The reign of dinosaurs on Earth was long. For about 165 million years they dominated all continents, and today they have captivated our imagination. But they were far from the only animals on Earth. They shared their world with many species as strange and wonderful as themselves, some you may not know about.
Nor will archosaurs be on this list. The term archosaurus refers to the clade that dinosaurs belong to, along with their modern counterparts, birds and crocodiles. But they used to be even more diverse, including flying pterosaurs and some ancient marine reptiles. Everything else is fair game.
It is difficult to say exactly when the first dinosaurs appeared, with estimates ranging from 250 to 235 million years ago. The first true non-avian dinosaurs appeared about 243 million years ago and became extinct 66 million years ago. Any species that could intelligently exist during that time has a chance of being included.
Now let’s take a trip back in time to see some very strange creatures!
Connected: Top 10 Dinosaur Fossils Frozen in Time
ten A sort of turtle
Sinosaurosfargis junguyensis lived in what is now southwestern China 243 million years ago. And it looks like any turtle should look, with an expanded ribcage. However, unlike many modern turtles, which are protected by very large, hardened scales along their backs, the “shells” of ancient turtles often consisted of many smaller osteoderms, scaly bony deposits on the skin.
Except that Sinosaurosfargis was clearly not a tortoise. He certainly had a common turtle ancestor. But it split off from that lineage millions of years before the first “true” turtles began to appear.
Interestingly, the same bony integuments in this species somewhat distorted the ideas about the evolution of the turtle shell, since this was especially lacking in the real turtle ancestors.
9 Not quite the first mammal
A tiny megazostrodon that roamed the dry land of late Triassic France 200 million years ago could have been mistaken for a strange rat or shrew. But this little creature is of great importance to many paleontologists.
This little guy is considered a transitional form between cynodont mammals and true mammals, making it one of the most significant discoveries in the study of mammalian evolution. However, exactly where it fits into the mammalian family tree remains somewhat debatable, as does the debate over exactly when mammals actually became mammals.
However, Megazostrodon was probably too busy eating bugs to think about his rather confusing place in the world.
Okay, okay, I know I’m technically kidding me. Actually, I don’t mean the modern tuatara…Sphenodon point– but most likely the Order of Sphenodontia. Because I couldn’t bring myself to choose just one.
The Sphenodontids established themselves in the early Jurassic, just under 200 million years ago, and were once a very diverse group. They were part of a larger group called the Rhynchocephalians, a sister group to the Squamates (modern lizards and snakes). Basically, it was a diverse group of not-quite-lizards, very similar in design, but distinct enough to be classified separately.
However, unfortunately, all rhynchocephalians, with the exception of one genus – Sphenodon – eventually fell into decline and died out millions of years ago. Only the tuatars remain, now threatened by human activity.
7 lizard fish
Ichthyosaurs (literally “fish lizard”) were a highly diverse group of marine reptiles that evolved about 250 million years ago.
However, for the purposes of this list, I am including the dolphin-like Stenopterygius, which lived approximately 180 million years ago. The reason for this choice is a particularly well-preserved specimen that shows just how strange these creatures were.
This specimen retained not only traces of pigment on the skin, but also a layer of fat under it. Although this find is not unambiguously warm-blooded, it is further evidence that these creatures regulated their body temperature to some extent, an important trait for reptiles that regularly dived into the depths of the ocean.
At some point, ichthyosaurs may have been among the top predators of the Mesozoic seas. But in the end, they died out about 90 million years ago, 25 million years earlier than the non-avian dinosaurs.
6 Beaver Otter
Castorocauda lutrasimilis is one example of how nature tends to use the same design motif over and over again. Much of its body was very similar to that of the modern beaver, from its flattened, scaly tail to its small, webbed feet.
However, it was not a primitive rodent. Instead, its narrow skull was equipped with many needle-sharp teeth, well suited for catching fish, unlike modern otters. Interestingly, the fur of this 164-million-year-old creature is also remarkably similar to that of modern aquatic mammals, replete with outer hair and dense undercoat.
