Jurassic Park III” continues the tradition of American filmmaking in which a successful movie’s story and characters are stretched so far beyond recognition for a sequel that the result is just twisted and grotesque enough to be enjoyable.

With its third installment, “Jurassic Park” now joins the pantheon of films that includes “Jaws,” “Rocky,” and “Superman,” in which sequels dirtied the film’s name so badly that the merits of the original film are forgotten. Rocky Balboa’s struggle for dignity among Philadelphia’s prizefighters is heroic; Rocky Balboa’s effort to end the Cold War a decade later, on the other hand, is absurd.

“JP3” lands Dr. Alan Grant (Sam Neill) back on the dinosaur-infested island off Costa Rica, this time with a divorced couple (William H. Macy and Tia Leoni) searching for their teenage son. Since his last trip, Grant has learned that velociraptors, the super smart dinosaurs made famous by the first two movies, might have the ability to communicate verbally. How to get these people deserted again must have been a stumbling point in the script and might have been one of the problems that writing team Alexander Payne and Jim Taylor (“Election”) were brought in to solve. The movie follows Grant and company as they are picked apart by the beasts on their trek to the island’s coast.

But the film’s similarities to the rest of the “Jurassic Park” movies end here. The most apt predecessor to “JP3” is 1983’s “Jaws 3-D,” another film culled from the characters of a popular thriller by Steven Spielberg ,who produced “JP3.”

“JP3” is not a great movie, but is still irresistible. The movie isn’t quite as cynical as its formula, with more than a few hints of dark humor. This time, nobody is rooting for these rubes to survive. The parents are dangerous and self-absorbed half-wits who probably aren’t fit to raise a child. Anyone dumb enough to be stuck on an island known by the world to be covered in dinosaurs is just nature’s way of keeping these hungry beasts fed.

One example of the film’s sly humor has Grant and the recovered son, Eric (Trevor Morgan), discussing Grant’s books about the island. His conclusions are jabs at the first two movies: The story was better when the characters liked dinosaurs and all the talk about chaos theory was too self-important.

In another scene, Grant uses a satellite phone to call the U.S. for help, but the child who answers waits to watch Barney the Dinosaur on television before delivering the message.

“JP3” deprives the audience of seeing any characters well devoured, one of the great pleasures of the first two “Jurassic Park” movies. Instead, dinosaurs have found it more efficient simply to break the characters’ necks, ninja-style.

“JP3” is more a companion piece to “Jurassic Park” and “The Lost World” than a sequel. In no justifiable way can the series be called a trilogy. The only character retained from the first two movies, Grant, is played as a caricature crying doom from the moment they land. “JP3” has the feel of a direct-to-video follow-up and should be on the shelves at Blockbuster Video next to “Darkman 3: Die Darkman Die” and “The Substitute 3: The Winner Takes All.”

Fans of the predecessors likely will recognize “JP3” as a lazy and cheap effort, but its quick pace and swift action entertains more than it bores.