10 Facts About Kronosaurus

How Much Do You Know About Kronosaurus?

Nobu Tamura

One of the largest and deadliest marine reptiles in the history of life on earth, Kronosaurus was the scourge of the early Cretaceous seas. On the following slides, you'll discover 10 fascinating Kronosaurus facts.

Kronosaurus Was Named After a Figure from Greek Myth

Kronos eating his children (Flickr).

The name Kronosaurus honors the Greek mythological figure Kronos, or Cronus, the father of Zeus. (Kronos wasn't technically a god, but a titan, the generation of supernatural beings preceding the classic Greek deities.)  As the story goes, Kronos ate his own children (including Hades, Hera and Poseidon) in an attempt to preserve his power, until Zeus stuck his mythological finger down dad's throat and forced him to throw up his divine siblings!

Specimens of Kronosaurus Have Been Discovered in Colombia and Australia

The two species of Kronosaurus (Wikimedia Commons).

The type fossil of Kronosaurus, K. queenslandicus, was discovered in northeastern Australia in 1899, but only officially named in 1924. Three-quarters of a century later, a farmer turned up another, more complete specimen (later named K. boyacensis) in Colombia, a country best known for its prehistoric snakes, crocodiles and turtles. To date, these are the only two identified species of Kronosaurus, though more may be erected pending the study of less-complete fossil specimens.

Kronosaurus Was a Type of Marine Reptile Known as a "Pliosaur"

Wikimedia Commons

Pliosaurs were a fearsome family of marine reptiles characterized by their massive heads, short necks, and relatively broad flippers (as opposed to their close cousins, the plesiosaurs, which had smaller heads, longer necks, and more streamlined torsos). Measuring 33 feet from snout to tail and weighing in the neighborhood of seven to 10 tons, Kronosaurus was on the upper end of the pliosaur size scale, rivaled only by the slightly more difficult-to-pronounce Liopleurodon (see slide #6).

The Kronosaurus on Display at Harvard Has a Few Too Many Vertebrae

Harvard University

One of the world's most impressive fossil displays is the Kronosaurus skeleton at the Harvard Museum of Natural History in Cambridge, MA, which measures over 40 feet from head to tail. Unfortunately, it seems that the paleontologists assembling the exhibit accidentally included a few too many vertebrae, thus propagating the myth that Kronosaurus was much bigger than it actually was (as stated in the previous slide, the largest identified specimen is only about 33 feet long).

Kronosaurus Was a Close Relative of Liopleurodon

Liopleurodon (Andrey Atuchin).

Discovered a couple of decades before Kronosaurus, Liopleurodon was a comparably sized pliosaur that has also been subject to a fair degree of exaggeration (it's unlikely that Liopleurodon adults exceeded 10 tons in weight, more dramatic estimates to the contrary). Although these two marine reptiles were separated by 40 million years, they were extremely similar in appearance, each equipped with long, bulky, tooth-studded skulls and clumsy-looking (but powerful) flippers.

The Teeth of Kronosaurus Weren't Especially Sharp

Wikimedia Commons

As huge as Kronosaurus was, its teeth weren't very impressive--sure, they were each a few inches long, but they lacked the lethal cutting edges of more advanced marine reptiles (not to mention prehistoric sharks). Presumably, this pliosaur compensated for its blunt teeth with a lethally powerful bite and an ability to chase prey at high speed: once Kronosaurus got a firm grip on a plesiosaur or marine turtle, it could shake its prey silly and then crush its skull as easily as an undersea grape.

Kronosaurus May (or May Not) Have Been the Biggest Pliosaur That Ever Lived

Wikimedia Commons

As stated in previous slides, the size of pliosaurs is susceptible to exaggeration, given errors in reconstruction, confusion between various genera, and sometimes the inability to distinguish between juvenile and full-grown specimens. Still, it's possible that both Kronosaurus (and its close relative Liopleurodon) were outclassed by an as-yet-unidentified pliosaur recently discovered in Norway, which may have measured as much as 50 feet from head to tail!

One Genus of Plesiosaur Bears a Kronosaurus Bite Mark

Dmitry Bogdanov

How do we know that Kronosaurus preyed on its fellow marine reptiles, rather than contenting itself with more tractable prey like fish and squids? Well, paleontologists have detected Kronosaurus bite marks on the skull of a contemporaneous Australian plesiosaur, Eromangosaurus. However, it's unclear if this unfortunate individual succumbed to the Kronosaurus ambush, or went on to swim the rest of its life with a gruesomely misshapen head.

Kronosaurus Probably Had a Worldwide Distribution

Dmitry Bogdanov

Although Kronosaurus fossils have only been identified in Australia and Colombia, the extreme distance between these two countries points to the possibility of a worldwide distribution--it's just that we haven't yet discovered Kronosaurus specimens on any other continents. For instance, it wouldn't be surprising if Kronosaurus turned up in the western U.S., since this region was covered by a shallow body of water during the early Cretaceous period and other, similar pliosaurs and plesiosaurs have been discovered there.

Kronosaurus Was Doomed by Better-Adapted Sharks and Mosasaurs

Prognathodon, a mosasaur of the late Cretaceous period (Wikimedia Commons).

One of the odd things about Kronosaurus is that it lived during the early Cretaceous period, about 120 million years ago, at a time when pliosaurs were coming under pressure both from better-adapted sharks and from a new, even more vicious family of reptiles known as mosasaurs. By the cusp of the K/T meteor impact, 65 million years ago, plesiosaurs and pliosaurs had gone completely extinct, and even mosasaurs were fated to perish at this deadly boundary event.