Welcome to the 5th and final of my #PrehistoricPlanet threads in which I talk about the science and background to what we showed in this new @AppleTVPlus @bbcstudios production. This time we look at EP 5: FORESTS… #dinosaurs #Cretaceous 
I was lead scientific consultant on #PrehistoricPlanet and was extensively involved in our many decisions, all of which were science-led or scientifically informed. I was, of course, merely one among many in a HUGE team that involved hundreds of very talented people!
Ep 5 focuses on the #dinosaurs and #pterosaurs that lived in forests during the Maastrichtian (the final part of the Late #Cretaceous). The Maastrichtian world was heavily forested, with temperate, subtropical & tropical woodland covering around 78% of the land surface…
Here’s a reminder that Prof Bob Spicer and @Climate_AlexF built a detailed biome & climate simulation for #PrehistoricPlanet, thus giving us a huge quantity of cutting-edge insight on plant distribution, rainfall, temperature, seasonal change and more...
You can read about that research here… theconversation.com/prehistoric-pl… #PrehistoricPlanet
Ep 5 of #PrehistoricPlanet begins in South America – specifically Brazil – where we see a group of the giant titanosaurian #sauropod Austroposeidon walk through a forest in search of foliage. Austroposeidon – named in 2016 – is a giant about 25 m (82 ft) long…
Limb proportions, pelvic anatomy & vertebral articulation shows that #titanosaurs were tall-shouldered with a neck that could be held in an elevated pose (diagram by @raptordanny): they were high browsers that reached high up into the canopy to a height of around 12 m (40 ft)…
#Titanosaur teeth occlude tip to tip, so they were built for snipping. We think that these sauropods cut foliage, swallowed it quickly, and then indulged in hindgut fermentation (the same digestion style used by most herbivorous birds, lizards and giant mammals)…
We mention that the herd consumes ’10 tonnes’ of plant food per day. This isn’t a hypothetical but based on research (by Martin Sander and colleagues in Germany) showing that giant sauropods consumed c 500kg of plant material per day. We assumed around 20 animals in the herd…
Austroposeidon is so far known only from a single specimen, so we cannot pretend to be experts on its behaviour, social life or geographic range. What we show is sensibly inferred from better-known #sauropods and living big herbivores…
Tracks and associated skeletons show that #sauropods were mostly social animals, the proportionally tiny babies and cow- and rhino-sized youngsters living separate lives from the multi-ton adults…
Thus herd-dwelling should be considered well supported, as should presence across a wide geographical area. Austroposeidon is known from a geological horizon that yields a low diversity of mostly dry-adapted plants but... #PrehistoricPlanet
... our climate and biome model showed that densely forested areas were within relatively close proximity…
The idea that giant #sauropods sometimes (or often) pushed down trees to access growth in the crown has often been mentioned, and has its basis in the behaviour of living megaherbivores (elephants especially)...
It seems reasonable to think that #sauropods did this at least on occasion. Remember that sauropods in general – and titanosaurs in particular – appear well suited from anatomy to adopt a bipedal (or tripodal, tail for support) pose on occasion...
... their hind limbs are sufficiently strong enough for this, and they have the musculature, hip strength and vertebral anatomy to allow it (they were better at bipedal rearing than elephants and other big mammals)…
Herbivores of just about all kinds display preference for young leaves (since they are the least tough and least toxin-rich), and these are often the most out of reach…
We then move to North America and to the giant ceratopsian #Triceratops. Our look for this animal incorporates new information on skin and scale anatomy, and on computer modelling which reconstructs the forelimb gait (it wasn’t like that of big quadrupedal mammals)…
The look of the baby is not in any way hypothetical but based on the look of juvenile specimens. They reveal a shortened face, near-vertical supraorbital horns and numerous other differences relative to adults… #PrehistoricPlanet
The story perhaps creates the _impression_ that we’re seeing the ‘one baby per family’ trope so common in dinosaur media, but there are other babies there, I swear. #PrehistoricPlanet
There is no evidence that #Triceratops visited caves, but this is a viable piece of behaviour given that a variety of animals do this today. Most famously, elephants at Kenya’s Mount Elgon travel underground to mine salt-rich clay; bushbucks and rhinos visit these mines as well…
Crocodiles are known to travel deep underground on occasion (apparently for shelter from hot weather). Limestone caves potentially with clay licks like those of #PrehistoricPlanet are likely to have been present in the newly rising Rockies when #Triceratops was alive…
We show the #Triceratops engaging in geography (the eating of soil for its mineral content). Again, this is a behaviour that’s widespread in the natural world today, including in many plant-eating birds, tortoises and iguanas as well as numerous mammals...
