When Evolution Made The Same Animal Twice

You have most likely heard of the saying, work smarter, not harder. And there is no more vocal advocate for this than nature itself. And this is obvious when you take a peek into evolution, as animals, typically evolved, become more and more effective for their chosen environment. And one of the most interesting cases of this is seen in convergent evolution, which simply put, signifies the idea, if it ain't broke, don't fix it. But is more specifically defined by, unrelated animals evolving the same or similar features independently. Like how bats and whales both possess echolocation, or the fact that many wildly different groups of animals possess eyes, like insects vs mammals. And when you really take a good look at animals, you'll notice that most do have shared similarities with others. But, it's only once in a blue moon, that two unrelated creatures, end up evolving so similarly, that they basically look like almost exact copies of one another. Take legless lizards and snakes for example, who could basically pass for twins, but haven't shared a common ancestor for over 100 million years, which is longer than the time between humans and cats. And yet we, look very different. And this phenomena is by no means a modern trend, extending well into the past too. And thus leading to the odd case of a few modern animals, looking a lot like those of prehistory, and in some ways, giving us about the closest thing we have to time travel. One of the most uncanny cases of this, actually involves two icons, both from the past and present, ichthyosaurs and dolphins. While many marine animals have evolved similar body plans to cut down on drag, dolphins and ichthyosaurs took it to the extreme. So much so, that ichthyosaurs are commonly referred to as the dolphins of the Mesozoic, despite being reptilian. And the two shared over 20 odd features, which in conjunction to general body shape, included finger bones, elongated front skulls, short necks, live births, smooth skin, and likely similar coloring, with their topsides being darker while the bottom was lighter. But perhaps the oddest of all, is that recent evidence implies, that ichthyosaurs also had a trait that is rarely seen in reptiles, or even marine animals overall, but is very common in marine mammals, including dolphins. And that is blubber, which serves to help provide insulation and protection in colder waters. Additionally, their senses might have been more alike than first thought, as both had powerful eyes for low light and increased pressure environments, and ears that were extremely dense and massive, providing excellent hearing. The amount of likeness further extended to their lifestyles, because though ichthyosaurs did have diverse diets depending on their size, most still stuck to fish, cephalopods, and crustaceans, so nearly identical to that of a dolphin's menu. And it's this similar lifestyle that may have pushed both to end up evolving in very similar ways, just millions and millions of years apart. With the ichthyosaurs having first appeared during the early Triassic, and dying 90 million years ago. And naturally, because there were so many ichthyosaur species throughout the 150 million years of its existence, not all of them ended up being as identical to dolphins as the next. But there was one group that really took the cake, and that was the ophthalmosauridae, who sometimes had such similar design and size to dolphins, that underwater, you might not have been able to notice that it was actually a marine reptile. And yet somehow, their resemblance to each other still does not compare to an even older pairing, which starts with this. What you're looking at is for all sense and purposes, a crocodile. Or at least a crocodilian, or so you'd think. Because in reality, it isn't. Rather, it is a phytosaur, an extreme mimic, that evolved roughly 196 million years before true crocodiles, and belonged to the Archosauromorpha clade, which contains all reptiles more closely related to archosaurs, like dinosaurs and crocodiles, than to lepidosaurs, aka lizards, snakes, and tuataras. And yes, I did say crocodiles there, but the two are actually very unrelated, a bit like how humans are mammals, but very distantly related to, say, marsupials. And even groups like plant-eating aeotosaurs, or the bipedal chuvasaurus, are more closely related to crocs than the phytosaur is, which makes it all the weirder that phytosaurs are pretty much the exact copies of crocodiles, possessing armored bodies, long snouts, cone-shaped teeth, low legs, and specialized tails. It's believed that they also lived out a semi-aquatic lifestyle, showing that the design of a croc works wonder in many situations, no matter the time. And the two's sheer likeness is one argument for why aliens might not be really all that different from life on Earth, assuming they live in similar environments, that is. Because if something works in one place, it'll probably work in another. And these days, researchers say that the differences between phytosaurs and crocs were only minor, with most contrasting features not even being external, as phytosaurs had slightly more primitive ankle bones, denser and more extensive armor, and a lack of a secondary palate, which lets crocs breathe even with water in their mouths. Although it is possible that they actually had fleshy palates that just did not fossilize. And on the outside, the biggest difference between the two was that phytosaurs had nostrils near or above the level of their eyes. So in other words, basically no difference at all. And this example is perhaps the most extreme case of convergent evolution regarding crocs. But surprisingly, it's not the only one, with a lesser, but more perplexing case, coming from a whale of all things. And actually, one of the first