Paleo Safaris: Ice Age Australia

Queensland, Australia, 50,000 years ago

The last Ice Age is usually associated with cold, frozen landscapes with Mammoths, Sabre Toothed Cats, Woolly Rhinos and Ground Sloths dominating the landscape. However in some places on earth these conditions and animals weren’t present at all. For an example of this look no further than Australia. Instead of colder temperatures, the Ice Age caused Australia to become drier in glacial periods and wetter in interglacials. During interglacial periods conditions were mild enough to allow for more extensive temperate forests and dry grassland to grow and encircle the vast central desert. Just like today, Australia was home to a host of weird and unusual animal species exclusive to the continent. For example there were (and still are) not many placental mammals; the large phylum that encompasses the majority of all mammal families elsewhere in the world, from cats, to whales, to cows and to humans. Instead a completely different type of mammal is dominant here. They are the marsupials. Their main distinguishing trait is their young being born very early in development and then spending the rest of the development cycle maturing in an external skin pouch instead of internally in a placental linked womb. If we journey back 50,000 years we find that Australia’s signature marsupials can still be spotted; Kangaroos leap across the arid land, Koalas snooze in the afternoon sun and Wombats lumber along the forest undergrowth. However among these animals also live a large cast of unfamiliar Australian fauna.

It’s late April, and on the arid plains of Queensland, Central Australia one marsupial munches on the dry grass in the dead of night. It’s bigger than any Australian animal alive today, about the same size as a Rhino but is a close relative of the Wombat. This is Diprotodon; at 3 metres long, 1.8 metres tall and roughly 2.8 tonnes it is the largest marsupial that has ever lived. Diprotodon usually live in big herds that seasonally migrate across the Australian outback, but this young male has become separated from the rest of the herd. He picks up the sound of a disturbance in the bush and notices something moving quickly through it. He looks up towards the sound and readies himself for an attack! The animal emerges! But to the Diprotodons relief it’s not what it was fearing. Instead it is a female Thylacine, on the hunt for prey that is more her size. Thylacines are only a metre long and weigh 17 kilos (smaller than a medium-sized dog) and as such usually stay out the way of the larger animals. Once he realises that the Thylacine is no threat the big Diprotodon goes back to munching on the surrounding grass. In fact the female Thylacine that is more relieved that there was no escalation in this encounter. Getting trampled by the rhino sized marsupial would have been fatal not only to her, but to her unborn baby.

File:Diprotodon optatum.jpg
Diprotodon. The largest Marsupial to ever exist!
Image Credit: Nobu Tamura, http://2.bp.blogspot.com/-5Ckt4LUHKz8/T9dwmTycaMI/AAAAAAAABt8/70-K8CMYL5k/s1600/Diprotodon_BW2.jpg

By late May when we next see her, the female Thylacine has now officially become a mother! Within the safety of her pouch pokes out the head of her joey. Sadly he is the only survivor of an original litter of four. Two of his siblings were stillborn and the other couldn’t reach the pouch and perished in the harsh Australian environment. He is not yet strong enough to leave it yet and is still totally dependent on milk he gets from mammary glands within the pouch. While she’s carrying around this new arrival, the female Thylacine will be keen to take any free meal she can find. She is in luck as the distinctive smell of carrion wafts through the wind. Using her keen sense of smell she tracks the scent towards its source; a Diprotodon that has succumbed to old age and the battering heat of the Australian sun. However she is not the only predator drawn to the carcass. To her left emerges a crocodile! But there is no river or lake for miles around. How can this be?! This is no ordinary crocodile! This is a Quinkana. A 6 metre long crocodilian who, unlike its water loving relatives, is almost entirely terrestrial with legs that are located more underneath its body to allow it to chase down prey. Quinkana is another animal that dwarfs the Thylacine. However she is more nimble, and if she’s careful she can sneak up to the carcass and steal a mouthful or two before the Quinkana notices. She starts to stealthily venture towards the other side of the carcass as the Quinkana tears into it. But then she hears a sharp hiss from the thicket! She flees the scene as another giant reptile enters stage right! Megalania. A 7 metre long monitor lizard, roughly twice the size of a Komodo Dragon! It too has smelt the carcass and unlike the Thylacine it has the size and power to potentially muscle the Quinkana off the carcass. The Megalania grabs the hind leg of the carcass and attempts to drag it away. But the Quinkana isn’t going to let go easily and proceeds to grab onto the carcasses’ neck. A massive tug of war ensues between the two reptiles, one that could potentially escalate further! Understandably the Thylacine isn’t willing to stick around to find out the result and with the two giant predators all over the carcass there is no chance of her stealing anything now. Frustrated, she is forced to move on.