Gopher tortoises in some areas deliberately visit specific rock faces to mine them for minerals: I wrote an article about this issue here… web.archive.org/web/2015051907…
Two ideas have been put forward to explain geophagy: one that the sediment serves to neutralise toxins in plants, and one that it acts as a dietary supplement. Our narration expresses preference for toxin defence but we aren’t eliminating the other possibly by default...
Next we come to a sequence that's proved something of a fan favourite: #Carnotaurus. We show a male Carnotaurus clearing a display area before vocalising and then displaying to a potential mate… #PrehistoricPlanet #dinosaurs
#Carnotaurus has conventionally been depicted as an animal of arid, rocky places but the reasons for this tradition aren’t especially clear. Associated flora and sedimentological data actually reveals persistent freshwater and...
.... a mixture of vegetation in the location the single known specimen was discovered, and climate modelling shows that both deciduous and evergreen forest was located nearby… #PrehistoricPlanet #Carnotaurus
Based on its elaborate, gnarly snout surface and conical horns, it looks likely that #Carnotaurus engaged in head-to-head-shoving or butting contests. Note that what’s seen in #PrehistoricPlanet isn’t meant to depict the entire behavioural repertoire of the animal...
Instead, we show something more surprising: an arm-twirling display whereby a male aims to impress a female… #carnotaurus #PrehistoricPlanet #dinosaurs
Do we know that #Carnotaurus really did this? The reasoning behind this behaviour is fairly complex. Carnotaurus is one of several abelisaurid theropods that had proportionally small, reduced arms... #PrehistoricPlanet
A popular idea on these arms is that they were relictual: essentially with no practical use to the animal, and ultimately non-functional relative to the role they had in the ancestors of these #dinosaurs...
However, an unusual spherical head and long humerus (upper arm bone) indicates an unusually wide range of motion for a theropod, this in turn implying an unusual function for the forelimb as a whole…. #PrehistoricPlanet #carnotaurus
Two different sets of authors have therefore suggested that the arms might have been used in display, their appearance perhaps enhanced by soft tissue display structures or bright colours....
It might seem odd to think that a structure that’s small (relative to that present more broadly in theropods) could have a specialised display role (you’d expect the structure to be bigger than average, not smaller) but… [attached photos taken at Natural History Museum LA]
... a counter-argument to that is that these animals were working with what they have: they belong to a group where small forelimb size is ancestral. An analogue is provided by certain antelopes that have proportionally tiny horns relative to ancestral antelopes...
Yes, their horns are small relative to those of other antelopes, but they still function as sociosexual structures at the species level…
The argument has also been made that the forelimbs of #Carnotaurus lacked an adequate nerve supply for any important role. This argument is based on comparisons with emu [wing photo attached!] and kiwi (both of which have relictual, essentially useless forelimbs), but...
.... it ignores cassowaries (where the forelimbs possess long spikes and may well have an important role), so it isn’t a decisive argument…
Ultimately, I would argue that our view of a colourful, dancing, displaying #Carnotaurus provides a key take-home for viewers: you really should be thinking of #dinosaurs as visually oriented, behaviourally complex, surprising animals.
Even though debate surrounds the precise details of what they were doing, they were doing some amazing, fascinating stuff, just as modern animals are… #Carnotaurus #PrehistoricPlanet
We move to eastern Asia, where we see the long-snouted alioramine tyrannosaur Qianzhousaurus hunting the crested Corythoraptor. Corythoraptor is an oviraptorosaur, a group of maniraptoran theropods known for sure to have a full, bird-like plumage... #dinosaurs #PrehistoricPlanet
We always thought that this animal would look, in life, something like a giant, long-necked, long-legged gallinaceous bird (like a grouse or peacock-pheasant). An interesting thing about these animals (and it’s something apparently widespread in non-bird dinosaurs) is that...