Unlike most modern mammals, Castorocauda likely laid eggs, leading some to speculate that its lifestyle may have resembled that of the modern platypus.
5 long lizard
The origin of snakes and the loss of their limbs remains one of the most contentious controversies in the paleontological community. So when a fossil of a Brazilian serpentine reptile somehow appeared in Germany under dubious circumstances (given that taking fossils out of the country had been illegal since 1942) and was examined, many were understandably delighted.
You see, most of the primitive snakes known to science, as a rule, have already been partially legless, possessing no more than one set of limbs. It was different. So finally finding a snake with four limbs would really be a shock.
But it wasn’t supposed to be. It was Tetrapodophis amplectus, which lived in the early Cretaceous period about 120 million years ago. And it really was just a very long lizard, and not a snake at all.
However, this does not mean that this creature has not added anything to the discussion. Tetrapodophis was a burrowing digger, and the structure of its tiny limbs is often compared to that of known primitive snakes. It is now believed that snakes eventually lost their limbs in order to become more adept at burrowing, as this little lizard did.
four ancient platypus
Yes, they get even weirder.
Modern monotremes are descended from a very old line, although it is not known exactly how old it is. Estimates of the time of separation from other modern mammalian lineages range from the early Triassic to the Jurassic. However, the oldest known relative of the platypus, Teinolophos trusleri, can be comfortably dated to the Early Cretaceous about 120 million years ago. Many other related species followed after that.
Unfortunately, most of these fossils are incomplete. However, it has been suggested that the traits that make the modern platypus so damn weird originated here. Although only one species of platypus remains today, they were once a very diverse group whose reach even extended beyond Australia, as did the South American platypus. Monotrematum sudamericanum.
And another fun fact! Another very strange creature, the echidna, actually split off from a relative of the platypus somewhere between 20 and 50 million years ago (or even earlier).
3 Antarctic sea dragon
Recently featured in the BBC prehistoric planet, kaikaifilu hervey was the king of the Late Cretaceous Antarctic seas 66 million years ago.
Kaikaifilu was a mosasaurus, a marine reptile most closely related to modern lizards and snakes. In particular, kaikaifilu was a kind of tylosaurine mosasaurus, which meant that it had a longer and more serpentine body than the comparatively bulky mosasaurian mosasaurs.
Its estimated length was an impressive 33 feet (10 meters) long, the largest from the South Pole, and it was probably the region’s apex predator. However, his reign did not last long, as all mosasaurs became extinct at the end of the Cretaceous.
2 “Crazy Beast”
Adalatherium Hui certainly had to make a strong impression on its discoverers to get such a name. And I assure you, it did.
In the words of lead researcher David Krause: “Knowing what we know about the skeletal anatomy of all living and extinct mammals, it is difficult to imagine that a mammalian-like adalaterium could have evolved; he bends and even breaks a lot of rules.”
All this suggests that this Madagascar creature that lived 66 million years ago was very, very strange.
First, it had more holes in its skull than any other mammal. It had strange teeth, unlike those of any other mammal. It had more vertebrae than any modern mammal. In addition, the researchers spent a lot of time trying to figure out how he walked because “the front half…doesn’t match the back half.”
And this seven-pound (3-kilogram) weirdo was probably still a baby!
Okay, maybe I’m cheating a little again.
Technically, one of the earliest primates (or perhaps one of the earliest direct ancestors), Purgatorius janisae, is only known from fossils dating immediately after the Cretaceous extinction. However, studies have shown that this genus is probably much older, perhaps around 81 million years ago. So I don’t feel guilty.
Purgatorius, to put it mildly, looked like someone had mistaken a ferret for a squirrel. But it also had the flexible ankle and wrist joints that became a staple in later primates, allowing it to thrive in the treetops and far outnumber most predators.
And things will only get crazier for the primates.
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