This thread is still under construction
This is a thread for discussing all kinds of prehistoric animals. Talk about latest discoveries. Ask questions. Share fossil collections. Maybe even ID a bone you might have found in the rocks.
There are a couple of eras before the ones in the title that contains life, but they're mainly simple single cell organisms, or simple multi-cell organisms. That and I couldn't fit them all into the title. The most complex organism are jelly fishes. Where life came from is a very complex subject with various theories too difficult to cover in a thread like this. I can tell you that life started out as simple single cell organisms like bacteria and archaea. It's believed that these simple organisms were carried around by the water currents, and sometimes they would bump into each other; allowing them to exchange their DNA. This is sex. It's also about as sexy as this thread's going to get. I believe photosynthesis also started here. The real explosion of life happened in the Paleozoic Era.
Paleozoic era - I think this is the best place to start. Life went from single and multi-cell organisms to complex animals very quickly! We started with things like arthropods (invertebrates with exoskeletons) to vertebrates. Fish were one of the fish vertebrates. There are also precursors to squids, as well as plant life exploding on land. These plants started poisoning the earth with a gas known as oxygen. Insects evolved to eat this new plant life on land, and also took flight. The insects also encouraged fish to pop out of the waters to prey on them, and eventually evolving into tetrapods (animals with 4 legs). Early tetrapods were amphibians. Reptiles and synapsids/therapsids soon followed. The synapsids are especially interesting. Some of them looked like hairy little reptiles, while the reptiles revolutionized egg laying. Sharks, cockroaches, and even horseshoe crabs started during this era. However, at the end of the Paleozoic era (the Permian Period) was one of the most devastating extinctions in the history of the planet. Roughly 80% of life on earth was wiped out. We were this close to having never existed.
Some Notable Animals of the Paleozoic
Mesozoic era - The extinction event was so catastrophic, that it took well into the mid Triassic before it was back to being as diverse as before. The synapsids held on from the great extinction, along with a group of reptiles call archosaurs. There is debate whether the archosaurs started in the Permian Period, but whatever's the case, a group of reptiles did survive, and boy did they survive. Archosaurs would evolve into crocodilians, birds, pterosaurs and of course, dinosaurs. Reptiles really started to dominate the planet. Dinosaurs dominated the land. They came in all shapes and sizes. Dinosaurs were some of the biggest land animals to ever walk the planet, and were found in every kind of environment you can think of. That includes arctic environments. This is thanks to the evolution of feathers and integuments on the bodies of many dinosaurs. Other strange reptiles such as mosasurs, plesiosaurs, and icthyosaurs dominated the seas. Pterosaurs ruled the skies. Though during the mid-Jurassic, some early proto-birds shared the skies with these pterosaurs. Although none of them ever reached the size of pterosaurs. The therapsids in the other hand became smaller and smaller. Eventually evolving into mammals. Mammals for the most part were small and lived in the shadows of the reptiles. Grass started evolving in India towards the end of the Mesozoic. Flowering trees and bees also started towards the end of the Mesozoic. Then it all came to an end in a mass extinction. Around 60% of all life on earth vanished.
Some Notable Animals of the Mesozoic
Lystrosaurus
Size: 1 meter
Age: Permian - Early Triassic
Diet: Herbivore
Bio: A therapsid that survive the Permian extinction and into the Triassic. Thanks to the catastrophic event of the Permian extinction, Lystrosaurus was able to dominate the planet during the early Triassic like no other animal. It's estimate 90% of land vertebrates were Lystrosaurus. No other single animal dominated the planet to the extent that Lystrosaurus had.
Typothorax
Size: 2.5 meters
Age: Late Triassic
Diet: Herbivore
Bio: An armored aetosaur. A distant relative to crocodiles, but Typothorax is a herbivore. It also bares a striking resemblance to a group of dinosaurs call nodosaurs with it's overall body shape and armor plates. The dorsal plates on Typothorax are incredibly wide, covering half of its body.
Cyclotosaurus
Size: 4+ meters
Age: Late Triassic
Diet: Carnivore
Bio: An amphibious carnivore. It is one of the largest and most successful amphibians with a fossils from in Greenland all the way to Thailand. It's also one of the few vertebrates living in the highest northern altitude during the Triassic period.
