Exploring the Prehistoric Planet: Islands

Welcome to a somewhat overdue (mega)thread devoted to the @AppleTV / @bbcstudios series #PrehistoricPlanet season 2 (#prehistoricplanet2 if you will), streaming NOW, and specifically to the first episode: ISLANDS... pic.twitter.com/FXBL4W6tP0

— Darren Naish (@TetZoo) June 14, 2023

Islands is one of my favourite episodes of #PrehistoricPlanet2. We knew early on that we’d cover stories relevant to the Late Cretaceous island faunas of Romania and Madagascar (since both places have revealed numerous amazing Late Cretaceous island-dwelling animals), but…

— Darren Naish (@TetZoo) June 14, 2023

... what else could we show? The producer for this episode – Paul Stewart – worked really hard to find appropriate stories, and succeeded in focusing on amazing animals doing interesting things…

— Darren Naish (@TetZoo) June 14, 2023

As you’ll see, the decisions that Paul and the rest of the team made were very much focused on science and natural history: I have to emphasise how much research was done behind the scenes on #PrehistoricPlanet (shout-outs to Tom L and Ali T for so so so much research)...

— Darren Naish (@TetZoo) June 14, 2023

We really strived to be as authentic as possible. As ever, I also have to say that making #PrehistoricPlanet was a huge group effort, involving the combined efforts of over 1500 people… pic.twitter.com/9yiUz2ANjA

— Darren Naish (@TetZoo) June 14, 2023

Filming in the real world involved numerous people on site (for Islands: shout-outs to Bex and Ellen), then there was editing, compositing, sound design, music, steering by team leaders, plus all the admin, people management and so on that comes from combining a team this large.

— Darren Naish (@TetZoo) June 14, 2023

In the thread here, I very much concentrate on the creative and science-based decisions I was involved in, so please excuse me for being biased and selective in what I cover. Ok, here we go…

— Darren Naish (@TetZoo) June 14, 2023

Islands opens in Romania as we meet a Zalmoxes that’s been swept out to sea on floating vegetation. High sea levels meant that Europe was flooded at this time, higher areas existing as subtropical archipelagos. Zalmoxes will be familiar if you watched #PrehistoricPlanet season 1. pic.twitter.com/xE8c2p8kLQ

— Darren Naish (@TetZoo) June 14, 2023

Zalmoxes is a small bipedal iguanodontian ornithopod, a member of the same big group that includes Iguanodon and the hadrosaurs (the so-called duckbills). Specifically, Zalmoxes is part of an unusual robust-skulled iguanodontian group called Rhabdodontidae... #dinosaurs pic.twitter.com/sYhxxh9Ybz

— Darren Naish (@TetZoo) June 14, 2023

Zalmoxes species ranged in size from 2-3 m, and the suggestion has been made that they were small, specialised island endemics… #PrehistoricPlanet #dinosaurs

— Darren Naish (@TetZoo) June 14, 2023

That might not be true; it might instead be that they simply inherited the small size that was ancestral for the group. But, whatever, rhabdodontids of various sorts occurred on most of the islands present west to east across Europe at this time…

— Darren Naish (@TetZoo) June 14, 2023

A nearby #mosasaur – a member of the widespread, robustly built, thick-toothed genus Prognathodon – is a real and present danger in the sequence. Prognathodon is a mosasaurine mosasaur and thus would have looked similar to its cousin Mosasaurus... pic.twitter.com/NBgSeJe66C

— Darren Naish (@TetZoo) June 14, 2023

Its stout teeth suggest that (like living lizards with teeth of this sort) it was a generalist, and basically able to exploit animal prey of all kinds… (Prognathodon skull here by Ghedoghedo, CC BY-SA 4.0) pic.twitter.com/NGCyK0s9L9

— Darren Naish (@TetZoo) June 14, 2023

Openings on the #mosasaur palate might reveal the location of the Jacobson’s organ, a palatal structure that lizards and snakes use in collecting chemicals from the environment via the tongue…

— Darren Naish (@TetZoo) June 14, 2023

Mosasaur experts mostly think that #mosasaurs had a forked (or bifid) tongue that they used in collecting chemical particles: the mosasaur tongue has sometimes been depicted as long, slim, deeply forked and similar to that of snakes...

