Street Journal’s Digits blog) (Legal documents, via Scribed user marrington_2)