Dimorphodon
Size: 1 meter in length, 1.5 meter wingspan
Age: Early Jurassic
Diet: Carnivore
Bio: A small pterosaur with a large head, and sharp teeth. It had 2 distinct types of teeth in its mouth. There's debate over what Dimorphodon really ate. It's fossils was found on coastal regions, so it was thought to eat fish. However, studies on the skull shows it's better for snapping and holding. Meaning it's jaws and close quickly, but the teeth won't penetrate its prey due to the lack of force. Now, it's more likely to be an insectivore, or a specialized carnivore that hunted smaller animals like lizards and frogs. It's nowhere near big or powerful enough to lift a person. I'm just saying.
Shonisaurus
Size: 15 meters - 21 meters
Age: Late Triassic
Diet: Carnivore
Bio: A large, if not one of the largest marine reptile. It's body shape is very dolphin-like, showing just how effective this body plan is for marine animals. There is a reason it's listed as 15 - 21 meters though. One species S.popularis is 15 meters. A second species, S.sikkanniensis, at 21 meters, might not be Shonisaurus, but a different icthyosaur call Shastasaurus. A 2013 study says sikkanniensis is a Shonisaurus, and not Shastasaurus.
Tylosaurus
Size: 15 meters
Age: Late Cretaceous
Diet: Carnivore
Bio: A large marine lizard, closely related to today's monitor lizards and snakes. This reptile had a long cylindrical snout. Early depiction of this reptile lack the fluke at the end of its tail, and instead, a crest on its tail. This is incorrect.
Elasmosaurus
Size: 10 meters
Age: Late Cretaceous
Diet: Carnivore
Bio: A marine reptile with an unusually long neck, and short body and tail. Its neck isn't very flexible, and allowed limited movement. It's hypothesized to have used its neck in one (or more) of these methods to hunt. It could be used to dig for prey hiding on the sea floor; or it could retract, and then strike almost like a snake; or it could stalk fish by hiding below, and then raising its head up to strike, since it's eyes or on the top of the skull.
Jugulator
Size: 750 g in weight
Age: Late Cretaceous
Diet: Carnivore
Bio: A large mammal from the Cretaceous. Well, large for its time. It's still under a meter, and just listed with its weight instead. This tree dweller that resembled a squirrel. It's believed to be able to glide through the air as well.
Herrerasaurus
Size: 6 meters
Diet: Carnivore
Bio: One of the earliest dinosaurs. It's so early, that it actually shares similar features with other non-dinosaurian archosaurs. The discovery of a complete skeleton helped prove that it is indeed a dinosaur. It has all the basic body plan of a typical theropod dinosaur. It does have 5 toes, with one 3 bearing the weight of the animal, and also 5 fingers. The last 2 fingers were only stubs. Hands like this aren't typically seen in theropod dinosaurs.
Plateosaurus
Size: 5 - 10 meters
Diet: Herbivore
Bio: A dinosaur with a very confusing history. Even its size fluctuates greatly. Fully grown adults can be as small as 5 meters, or as big as 10 meters. A lot of debate about its posture. It's seen as both a quadruped and biped. It's now believed to be a bipedal animal, due to to wrists not being able to turn in such a way to allow them to walk on all 4.
Archeopteryx
Size: About the size of a raven
Diet: Carnivore
Bio: It's a bird! It's a dinosaur! It's, actually both! When it was discovered, birds and dinosaurs were still considered to be different groups of animals. As the years go by, and more discoveries, we realize birds evolved from dinosaurs. Whether it's capable of flight, or just gliding is unknown, but evidence for gliding is stronger due to the way its wings and arms.
Rahonavis
Size: 0.6 meters
Diet: Carnivore
Bio: This animal's relationship is hotly debated. At first, it was thought to be avian branch of dinosauria. However, subsequent studies show it's closer to the dromaeosaur branch of dinosauria. This issue is still being debated today. Even if it's closer to the avian branch, this creature posses a sickle claw, similar to that of dromaeosaurs, as well as many other traits associated with dromaeosaurids.
Kulindadromeus
Size: 1.5 meters
Diet: Herbivore
Bio: An ornithiscian dinosaur from Russia found covered in proto-feathers and scales. It's one of the earliest dinosaurs to be discovered covered in filaments, and pushed back the idea that only theropod dinosaurs had feathers. In fact, it's closest relative, the pterosaurs also had filaments on its body. This discovery also leads paleontologists to suspect that dinosaurs only inherited feathers from a common ancestor, and wasn't something that evolved independently.