... sexual dimorphism wasn’t obvious, at least not in terms of shape. Both males and females apparently have similarly shaped crests and so on… [attached diagram from Lü et al. 2017: nature.com/articles/s4159…] #dinosaurs #PrehistoricPlanet
We describe Qianzhousaurus as ‘about 30 ft long’, which is a bit longer than what’s usually given (23 ft). However, we confirmed with @SteveBrusatte that this length is perfectly acceptable… [skull images from Lü et al. 2014: nature.com/articles/ncomm…] #dinosaurs
The hunting behaviour we portray – involving stealthy approach, swift ambush, failure on the part of the predator and later use of stormy weather to conceal approach – is all based on events seen in the natural world today and applicable to forest-dwelling predatory #dinosaurs…
I was so happy with this sequence because there has long been a need for media that shows #dinosaurs in an ‘autumnal’ setting: many dinosaurs lived in temperate, deciduous forests where yellows, oranges and browns would have dominated the foliage during cooler parts of the year…
Fire was a constant in the #Cretaceous world (NOT due to higher oxygen levels: Cretaceous oxygen was – at about 22% of the atmosphere – similar to that of today), and our next sequence shows a North American environment affected by fire...
As discussed in the previous thread (on ep 4: Ice Worlds), it seems likely that #dinosaurs and other Cretaceous animals were familiar with fire, with fire-prone landscapes and with post-fire environments, and might even have known how to exploit them…
We wanted to highlight this idea by showing #dinosaurs making use of ash and charcoal: materials that were abundant and familiar in the Late Cretaceous world.
Many modern animals eat charcoal since it works as a nutritional supplement, and neutralises toxins, so charcoal-eating is depicted as we see the giant ankylosaur Anodontosaurus wander through the scene. It’s notable for its incredibly impressive tail club… #PrehistoricPlanet
We then see a dromaeosaur, a member of the same family as #Velociraptor. It's the mid-sized Canadian form Atrociraptor, currently known only from skull bones and teeth. These show it had a ‘boxy’ head and less variation in tooth anatomy relative to certain other dromaeosaurs…
What might this animal do in a burnt landscape? Birds use ash for ‘bathing’ (it suffocates parasites) but a few birds deliberately hold their wings over smoke or fire. We’re not sure why: to kill pests, to cause feathers to change shape (they do this when heated) or for fun…
There is in fact a very curious 1959 book by zoologist and author Maurice Burton written about this, titled The Phoenix Re-Born, check out various of the photos it includes… (my personal copy was kept in the #PrehistoricPlanet office)…
This behaviour is mostly limited to very intelligent birds – mostly corvids – so the argument could be made that it shouldn’t be depicted in an animal like a dromaeosaur. While nobody is arguing that dromaeosaurs were of corvid-like intelligence, the possibility that...
.... they were relatively intelligent is on the table, and again I would like people to take seriously the suggestion that these animals could well have surprised us in flexibility, innovation and smarts...
Remember that even ‘small brained’ animals like certain lizards and fish have proved adept at complex tasks…
A very interesting and informative thread which very much touches on the same points we did in building this fire-based sequence has been produced by @Ivo_Jacobs_, do check it out…
https://mobile.twitter.com/Ivo_Jacobs_/status/1530675758082928640#PrehistoricPlanet #dinosaurs
Sticking with maniraptoran theropods, we next return to Asia where we see a group of juvenile therizinosaurs, living in a sibling group independently of adults. Fossil evidence suggests that the juveniles of at least some theropods were independent and left the nest in a group…
Therizinosaurs had a beak, small teeth with serrated, leaf-shaped crowns, and a jaw shape indicating a low bite force relative to that of other theropods. They also had wide hips, robust hindlimbs suited for slow movement, and long hand claws that are not suited for predation…
Combined, it seems that they were herbivores that reached into foliage and ate leaves. They might also have opportunistically consumed fungi, fruits and other items found in forested habitats, and it might be that they were semi-omnivorous, especially as juveniles.