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Quinkana. One of the many large predators our Thylacine family has to avoid!
Image Credit: Mr Fink, https://commons.wikimedia.org/wiki/File:Quinkana_fortirostrum.JPG

It is now late November and the baby Thylacine has finally left the safety of the pouch and is taking his first independent steps into a wider world. The Australian summer is now in full swing. Conditions are much hotter and drier, and all animals are feeling the strain. One such animal is Genyornis. Genyornis is a flightless bird that is part of the ratite family; the same family that contains the Ostrich of Africa and another Australian bird called the Emu. However Genyornis is a giant, and at 2 metres tall it is about 6 times bigger than a regular Emu. Genyornis is a vegetarian, feeding on leaves and seeds, and it is this that draws it close to a nearby tree. The tree also provides much needed shade and allows the Genyornis some respite from the hot sun. But it is not as safe as it thinks it is. The Genyornis looks round, alerted by a sound coming from the nearby bush. But before the bird can even react a powerful marsupial slams into it and bites very hard into the Genyornis’ neck. It’s all over in just a few seconds. This predator is the largest Mammalian carnivore in Australia; a Thylacoleo. The Thylacoleo looks around, checking that no other large predator has caught wind of the fresh kill, then drags the big carcass up into the safety of the tree to consume at her leisure. Unbeknownst to her the female Thylacine and her joey have been awoken by the disturbance. Thylacines are nocturnal, meaning they operate mostly between Dusk and Dawn, and so the pair were taking the opportunity to have a daily siesta! The mother knows better than to linger around a full grown Thylacoleo and ushers her joey away to find a quieter place to nap. At first glance Thylacoleo looks similar to the big cats that occupy the rest of the world. However like Diprotodon this “Marsupial Lion” is actually another relative of the wombat. Thylacoleo is an incredible animal, perhaps the most unique mammalian carnivore to ever live. The bite that instantly ended the Genyornis’ life is the strongest pound for pound bite of any mammal ever! It’s even stronger than an African Lion despite Thylacoleo being nearly half its size! Like big cats Thylacoleo possesses large retractable claws and these, along with its dentition of large stabbing incisors and sharp shearing carnassials (i.e. molars) make this marsupial quite the formidable hunter. The Thylacine family definitely made the right choice in avoiding it!

File:Leon marsupial, Thylacoleo carnifex 3d restoration.jpg - Wikimedia  Commons
Thylacoleo. The most unique Mammalian carnivore to ever exist.
Image Credit: Jose Manuel Canete, https://commons.wikimedia.org/wiki/File:Leon_marsupial,_Thylacoleo_carnifex_3d_restoration.jpg

Fast forward to early February and the end of the Australian summer is approaching. With each passing day the baby Thylacine grows stronger and more independent. He also isn’t the only youngster around anymore. Not far from the Thylacine family a group of Procoptodon (or “Short Faced Kangaroos) lie in the shade of the nearby trees. These giant members of the Kangaroo family grow up to 2 metres tall and weigh 230 kilograms. Despite this size, they are still capable of hopping and reaching great speeds as other kangaroo species are*. They’re also just as dangerous, a fact that two males are demonstrating by sparring together. The kicks from their strong legs can crack bones and result in serious internal bleeding. But in this session both males walk away scot free. The Procoptodon joeys are also sparring, copying the behaviour of the males. But for these youngsters this is more playfighting than real sparring! Life for our Thylacine family finally seems peaceful. But there’s a dangerous smell in the air. The smell of smoke. A fire has started in the east, and to the sides of the flames are the cause. Humans. Their flaming torches have lit the surrounding dry grass with the aim of driving the Procoptodon out into the open. However the fire has also engulfed all the other animals in the area and all around the flickering red and orange flames the Thylacine mother and child hear the terrified cries of animals engulfed by smoke and flames. The fire spreads panic and chaos all over the place and out of the nowhere the mother Thylacine is smacked into by another big animal. Both animals are dazed by the blow and the mother Thylacine looks up at the Thylacoleo, who has managed to shake off the blow and stagger to her feet. This is a nightmarish for the Thylacine and yet all she can think of is the safety of her joey somewhere in the fire. But the Thylacoleo could care less about the Thylacine right now and runs on past her. In shear panic the Thylacoleo had only accidently ran into the Thylacine while trying to escape! The mother Thylacine desperately calls out for her joey. One coughing bark; nothing. Another two barks; still nothing! The fear is absolutely overwhelming now and to her it truly feels like the end of her world. But then she hears a bark, one she recognises! It’s her joey, still alive! The pair run for their lives but no matter which way they turn the fire blocks their path. Running out of places to go there seems to be no escape as the fire surrounds them and starts to burn brighter and hotter….