whales. The Ambulocetus. Yes, it may be hard to believe, but this is in fact a cetacean, having lived some 47 million years ago, and was amphibious, not aquatic. It represented a transitional point in whale evolution, and was in some ways closer to crocs than its eventual descendants, with researchers believing it behaved a lot like modern crocodiles, waiting close to the water's surface in order to ambush large animals, using strong, large jaws to drown or thrash prey into pieces. Furthermore, like crocs, its eyes were situated on the top of its head, allowing it to peek above water, and it had a nasal cavity with bony walls that helped to keep its airways open while killing prey. Much like a croc. I mean honestly, minus the fur and some other differences, this was essentially the mammal's version of a croc. And funnily enough, in another twinsie situation, crocs also then had their own whale, the Stomatosuchus. Now this is an extinct crocodilian from the late Cretaceous, who actually lived alongside the Spinosaurus, but unsurprisingly, had a pretty different life, and one quite different from most crocs too, considering that it possessed a massive, extremely stretchy throat pouch that allowed it to scoop up and engulf fish and sharks in one swoop, kind of similar to how certain baleen whales, and pelicans for that matter, feed today. With the biggest difference being that instead of having baleen or a toothless beak, the Stomatosuchus had many tiny teeth that interlocked when biting down, forming a biological zipper of sorts, and ensuring that any animal inside its mouth was doomed. And its size also drew from whales, it seems, as adults regularly reached 10 meters or 33 feet long, making it one of the biggest animals you could find in the water at the time. But sadly, as far as we know, this bizarre creature did not stick around for long, and thus ensuring that whale crocs did not make it to today. Now while it might seem that water was the place where everyone was copying each other, it definitely happened on land too, and even occur between dinosaurs and mammals, perhaps best demonstrated by ankylosaurs and armadillos. At first you may not see it, but when you really compare the two, you'll notice that it's strange how similar they are, given their huge difference in time and relation, yet both have ended up with near full-bodied armor designed to protect against external threats. And if we cheat a little and include extinct armadillos, the similarity becomes quite hard to unsee. As one foregone group, the glyptodonts could literally pass for ankylosaurs, with a couple growing to extremely large sizes, actually outsizing small cars, and possessing tail weapons akin to what was actually seen in a few ankylosaurs, notably the ankylosaurus. And the armadillo which achieved this the most was arguably the dodecaris, which lived in South America during the Pleistocene and Holocene, and was equipped with a huge spiked tail that could be used like a wrecking ball to pulverize bone. And this design worked for them for a surprisingly long time, with them having survived up until humans reached South America, which is around when they went extinct. And simultaneously, other mammals have also ironically convergently evolved to be similar to ankylosaurs, beyond just the armadillos. Like the pangolins, for example. A strange order of mammals that evolved large protective, keratinous scales that overlay across their entire bodies, giving some resemblance to certain ankylosaurs who had extensive armor but lacked tail clubs. And this just really goes to show that when danger exists, sometimes it's a good idea to just double down on defense and not bother with the rest. But the same can also be said about offense, where in the case of herbivores, evolution has shown time and time again that a charge and ask questions later kind of build is a lot of the times the best way to go. Nicely exemplified by elephants, and an animal so old that mammals didn't even exist when it was alive. The placerius. This was an extinct dicynodont that hailed from Triassic North America around 230 million years ago, and had two prominent tusks just like elephants. And while many others in its family did also have tusks, what was unique about the placerius was that they were much longer in general, pointed downwards, and were used in almost the exact same way that elephants used theirs, for digging, display, and combat. And again as seen in elephants, placerius also demonstrated sexual dimorphism with its tusk size, with males often having longer, more visible ones, while they were reduced in females. Additionally they, or rather elephants, followed in their footsteps because while placerius wasn't nearly as big as an elephant, with matured individuals only weighing about 1.1 tons, it still made them the largest herbivores of their times, just like how proboscideans are today. But what's funny is that this size is actually more similar to a hippo's weight, with whom researchers also think it shares convergent traits. So it was kind of like a strange elephant-hippo hybrid, and it may have spent much of its life slinking around in shallow waters and along banks, eating vegetation, and sharing a few hippo-like features including a powerful neck, strong legs, and a barrel-shaped body. This makes it all the more coincidental that some prehistoric elephants also looked a little bit like hippos too, such as the platybelodon, despite hippos being more closely related to whales than their trunked contemporaries. Now another instance that very much proves that charging just works is actually seen in a neighbor of hippos and elephants, the rhinoceros. These guys first evolved in Asia before spreading out across much of the world, partially thanks to them getting versatile centered horns that jut upwards and