10 Mousey Facts About Mussaurus

Scientists know little about what growing up in the age of dinosaurs was like, but Mussaurus can help us better explore this intriguing subject. 

1. Its Name Means “Mouse Lizard.”

Was Mussaurus especially rodent-like? No, but babies measuring under 8 inches long have been unearthed, hence the cute-sounding genus name.  

2. It Gets a Cameo in Michael Crichton’s The Lost World.

Early on, one of the novel’s protagonists gingerly picks up a palm-sized Mussaurus. However, for reasons unknown, Spielberg cut this little herbivore from The Lost World: Jurassic Park, his 1997 film adaptation.

3. Mussaurus is Often Mistaken for a Dinosaur Record-Holder.

Mussaurus was originally discovered in 1979 and, at the time, was known only from hatchling remains. Ever since, popular science books have been touting it as the “world’s smallest known dinosaur.” But don’t call Guinness just yet! Paleontologists estimate that average adults would have been over 10 feet long, making Mussaurus far too large to merit this distinction—an assessment vindicated two years ago, when a quartet of grown-up specimens emerged.

Today, the tiniest living dino is the bee hummingbird (Mellisuga helenae), which can comfortably perch on the end of a pencil. But what about those non-avian, extinct varieties? China’s 16-inch Anchiornis huxlei (pictured above) currently takes the cake.

4. Creepy-Crawlies Might Have Been on its Menu.

Paleo-artist Gregory S. Paul believes that, given the shape of their teeth, “small juvenile Mussaurus ... supplemented their diet with insects.” Hey, arthropods are a great source of protein—don’t knock ‘em ‘til you’ve tried ‘em!

5. The Oldest-Known Dinosaur Nest Likely Belonged to a Mussaurus.

In Patagonia’s bountiful fossil beds, seven juveniles were spotted hanging out together next to a pair of decently-preserved eggs. If this actually represents a dinosaurian nesting site, at 215 million years old, it would be the earliest we’ve yet discovered.

6. It Preferred Walking on All Fours.

Mussaurus hatchlings had some relatively long bones in their forelimbs, so the wee beasties most likely got around quadrupedally.     

7. Mussaurus Was Originally Misidentified as a Different Dino.

Remember those mature Mussaurus we brought up earlier? Despite the fact that they lived in Argentina, paleontologists once mistook them for Plateosaurus, a long-necked, stiff-tailed genus known exclusively from Europe (though, in all fairness, those two continents were connected back then as parts of a huge landmass called “Pangaea”).

8. It Had “Extremely Thin” Eggshells.

“You’re a tough egg to crack” … or are you? Mussaurus eggs are notable for having unusually thin shells, compared to most sauropodomorphs (“long-necked” dinos), whose babies had to fight through much thicker casings. Maybe their descendants evolved heftier eggshells as a defense against omelette-savoring predators.

9. Mussaurus Parents Probably Stuck Around.

To many animals, getting abandoned by dads and moms is considered normal. But the fact that partially-grown juvenile Mussaurus have been found near egg fragments might imply some level of parental care. In all probability, the little bundles of joy would have needed it—babies had awkward proportions and were likely rather helpless.

10. Mussaurus Heads Would Have Changed a Lot with Age.

There’s a reason the DMV doesn’t let you use a baby photo on your driver’s license. As people grow, their appearance changes dramatically, and dinosaurs were no different. Relatively speaking, newly-hatched Mussaurus had bigger eyes, shorter snouts, and larger nasal bones than older individuals.

New LEGO Set Recreates Jurassic Park's Iconic Velociraptor Chase Scenes

Jurassic World: Fallen Kingdom, the fifth installment in the Jurassic Park franchise, is skulking into theaters on June 22. That makes now the perfect time to revisit the original film in LEGO form.

This LEGO set, spotted by Nerdist, depicts some of the most suspenseful scenes from the 1993 movie. There's the main computer room where Ariana Richards's Lex shows off her hacker skills while Alan Grant (Sam Neill) and Ellie Sattler (Laura Dern) struggle to keep a hungry dinosaur from barging in. Just like in the film, the door features a deadbolt lock that's velociraptor-proof (though, unfortunately for the characters, the detachable window is not). Other Easter eggs hidden in this part include a map of Isla Nublar and a screener saver of LEGO Dennis Nedry (Wayne Knight).

In the neighboring room, you'll find the cold storage unit where the dinosaur embryos are kept, along with the fake shaving cream can Nedry uses to steal them. The final section is the kitchen, where Tim (Joseph Mazzello) and Lex are stalked by the velociraptor. There's less room for them to hide in the LEGO version compared to the movie set, but there is at least one functioning cabinet for Lex to tuck herself into. Closer inspection reveals even more details from the film, like the lime-green Jello Lex is eating when the raptors first arrive and the step ladder the gang uses to escape into the air ducts during the final chase.

LEGO Jurassic Park set.

LEGO Jurassic Park set.

LEGO Jurassic Park set.

The Jurassic Park Velociraptor Chase set is currently available from the LEGO shop for $40.

[h/t Nerdist]

All images courtesy of LEGO.

Why Are There No More Dinosaurs?

WHY? is our attempt to answer all the questions every little kid asks. Do you have a question? Send it to

Actually, there are still dinosaurs: Birds! But let’s talk about that a little later. Scientists have found clues in rocks and fossils that tell us that by 65 million years ago, the climate (CLY-met), or usual weather, of the Earth had changed a lot, becoming cooler and drier. That was hard on the heat-loving dinosaurs. But that’s not why almost all of the dinosaurs became extinct, or disappeared forever. Scientists think a terrible event occurred that killed them off.

In 1991, scientists discovered a huge 110-mile-long crater, or hole, in the Gulf of Mexico. They think this crater was made by a giant, fiery, 6-mile-wide asteroid (AST-er-oyd) from space that smashed into the Earth about 65 million years ago. The impact was more powerful than any bomb we have ever known. Scientists believe this event killed most plant and animal life—including the dinosaurs. The asteroid probably caused shockwaves, earthquakes, fireballs, wildfires, and tidal, or really big, waves. It also sent huge amounts of dust and gas into the atmosphere, which is like a big blanket of air that surrounds the Earth. That was really bad for the planet.

The dust blocked sunlight, making the planet very cold and dark. Then, over time, the gases trapped heat, causing the Earth to get even hotter than it was before the asteroid hit. This change was deadly for most dinosaurs, and they became extinct. But birds survived. Many millions of years earlier, they had evolved (ee-VOL-ved), or changed slowly over time, from one group of dinosaurs. And when the dinosaurs disappeared, mammals diversified (die-VERSE-uh-fide), or changed, into many different kinds of animals—including us, many millions of years later. So the next time you see a bird swoop by, wave hello to the little flying dinosaur!    


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