File:Procoptodon BW.jpg - Wikimedia Commons
Procoptodon: The giant kangaroo targeted by the fire wielding humans!
Image Credit: Nobu Tamura, http://1.bp.blogspot.com/-caAabAGbDtI/T9UY-vMc6oI/AAAAAAAABoI/ARER5hK_3Dw/s1600/Procoptodon_BW2.jpg

Later that evening the fire finally dies down. The humans have long since moved on with their prizes. But in their wake lie the consequences of their actions. From black widow spiders, to wallabies, to Diprotodons and Procoptodons all manner of life has burnt to a crisp. Not even the mighty Megalania and Quinkana, those two reptiles vying for top predator supremacy, could escape the flames. As fierce as they were, they were ultimately no match for a species who could wield a superweapon like fire. Luckily our Thylacine family managed to survive the fire by seeking refuge in a large and deep burrow. Walking through the burned vegetation and past the bodies, the mother recognises a familiar face. It is the female Thylacoleo. Once a great threat to our Thylacine, the Thylacoleo lies motionless with smoke floating from her burnt skin like a blown out candle. The Thylacine regards her from as close as she has ever managed before. But this time there’s no response, and after a while the Thylacine and her child, as always, are forced to move on to survive. This tragedy is a sign of things to come for the great megafauna of Australia. Even 50,000 years ago species like the Thylacoleo are in decline and within 30,000 years nearly all of the spectacular animals we have encountered on this journey will have disappeared. While the humans’ efficient hunting strategies are a threat the herbivores of Australia are unprepared for, and one the carnivores can’t hope to match, they are not the main reason why the megafauna disappear. By comparing the extinction dates of the Australian megafauna with the arrival of humans it was found that they were actually able to co-exist together for nearly 20,000 years, a piece of information that doesn’t correlate with overhunting. Instead there is another danger, one more devastating than even the humans; the changing climate. Over time Australia becomes even drier and more arid. This results in habitat loss and without their habitat this Ice Age ecosystem will not be able to survive. As for the plucky Thylacines, they will manage to cling on for a while longer. However even they will eventually be unable to adapt to the new human world. After going extinct on mainland Australia 2,000 years ago they were reduced to a small population living exclusively on the island of Tasmania, leading to their more commonly known name of “The Tasmanian Tiger”. However the arrival of Europeans in Tasmania would put them under even greater pressure than before. Their habitat was destroyed to make way for farms, imported disease would strike them down and Europeans would kill them in the mistaken belief that they hunted their sheep and cattle. The last Thylacine, a male that’s often incorrectly thought to have been called Benjamin, passed away on the 7th of September 1936 in Beaumaris Zoo in Hobart Australia. Tragically it is thought that he was a victim of neglect, locked out of his shelter and left out in the bitter cold of the Australian night. It was a truly sad end to a species that was a remnant of a lost world.

pungulv – Store norske leksikon
The Thylacines. The plucky heroes of this safari!
Image Credit: John Gould, https://snl.no/pungulv

*EDIT: This sentence is inaccurate and a mistake on my part! Procoptodon and its relatives, the Sthenurinae Kangaroos, are NOT thought to have hopped like modern Kangaroos do. Instead the currently accepted theory is that they walked on two legs (a bit like humans do). This idea was put forward by a study published in 2014 by Janis, Buttrill & Figueirido and backed up by a 2019 paper by Janis et. al. Links to both papers can be found below in the References/Further Reading section.

