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This article is not part of the Walking with... universe.
This article covers a subject that is part of the real world, and thus should not be taken as a part of the Walking with... universe.
Despite Walking with... being a documentary series, several paleontological inaccuracies appear throughout some of the shows. However, most of the errors are caused by newer and more recent discoveries. Here's a list of them.
Spinosaurus and Suchomimus likely never coexisted, as they lived in different parts of Africa (respectively, Egypt and Niger), although they did live at the same time.
Spinosaurus had shorter hindlegs, unlike the long-limbed one seen in the app. Its hallux should also be touching the ground, and its toes were most likely webbed. However, these discoveries were made after the app's release.
Psittacosaurus, according to a study in 2016, had a series of brown colors to camouflage and had a membrane on its hind legs.
Coelophysis had sexual dimorphism, unlike the ones in the show, which were all the same.
There is no conclusive evidence that Coelophysis was cannibalistic. This was based on a fossil of Coelophysis with jumbled up bones in its stomach cavity, but these turned out to be species of small crocodylomorphs, rather than the juveniles they were long mistaken to be. However, this was discovered after the release of this episode. However, it is not impossible. Evidences of cannibalism have been found in other species of dinosaurs, and maybe Coelophysis was one of them.
Coelophysis may have had feathers, but it is highly debated.
No theropod had pronated wrists.
Placerias were probably not hippo-like.
Archosaurs generally don't mark their territories with urine, unlike the male Postosuchus in the show. It's likely that, just like their crocodilian relatives, Postosuchus didn't mark their territory at all, maintaining and defending their hunting ground from intruders.
Thrinaxodon was from the early Triassic, not the late. However, an unnamed species of cynodont is known only from teeth in the Chinle Formation so the reconstruction of this cynodont was therefore based primarily on Thrinaxodon. Other cynodonts, like Arctotraversodon, Boreogomphodon and Oligokyphus, lived 220 million years ago in what is now North America, but these species were most likely all herbivores, and don't match the morphology of the cynodont seen in the episode.
Plateosaurus couldn't move in a quadrupedal stance. However, this discovery was made after the release of this episode.
Coelophysis didn't live at the same time as Placerias. However they were both from the Ghost Ranch Formation.
Coelophysis didn't coexist with Plateosaurus, who lived in Europe, not North America. It also did not live at the same time as Coelophysis.
Coelophysis didn't live 220,000,000 BCE. It evolved at least 203,000,000 BCE and lived to at least into the Early Jurassic approximately 196,000,000 BCE or possibly even later. A better substitute was Camposaurus, a relative of Coelophysis who did existed during the Norian stage, where the episode is set.
Placerias is a stem-mammal, not a reptile.
Peteinosaurus is found only in Europe, not North America. However, since all of the continents were joined, it may have traversed into North America, occasionally. Some species of triassic pterosaurs did existed in North America, but they were part of the Eudimorphodontidae family.
Postosuchus is now known not to have walked in a quadrupedal posture. It is instead belived to be bipedal, although this theory is still debated.
Ornitholestes didn't have a nasal crest. But this wasn't found out until a recent time, long after production was finished.
Ornitholestes almost certainly was covered in feathers, which did appear in the companion book.
Diplodocus held its neck in a slightly higher position than shown in the series.
There is no evidence for such an egg laying structure in Diplodocus. It is most likely that large sauropods preferred to lay their eggs while laying on the ground, with their cloaca close to the ground of the nest. However, at the time the documentary was made, the egg laying structure was purely speculation by the creators.
Anurognathus were micro nightjar-like insectivores, and probably did not behave like modern Oxpeckers. Its anatomy is also very inconsistent with the real animal, with a typically elongated neck, deep skull and small wings
Anurognathus wasn't found in North America, only in Germany. (Although there are other types of pterosaurs from the Morrison Formation, such as Mesadactylus and Kepodactylus) This error was fixed in The Complete Guide To Prehistoric Life book.
