Prehistoric creatures and robots were in a photo finish for the Fourth of July box-office crown Sunday, with “Transformers: Revenge of the Fallen” and “Ice Age: Dawn of the Dinosaurs” tied with $42.5 million each.

Final numbers Monday will sort out which movie actually came in first, Paramount’s “Transformers” or 20th Century Fox’s “Ice Age.” Numbers reported during the weekend are estimates based on the studio’s projections for how much business the movies will do on Sunday.

“I’ve seen squeakers before in my time, but never one like this,” said Paul Dergarabedian, box-office analyst for Hollywood.com.

In past close finishes, studios have accused each other of inflating their Sunday estimates to gain first-place bragging rights, only to have another movie take the No. 1 spot once final numbers are reported the next day.

“This shows a lot of respect between the two studios,” Dergarabedian said. “They’re just saying `Look, as of right now, it’s too close to call.’”

Universal’s crime saga “Public Enemies,” starring Johnny Depp and Christian Bale, debuted a solid No. 3 with $26.2 million.

It’s rare when box-office rankings are so close, particularly in summer, when movies typically have huge opening weekends then trail off to make way for the next blockbuster.

But the action adventure “Transformers” held up well from its $109 million debut the previous weekend, while the animated sequel “Ice Age” packed in family crowds.

With a $293.5 million domestic total after just 12 days, “Transformers” shot past Disney and Pixar Animation’s “Up” to become the year’s highest-grossing movie. The sequel reunites human stars Shia LaBeouf and Megan Fox with shape-shifting robots in a war against evil machines.

“Ice Age,” the third installment in the cartoon franchise, brings back voice stars Ray Romano, Denis Leary, John Leguizamo and Queen Latifah as the gang of extinct animals encounter a lost world of dinosaurs underground. Since opening Wednesday, “Ice Age” has taken in $67.5 million.

Other studios generally were tracking “Transformers” and “Ice Age” within a few hundred thousand dollars of each other.

“It’s just so close,” said Bert Livingston, Fox distribution executive. “It all comes down to Sunday for us. We are elated to be in that rarefied air with one of the biggest event movies ever.”

With the Fourth of July falling on Saturday, usually Hollywood’s busiest day, revenues trailed off as people skipped movies to watch fireworks and go to cookouts or other outdoor activities.

“Public Enemies,” starring Depp as 1930s gangster John Dillinger and Bale as FBI man Melvin Purvis, pulled in an audience of older adults who often do not pack theaters for summer’s action tales, family flicks and comedies.

“We felt this was going to be the right moment to insert something with a little bit more substance into the mix,” said Adam Fogelson, Universal’s president of marketing and distribution.

“Up” reached a milestone of its own, its $6.6 million weekend lifting its domestic haul to $264.9 million, passing “The Incredibles” ($261.4 million) to become No. 2 on the Disney-Pixar hit list behind “Finding Nemo” ($339.7 million).

With $10.4 million, the Warner Bros. bachelor-party comedy “The Hangover” became the year’s fourth movie to cross the $200 million mark, climbing to a domestic total of $204.2 million.

Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Hollywood.com. Final figures will be released Monday.

1 (tie). “Ice Age: Dawn of the Dinosaurs,” $42.5 million.
1 (tie). “Transformers: Revenge of the Fallen,” $42.5 million.
3. “Public Enemies,” $26.2 million.
4. “The Proposal,” $12.8 million.
5. “The Hangover,” $10.4 million.
6. “Up,” $6.6 million.
7. “My Sister’s Keeper,” $5.3 million.
8. “The Taking of Pelham 1 2 3,” $2.5 million.
9 (tie). “Year One,” $2.1 million.
9. (tie). “Night at the Museum: Battle of the Smithsonian,” $2.1 million.