allow them to dish out some pretty immense damage, especially when coupled with their enormous size. And unsurprisingly, we see throughout history quite a few animals develop this design as well, specifically being large and having upward tusks, like ceratopsids, whose horns were also centered and were used as a means of deterrence, defense, and display. Yet the weirdest similarity with rhinos didn't come from dinosaurs, but another mammal, the trigodon. What's really strange about this creature is that not only did it have a short frontal horn on the top of its head, but it was also highly rhino-shaped, with the two sharing very similar body structures and proportions. So much so, in fact, that before a horn was even discovered, just based on its skeletal structure alone, some paleontologists believed that the trigodon was actually a species of rhino. However, interestingly enough, not only was it not a rhino, but it also lived where rhinos never actually appeared, South America. Meaning that in a totally rhinoless place, this creature evolved to be nearly identical, and at the same time that the rhinos were already alive, as it evolved only some 11 million years ago or so, and persisted to just about 4 million years ago. And like the rhinos, it is presumed to have used the horn in a very similar way, although it did live in a quite different environment that was both extremely wet and littered with rivers and lakes, as it inhabited a now no longer existing mega wetland. Funnily enough, while its closest living relatives happens to be a group that includes rhinos, the two are ultimately not that related, as after all, the group to which it belongs to, the Noto Ungulata, is literally in extinct order, so taxonomically, quite out there. But that being said, Noto Ungulata did happen to exist for over 60 million years, and as such there have been over 150 genera belonging to this group, so it may not be surprising that rhinos are not the only animals they've come to look alike. With a more striking example being rabbits, as seen with the Pachyrhucos. It's honestly unbelievable that this Eocene dated animal was not a rabbit, and yet it surely was a Noto Ungulata, just like the Trigodon, meaning it was closer to zebras than her hopping friends, although its skeletal structure does suggest that it could hop if it wanted to. And not only that, but it essentially matched a rabbit in every way, having a short tail, long hind feet, rabbit-like teeth, and of course, the iconic long wide ears. With the only major difference being that the Pachyrhucos was perhaps nocturnal, or so researchers believe based off of its large eyes. Now them being an almost one-for-one copy is likely the result of its lifestyle, and the fact that it lived in very similar environments to rabbits. Which again really shows how if something works, you can expect it to manifest again and again in nature. I mean just look at the marsupials, who are also known to mimic placental mammals, despite their last common ancestor being over 140 million years ago. Even the most iconic extinct marsupial, the Thylacine, was guilty of this, bearing a striking resemblance to canines, especially wolves and dingoes, with which it shared a very similar skull that to most people are not able to distinguish between them. The teeth and body were also very similar, and from a general anatomical sense, the Thylacine is much closer to canines than other Australian marsupials, even though genetically, it's way closer to a wombat or kangaroo than any canid, and evolved this appearance completely independently, with the last ancestor between it and canids being dated all the way to the Jurassic. The sheer coincidence of this convergent evolution is further emphasized when you consider that we are more related to a dingo than it is to a thylacine, and researchers believe that like in many cases, this odd situation is a result of similar environmental pressures that made a canid-like body plan the best choice. And another mind-boggler involves one of the most distinct animals out there, turtles. Their shape and carapaces make them extremely unique, but alas, even their individuality hasn't stopped nature from making turtle-like creatures that don't have anything to do with them, like the Placodonts. This was an extinct order of marine reptiles that existed throughout the middle and late Triassic, and were members of the superorder the Sauropterygia, which by the way, includes plesiosaurs and nothosaurs. Now, some of the Placodonts did not look much like turtles, but others, they sure did, especially the Henodus, which really did look like some proto-turtle, having a very similar shell that was composed of a plastron on the bottom and a carapace on top that also took up its midsection, leaving just their head and very behind sticking out, with a big distinguishing trait in its shell being that it was more bony than that of a turtle. But like for turtles, those shells would have offered Placodonts a high level of protection, which was much needed, as in those times, the waters of Earth were home to some creepy and dangerous aquatic animals. And fascinatingly, the Placodonts were not the only members of the Sauropterygian to convergently evolve traits shared with turtles, as the same situation was seen in certain Sarasvirajidae, another family which evolved extremely turtle-like shells and general body shapes, despite not being the evolutionary branch that gave way to turtles. Thus, if they or the Placodonts had not gone extinct, then we might have had multiple turtle-like animals roaming the world, which I know Nemo would have loved. And another very unique looking creature that did not escape convergent evolution are Stingrays, who had a lookalike that lived hundreds of millions of years before they emerged, the Rhinonids, a bizarre