Could the nests of social insects have been on the menu too? It seems likely that they might have exploited bee nests if they encountered them…
The fact that the youngsters are shown climbing – albeit clumsily – is a sort of call-back to a hypothesis published in the 1990s (and not supported by anyone who studies these animals today) whereby #therizinosaurs were posited as tree-climbers that predated on social insects…
Were social bees present in the Late #Cretaceous? Molecular studies and fossils show that the bee radiation was well underway by the Maastrichtian and that early members of most modern lineages – including the honeybee lineage – were in existence by this time...
We don’t know for sure that honeybees similar to those of today were definitely present, but some experts think they were and that’s what we went with.
The giant adult Therizinosaurus in the sequence is stated to be ‘almost 30 ft tall’, and some people have pointed to this as an error. It’s not. If we depict an adult standing as tall as possible, it can exceed 7.4 m (24 ft)…
#Therizinosaur fossils reveal a complete feathery coat with spine-like filaments distributed among the feathers. The giant arms sported scythe-like claws that were about 1 m (3 ft) long: the biggest claws of all time... #dinosaurs
What a fantastic animal, and another reminder of how incredible – absurd, if you like – so many of these #dinosaurs were… #PrehistoricPlanet
The final sequence is set in what’s know Romania where mixed forests were home to various island-dwelling dinosaurs, rabbit-sized mammals, large lizards and other animals…
Our main character is the gigantic #azhdarchid #pterosaur #Hatzegopteryx, one of the largest flying animals we know of. Its wingspan was around 10 m (30 ft) and it weighed around 225 kg (500 lbs)…
A substantial amount of additional material that likely belongs to #Hatzegopteryx is known (I had the opportunity to study it while working in Romania) but it remains mostly unpublished.
The view of #Hatzegopteryx shown in #PrehistoricPlanet – that it was a relatively thick-necked azhdarchid, capable of grabbing and swallowing small dinosaurs – is based predominantly on Naish & Witton (2017)… [image by @MarkWitton] #azhdarchids
We see juveniles of the small ornithopod Zalmoxes, and the hadrosaur Telmatosaurus, an ‘old fashioned’ member of its group that belongs to an older lineage than the much bigger, evolutionarily younger saurolophines (like Edmontosaurus) and lambeosaurines (like Olorotitan)…
#Titanosaurs appear too (they are either Paludititan or an unnamed species previously included in Magyarosaurus), and the episode ends as the #Hatzegopteryx indulges in a quad-launch from the beach and literally flies off into the sunset…
As you’ll know if you’ve been paying attention to discussions about #PrehistoricPlanet, there was concern – if that’s the right word – that the series would end with the extinction event, in which case we might get to witness a horrific and quite depressing spectacle...
... centred around death and destruction (it's not shameful to admit you cried at the end of Walking With Dinosaurs). I’m pleased to emphasise that this was never part of our plan...
As per the other threads, there’s so much that I could have said (even though this was the longest of these threads produced so far). I hope this was interesting. It was a massive honour to work on this project and be part of such an amazing team…
If you liked #PrehistoricPlanet and want to see us do more, do tell your friends and family and please give us good rating on review sites and such. This is now the 5th of these threads I’ve done, for others, follow links below…
To see the thread for EP 1 COASTS, go here...
https://twitter.com/TetZoo/status/1528783515885641728(cont) #PrehistoricPlanet
To see the thread for EP 2 DESERTS, go here...
https://twitter.com/TetZoo/status/1529795393378308097#PrehistoricPlanet
To see the thread for EP 3 FRESHWATER, go here...
https://mobile.twitter.com/TetZoo/status/1530157214392012802#PrehistoricPlanet
And to see the thread for EP 4 ICE WORLDS, go here...
https://mobile.twitter.com/TetZoo/status/1536758900199923714Ok, that's it for now. Thanks for reading, I hope you found this interesting :) #PrehistoricPlanet #dinosaurs
As ever, some amusing typos in this thread. The best might be the correcting of 'geophagy' (the eating of soils and rocks) to 'geography'. Thanks, autocorrect, you never fail.
• • •
Missing some Tweet in this thread? You can try to
force a refresh