Allosaurus was mentioned to be the top predator of its age. The top predator would have actually been the larger Saurophaganax (if it was a separate genus to Allosaurus) and Torvosaurus. Probably the latter was around during the time and location seen on the episode, as it was in the Kimmeridgian stage, where Allosaurus and Torvosaurus were around. Saurophaganax lived in the Tithonian stage, only a few million years after.
The head design of Allosaurus is inaccurate. Corrected (somewhat) in the Ballad of Big Al.
Brachiosaurus may have had spines on its neck, but it is debated.
Stegosaurus may have had sexual dimorphism, but in the show, all the Stegosaurus are modeled the same.
Stegosaurus could not change the colors of its plates by flushing blood into them, as preserved integument impressions of Hesperosaurus have shown stegosaur plates were covered in a horny sheath, not skin.
Diplodocus could not reach adulthood in only a decade. The average amount of time it would take for Diplodocus to reach full size was forty years.
Allosaurus is now known to have used its head like an axe to kill prey, as it has a bite force weaker than a lion's, but its head could withstand a force 18 times greater than its bite. However, in this episode, it is depicted attacking a baby Diplodocus similar to a Tyrannosaurus, an animal with a strong bite and a completely different attacking style to an Allosaurus.
Liopleurodon wasn't even half as big as it was in the show. It wasn't 25m long and 150t, but more like 6–10m and 5-8t, the size of an orca. There is evidence of pliosaur bite marks that indicate an animal 25 m long, but it's unlikely that the attacker was a Liopleurodon. However, other species of pliosaurs are known to have reached at least 15 meters long!
Long neck Plesiosaurs and short neck Pliosaurs are now thought to have flukes on their tails, and not smooth lizard-like tails like in the series. Although this is probably not universal.
Liopleurodon lived from 160,000,000 BCE to 155,000,000 BCE, not 149,000,000 BCE. A possible replacer would be the much larger Pliosaurus, who lived at the time, and could also reach to gigantic sizes (very likely more than twice the size of Liopleurodon).
There is no evidence that Ophthalmosaurus migrated towards coasts to give birth, although it is not impossible (and it is obviously an intelligent decision).
Cryptoclidus lived from 186,000,000 BCE to 164,000,000 BCE, not 149,000,000 BCE. A possible replacement would be Colymbosaurusor Kimmerosaurus, which lived at the time.
A study of a few ichthyosaurs, Tylosaurus, and an extinct sea turtle, indicate they were mostly black or dark in colour. This doesn't mean that they where completely black, or that other non-detected colours weren't there. It also doesn't directly involve Opthalmosaurus (despite it is already depicted with a somewhat dark colour in the show).
Rhamphorhynchus lacks many skeletal features required for a skim feeder, therefore he probably didn't fish that way.
The shape of the lower jaw was slightly off in Rhamphorhynchus.
Rhamphorhynchus had longer wings.
Some of the animals seen in the episode didn't live in the late Jurassic, instead they lived in the middle Jurassic such as Cryptoclidus. Hybodus lived in both the middle and the late Jurassic. Others like Liopleurodon, Eustreptospondylus and Ophthalmosaurus lived only in the late Jurassic, while Rhamphorhynchus lived near the end of the late Jurassic. Only Hybodus and Rhamphorhynchus are known to have lived 149 million years ago (even Ophthalmosaurus was probably extinct a million years before).
Eustreptospondylus lived 162,000,000 BCE, not 149,000,000 BCE. A possible replacement would be the recently discovered Juratyrant, which was a five-meter long relative of the Cretaceous Tyrannosaurus.
Modern sea turtles hadn't evolved yet. They evolved in the Early Cretaceous. However, the species shown in the show could be a unrelated species of sea turtle, like Plesiochelys. This one wasn't related to the modern sea turtle lineage, belonging to a completely different extinct lineage of saltwater turtles, that lived in the late Jurassic.