References/Further Reading

An article on the National Museum Australia’s website about the extinction of the Thylacine in 1936

National Museum Australia, “Extinction of the Thylacine”, National Museum Australia, www.nma.gov.au, https://www.nma.gov.au/defining-moments/resources/extinction-of-thylacine#:~:text=On%207%20September%201936%20only,the%20time%20of%20European%20settlement.

Rovinsky et. al. 2020. A paper that provides a new size estimate for the Thylacine

Rovinsky Douglass S., Evans Alistair R., Martin Damir G. and Adams Justin W. 2020Did the thylacine violate the costs of carnivory? Body mass and sexual dimorphism of an iconic Australian marsupialProc. R. Soc. B.28720201537, http://doi.org/10.1098/rspb.2020.1537

An interesting web page from the Thylacine Museum section on the Natural Worlds website on Thylacine Reproduction and Development

Natural Worlds, “Biology: Reproduction and Development”, www.naturalworlds.org, http://www.naturalworlds.org/thylacine/biology/reproduction/reproduction_2.htm?fbclid=IwAR13a8Y9GJTCG6vT2vR-GNc8Xv96M7t5aYSE8WsQKjCTaojxQFIZJeju6EM

And another web page from the Thylacine Museum on Thylacine sounds.

Natural Worlds, “Vocalisation”, http://www.naturalworlds.org, http://www.naturalworlds.org/thylacine/biology/behaviour/behaviour_12.htm

• A video by Ben G Thomas (uploaded coincidentally while I was writing this blog article) about the Marsupial Lion, Thylacoleo

An article written by Alice Klein for New Scientist on Thylacoleo

Klein, Alice, “Australia’s ‘marsupial lion’ was a meat-ripping, tree-climbing terror”, New Scientist, www.newscientist.com, 12th December, 2018, https://www.newscientist.com/article/2187990-australias-marsupial-lion-was-a-meat-ripping-tree-climbing-terror/

An article on National Geographic by Laelaps (Riley Black) on the new size estimate of the giant monitor lizard Megalania.

Black, Riley, “Australia’s Giant, Venomous Lizard Gets Downsized”, National Geographic, March 19, 2014, www.nationalgeographic.com, https://www.nationalgeographic.com/science/phenomena/2014/03/19/australias-giant-venomous-lizard-gets-downsized/

Hocknull et. al. 2020: A study that provided evidence that the extinction of Australias megafauna (specifically in the Eastern Sahul region) was mainly due to a changing climate.

Hocknull, S.A., Lewis, R., Arnold, L.J. et al. Extinction of eastern Sahul megafauna coincides with sustained environmental deterioration. Nat Commun 11, 2250 (2020). https://doi.org/10.1038/s41467-020-15785-w

A 2017 article published on The Conversation, written by Gilbert Price, about Diprotodon and it’s seasonal migrations across Ice Age Australia

Price, Gilbert, “Giant marsupials once migrated across an Australian Ice Age landscape”, 27th September, 2017, www.theconversation.com, https://theconversation.com/giant-marsupials-once-migrated-across-an-australian-ice-age-landscape-84762?fbclid=IwAR0G3JDp8KZo-HTLBPIPGIyu2mMKW6yAZ5RlAipREqCL0VZjckZkZhvvGXM

The Australian Museums factfile on Procoptodon. Last updated in 2018 and written by Anne Musser

Musser, Anne, “Procoptodon goliah”, 4th December, 2018, www.australian.museum.com, https://australian.museum/learn/australia-over-time/extinct-animals/procoptodon-goliah/

Janis, Buttrill & Figueirido 2014 paper on Sthenurine (e.g. Procoptodon) locomation

Janis CM, Buttrill K, Figueirido B (2014) Locomotion in Extinct Giant Kangaroos: Were Sthenurines Hop-Less Monsters? PLoS ONE 9(10): e109888. https://doi.org/10.1371/journal.pone.0109888

Janis et. al. 2019 paper that followed up the 2014 study on Sthenurine locomotion by examining the humerus bones of these extinct giant Kangaroos

Janis, C.M., Napoli, J.G., Billingham, C. et al. Proximal Humerus Morphology Indicates Divergent Patterns of Locomotion in Extinct Giant Kangaroos. J Mammal Evol 27, 627–647 (2020). https://doi.org/10.1007/s10914-019-09494-5

Prehistoric Wildlife’s factfile on Genyornis

Prehistoric Wildlife, “Genyornis”, www.prehistoric-wildlife.com, http://www.prehistoric-wildlife.com/species/g/genyornis.html

Titanoboa: The Supersized Snake

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A life sized model of Titanoboa, in the process of gorging on a crocodilian, from the Smithsonian Museum of Natural History.
Image Credit: Ryan Quick, https://www.flickr.com/photos/order_in_chaos/7684792594/

It’s a giant snake.