— Darren Naish (@TetZoo) June 14, 2023

We opted instead to go for a tongue more typical of anguimorphs (the big lizard group that #mosasaurs might be part of, read on): still bifid, but shorter, thicker and less mobile… (slow worm image by DuncanFoto, CC BY-SA 4.0) pic.twitter.com/uSMboTS8wO

— Darren Naish (@TetZoo) June 14, 2023

Incidentally, one thing I’ve learnt from the #mosasaur coverage of #PrehistoricPlanet is that people still mostly imagine these Cretaceous #lizards to be close cousins of monitor lizards. That isn’t true and hasn’t been for some decades now...

— Darren Naish (@TetZoo) June 14, 2023

#Mosasaurs might be part of the same big lizard group as monitors (Anguimorpha; slow-worms, glass lizards and gila monsters are among the group’s other members), but… pic.twitter.com/aopLuThAfK

— Darren Naish (@TetZoo) June 14, 2023

… if they are it doesn’t seem that they were especially close to monitors. And #mosasaurs may not be anguimorphs at all anyway, but part of a different lineage entirely. So quit it with the comparisons between mosasaurs and monitors!

— Darren Naish (@TetZoo) June 14, 2023

We made several bold decisions in this sequence. In fact, the entire story here revolves around a concept discussed over the course of decades in the zoological literature but rarely presented to popular audiences: namely, rafting as a means of dispersal.

— Darren Naish (@TetZoo) June 14, 2023

Rafting refers to the phenomenon in which living things disperse over water – including across entire oceans (!) – via use of a floating platform…

— Darren Naish (@TetZoo) June 14, 2023

Rafting simply _must_ have occurred a great many times in the history of life, since it provides the only sensible explanation for the distribution of such things as monkeys in the Americas, lemurs in Madagascar and iguanas in Fiji…

— Darren Naish (@TetZoo) June 14, 2023

The term ‘raft’ is problematic, since it creates the impression that animals are making crossings on a few floating logs. The ‘rafts’ that people have seen (sometimes carrying animals out to sea) are more like small floating islands... pic.twitter.com/jEAr9CPoel

— Darren Naish (@TetZoo) June 14, 2023

Paul has seen such events himself and his experience was essential in the construction of the raft used in the sequence…

— Darren Naish (@TetZoo) June 14, 2023

What about rafting and #dinosaurs? Palaeontologists have mostly argued that dinosaurs owe their distribution to vicariance (the phenomenon whereby species live where they do due to the impact of geological barriers and events), not dispersal…

— Darren Naish (@TetZoo) June 14, 2023

However, the 2021 publication of the Moroccan hadrosaur Ajnabia led its describers to suggest that dispersal across oceans – in cases by rafting – likely did have a role in dinosaur distribution (reconstruction of Ajnabia by Raúl Martín)... #dinosaurs pic.twitter.com/zB99rU7aEH

— Darren Naish (@TetZoo) June 14, 2023

Rafting is such an important factor in the colonisation of islands that we simply had to feature it. There’s no direct evidence that Zalmoxes rafted anywhere, but a rafting sequence, Paul and I decided, was crucial for this episode...

— Darren Naish (@TetZoo) June 14, 2023

In fact, Paul had wanted to show a rafting sequence since the days of The Velvet Claw (and... if you don’t what that is, check it out)… pic.twitter.com/gJSYASY9VZ

— Darren Naish (@TetZoo) June 14, 2023

Rest of thread coming soon....