The species of Ornithocheirus in the program has recently been reclassified as its own genus, Tropeognathus, rather than being a species of Ornithocheirus. However, it was a species of Ornithocheirus when the program was made.
Tropeognathus had a wingspan of only 7-8.2 m (23–27 ft) max. So it was not as large as depicted in the show.
There is no evidence that Tropeognathus traveled the globe, as fossils have only been recovered from South America.
Tapejarids might have been herbivores/frugivores.
Tapejarids are depicted with ornithocheirid-like limb proportions, with massive forelimbs and short hindlimbs, offering them a cumbersome terrestrial gait. In reality, these pterosaurs, like their azhdarcid relatives, had longer hind limbs and shorter wings (albeit still obviously much larger than the hindlimbs), allowing them to be effective terrestrial foragers.
The Tapejara shown (according to morphological issues) would more accuretally be identified as a species of Tupandactylus.
Sexual dimorphism isn't documented in tapejarids, although some species could have had it.
Tapejarids lived inland, not on the coast. However, it is possible that at least one species speciated in coastal life.
The walking pose of all the pterosaurs are far off.
Tropeognathus and Tupandactylus, like all pterosaurs, are both known to have possesed pycnofibers, a feature not present in the reconstructions of the two species seen in the episode.
The N. American “Iguanodon” are now classified as their own genus, Dakotadon.
Iberomesornis has modern bird traits not found in Enantiornithes, like scaly feet (instead of owl-like feathered feet or even Microraptor-like hindwings) and retrices (Meaning it should have these features).
Iberomesornis lacks the two, long, tail feathers that the real animal had.
Utahraptor wasn't found in Europe. Other dromaeosaurs lived in Early Cretaceous Europe, like Nuthetes and Dromaeosauroides, but these lived in the Berriasian stage, not the Barremian stage. Another dromaeosaur, Ornithodesmus, did exist in the European Barremian, however, it was too small to replace the Utahraptor on the show.
Utahraptor did have feathers running head, to toe, to tail; only the tip of the snout was visible. It even had feathers on its arms that made them look like wings. Additionally, it was impossible for the hands to be pronated without being broken. They held them at the side. The same errors are for Velociraptor (see below).
There is no solid evidence that dromaeosaurids (except Deinonychus) hunted in groups. Of course this doesn't mean they didn't.
Polacanthus isn't known from North America, only Europe. (A better candidate for this animal would be Gastonia, since Gastonia lived in the Barremian in North America, but it's anatomy doesn't really match the one of Polacanthus).
Since Tropeognathus was not a globe traveler, Tupandactylus lived inland, Iguanodon and Polacanthus lived in Europe and Utahraptor lived in North America, the plot of the episode would have been impossible to happen in reality since Pangea is gone at this time. However, it could be assumed that the Tropeognathus is just another species of ornithocheirid, and the Utahraptor another species of dromaeosaur.
Giant pterosaurs are now known to not have been consummate gliders.
There is no evidence that Leaellynasaura could go into a form of hibernation, but it is still possible.
Muttaburrasaurus was less hadrosaur than shown in the show, even though it was a rhabdodontomorph. It should be wholly bipedal rather than partially.
There is no evidence Muttaburrasaurus were migratory, but they still could be.
It's now known that Australovenator is not an allosaurid, but instead belongs to a group of dinosaurs know as Megaraptorians, a group whose classification is disputed. However, the show does identifies them as allosaurs, a name that could represent Allosauroids in general (which therefore may include the Megaraptorians).
Leaellynasaura might have had feathers to keep it warm.
Australovenator didn't live 106,000,000 BCE. It lived as early as 95,000,000 BCE. However, it is known that other megaraptorians lived around that time and place. Rapator lived very close to 106 million years ago, in Australia.
Muttaburrasaurus could not make noises with its nasal arch, because it was bony.
Steropodon is depicted as looking similar to a modern coatimundi, when in reality, it was a monotreme and looked like the modern platypus.