That’s what most people think when it comes to Titanoboa cerrejonensis, meaning “Giant Boa from the Cerrejón”. It looks like something straight out of a straight to video B-list horror movie; an animal that is very familiar but scaled up to gargantuan proportions. The giant extinct shark Megalodon has this same problem and I think just labelling animal like these two as “just an oversized [insert animal here]” doesn’t tell the whole story. In this blog article I shall look at the truth about this giant snake, and find out just what kind of animal it really was.

Now the first thing that documentaries and any paleo-obsessed person will tell you about Titanoboa is that it was very big. They are not exaggerating! The study (published in 2009) that first described Titanoboa estimated that it grew up to 13 metres long; almost double the length of The Reticulated Python, the largest living snake. If that wasn’t enough other palaeontologists argue that Titanoboa could have grown even larger, to lengths approaching 14.5 metres! For comparison that’s longer than a bus (as most extinct animal books will boldly state) and a Titanoboa would have no problem rearing up to tower over a human if it had ever encountered one. Titanoboa lived 60-58 million years ago during a time known as the Palaeocene period. Its size gives Titanoboa the record as the largest land animal that we know of from this time, and also the title of the largest land predator since the demise of the non-avian dinosaurs, which only happened 7 million years before Titanoboa existed.

The first fossil that was identified as belonging to a Titanoboa was a single vertebrae unearthed from a coal mine in the Cerrejón region in Northern Colombia in 2007. This wasn’t actually the first fossil ever found of it, but was the first that was recognised as belonging to a new animal. The snake identification was made due to the fossil vertebrae’s similarities to modern snake vertebrae. From just this one bone, palaeontologists were able to deduce several key bits of information about Titanoboa. Firstly, the vertebrae was very similar to those found in modern day boa constrictors and Anacondas, suggesting that these snakes are Titanoboa’s closest living relatives (and that is reason for the “boa” part of Titanoboa!). Secondly the vertebrae was massive, almost twice the size of an Anacondas, and by scaling with measurements from them the authors of the 2009 study were able to obtain their 13 metre length estimate. After this find, further fossil expeditions to the Cerrejón have unearthed further remains including up to 100 further vertebrae and a partially complete skull. The skull is particularly exciting as snake skulls are delicate and don’t usually preserve well in the fossil record.

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A cast of a fossil vertebrae from a Titanoboa, on display at the Museo Geológico José Royo y Gómez, Bogotá, Colombia.
Image Credit: Rextron, https://commons.wikimedia.org/wiki/File:Titanoboa_vertebra_1.jpg

So how would this supersized snake have lived? Well the answer is that it would have had a similar lifestyle to that of modern Anacondas, just on a larger scale. Like all Boas, Titanoboa would not have possessed venom. Instead it would have hunted in the same way as modern day Boa Constrictor snakes; wrapping its body quickly and tightly around its prey and using its large body muscles to squeeze it hard. This action would break bones and cause suffocation as the prey’s windpipe and chest cavity were constricted. Once its prey had been subdued Titanoboa would then open its dislocatable jaws very wide and swallow it whole, sometimes taking hours to do so. Animals on Titanoboa’s menu included the numerous species of crocodilians and turtles that also inhabited the Cerrejón region. Like modern day Anacondas Titanoboa would’ve spent a lot of its time in water, swimming around the lakes and rivers of its very hot, very humid rainforest home. In these rivers lived another major source of food for the snake; fish. The skull of Titanoboa was found to contain more teeth than those of a modern boa, and the the teeth themselves were more loosely attached to the skull. This would’ve allowed the snake to more easily grab and hold onto wriggly, slippery prey. Furthermore fossils have been unearthed from the Cerrejón dirt of lungfish that grew up to 3 metres long! This large fish would have certainly provided a filling meal for a Titanoboa.