— Darren Naish (@TetZoo) June 14, 2023

These pathologies likely had multiple causes but we planned to show some of them occurring as the consequence of an attack by the ‘hippo-faced’ crocodyliform Mahajungasuchus, and we actually got very far in showing such a scene before it had to be abandoned... #PrehistoricPlanet

— Darren Naish (@TetZoo) June 16, 2023

In keeping with our emphasis of non-dinosaurs, we also wanted to showcase the presence of unusually large mammals on Late Cretaceous Madagascar. It’s fair to say that mammals never got much coverage in #PrehistoricPlanet. I hope that people can understand why this was so...

— Darren Naish (@TetZoo) June 16, 2023

-- we just can’t do everything, and for – again, I hope understandably – simply _had_ to focus on big superstar animals more than more ‘familiar’ ones. There were plans early in the project to...

— Darren Naish (@TetZoo) June 16, 2023

.... feature various multituberculates (you can call them MTBs for short), early therians and others – I designed initial concept art for several species – but all had to be abandoned…

— Darren Naish (@TetZoo) June 16, 2023

Anyway, we focus on the badger-sized Adalatherium, a gondwanathere published in 2020 and brand-new when we decided to feature it. Producer Paul did his PhD on badgers (proper European badgers, that is) and there was a joke that we were featuring one of his favourite animals... pic.twitter.com/Du7OyxdiJZ

— Darren Naish (@TetZoo) June 16, 2023

However, Adalatherium is so odd in so many ways that what we have is quite unique. Again, what an incredible job from the MPC team in bringing it to life. The concept art, again, was Gabriel Ugueto’s @SerpenIllus… #PrehistoricPlanet pic.twitter.com/nAp7eolimR

— Darren Naish (@TetZoo) June 16, 2023

Mammals were diverse and abundant in the Age of Dinosaurs, and an interesting thing about many of them – many, not all – is that they must have been egg-layers, like the living monotremes (the echidnas and platypus).

— Darren Naish (@TetZoo) June 16, 2023

We really wanted to show Adalatherium as an egg-layer in order to bring this message home but… would it be correct to show a gondwanathere as an egg-layer?

— Darren Naish (@TetZoo) June 16, 2023

We have no direct data on the reproductive habits of these animals. However, some experts have argued that gondwanatheres are allied to multituberculates, and (as of 2020) there had been a small amount of discussion on the reproductive habits of MTBs...

— Darren Naish (@TetZoo) June 16, 2023

... some experts positing egg-laying, others saying that they were likely viviparous…

— Darren Naish (@TetZoo) June 16, 2023

What, then, to do about a gondwanathere? We asked a few Mesozoic mammal specialists for a steer on this but they refused to commit. In an effort to work out what might be going on, I reviewed what authors had said, the result being this 2020 article… https://t.co/gKEQWNDCcF pic.twitter.com/fFgOgX5pUW

— Darren Naish (@TetZoo) June 16, 2023

We basically convinced ourselves that we were ok to go with egg-laying, and we also opted to be innovative and show the Adalatherium using a reproductive strategy not present in the highly specialised egg-laying mammals of today...

— Darren Naish (@TetZoo) June 16, 2023

... since our mother produces a much larger clutch than monotremes. There are, after all, a great number of Mesozoic mammal lineages and it’s utterly reasonable to show certain of them using strategies different from those used by echidnas and platypuses…

— Darren Naish (@TetZoo) June 16, 2023

I won’t say exactly how we filmed the hatching scenes we did, but what a success. In fact our Adalatherium youngsters look fantastic at all ages... pic.twitter.com/tGxtd7CPp9

— Darren Naish (@TetZoo) June 16, 2023

A problem we always faced in making #PrehistoricPlanet was making hard decisions on things that might ultimately be shown to be wrong, or – at least – arguable...

