Hold on to your butts! After a 13-year hiatus, the Jurassic Park series will finally come roaring back into theaters June 2015. The new flick’s first official trailer debuted today; here’s a brief introduction to the prehistoric critters it promises.   

1. Gallimimus (0:45-0:46)

Lived: Roughly 73 million years ago (late Cretaceous period)   

Range: Mongolia

Diet: Probable omnivore (possibly with a bias toward plants)

Maximum Length: Approximately 26 feet (8 meters)

Name Means: “Chicken mimic”

A JP veteran, Gallimimus can be seen racing through the first two films. This leggy creature belongs to a group of ostrich-like dinos known as ornithomimids, which once frolicked through present-day Asia and North America. Gallimimus’ jaws were both toothless and, in some places, only a few millimeters thick, so the creature may have swallowed tiny rocks called gastroliths to help break down un-chewed food inside its stomach.

Unfortunately, Jurassic World’s trailer does make one big mistake (scientifically) with its Gallimimus flock. Take a peek at their hands. You may notice that the animals’ palms are turned upwards as they run. In real life, these palms would have been facing each other in a “clapping” position similar to that used by modern birds. 

2. Stegosaurus (0:47-0:49)

Lived: Roughly 150 million years ago (late Jurassic period)

Range: Western North America

Diet: Herbivore  

Maximum Length: Approximately 30 feet (9 meters)

Name Means: “Roof lizard”

Beloved the world over for those dramatic back plates and spiky tail, Stegosaurus also featured chain mail-esque throat scales, presumably to guard its jugular. Oddly, the animals’ hind legs were significantly longer than its front ones, leading some experts to suggest that Stegosaurus may have reared up to snag low-hanging tree limbs. By the way, this dino’s spikes were meant for business: a hole which perfectly matches the tip of one was found in the fossilized backbone of an unlucky, flesh-eating Allosaurus. Yikes! 

3. Apatosaurus (0:47-0:49, 0:51-0:58)


Lived:  Roughly 150 million years ago (late Jurassic period)  

Range: Western North America

Diet: Herbivore; for more details, go here.  

Maximum Length: Approximately 80 feet (24 meters)

Name Means: “Deceptive lizard”

Back in April, a leaked Jurassic World brochure hinted that Apatosaurus might score some screen time. Thanks to a scientific screw-up, this big fellow’s best known for indirectly nullifying the name Brontosaurus, which had been given to a dinosaur that later turned out to actually have been an Apatosaurus species. An American sauropod, or long-necked dinosaur, Apatosaurus is notable for its bulky skeleton and weird neck anatomy (abnormally-large “cervical ribs” are anchored to its vertebrae, giving them strange, exaggerated shapes that’ve confused many a scientist).

4. Mosasaurus (1:06-1:10)

Lived: Roughly 66-70 million years ago (late Cretaceous period)

Range: Western Europe

Maximum Length: Approximately 56 feet (17 meters).

Diet: Carnivore

Name Means: “Meuse lizard” (after the Meuse river of northern Europe, where its remains were first discovered).

Unlike the other beasties in this preview, Mosasaurus wasn’t a dinosaur at all but instead a close relative of today’s snakes and monitor lizards (it may have even had a forked tongue). Ocean-going mosasaurs had flexible, serpent-like jaws and—like overgrown pythons—most species probably would have had to swallow their prey items whole (or at least in supersized chunks). Recent years have been good to mosasaur paleontology; we now know, for example, that these amazing predators had shark-style tail flukes.

And speaking of sharks, go back and restart the video at 1:06. Jurassic World’s customers clearly enjoy seeing the resident mosasaur devouring great whites, but the fossil record shows that some prehistoric sharks were capable of turning the tables and feeding on these reptiles. Maybe we’ll see a fight; cross your fingers!

5. Velociraptor (Sort of) (2:21-2:25)

Lived: Roughly 71-75 million years ago (late Cretaceous period)

Range: Mongolia

Maximum Length: Approximately 6.5 feet (2 meters)

Diet: Carnivore

Name Means: “Swift robber”

The so-called Velociraptors in all four Jurassic Park movies actually look almost nothing like the genuine article. In fact, they were based on a related dino known as Deinonychus, which was appreciably bigger but still fell a bit short of JP’s raptors dimension-wise.

Velociraptor doesn’t need Hollywood’s help to be interesting. The carnivore definitely didn’t fly, yet its upper arm bones came with “quill knobs”—anchoring points onto which powerful feathers are rooted in modern birds. Its tail contained bony rods that could have stiffened the appendage into a handy counterbalancing tool for making narrow turns.

And recent research suggests that, contrary to what Steven Spielberg might have you believe, those dreaded sickle-shaped claws were built not for slashing but for gripping. Theoretically, a hungry Velociraptor would leap onto its victim, bury those digits, and hang on for a deadly rodeo. Now there’s a cinematic image for ya!

BONUS: Random, Genetically-Modified, Man-Eating Hybrid (-asaurus)

Yeah, Jurassic World’s plot includes a brand-new dino-monster with spliced DNA and a serious attitude. What DNA will this dino have? We'll just have to wait for the movie to find out.