Cryolophosaurus
Size: 6.5+ meters
Diet: Carnivore
Bio: One of the few arctic dinosaurs that we know of. Notable for its strange crest on its skull. It's one of the earliest large theropods, and the only specimen we have isn't a fully grown individual. Being an early dinosaur, it's harder to classify due to it having both advance and primitive features in its bones.
Omeisaurus
Size: 20 meters
Diet: Herbivore
Bio: A strange sauropod from China with uniquely long neck and relatively short tail. The neck alone was 9 meters. It's known from multiple species living in the same habitat. The smallest species were 11 meters long, while the biggest species were around 20 meters. There's dispute on whether its tail had a club.
Kentrosaurus
Size: 4.5 meters
Diet: Herbivore
Bio: A smaller Stegosaur with an unusually long tail with tall spikes. Studies suggest that it could swing its tail in wide arcs of 180 degrees. The speed of the swings as high as 50 KM/h. This long tail also brings its center of mass further back compared to other stegosaurs. It's suggested that it could rear up on its hind legs to reach taller plants when feeding.
Leedsichthys
Size: 16 meters (?)
Diet: Plankton
Bio: Leedsichthys is one of the largest bony fishes. It's length is hard to nail down since the fossils are very fragmentary. This is due to most of it being cartilage, and they're hard to fossilize. It's length has been estimated between 9 meters to 16 meters. So fragments suggests the possibility of 20 meters. The fossilized gills shows that it is a filter feeder, feasting mainly on plankton.
Shunosaurus
Size: 9.5 meters
Diet: Herbivore
Bio: Shunosaurus has the second shortest neck of any sauropod. It's tail is armed with a club and equipped with two 5cm spikes. A good defensive weapons against predators. This is another example of convergent evolution where unrelated animals evolve similar features.
Sauroposeidon
Size: 28 meters
Diet: Herbivore
Bio: Currently the tallest dinosaur that we know of. Sauroposeidon could reach a height of 18 meters. It was initially thought to be closely related to Brachiosaurus, but recent research identifies it as a titanosaur. Another sauropod called Paluxysaurus was recently recognized as Sauroposeidon, therefore the name Paluxysaurus is no longer valid.
Yi Qi
Size: 0.3 meters
Diet: Carnivore/Insectivore
Bio: A feathered dinosaur with bat wings! It has an unusually long 3rd finger that appears to support membrane of skin used for gliding. The membrane itself is also supported by a bony strut attached to the wrist. This is the only dinosaur to have such a feature. It's currently accepted as a glider due to the lack of large pectoral muscles, but it's membrane wing also presents a different problem for gliding. Gliding animals have membrane along the side of its body, and not a wing. Having wings would change its center of gravity. It might have had a long tail to help balance it out, but since that part of the fossil is missing, we won't know until we find more of it.
Quetzalcoatlus
Size: 11 meters (wingspan) 3 meters (height)
Diet: Carnivore
Bio: Quetzalcoatlus is one of the largest known flying animals of all time. It's so big, that Doug Henderson suggested Quetzalcoatlus couldn't fly. However, this research was criticized for using outdated pterosaur models. Biomechanical research into it's flight suggests it flew with a combination of power strokes and transitioned to thermal soaring.
Yangchuanosaurus
Size: 10.5 meters
Diet: Carnivore
Bio: A fairly typical large theropod and relative of allosaurids. Its skull is shorter, but taller compared to other theropods. The rough nasal suggests it might have gave the skull a hump like structure, or some kind of facial ornament. It was the largest predator in its landscape.
Masiakasaurus
Size: 2 meters
Diet: Carnivore
Bio: A small carnivore with strange projecting teeth. The front teeth are long and spoon-shaped with hook edges. It's probably used to catch fish or small prey. The back teeth were more inline with traditional theropod dinosaurs. Masiakasaurus is classified as a basal abelisauroid.
Yutyrannus
Size: 9 meters
Diet: Carnivore
Bio: A large feathered distant relative of Tyrannosaurus rex. It is the largest dinosaur preserved with evidence of feathers. Though feathers are often suggested to be used for insulation, the average annual temperature of Yutyrannus's environment was around 10 degrees Celsius. Hardly arctic temperatures. Feathers may have also served as a form of display.