Koolasuchus lived 120,000,000 BCE and was extinct by this time. As it was the last temnospondyl ever, it's role was most likely replaced by crocodylomorphs, like Isisfordia (however this one in specific was too small, but it could still be able to hunt small juvenile dinosaurs).
Muttaburrasaurus probably did not have thumb spikes.
Dromaeosaurus has the same mistakes as Velociraptor and Utahraptor as well as 2 additional ones. The head is too blocky and stout and they died out 72,000,000 BCE, not 65,500,000 BCE. (Although there were two different dromeosaurids, Acheroraptor and Dakotaraptor, which lived in Hell Creek.).
Dinilysia didn't live at the same time as the other species in the episode, as they died out nearly 20 million years earlier. It also only lived in South America, while the episode takes place in North America. A better replacement would possibly be Coniophis, which lived in North America (however, it had small legs, unlike the one seen in the show).
Many aspects of Tyrannosaurus mating behavior in the show was speculation, and maybe were not reflected by the real nature of the animal.
The Tyrannosaurus is depicted as a solitary creature. However, Phil Currie has found some evidence supporting that tyrannosaurids hunted in groups. But this doesn't have to be conclusive.
It is widely accepted that Tyrannosaurus actually took extensive care of their young, and the males may have even participated in caring for them as well. In the program, the female scares away the male and the narrator says the mother will only care for the chicks for 2 months.
Tyrannosaurus' hands should be facing inwards, not downwards. The rear teeth, legs, and tail also seem a little shorter. The head is just very slightly too blocky. Tyrannosaurus is depicted as being 5 tonnes, but specimens 8-10 tonnes are not uncommon. But The Complete Guide To Prehistoric Life seems to have corrected these mistakes.
Tyrannosaurus is now known to have extremely powerful muscles in its neck and jaws; combined with its teeth that made its bite deadly.
Concrete evidence that female Tyrannosaurus were bigger than males isn't solid anymore.
"Anatotitan" is now known as Edmontosaurus annectens, though it was assigned to the genus Anatotitan at the time, so it is technically not an error.
E. annectens also lacks a fleshy crest akin to that of a rooster on its head. However, this is a relatively new discovery. Though this is only known from E. regalis at the moment, may have been a sexually dimporphic feature, and has been disputed.
E. annectens and hadrosaurs in general didn't have thumb spikes like their Iguanodon cousins.
Deinosuchus was extinct by this time, and is described as being a "1-ton crocodile". In reality, Deinosuchus weighed 9 tons and is more of an alligator than a crocodile. There were crocodilians during this time and period, Borealosuchus and Brachychampsa, but both were too small to fill the role of the crocodilian shown in the episode.
We now know that the eyes of smaller ornithopods are pronounced in a way that makes them look angry. This feature is also seen in eagles.
There are multiple inaccuracies for Quetzalcoatlus: The head is bigger and has a large flat crest instead of a tiny notch at the back of the head. The neck is much, much, longer than the program's design. The final result ends up looking more like another pterosaur, Ludodactylus. The design of the animal would be more accurate if it was a nyctosaurid or a pteranodontid (despite the size does not really match).
Didelphodon was not badger-like. In reality, it had a head like a Tasmanian Devil and a body like an otter.
Ankylosaurus was not as tall in reality as it appeared in the series.
Andrewsarchus is depicted as a mesonychid, when it was a more entelodont-like artiodactyl. However this is a very common and big mistake as most drawings/paintings of Andrewsarchus depict it as a mesonychid. Only a few correct drawings exist.
Dorudon was most likely not a social animal. But because they were mammals, socialization is far from unlikely.
Basilosaurus could not live as deep in the ocean as portrayed in the episode. A study of its vertebrae reveals that it was too weak to specialize in deep diving. It instead would stay close to the surface.
Basilosaurus swam in a serpentine way and had weak muscles so it couldn't swim fast for long.