— Darren Naish (@TetZoo) June 16, 2023

Shortly after we finished our Adalatherium sequence, Weaver and colleagues published a study (this was in 2022) showing that the bone histology of MTBs was similar to that of placental mammals, not egg-laying monotremes (diagram from Weaver et al. 2022; art by @AndreyAtuchin)… pic.twitter.com/ULsPkAYsaG

— Darren Naish (@TetZoo) June 16, 2023

Ergo, MTBs likely did not lay eggs. By inference, the possibly related gondwanatheres perhaps did not too. Buuut it remains possible that gondwanatheres were very different from MTBs (and may not be close to them at all): what we show in #PrehistoricPlanet remains a possibility…

— Darren Naish (@TetZoo) June 16, 2023

We move on to #dinosaurs on an island near James Ross Island near the Antarctic Peninsula. We focus on the paravian theropod Imperobator (found 2007, named 2019), and the elasmarian ornithopod Morrosaurus (found 2002, named 2016; reconstruction here by lythronax-argestes)... pic.twitter.com/s8NxENvtzH

— Darren Naish (@TetZoo) June 16, 2023

The poles were much warmer during the Late Cretaceous than they are today, but the detailed palaeoclimate model produced for us by @Climate_AlexF, Bob Spicer and Paul Valdes was still consistent with the winter-time presence of freezing temperatures, and hence snow and ice... pic.twitter.com/I8cwEHS5OL

— Darren Naish (@TetZoo) June 16, 2023

These dinosaurs lived in environments that were forested and temperate for much of the year, but certainly cold on occasion. The animals must have been adapted to such changes...

— Darren Naish (@TetZoo) June 16, 2023

Imperobator is not well known – it’s based almost entirely on an unusual foot about 45 cm long (image from Case et al. 2007) – but this possesses features of paravians, the big group that includes dromaeosaurids, troodontids and birds... pic.twitter.com/iqlSIMCF0k

— Darren Naish (@TetZoo) June 16, 2023

By the way, the name Paraves means ‘besides birds’ and is thus not ideal given that it _includes_ birds. Imperobator would have been similar to those paravians we know from better remains, with a full plumage, a long, feathered tail, feathered forelimbs and longish toothed jaws. pic.twitter.com/frJSWzRm3k

— Darren Naish (@TetZoo) June 16, 2023

There’s a tendency when reconstructing feathered dinosaurs of cool places to make them look like white snow-beasts. We avoided that; initial looks that I devised for both animals were redrafted by Gabriel Ugueto @SerpenIllus before being handed to MPC. Again, what a success…

— Darren Naish (@TetZoo) June 16, 2023

A plan at one point was to emphasise how the two animals had different methods of manoeuvring, Morrosaurus using the mass of its tail to help shift its centre of gravity, and Imperobator using the feathered surfaces of its forelimbs and tail as air-brakes… pic.twitter.com/Wi1T8rpZOv

— Darren Naish (@TetZoo) June 16, 2023

Now, finally, we come to the last sequence of Islands, and one of the most beloved sequences in all of #PrehistoricPlanet 2. Namely, that featuring courtship and mating in Hatzegopteryx. #azhdarchids pic.twitter.com/iAn9yITl9n

— Darren Naish (@TetZoo) June 16, 2023

Again, it goes without saying that we know almost nothing about these things. However, we can make extrapolations and speculations based on what the fossils show, and on the ‘rules’ that exist among the living relatives of pterosaurs (the archosaurs: crocodylians and birds)…

— Darren Naish (@TetZoo) June 16, 2023

Our starting point is that these animals were sexually dimorphic, the males having larger, more elaborate head crests than the females. This is inferred across azhdarchoids (the big group that includes azhdarchids) more broadly...

— Darren Naish (@TetZoo) June 16, 2023

Melanosomes on azhdarchoid crests (shown here, from Cincotta et al. 2022) indicate that the crests were colourful, which is more evidence for a role in sexual display. The flamboyant azhdarchoid shown here - by @BobNichollsArt - was reconstructed on the basis of this evidence... pic.twitter.com/JOTX7qDXia

— Darren Naish (@TetZoo) June 16, 2023

A special ‘breeding season’ colouration is not unusual in living animals (lizards, but birds especially) and I don’t see this as an unreasonable speculation for such showy, display-oriented animals… #PrehistoricPlanet #azhdarchids pic.twitter.com/T27IKLMlQE

