A Paleonerd's Analysis - BBC's Walking With Dinosaurs Part 2

Well then, amongst the paleo-media sensation which is Dakotaraptor, I just managed to finish  Part 2 of my analytical dive the series which is Walking With Dinosaurs. If you haven't read my analysis of the first two episodes, you can be sure to check them out here. For those of you which have, however, this next part will be covering the third and fourth episodes of the series, Cruel Sea and Giant of the Skies. Oh, and if you haven't heard about Dakotaraptor yet, go now! It's awesome! Seriously, I'll wait for you. Heck, maybe I'll even find the time to write a post on it.

Like last time, these notes are not just limited to me checking over the facts presented, but just observations on a variety of things in the series, good and bad (but mostly bad). I will also not go into too much detail about all the animal models, as that would take WAY too much time and probably end up sounding rather repetitive.

Cruel Sea

• Only 15 seconds in and we’re already over-embellishing this Liopleurodon by giving a poor Eustreptospondylus the axe.
• Also, how the heck did the Liopleurodon get that close to shore? I’m sure we all know that the moment an eighty foot long animal tried to do that, it’d be beached.
• The idea for the above probably came from knowledge that orcas will skid to catch prey in shallow water, but even then orcas are much smaller than this Liopleurodon, and they preform it on sandy beaches, not rocky slopes.
• Time frame is Oxfordshire during the Tithonian 149 mya. Most of the animals in this episode actually do manage to hail from Oxford, but a lot are actually from the older Oxfordian (157.3–163.5 mya). (Hint: note the names…)
• Speaking of things too heavy to haul out on land, how the heck are the Cryptoclidus, which the documentary says weigh eight tons, hauling themselves around a beach?
• Also, recent discoveries have shown that cryptocleidoid plesiosaurs had tail flukes, which was a surprise when first announced in 2010. Nobody knows how or if they worked in locomotion, but they still definitely had them.
• The Rhamphorhynchus are skimming. Short answer: this probably didn’t happen. Long answer: read Mark’s post over on his blog.
• Also, the Rhamphorhynchus have some really ugly models, even by the standards at which scientists often describe them as snagly-toothed ugly little bulldog-pterosaur things.
• “Most sea reptiles return to the land to lay eggs” – Presumably they’re talking about other marine reptiles at the time with that statement, but that seems no longer true. In fact live birth is now known in almost every major group of Mesozoic marine reptiles (sea turtles are an exception), or can be inferred from their anatomy.
• Speaking of which, I also wish they expanded on the possibility of parental care in ichthyosaurs. Sure it’s a bit speculative, but there’s a close correlation between live birth and parental care in reptiles (there are outliers from this trend though).
• Bit glad that they mentioned that the sharks were honing in on the pregnant Ophthalmosaurus via hearing rather than the rather stereotypical explanation of smell.
• Oh crap the Liopleurodon is back. What? No I’m not worrying about the Ophthalmosaurus, I’m worried about the number of inaccuracies and embellishments I need to sit through.
• Wait, when the back half of the Ophthalmosaurus hits the seafloor, it no longer has the tail of the baby sticking out of its cloaca. Did it escape the jaws of the pliosaur?
• Few people know the story of why the Liopleurodon in this episode is so big, so I’ll explain. Some early size estimates based on the scaling of a Liopleurodon skulls found that Liopleurodon might’ve reached something like 12 meters in length based on some of the larger Oxford skulls. These same models were then used in another study which scaled the skull’s teeth up to the same sizes observed in the bones of some cryptocleidoid plesiosaurs, thus producing some ridiculous 25 meter estimates, which was used in the documentary. Obvious to say, these methods of scaling were shown to not be very accurate. Later, more accurate modeling methods based on what was known from more complete pliosaurs (notably the Australian Kronosaurus) shrunk Liopleurodon down to a much more believable 6 meters in length that it is today.
• Going with the idea that its 25 meters long, I should probably note that animals of this size DO NOT like to live so close to shore. Even orcas, which are only around 7 meters long, actively avoid shallow reef-like waters while hunting because it doesn’t provide enough space to launch hunts or ambushes. An animal of this size should be living in the open ocean far away from reefs.
• “Liopleurodon. At 150 tons, it is the largest and most powerful carnivore ever to live on the planet.” - Sounds like something I’d expect someone pandering to fanboys to say. Quickly! Someone write an awesomebro fanfic about the WWD Liopleurodon fighting the Jurassic World Mosasaurus! You’ll make millions!
• “His size means he is probably over 100 years old.” – I object to that. Do we even have any studies on pliosaur/plesiosaur longevity? I don’t ever remember seeing one.
• There’s a mention rather briefly about how Liopleurodon smells its prey using a water-movement system in the nostrils as “radars to hone in on prey”. Presumably this is a butchered explanation of the dual waterflow system in pliosaurs (and possibly other marine reptiles), in which water enters the mouth, flows through the nasal cavity, and exits the nostrils, allowing for a constantly active sense of smell.
• The Ophthalmosaurus hide in underwater caves at night for protection against predators, despite the fact that, you know, they need to breathe.
• The way that the Eustreptospondylus in this episode manages to swim should be some kind of meme. I’m not sure what the meme would be for, but it would be downright hilarious.
• The Eustreptospondylus is presented as some kind of specialist sea-combing dinosaur. This speculation, as far as I know, is unique to the documentary as I cannot find any specific suggestions for this lifestyle prior to the show’s airing. I think it was presented because the only known specimen of this genus was found in the ocean near an island, but it could equally be parsimonious to say that the animal was simply washed out to sea from a larger island area. There are no particular traits in its anatomy suggesting a sea-combing lifestyle.
• Two Eustreptospondylus squabble briefly over a “sea turtle” plastron. Given that modern type sea turtles first appeared during the Cretaceous, this plastron is probably meant to be from a Plesiochelys, which were a major component of Late Jurassic shallow water ecosystems, but not true sea turtles themselves.
• There’s a brief scene where a young Rhamphorhynchus digs into some tree bark looking for beetle larvae. Interestingly, despite the obvious diet of seafood in older induviduals, “flapling” Rhamphorhynchus (and many other pterosaurs for that matter) show short, triangular snouts which might prove superbly adapted to feeding on small invertebrate prey. Sadly, the individual itself doesn’t look at all like what we know of “flapling” specimens, simply being a shrunken down juvenile. (Note that most Rhamphorhynchus specimens are of half-grown juveniles, with only a handful of true adults known.)
• After a group of horseshoe crabs breed, a flock of Rhamphorhynchus settle down to feed on their eggs. Not sure if this is based off the behaviors known for migrating Calidris canutus, but it seems so.
• Ok, this is weird. While the Rhamphorhynchus are feeding, a Eustreptospondylus tries to snag one while they’re preoccupied. If you follow the movement of its jaws closely, you can clearly see it grab two separate Rhamphorhynchus, let both of them go, and then finally settles on a third one it manages to pin beneath its foot. Um… why?
• Also, these poor Rhamphorhynchus aren’t utilizing proper quadrupedal launch. Instead they’re just skipping across the ground on their hind legs flapping their forearms aimlessly. No wonder they’re so easy to grab while taking off.
• Just noticed this now, but the Eustreptospondylus puppet model has its earhole in the wrong place. Dinosaurs had their ears behind their skulls, not on top of the temporal fenestra. Having it in the place shown here, it wouldn’t be able to hear at all because there’s a major jaw muscle in the way.
• Back in the ocean, another female Liopleurodon shows up in the male’s territory, which leads the male to confront her in a fight. This is rather strange, as I’d expect the male to be more interested in mating. Didn’t we just clarify a little while ago that it was still the mating season for other marine reptiles? Why are the Liopleurodon acting different?
• “Her flipper has been badly ripped...” – Looks fine to me. There isn’t even any visual trauma on it as she swims off.
• After the big storm, the big male Liopleurodon becomes stranded on a beach. See, that’s what happens when you’re a 150 ton animal living in a shallow-water reef ecosystem. You’re basically asking to get stranded.
• Also, the Liopleurodon looks at lot smaller than 80ft when lying out on the beach next to the Eustreptospondylus. It appears to be 50ft maximum, which might be in line with the largest unpublished pliosaur specimens.
• “The greatest carnivore the Earth has ever seen.” – I can hear the fanboys panting. Stop it. Don't encourage them.

Giant of the Skies

• “In life he was the most magnificent beast ever to take to the wing.” - Quetzalcoatlus is pretty magnificent too, and we knew it was more massive than Tropeognathus at the time this series was made. Then again, I guess that is all interpretative.
• The model used by the documentary has minute pycnofibres on it, but most of the body still looks like bare skin. This doesn’t fit in with what we know (and knew at the time) about pterosaur body coverings.
• Time frame is 127 mya, which would be the Barremian period of the early Cretaceous. However, half of the animals in this episode are actually from the Albian (100.5 - 113.0 mya), including the Tropeognathus, and one is even from the Cenomanian (93.9–100.5 mya).
• Also, Branagh states that the continents by the early Cretaceous had only just started to break up outside of the typical Laurasia-Gondwana distribution. While that might be true for some parts of Gondwana (notably the tentative dates behind the separation of South American and Africa), the rest of the world should have already been breaking up since at least the middle Jurassic. Heck, the last episode was all about the broken island chains that would eventually become Europe.
• It’s now Tropeognathus mesembrinus, not Ornithocheirus, as this species was found to be distinct enough to warrant its own genus.
• Size is WAY too exaggerated on the Tropeognathus. Even for the time, I’m pretty sure the 12 meter estimated wingspans were heavily doubted by the scientific community. Most modern estimates put it around 6-7 meters, which is roughly the same size as other giant flying oceanic avemetatarsalians (Pteranodon, Pelagornis, etc.). Brings up an interesting question as to why they all group around this size…
• The Tropeognathus holds a human-like, bipedal stance for a few moments while it’s landing. David Peters, anyone?
• The specific species of “Tapejara” used in the episode, T. navigans was reclassified to the genus Tupandactylus in 2007. Also, they are completely disproportionate, and based on what we now know about tapejarid pterosaurs, this group were probably inland-dwelling omnivores, not oceanic piscivores.
• “…but on the land they are cumbersome” - That’s true for some specialist oceanic species featured in the show, like Tropeognathus and possibly Rhamphorhynchus, but almost every other pterosaur featured on the show were competent walkers, and possibly even runners in the case of many azhdarchoids like the Tupandactylus.
• They show different-sized crests for males and females, which predicted the actual discovery of sexual dimorphism in pterosaur crests.
• “What he is about to undertake, is the most astounding journey in the animal kingdom.” First of all, how the hell do you know that Kenneth Branagh? Second, have you ever heard of a little bird called Sterna paradisaea? Flying from Brazil to Europe across an Atlantic (which is only half the size it is today) cannot compare to what tiny little Sterna paradisaea do twice every year.
• The “Iguanodon” the Tropeognathus encounters in North America were reclassified to the genus Dakotadon. Also, Dakotadon are from South Dakota, while Branagh claims that the Tropeognathus had only just reached the southern tip of North America. That’s like seeing wild American plains bison (Bison bison bison) in Central American rainforests…
• The Polacanthus accompanying the herd is even more lost. Polacanthus fossils are only known from Britain, not North America. I guess this could possibly be a Gastonia (which the WWD model somewhat resembles), but even then it’s the same problem that the Dakotadon have.
• Tropeognathus, an oceanic pterosaur which probably spent months flying out over the sea at any given time and would probably need to encounter storms regularly, can’t fly in rain. People really need to stop underestimating what pterosaurs were capable of. So glad we have such great pterosaur experts now setting our views of these animals straight.
• “[Iguanodon] are among the most successful dinosaurs on the planet, populating every continent…” – Then, everything changed when the taxon splitters attacked…
• Branagh says that Iguanodon were the first large herbivorous animals capable of advanced chewing. If he is referring to the Iguanodontia as a whole and not just Iguanodon, I guess that’s somewhat true, but many other groups of dinosaurs could also masticate and developed advanced chewing techniques at around the same time. (Ankylosaurs come to mind, for example.)
• There’s a short segment about how flowers "originated" in the Cretaceous. Depends a bit on what you mean by "originated". True flowering plant fossils are known from the Early Cretaceous, 130 mya, but what looks like angiosperm pollen has been found from as far back as the Triassic, and some molecular clocks suggest the ancestors of true angiosperms split off from other plant groups 300 mya. Still, if they're going by "true flowers", then I guess this is true as well.
• We get a cool look at what we thought at the time to be the parasitic flea-like creature called Saurophthyrus. Saurophthyrus and other insects like it were once thought to be specialist pterosaur parasites, using their elongate blood-sucking mouthparts to feed on the blood-filled wing membranes of pterosaurs. More recent studies have been more skeptical of them being “pterosaur specialists,” as their mouthparts don’t seem any more specialized to specifically pterosaurs than they do various other Mesozoic animals.
• The pterosaurs be-a-skimming. As I mentioned above with Rhamphorhynchus, this needs to stop.
• The pliosaur in this episode is officially listed as being Plesiopleurodon, despite being just re-used stock footage of the Liopleurodon from last episode. Either way, Plesiopleurodon is known from the Cenomanian of North America 98 mya, not the Barremian 127 mya, so both are equally distant in time (give or take 20 to 30 million years) from the age this is supposed to be set.
• While bringing up the pliosaur, Branagh also mentions that there’s dangers to flying low over the ocean, as if the pliosaur is actually going to jump up and eat our Tropeognathus. This, of course, goes back to early paleoart showing marine reptiles jumping out of the water to try and catch pterosaurs, but it’s always been a stupid idea IMO. How is massive marine predator going to manage to jump out of the water at a small, fast-moving animal in flight when, by the time it’s in view and you’re ready to strike, it’s already passed by? Moreover, how worth it is it to do this to eat something that weighs, at the absolute most, only about 50 kg? This concept has always sounded incredibly stupid to me.
• Ok, this “European species” of Iguanodon seems to confidently be Iguanodon bernissartensis, and not one of the countless European iguanodonts that was lumped into its genus at the time. The model itself also looks great, and actually manages to stay pretty accurate to this day. Unlike the next critter...
• And now, for the moment you’ve all been waiting for… *Drumroll* UTAHraptor in EUROPE!
• Is it just me, or are the Utahraptor models are really ugly? Not only are they shrink-wrapped and look anorexic, but they have a lot of features in the skull and neck which remind me of varanid lizards. (Not that varanids aren’t beautiful animals, just that it’s a bad reference.) Oh, and they have their ears in the temporal fenestra too. Is this a problem with all the models that I'm just now noticing?
• “…long fingers help [the female Utahraptor] to latch onto swift-moving, larger prey…” Dromaeosaur fingers were pretty immobile and stiff, actually, which likely helped keep their wings strait. However, juveniles had more flexible fingers than adults, which with a growing body of evidence suggests that they might have been partially arboreal while young.
• After the Utahraptor is unsuccessful at jumping on the Iguanodon, the Iguanodon stops running, turns around, and seems to be taunting it for a moment. A lot of large herbivorous mammals actually do similar things, so I wonder if that’s what they were going for.
• Branagh says that dromaeosaurids were not fast runners, but rather had the short, stalky legs of a sprinting and wrestling animal. Finally! A documentary that gets this trait common to dromaeosaurinae correct.
• I’ve noticed that the Utahraptor, despite having no wing feathers, are actually managing to hold their forelimbs consistently in a bird-like pose, even while running. Props on them for getting this right, as even recent documentaries incorporating feathers have a tendency to have the hands droop or be held in odd positions.
• “These though are birds, flying dinosaurs that share the same ancestors as the carnivorous raptors. Instead of scales, they have evolved feathers…” If only they knew... Oh wait, they already did…
• He mentions something about feathered wings being more resistant to damage than membranous wings. Not sure exactly how true this is, but bats can manage to fly around with huge holes in their wings and are still competent in the air, so I don't think a few bumps or scrapes would really effect a pterosaur's wings.
• When the old male finally makes it to the mating grounds we see that the female Tropeognathus have sexually dimorphic jaw crests. There have been proposed cases of sexual dimorphism in the crests of ornithocheirid pterosaurs, but it has not been studied in detail or confirmed, despite the large number of fossils perfectly available for such a study. (Wink, wink, nudge, nudge…)

Whew, that was a lot of note-taking. A lot of stuff certainly has changed in the time since the series aired, but with these last two episodes at least, I was still able to find some admirable things about them. Will definitely be fun to look at the last two episodes soon. I remember the fifth episode in particular to having always been my favorite growing up, so I'm definitely psyched to get to that one soon.

Cheers!

P.S. If you don't know what Dakotaraptor is by the end of this post, shame on you. Go look it up right now.