It is unlikely Australopithecus afarensis could scare off large chalicotheres, unless these were quite skittish in nature (something that hardly can be determined with mere fossils).
Deinotherium most likely had a longer trunk in real life. If its trunk was as short as in the series, it would have trouble drinking as its legs were long and poorly built for kneeling, like an elephant's.
Phorusrhacos probably did not have wing claws, just like the seriema, its closest living relative.
Phorusrhacos was probably stockier and had a shorter neck than is shown in the series, though still most likely 10 feet (3 meters) tall.
Phorusrhacos lived in the Miocene (20,000,000-13,000,000 BCE), not the Pleistocene of 1,000,000 BCE. With accuracy, the show should not have shown any terror birds in that matter, as the last surviving member of this group was the North American Titanis, which also became extinct 800,000 years earlier.
There is no evidence that Megatherium ate carrion to supplement its diet, though there is still suspense that it was a meat-eater, even though it seems a little bit odd and unlikely.
Terror birds could fight and even kill Smilodon, despite the show does not depicts this. However, terror birds were not as strong as adult Smilodon, and would probably lose a fight with one, let alone enter in one. Despite terror birds were pretty much apex predators at the time, their significance declined with the presence of stockier mammalian predators from North America, like dogs, cats and bears.
Smilodon living in social groups is a controversial theory at best, but all experts agree that the lion pride idea is extremely unlikely, since male and female Smilodon showed no sexual dimorphism, in sharp contrast to lions, where the two sexes are very differently built.
Smilodon was a bulky, short ledged predator that was built to ambush and wrestle its prey to the ground like a bear, and was ill equipped for high speed chases and quick, sharp turns like modern big cats, so the Macrauchenia chase scene is entirely inaccurate.
Cave Lions had much longer, tufted, tails, like a modern lion, a primitive mane, and a faint striped pattern, we know this from cave art. The one seen in the episode shared a similar (or identical) model with Smilodon minus the sabres, which is why it exhibits these inaccuracies.
The Neanderthal species had died out 40,000 years ago, 10,000 years before the time that the episode takes place in.
Some paleanthropologists believe the African Homo heidelbergensis is merely an archaic form of modern humans. However, this is debated.
Some paleanthropologists do not recognize Homo ergaster and Homo erectus as separate species. Even if they were separate, some believe H. erectus did survive and evolved into the highly controversial H. floresiensis. Anyway, Homo ergaster is still a valid species, as well as Homo erectusand it is required a further research to reach to a conclusion to this systematic problem.
Lucy was not killed by being hit with a stick. It's been determined that she probably died from falling out of a tree. However, the reasons for the fall may still be uncertain.
Homo naledi is more likely to be our ancestor than Homo habilis, due to the fact that it had a Nuchel ligament, and H. habilis does not. However H. naledi was discovered in 2015, more than a decade after Walking with Cavemen aired, so they could not have known this. Also, this is more likely not true at all, because Homo naledi lived from 335 to 236 thousand years B.C., which means, they were too young to be considered our ancestors. Homo habilis is more primitive and probably evolved to Homo sapiens and Homo naledi separately.
During a brief moment when going underwater, a Basilosaurus can be seen. However, it says that this is happening during 8,000,000 BCE, and Basilosaurus lived until 36,000,000 BCE. However, very slightly similar cetaceans lived during that time, like the beaked whales.
There is no evidence for Cephalaspis swimming into fresh water to lay eggs, although it is not impossible.
Brontoscorpio lived at a different time then Cephalaspis, one in the Silurian, the other in the Devonian, with only a four million year gap between the extinction of the former and the arrival of the latter.
Brontoscorpio was found in England not Wales and was possibly a terrestrial true scorpion. However, given the geographical proximity of the two places (even during the Silurian) it's still considerable that Brontoscorpio inhabited Wales.
Cephalaspis was not ancestral to tetrapods. At the Late Silurian, the most likely replacement would be the already full jawed Psarolepis.