— Darren Naish (@TetZoo) June 16, 2023

The male constructs a symbolic nest that includes a deceased baby dinosaur, and our idea to go with this concept was inspired by Paul’s experience with birds-of-paradise and bowerbirds (he filmed many of the sequences you’ll know from other documentaries)... pic.twitter.com/ffRO9muMeu

— Darren Naish (@TetZoo) June 16, 2023

All this is speculative, but inspired by behaviours that showy archosaurs use today. As ever, my argument (and that of the #PrehistoricPlanet team more widely) is that we should embrace, to a degree, the idea that extinct animals were sometimes as surprising as living ones…

— Darren Naish (@TetZoo) June 16, 2023

In fact, it’s misleading to be conservative _all the time_, since the living world surprises us with weirdness all the time: it seems more correct to assume that weirdness in the past was routine and commonplace than the opposite...

— Darren Naish (@TetZoo) June 16, 2023

I have to note that Hatzegopteryx courtship scene has inspired some brilliant fan-art, some of which is shared here… #PrehistoricPlanet #azhdarchids pic.twitter.com/RIsA0wyof7

— Darren Naish (@TetZoo) June 16, 2023

On the gift of the dead dinosaur… such behaviour is called ‘nuptial gifting’ and is seen in predatory animals today; it’s widespread in arthropods but is also present in predatory birds such as shrikes, hornbills, and several cuckoo and kingfisher species...

— Darren Naish (@TetZoo) June 16, 2023

Because some of these birds are modern analogues of our predatory, vaguely hornbill-like #azhdarchids, nuptial gifting again seems like a reasonable speculation…

— Darren Naish (@TetZoo) June 16, 2023

We reasoned that such big, potentially dangerous animals would use a series of ritualised postures to signal non-aggressive intent, something seen widely in living archosaurs...

— Darren Naish (@TetZoo) June 16, 2023

The male displays by ‘sky-pointing’, by displaying his wings, and by combining these movements with a vocal display (our #pterosaurs make deep, drumming or booming sounds, again based on analogy with living archosaurs)... pic.twitter.com/7FlmxKghqV

— Darren Naish (@TetZoo) June 16, 2023

Finally: mating. We know essentially nothing about the mating habits of #pterosaurs so, again, had to make a series of conclusions for the sequence to work. Here I want to emphasize that pterosaurs had been flying the skies for over 160 million years at this point...

— Darren Naish (@TetZoo) June 16, 2023

.... meaning that we really should be imagining them as highly specialised (arguably more so than birds and bats) for aerial life. For that reason, we decided on a brief mating event that involves rapid, err, exchange… pic.twitter.com/FIiBiuAso0

— Darren Naish (@TetZoo) June 16, 2023

The male has a light hold of the filaments on the back of the female’s neck: a ritualised, ‘ceremonial’ version of the neck-grip we infer to have been widespread across reptiles…

— Darren Naish (@TetZoo) June 16, 2023

And that is that, the end of this episode 1 mega-thread! This took some time to put together, but I hope it provides useful and interesting information on what we portrayed and why we did it. Here's your reminder that #PrehistoricPlanet is streaming now on @AppleTV... pic.twitter.com/Stsi6wRSZi

— Darren Naish (@TetZoo) June 16, 2023

Remember also that there's an official #PrehistoricPlanet #podcast, featuring executive producers Jon Favreau and Mike Gunton, series producer Tim Walker, David Attenborough and others from the team, available here ... https://t.co/1h5A9bWRlW pic.twitter.com/RhH2rL2eF6

— Darren Naish (@TetZoo) June 16, 2023

Thanks to all those who’ve said positive things about #PrehistoricPlanet, we appreciate your support :) And huge thanks too to everyone who worked with me on this amazing project and enabled it to come to life, what a ride! Threads on the other episodes are coming soon... pic.twitter.com/V5ZfCc2aSq

— Darren Naish (@TetZoo) June 16, 2023