Wichita ? Ivan the T. rex gets to tuck in his gut from now on at the Museum of World Treasures in Wichita.

Alan Komrosky, the paleontologist who discovered the 40-foot-long T. rex four years ago, has been working on resin casts of the big boy’s bones since finding him in South Dakota and helping display his skeleton in a fighting pose at the museum two years ago.

But in those two years, a big part of Ivan was missing: the gastralia. In some crocodilians and some dinosaurs, that’s the lattice-work of bones that held in the gut and protected the intestines. Think ribs for the tummy, and you can see the point nature had in making gastralia.

“They used it to protect themselves from the other guys trying to slice open their intestines,” Komrosky said.

Komrosky was busy in the museum basement recently, spraying and gluing together the resin cast of the gastralia, and was planning to fit the cast into the rest of the dinosaur one floor up within hours.

Ivan is mostly the real deal: 60 percent of the display skeleton on the museum’s first floor are the real fossilized bones.

But few dinos are found intact or mostly intact, and like all other paleontologists, Komrosky used accurate casts of the missing bone pieces to fill out the skeleton for the display.

He found the bones to the gastralia at the same time he found the rest of the skeleton, but the gastralia, small and more fragile than the leg and back vertebrae bones, were scattered and broken. It took time to assemble them for study, and it would have been impractical to wire or glue the many pieces together for the display, so he planned to make the cast.

Komrosky and his dino hunting partner, Gary Olson, discovered Ivan’s bones in 2005 near the confluence of the Little Missouri River and Box Elder Creek, in South Dakota just a few miles from the state lines with Montana and North Dakota.

They sold Ivan to a Wichita couple who have not been identified publicly. The couple loaned Ivan to the museum.