In the part of the Devonian, there is an angelfish. It appears when the part starts and reappears when the Hynerpeton is chased by the Stethacanthus. However, there were no teleosts in the Paleozoic era, much less in the Devonian. However it is still possible to be a primitive actinopterin, a clade of bony fish that includes (beyond teleosts) the holostei and the chondrostei (the latter already present at the Devonian).
In the series, Petrolacosaurus is incorrectly identified as an ancestral synapsid, when in fact, it was an early diapsid and could therefore not have been the ancestor of any synapsids (e.g. Edaphosaurus). Furthermore, it is stated that the Dimetrodon was a reptile, when in fact, it was a synaspid (one could call them reptiliomorphs). Furthermore, the most basal synapsid, Archaeothyris, would have been a more suitable candidate.
The Dimetrodon hatchlings are shown with their back sails fully erect, when they probably wouldn't have grown yet.
The skin texture of Edaphosaurus and Dimetrodon are slightly off. They had scutes on their skin, similar but different to the ones on crocodilians. They are believed to lack the scales of lepidosaurian reptiles.
Dimetrodon is depicted as living in a desert-like environment, when in fact, Dimetrodon is known to have lived in a swamp-like environment. However, it is still possible that some populations lived in slightly more arid environments than the average.
The tops of some Dimetrodon's nureal spines may have been exposed bone rather than covered with a full sail, and some animals may have only had a sail halfway up the spines.
No species of spider is known to have been as large as the Mesothelae seen in this episode, now that Megarachne has been proven to be a species of sea scorpion. This doesn't mean that there isn't a Carbonifourus spider of this size, it just means that one has not yet been found.
Dimetrodon had incisors that were longer than the rest of their teeth.
Gorgonops and the Rhinesuchus are only known from South Africa, yet in Clash of Titans, they are portrayed living with Scutosaurus and a Siberian species of Diictodon, which were only found in Siberia. But the gorgonopsid was more likely an Inostrancevia since it lived at the same time and place as Scutosaurus and the Siberian species of Diictodon. Yet, in the show the Rhinesuchus is only identified as a Labyrinthodont, which is a subclass that already encompasses many other amphibians that could have lived in Siberia at the time.
Gorgonopsids are thought that they could have had fur.
Euparkeria is not an ancestor of the dinosaurs, being basal to crocodile-dinosaur split. Probably the most likely ancestor of the dinosaurs at the time was Tsylmosuchus which seems much more related to archosaurs (like dinosaurs, pterosaurs, crocodylomorphs, etc.).
Velociraptor may not have lived in heavily forested areas. All of the sites where Velociraptor fossils were found suggest that the animal lived in sandy, arid environments with many sand dunes (with one specimen apparently being smothered to death by a sand dune). However, knowing that there were two distinct species of Velociraptor, and that they were formidable and adaptable predators, it's still possible that some populations hunted in forested areas, although this can't be currently confirmed.
Velociraptor in the show lacks feathers. All Dromaeosaurids/Raptors had pennaceous feathers running from head to tail. It even had them on its arms to make them resemble wings.
Giganotosaurus was depicted on the show as the largest carnivorous dinosaur, though current size estimates favor Spinosaurus. However, it is true that Giganotosaurus was the largest land-dwelling carnivorous dinosaur that ever existed, as Spinosaurus was aquatic.
Argentinosaurus is said to have been the biggest dinosaur. Though that title may also belong to poorly known forms such as Amphicoelias fragilimus, Puertasaurus reuli, Bruhathkayosaurus matleyi, or Futalognkosaurus dukei.
Argentinosaurus's neck was probably held vertical not horizontal.
Argentinosaurus's body shape is largly based off Saltasaurus, like most titanosaurs were in the past. However, newer studies show that Saltasaurus had very different proportions from most titanosaurs.
Velociraptor's claw could not disembowel prey because the underside was round therefore the claw was used for stabbing and for imobilizing prey.
