Given that not even 10 years ago one of Bill Murray’s co-stars was an elephant, it has been a minor movie miracle to observe his comedic evolution from the wisecrack to the wistful.

Murray is still a riot, but between Lost in Translation and the films of Wes Anderson, for whom Murray is a muse and vice versa, the only person he effectively puts down is himself. His manic muscles have relaxed to the point where he’s a clown with a frown not worth turning upside down.

The richness of this rebirth gets great display again in The Life Aquatic with Steve Zissou, Anderson’s latest, a more inherently sad film that lacks as snappy a comic rhythm as his previous films (Bottle Rocket, Rushmore and The Royal Tenenbaums) but not the themes of life’s zest lost, charmingly idiosyncratic characters and sets and locales that spring to life from far corners of the imagination.

Murray stars as Steve Zissou, an undersea filmmaker whose work combines the authenticity of Jacques Cousteau with the overwrought sense of adventure of a Jerry Bruckheimer production. As this film progresses, with gunfights and action sequences that look like extensions of the Beastie Boys’ video for “Sabotage,” it becomes clear this is as close to Bruckheimer as Anderson will ever get.

But passion has been drained from Steve’s life — his skullcap-and-Speedo clad crew isn’t having fun anymore, there is no spark even in his adulterous tendencies against wife Eleanor (Anjelica Huston) and, worst yet, his best friend, Esteban (Seymour Cassel), was eaten by a jaguar shark on the last voyage.

Just as Steve announces intentions to find the shark and exact revenge by killing it, he meets Ned (Owen Wilson), a Kentucky pilot claiming to be Steve’s illegitimate son. Ned ultimately joins Team Zissou, embarking on a voyage that becomes less about revenge than it does the importance of interpersonal connection.

As is the case with Anderson’s other films, there are almost too many good actors here for too many to truly stand out. Wilson, Anderson’s other muse, plays Ned as a smug-free, stand-up gentleman, his voice still an intoxicating charm but now with more believable innocence. Willem Dafoe also nicely plays against type as Klaus, a team veteran overly sensitive to Ned’s arrival.

But this is Murray’s movie all the way, with seemingly small moments that have big implications. When Steve verbalizes his emotions not for laughs, but with brutal honesty, those moments are either precisely cutting or insightfully sad for a man facing mortality and fallibility on all fronts.

This is all blended with expectedly strange bits of comedy that work: the so-fake-it’s-funny diagrammatic dissection of Zissou’s boat, the Belafonte; a three-legged dog to which Steve takes a liking; a group of interns getting more than they bargained for after a run-in with angry pirates; and the pressing need to rescue the mission-underwriting “bond company stooge” from those pirates.

Instead of placing an instant grip on your attention, The Life Aquatic is a slow, measured character study, whose second-hour payoff is worth getting to even if it is more somber than what Anderson acolytes are used to. While it would be nice to be able to laugh a little more (acoustic-guitar versions of David Bowie classics sung in Portuguese only go so far), the film delivers a metaphor for the death of romantic and robust boyhood imagination with great subtlety.