order of Placoderms that were in no way related to what would one day become Stingrays. In fact, because they lived some 400 million years ago and went extinct not so long after, they never even got to see their twin, who evolved during the Cretaceous hundreds of millions of years later. But like the Stingrays Rhinonids were pancake-shaped bottom-dwelling creatures that had eyes on the top of their heads that allowed them to look up while relaxing on the seafloor, with their diets all being quite similar as well. Additionally, they too had wings, so you could say, like rays do, and the only way you could really tell one wasn't a Stingray was by touching it, as they were scaly and slightly armored, whereas Stingrays are of course smooth, in a sandpaper texture like way. You also would have needed to watch out around these guys, as they did not reach the same size as the rays do, and they lack the stinger at the end of their tails, rendering them quite harmless to larger creatures. But this did not stop them from spreading far and wide, and for a short time frame they could be found all across the world. And while not as ray-like as the Rhinonids, you did also have Eugalia Spitoforms too, which happened to live at the same time as the Rhinonids, despite not even belonging to the same order. These guys in general had body plans a bit like rays, but to be honest with you, I really just wanted to include them for their googly eyes and perpetually surprised expressions, which in my opinion makes them a bit convergent with surprised Pikachu, if you think about it. But don't be fooled, for this was not an adaptation to make animals think it was cute. Rather, some members had this sort of open mouth design that allowed them to quickly gobble up any prey drifting above them, while their funny googly eyes were probably used to easily detect potential danger in the area, or to spot prey. And considering Stingrays have their twins, you better not expect Manta Rays to escape this phenomenon either, because if you traveled to the Cretaceous, you would find the Aquila Lamna, an odd creature with prominent wings, or rather flippers. These guys, as far as we know, were limited to waters around Mexico, where they developed long and narrow wings tens of millions of years before Manta Rays did, and also evolved a filter-feeding diet, making them that much closer to rays. But unlike rays, Aquila Lamna was not a member of the Myliobatiformes, to which rays belonged to, but rather, it has been tentatively defined as a Mackerel Shark. In other words, it is more closely related to Great Whites, or the Megalodon, than it was to any ray. And the one partial giveaway is that beyond its wings, you notice that its body was more torpedo shaped, as seen in Mackerel Sharks. Furthermore, another distinguishing factor is that it likely did not fly through the water by flapping its wings, but instead achieved propulsion by using its tail to propel itself, while its wings simply acted as gliders, allowing it to seamlessly glide and conserve energy. And this worked wonders for it, which is why maybe researchers think it only went bust following the K-T extinction, and why a similar design emerged independently millions of years later. And now millions of years is a big lapse in time, but it is nothing compared to the gap seen in something that eerily resembles an animal close to our own hearts. Monkeys. What you are looking at here is not a proto-monkey, or even a long-lost ancestor to primates, but rather, a reptilian monkey-like creature that evolved 268 million years ago, during the Permian period, the Suminia. It was quite similar in size to the smaller monkeys of today. Yet what really made it a fascinating creature was that it independently evolved two pretty rare features both shared by monkeys. One being prehensile tails that allowed it to grasp and hold onto items, and even more rare, fully opposable thumbs, which is also shared by yours truly. Now, multiple animals do have prehensile tails and opposable fingers, but very few times has an animal evolved both. Plus the fact that it evolved these features over 200 million years before monkeys even appeared is something to consider as well. And then on top of this, there's even new evidence which suggests that it also had opposable toes, which seriously makes it the closest thing to a reptilian monkey. And unsurprisingly, it lived a lot like one too, using its array of tools to live a highly arboreal lifestyle in the Permian trees, where it probably did not feast on meat, but rather, leaves, as it was canine-less and had many teeth that were perfectly shaped for shearing and processing leaves, while its hands, feet, and tail kept it securely fastened to the tree it was in. So to conclude, convergent evolution equals amazing. Now I will say, while it might seem that this list is extensive, it should still be remembered that striking examples are the exception, not the norm. But it does again bring to light how environments and niches may be the biggest factor in how we look. And even in less obvious cases, we see just how prevalent convergent evolution is. Take the giant panda for instance, a large browser that feeds selectively whilst in a bipedal position. Nothing crazy, and yet, you see similar builds to this in multiple unrelated animals, but who do have related lifestyles, like the giant sloth Megatherium, the bizarre Calicotheres, and even dinosaurs, such as the Therizinosaurus, who like the rest, sported long claws as well, that might have aided in shearing leaves off branches, as pandas, calicotheres, and sloths did too. And all this converging makes you wonder, if nothing ever went extinct, then would the world actually look not so far off than it does now? And the answer is, who knows? Thanks for watching, and until next time, on ExtinctZoo.