Tarbosaurus's arms should be facing inwards not downwards. Its head is also slightly off.
Tarbosaurus was depicted as being smaller than Therizinosaurus, when in reality it was larger than it.
Saurolophus and hadrosaurs in general didn't have thumb spikes like their Iguanodon cousins.
Therizinosaurus was depicted featherless. It is almost certain that therizinosaurs had feathers.
Pteranodon didn't live in South America. It was endemic only to North America.
Pteranodon lived 86,000,000-84,500,000 BCE (possibly as late as 80,500,000 BCE), not 100,000,000 BCE (Pterodaustro would be a good choice because it also lived in Argentina but it was extinct 5 million years before the show even takes place). Ornithocheiromorphs and azhdarchoids were pretty common at the time, however. Perhaps, Aerotitan would be a good candidate for the role, as it was a toothless azhdarchid with a five-meter long wingspan. However, it was discovered nearly ten years after the show was released.
Same issues with Tropeognathus as in Giant of the Skies.
Pteranodon should have had pycnofibres (fuzz) on its body.
Male Pteranodon probably had a more vividly colored crest to attract females. The beak of all Pteranodons is also known to have curved slightly upwards.
Sarcosuchus would never have encountered any of the other animals in the episode, as it lived 112 million years ago, in comparison to the episode's setting of 100 million years ago, and lived in a different region of South America, Brazil. However, it is still possible that other pholidosaurs existed at the time and place of the show.
It is now known that the frill bones of Protoceratops increased in length and width during the ontogeny of the animal and that the growth of the frill was greater than than the overall growth of the animal.
It is known that Protoceratops most likely used it frill for sexual and dominance signaling
Protoceratops had quills on its tail, unlike the one in the program
Velociraptor and Tarbosaurus were unlikely to live so close to the sea, but it is possible that the featured animals were just close relatives of these, or a determined population of the said species that lived close to the sea.
Tanystropheus was an archosauromorph, they can't shed tails in defence.
Tanystropheus is depecited as a primarily aquatic animal, while most paleontologists now believe that it was more terrestrial, sitting on the coast and using its long neck to catch fish from afar.
Cymbospondylus is depicted as a predator of marine reptiles. However, its teeth were small and conical, likely meaning that it ate small fish, squid, and belemites. A better choice would be Thalattoarchon, an ichthyosaur that looked very similar to Cymbospondylus, but was known to have eaten other marine reptiles. However, it was only discovered after the show had aired. In anyway, Thalattoarchon didn't lived in the late Triassic, while Cymbospondylus did, and with the latter's huge size, it is still possible that he hunted small prey (including very small marine reptiles, like pachypleurosaurs).
Tylosaurus was 15 m and 7 tons, not 17 m and 20 tons.
A recent study on Tylosaurus has concluded that the animal was mainly black or dark in color, not brown like the series' depiction of the animal.
There is no certain evidence that mosasaurs like Tylosaurus lived in large family groups. Although, it is still possible that they gathered in large groups (not necessarily family groups), like many of it's close relatives the snakes and monitor lizards (i.e. garter snakes, komodo dragons).
Basilosaurus' ability to "sing" is quite inaccurate. It and other early whales lacked the melon organ that modern whales have that is used for this action. However, Basilosaurus could still produce vocalizations, however not through the melon organ.
Same issues with Dorudonas in Whale Killer. (see above)
Megalodon was depicted a little bit too similar to modern day great whites. Though scientists suggest that Megalodon did look like a stockier version of the great white. This cannot however be confirmed.
There's no total evidence that juvenile Megalodon would have lived in the shallows but its possible.
Megalodon lived in warm water more or less near from the coast, not in dark open sea like depicted in the series. However, this can be debated.
Creatures have the same issues as described in their respective sections. (See above)
Time periods of planet earth go much farther back then the Ordovician, but this was probably an artistic choice, as Nigel didn't go any farther back then this, and the time map would be significativly longer.