Caudipteryx
Size: 1 meter
Diet: Omnivore
Bio: Caudipteryx is an extremely bird-like dinosaur complete with pennaceous feathers. It had a small boxy skull and a beak-like mouth with teeth. It's tail ends with a fan of feathers, similar to a peacock. When it was first discovered, it sparked intense debate over bird's relationship with dinosaurs. Caudipteryx itself is still classified as an oviraptorsaur.
Anzu
Size: 3.5 meters
Diet: Omnivore (?)
Bio: An extremely large oviraptorsaur from North America. Only Gigantoraptor is bigger. Like all oviraptorsaurs, it's extremely bird-like. No evidence of feathers, but many of its close relatives had them, making it likely to have been feathered as well. Anzu has a toothless beak and a large dome shaped crest on its skull. The crest bone was paper thin, so it's unlikely to have been used for anything other than display.
Ankylosaurus
Size: 8 meters
Diet: Herbivore
Bio: The largest of the ankylosaurs. It has thick armor osteoderm from head to tail. The tail itself was armed with a large club. The club is attached to ossified bones on the tail, making it very strong and powerful. The size of Ankylosaurus changed greatly. Inside the skull is a complex nasal cavity that may have given it good sense of smell, while forward pointing orbits show a degree of stereoscopic vision.
Olorotitan
Size: 8 meters
Diet: Herbivore
Bio: A large hadrosaur with a hatchet like crest. Orolotitan has 18 neck vertebrae, more than any other hadrosaur.
Amargasaurus
Size: 10 meters
Diet: Herbivore
Bio: A strange sauropod with very distinct spines growing out of its neck. They can grow to be around 24 inches tall. These spines might have been used for combat or for display purposes. The spines on the neck has also been compared to that of Dimetrodon, making some suggest they supported a sail on the neck. However, it's argued that a sail would greatly reduce the mobility of the neck.
Regaliceratops
Size: 5 meters
Diet: Herbivore
Bio: Named after it's regal looking frill. This newly discovered ceratopsian may or may not be closely related to Triceratops. They're still debating that.
Deinocheirus
Size: 11 meters
Diet: Omnivore (?)
Bio: For almost 60 years, Deinocheirus was only known from a gigantic pair of arms. Efforts to find the rest of the skeleton paid off, and we now have 90% of the skeleton. The real animal was stranger than we ever imagined. It was indeed a gigantic ornithomimid, but that's where similarities end. It had a duck like bill, with a heavy jaw like a horse. It had short stumpy legs and a camel hump on its back. Though no feathers were found, the end if it's tail suggests it might have had a fan of feathers. It was a huge water fowl that might have eaten fish, plants, and smaller dinosaurs.
Dakotaraptor
Size: 5 meters
Diet: Carnivore
Bio: One of the largest dromaeosaurids, and closely related to Deinonychus. It lived with the likes of Tyrannosaurus, Triceratops, and Ankylosaurus. Dakotaraptor might be the adult form of another raptor call Acheroraptor.
Majungasaurus
Size: 6-7 meters
Diet: Carnivore
Bio: One of the best preserve abelisaurids. It had a small horn on the top of its skull, and very short but robust legs. It along with Tyrannosaurus are one of the few theropods with clear signs of cannibalism.
Suchomimus
Size: 10-11 meters
Diet: Carnivore
Bio: A fish eating spinosaurid. It had a long narrow snout, powerful arms with long claws, and tall neural spines along the hips. Though unlike Spinosaurus, the spines probably formed more of a hump on its back rather than a sail.
Tarbosaurus
Size: 10+ meters
Diet: Carnivore
Bio: This is basically Tyrannosaurus in Asia. It's so similar that for a time, it was regarded as just a different species. More thorough analysis shows it should be its own distinct genus. The easiest way to distinguish it from Tyrannosaurus is that the skull is narrower towards the back, and the arms are even smaller than that of Tyrannosaurus. The largest specimens probably reached similar size of an average Tyrannosaurus.
Therizinosaurus
Size: 10 meters
Diet: Herbivore (?)
Bio: Strange theropod with giant 3 foot long claws. It was more closely related to birds and raptors. This is a very confusing animal, as it has the neck like a sauropod, stumpy legs of a theropod, giant body, and long arms and claws. The claws might have been used for defense. Some even suggested they were used to dig up termites from termite mounds.
Last edited:
