Thread by @TetZoo

Welcome to the fifth and FINAL megathread on the award-winning, ground-breaking Apple TV+ series #PrehistoricPlanet 2, this one devoted to the North America episode. T. rex vs Quetzalcoatlus! Troodontids aplenty! Triceratops in battle! And more…

We have some people saying that this scene is realistic and reasonable, others that it seems a bit implausible based on modern animal behaviour, and others...

... weeping and screaming and jumping up and down while tugging at their hair and going red in the face. I have mostly avoided the drama since it's really not worth the time. #dinosaurs #azhdarchids #pterosaurs

The inspiration for this behaviour comes from comments that Mark Witton @MarkWitton and I published in an #azhdarchid-themed paper in 2015 (here and #OA… ) wherein we pointed out that...app.pan.pl/article/item/a…

@MarkWitton .... giant, long-billed, striding #azhdarchids wouldn't necessarily have been ripped to pieces within seconds should they choose to wander about in Cretaceous terrestrial environments.

@MarkWitton Like giant birds today, they would have gone long sections of their lives when big predators weren't an ever-present threat, and they might have been very capable of looking after themselves should danger arise in any case. Here' some concept art and some fan art…

@MarkWitton In the sequence, two #Quetzalcoatlus successful drive a T. rex from a carcass, at least for a short time while they eat a few kg of flesh from it. They make loud threatening noises (which are speculative: we have no idea on what sounds #azhdarchids made), make it clear that...

@MarkWitton ... the 2-m-long bill can serve as a dangerous stabby weapon, and also peck and jab the dinosaur while in flight.

@MarkWitton The sequence includes a few seconds that our series producer (Tim Walker) rightly noted as among the most significant moments in the whole of #PrehistoricPlanet: a >>badly filmed<<, poorly lit fragment where the object of interest (the T. rex) is not properly in frame.

@MarkWitton Think about that for a moment and what it means.

@MarkWitton It means that we were deliberately including 'badly filmed' moments in the show, all because we were doing what we could to make #PrehistoricPlanet feel more real, more like something that had actually been filmed by a real time-travelling camera crew.

@MarkWitton The T. rex retreats and leaves the #azhdarchids to the corpse. Maybe he comes back in 5 mins, maybe he comes back tomorrow. I absolutely object to the people who have confidently claimed that this scene is problematic or ridiculous.

@MarkWitton It isn't. Of course we can't say for sure, but it's at least plausible that a giant predator might choose to back down and avoid getting stabbed in the face, to be conservative and even 'cowardly'.

@MarkWitton Anyway, every predator has off days when it opts to behave atypically. Maybe that's what we filmed… a bit akin to those videos where alligators retreat after a pet cat swipes at them or a Saltwater crocodile runs away from a small barking dog…

@MarkWitton On another day, the crocodile might grab and kill the dog. Some of you will know which video I have in mind here…

@MarkWitton We move on to a marine scene set in the Gulf of Mexico for a meeting with a #mosasaur, the third species met this season. Previous #PrehistoricPlanet sequences featured the robust, chunky-toothed, widespread Prognathodon…

@MarkWitton This is its cousin Globidens (there are numerous species; our was mostly based on G. dakotensis), famous for its fat-crowned teeth. Concept art by Gabriel Ugueto @SerpenIllus shown here. #mosasaurs #marinereptiles

@MarkWitton @SerpenIllus Conventional thinking has it that these teeth were built for crushing shellfish, most likely giant inoceramid clams. Most experts now prefer the idea that these animals were often eating cephalopods like ammonites.

@MarkWitton @SerpenIllus Maybe they were, but studies of living reptiles show that rounded teeth enable a lizard to be a good generalist: sure, it can crush shelly prey but it feeds on a variety of other things as well. Maybe this was true for Globidens too. #mosasaurs

@MarkWitton @SerpenIllus We did plan at one point to feature those inoceramid clams. They're interesting not just for being huge but because they were used as homes for numerous small fishes and maybe other animals too.

@MarkWitton @SerpenIllus As with our other #mosasaurs, we showed extensive gingival tissues (gums) mostly concealing the teeth, something inferred from living anguimorph lizards and seemingly present in a fossil mosasaur with soft tissues preserved.

@MarkWitton @SerpenIllus Our Globidens otherwise has a forked tongue of the sort probably ubiquitous in #mosasaurs and is a streamlined 'whale-o-saur' whose look is inspired by current thinking on mosasaur overall shape as revealed by soft tissues.

@MarkWitton @SerpenIllus A large number of the big ammonite Sphenodiscus – dubbed 'tiger ammonite' because we came up with the idea of giving them stripes – are shown moving through the area. Very big individuals have a shell diameter of about 40 cm, though half this size is more typical.

We infer that these highly streamlined, narrow-shelled ammonites could swim continuously for a time using jet propulsion from the siphon, but we also show them using 'arm pumps' (where the arms – they are NOT tentacles! – and their skirting work together in...

... rapid contraction) when they need to take emergency action due to mosasaur pursuit.

The whole idea of #mosasaurs killing ammonites, perhaps disabling them via a bite to the biggest part of the shell, is a familiar one thanks to specific fossils that seemingly show mosasaur tooth marks.

Considerable argument has concerned the identity of the marks (are they really mosasaur tooth marks or epibiont attachment scars?).

Our mosasaur engages in what looks like 'surplus killing', a behaviour most associated with predatory mammals (like foxes) but also documented in insects (including antlions and predatory midge larvae) and suspected to be more widespread.

We went to a lot of trouble in modelling the change in pupil size and shape that would occur in a dying ammonite and also sure had to do our homework on what the soft parts of the body would look like when extracted from the shell. #mosasaurs #marinereptiles

The ammonites we've seen are all females, laden with eggs and preparing to attach their sausage-shaped egg capsules in the shallows. As I said in the previous megathread, we mostly think...

... that ammonites attached their egg masses to hard surfaces in coastal waters. The adults would have died after doing this, as is typical for cephalopods…

For the next sequence, we're back on land and at a lake-side somewhere in the vicinity of Wyoming, where a soda lake has formed. The main character here is the troodontid Pectinodon…

I recommended that we use this name in view of an unpublished, privately owned complete specimen that's been regarded as referable to this taxon. That's right: we >didn't< have the tiny holotype tooth (named by Ken Carpenter in 1982) in mind when opting to go with this name.

Again, we opted to portray these #dinosaurs engaging in bird-like post-hatching parental care, and gave the father an important role, something inferred from the sex discovered in maniraptoran fossils preserved with nests…

The juveniles were given a cryptic, blotchy plumage very different from the adult and a different feather configuration too. We see them eating the brine flies that gather along the edge of the lake.

It's not altogether clear that brine flies really were present in the Maastrichtian but it could be that ecologically similar dipterans existed. Showing this behaviour is wise, I argue, because...

... it emphasizes that #dinosaurs of this sort might have engaged in all sorts of opportunistic foraging and feeding behaviour: they didn't just eat small mammals.

This sequence – devised by producer Nick Lyon early in the history of #PrehistoricPlanet – was inspired by fly-eating behaviour seen in gulls and ducks. I was never keen on transferring the behaviour of modern animals to Cretaceous ones in such direct manner, but...

.... of course the fact that those birds engage in this behaviour makes it at least plausible for non-birds like troodontids.

Waterbirds of some sort were needed for the sequence and we opted to show presbyornithids. The locational setting for this sequence changed (initially it was India and the non-bird #dinosaurs were noasaurids) but once we opted to go with North America...

... the birds had to be 'Styginetta', an as-yet-unpublished Late Cretaceous anseriform…

… which – we assume – was similar to the far better known Presbyornis of the Paleogene. These were long-legged, duck-like birds and to portray them I had to ask around on things that no-one really talks about, like whether they had bill lamellae (ha ha, thanks @albertonykus)…

@albertonykus The script includes a line that I didn't like, something like "It's not just dinosaurs that are here. Birds are at the lake too" (say that in your best Sir David Attenborough voice)...

@albertonykus The fact that birds are a group of #dinosaurs is, as I've said at every opportunity in my career (see my books), an important point that dinosaur specialists should emphasize at every turn, not ignore, gloss over or forget!

@albertonykus So the line should be something like "Dinosaurs of another sort are present here – the dinosaurs we call birds", but alas. I did what I could. People in the media still insist on being conservative on issues like this.

@albertonykus The adult troodontid kills a presbyornithid by catching one as it takes off – not an easy scene to animate (big nod of appreciation here to our excellent MPC team, my god they worked hard)…

@albertonykus We couldn't show the father plucking and discarding feathers as he likely would in processing a feathered prey item – it was just too awkward to animate – and, as ever, were constrained in how much blood and gore we could show.

@albertonykus We pan out and move onto the next sequence…

@albertonykus We move to a conifer-dominated forest, also near the Rocky Mountains, where we learn that individuals of the horned dinosaur Triceratops horridus (it has a smaller nose horn and longer beak than T. prorsus) have gathered to display, fight, and mate for the seasonal rut.

@albertonykus Our need to show multiple specimens of #Triceratops meant that we had to build some amount of intrapopulational variation within our animals. This was done early on due to the role that Triceratops played in season 1.

@albertonykus Inspired by the real variation seen in #Triceratops fossils (not just of T. horridus but of other species and indeterminate individuals too), we depicted different lengths, thicknesses and curvatures in supraorbital horns, numerous nasal horn shapes, and...

@albertonykus .... some variation in frill shape and what the frill edges might look like.

@albertonykus For the rut sequence we opted to go somewhere special with respect to variation and there's an interesting story behind this.

@albertonykus Based on both the damage that's preserved on #Triceratops skulls and on the way the horns would interlock during combat, we devised a number of 'rules' for how fights would occur.

@albertonykus This work was based on papers by Andy Farke @AndyFarke and colleagues, published in 2004 and 2009. Dr Farke pioneered the use of scale models in his research, and we followed his lead :)

@albertonykus @AndyFarke When interlocking the supraorbital horns, we assumed that the aim would be to reach around the horns of the opponent, and thus stab the face, frill or shoulder of an opponent. This is what modern horned mammals and chameleons do and is consistent with damage preserved on fossils.

@albertonykus @AndyFarke It means that the horn on the 'outside' of the opponent's reach is the one that can do the most damage. As per the Farke work, we used model #Triceratops figures (and photos of me using my fingers as pretend horns) to show how this would work.

@albertonykus @AndyFarke But here's where we come back to the variation. Some #Triceratops individuals have insanely long supraorbital horns, so long that they could reach 'around' the horns of an opponent and potentially stab it without much effort.

@albertonykus @AndyFarke What would this mean for a fight, and for that individual's role in a rut?

@albertonykus @AndyFarke I'm talking here of a specimen at the Museum of the Rockies, excavated in 2010 and 2011, called Yoshi's Trike (properly MOR 3027). Its name comes from its finder (Yoshi Katsura) and its supraorbital horns are about 1.1 m long. They would've been longer with the keratin in place!

@albertonykus @AndyFarke Yoshi's Trike is not especially big overall and not, actually, an 'old adult', but our animal, which is based on 'him' (its sex is unknown), is portrayed as an old, battle-scarred animal late in his years. #Triceratops

@albertonykus @AndyFarke What does 'late in his years' mean, given that Mesozoic #dinosaurs (in general) were not especially long-lived? We followed unpublished data on histology which shows that at least some adult #Triceratops specimens were in their 30s.

@albertonykus @AndyFarke This is consistent with data from other Mesozoic #dinosaurs showing that individuals in their fourth decades were 'old'.

@albertonykus @AndyFarke The problem of animating Yoshi's Trike in combat with another individual is that its horns are so stupendously long that we had to devise clever ways of making them interlock with an opponent's without there being an immediate piercing of the opponent's chest! We managed it.

@albertonykus @AndyFarke And while it might be interesting to show a horned dinosaur killing another in combat like this – something that assuredly occurred, just as it does sometimes in modern horned animal combat – we always had to keep the violence in check.

@albertonykus @AndyFarke What would it look like if a horn got snapped in combat? Back in 1999, the original #WalkingWithDinosaurs showed a Torosaurus snapping off an opponent's horn during combat, with the break occurring right at the horn's base (where the horn is thickest and strongest).

@albertonykus @AndyFarke That always seemed a bit silly. As a sort-of callback, could we show a more realistic horn snap? It would have to occur in the horn's distal part, something we know happened due to fossils. We looked at a lot of gross pictures of broken animal horns to create something realistic.

@albertonykus @AndyFarke An interesting thing about non-bird #dinosaurs that I draw attention to where I can is that females had the same extravagant head gear as males. If males were fighting with horns, females were too...

@albertonykus @AndyFarke Intraspecific combat and competition isn't just for the boys. Females in many species are _at least as_ competitive as males, newsflash...

@albertonykus @AndyFarke We wanted to highlight this, and the sequence originally started with a female group establishing a dominance hierarchy before moving to the display ground where the males are. The 'winner' females would have been front of the line in terms of choosing the most desirable males.

@albertonykus @AndyFarke This idea is still hinted at in the sequence, since you see a group of females with an obvious 'leader' arrive on the scene. Don't blame me for the fact that we've made it look as if fighting is only for the boys! #dinosaurs

@albertonykus @AndyFarke Among the males, we focus briefly on the idea that a young male without 'battle damage' is deemed uninteresting by females since they equate his good condition with lack of experience.

@albertonykus @AndyFarke This is, of course, speculative but was inspired by observations indicating that females in antelopes, humans and other animals do indeed prefer males that have a modicum of wear and tear…

@albertonykus @AndyFarke Anyway, the male is selected by a female and mating occurs. The specific pose they adopt during this act wasn't just invented but based on what's been worked out in previous studies, specifically in Tim Isles's 2009 study of probable mating postures.

@albertonykus @AndyFarke Based on living archosaurs, we think that a ceratopsian female would bring the chest to the ground and elevate the pelvis, and the male would mount semi-bipedally.

@albertonykus @AndyFarke As ever with #PrehistoricPlanet, when showing juvenile dinosaurs an effort was made to show some or many, and to avoid the 'single lone calf' trope so typical of cinema and TV.

@albertonykus @AndyFarke For the final sequence of the episode, we move even further north to Alaska where we encounter two coelurosaurian theropods, both of which featured in earlier episodes: an ornithomimid labelled Ornithomimus, and the tyrannosaurid Nanuqsaurus.

@albertonykus @AndyFarke Nanuqsaurus is from the Prince Creek Formation, a unit that hasn't yielded the specific taxon Ornithomimus. However, there's evidence for indeterminate ornithomimids in the Prince Creek and we simply had to use the same logic as we did in...

@albertonykus @AndyFarke ... the "it's not really Velociraptor but of course we can't call it an indeterminate velociraptorine" case…

@albertonykus @AndyFarke We of course show Nanuqsaurus as a 'small' tyrannosaurid of 5 m or so, something that now appears incorrect in view of larger specimens, but we were going with was thought correct at the time. #dinosaurs

@albertonykus @AndyFarke In any case, it's not as if every single member of this very poorly known species _must_ be depicted as 9 m long, come on. #dinosaurs #PrehistoricPlanet

@albertonykus @AndyFarke Both of these #theropods are shown as fuzzy-coated, the ornithomimids having large feathers on their forelimbs as is implied by soft tissue discoveries that reveal the attachment of large quills (and thus presumably large, vaned feathers) on the forearm.

@albertonykus @AndyFarke The decision to make the Nanuqsaurus wholly fuzzy is a bit controversial seeing as we didn't do likewise for our Tyrannosaurus and Tarbosaurus adults. But at this point it's possible that species within a group like Tyrannosauridae were variable in this respect. #dinosaurs

@albertonykus @AndyFarke The idea that tyrannosaurids – even giants like T. rex – must be depicted >without feathers< is dogmatic, and even those studies that reported the presence of scaly skin in T. rex and skin did not discount the existence of feathering (of some sort) across part of the body.

@albertonykus @AndyFarke I still consider it likely that even giant tyrannosaurids were partly feathered. Nature is almost never black and white, and theropod integument was likely multiple shades of grey.

@albertonykus @AndyFarke Anyway, this sequence was always designed as a chase where we would get to see members of two of the most cursorial non-bird theropod groups engage in protracted pursuit...

@albertonykus @AndyFarke Producer Paul Thompson's inspiration involved dingoes and kangaroos, but of course to see this from the air you need big stretches of open ground…

@albertonykus @AndyFarke On that note, what we show in the sequence isn't the right habitat for either animal seeing as they actually lived in damp, heavily forested environments with a dense understorey, not on plains with sagebrush.

@albertonykus @AndyFarke Here I want to remind you that – while we did aim to be as accurate as we could be in habitats and flora for #PrehistoricPlanet – we had to operate under a number of constraints, some of which were the result of making a show during a time of global lockdowns and a pandemic…

@albertonykus @AndyFarke In previous sequences showing parent #theropods and their youngsters, we had males as the carers. This was inspired both by fossils which indicate that dads were involved in parental care in some coelurosaurian lineages, and by parental care in some birds (most notably ratites)…

@albertonykus @AndyFarke The parent in this case is a mother, because it's important to remind people that nature is diverse, and that there's rarely 'one rule' even within a single group (like Tyrannosauridae).

@albertonykus @AndyFarke The fuzzy babies have a look designed by Gabriel Ugueto @SerpenIllus and which is consistent with the spotty, ratite-like pattern developed early on in our project for the T. rex juveniles. They look simply fantastic… #PrehistoricPlanet

@albertonykus @AndyFarke @SerpenIllus And as the camera pans out, it's clear that we've come to an end, and thus to the end of the whole of #PrehistoricPlanet 2...

@albertonykus @AndyFarke @SerpenIllus A momentous TV event event – still streaming on Apple TV+ – I think widely recognised by people interested in natural history (not just in prehistoric animals) as a trailblazer. #PrehistoricPlanet

@albertonykus @AndyFarke @SerpenIllus I'm already on record as saying why #PrehistoricPlanet is so important: the public are constantly fed this view of #dinosaurs and #pterosaurs as lumpy, wholly scaly, ugly monsters, which is (so the argument goes) fine for Hollywood…

@albertonykus @AndyFarke @SerpenIllus … but doesn't reflect what we've actually learnt. They just weren't like that, and the opportunity to show what they _really_ were like – so we think based on current evidence – is vanishingly small when it comes to on-screen portrayal...

@albertonykus @AndyFarke @SerpenIllus Clearly, it was a massive privilege to be part of the #PrehistoricPlanet team and to help guide and steer this behemoth of a project. If you liked it, be sure to help spread the word, leave good reviews online, and tell your friends. AND...

@albertonykus @AndyFarke @SerpenIllus Remember that there's an official #PrehistoricPlanet #podcast, online here… #podcasts #podcastingapple.com/uk/tv-pr/origi…

@albertonykus @AndyFarke @SerpenIllus Remember also that this is the last of multiple megathreads I've published online already. I need to compile them into a thread themselves so that they're all findable in the same place, but I'm out of time...

@albertonykus @AndyFarke @SerpenIllus And that's where I’ll end. Thanks for reading, and thanks for the support and positive feelings so many of you have expressed about #PrehistoricPlanet. THE END.