File:Eunectes-murinus -Broghammerus-reticulatus- -Titanoboa-2.svg
A size comparison between Titanoboa (grey), Gigantophis (another prehistoric snake – Red), a Reticulated Python (light green), an Anaconda (dark green) and a human.
Image Credit: Gamma 124, https://commons.wikimedia.org/wiki/File:Eunectes-murinus_-Broghammerus-reticulatus-_-Titanoboa-2.svg

To be honest what fascinates me about Titanoboa is not just the snake itself, but the ecosystem that it was a part of. 58 million years ago the Cerrejón was a unique place because it was dominated by reptiles. Indeed journey back only 7 million years and this statement would still be true! But these reptiles weren’t like the non-avian dinosaurs. Instead they belonged to more familiar families. For example living alongside the supersized snake that was Titanoboa was Carbonemys; a prehistoric turtle that could grow as large as a small car! There were also multiple species of dyrosaurs; a now extinct group of crocodilians (the reptile group that contains modern day crocodiles and alligators) which could grow up to 6 metres long in large species like Acherontisuchus. The long standing theory as to why these reptiles could grow as large as they did is that in the Palaeocene period the world was going through what is known as a “thermal maximum”. This is a global warming event that resulted in the worlds average surface temperature was much higher than today, and this heat, combined with 50% higher Carbon Dioxide levels, created a warm and very humid world that was so hot that there were no polar ice caps! To get an idea as to what the Cerrejón region was like imagine the Amazon Rainforest but even hotter, more humid and more waterlogged. These were favourable conditions for reptiles, who could absorb the highly abundant heat and use it to keep themselves active and fuel their internal biochemistry for longer periods at a time. This heat also meant they could generate more energy for growing larger sizes. In fact Titanoboas size has been used by a team of palaeontologists led by Jason Head (Head et. al. 2009) to estimate that the average yearly temperature of the Cerrejón 58 million years ago was between 30-34 Degrees Celsius. This was definitely a place where packing some suntan lotion, loose clothing and insect repellent would have been necessary! But its not just temperature that produced these giant reptiles. After the K/T extinction event (which took place 65 million years ago and wiped out 70% of all life on earth – casualties included the non-avian dinosaurs, pterosaurs and marine reptiles), many ecosystems were left vacant and open for the survivors to claim them. Furthermore mammals at this time had, in general, yet to grow large enough to fill the large animal niches available. As a result other groups were able to claim these open niches for themselves. In some parts of the world these were birds, with some growing taller than a man, and in the Cerrejón it was the reptiles, with Titanoboa taking the job of top predator.

The Palaeocene was undoubtedly a unique and weird period in earth’s history, and Titanoboa is a prime example of what can happen when an extinction event and favourable conditions creates evolutionary openings. While some people will be glad that this snake isn’t around anymore (and it certainly wouldn’t help cure anybody’s ophidiophobia!) I personally wish it were possible to see a living, breathing Titanoboa. It is a paleontological icon for a reason; it’s not just a giant snake, it’s THE giant snake.

References/Further Reading

Head et. al. 2009 paper about Titanoboa and what it can tell us about the hot conditions of the Cerrejón region

Head, J., Bloch, J., Hastings, A. et al. Giant boid snake from the Palaeocene neotropics reveals hotter past equatorial temperatures. Nature 457, 715–717 (2009). https://doi.org/10.1038/nature07671

NOTE: This paper has had its critics, with a few other papers being published (e.g. Sniderman 2009, Denny, Lockwood & Somero 2009) offering arguments that dispute the claim that the large size of Titanoboa can be used to estimate the temperature of the Cerrejón region 58 million years ago

An article written by Guy Gugliotta for the Smithsonian magazine about Titanoboa

Gugliotta, Guy, “How Titanoboa, the 40-Foot-Long Snake, Was Found”, Smithsonian, www.Smithsonianmag.com, https://www.smithsonianmag.com/science-nature/how-titanoboa-the-40-foot-long-snake-was-found-115791429/

A factfile on Titanoboa written by Jonathan Bloch, one of the people who first described Titanoboa, for the Florida Museum.

Bloch, Jonathan, “Titanoboa”, Florida Museum, www.floridamuseum.ufl.edu, https://www.floridamuseum.ufl.edu/100years/titanoboa/

A YouTube video from the excellent PBS Eons on Titanoboa and the world it lived in

Hatzegopteryx: The King of Hațeg Island

The Kings of the Island
Image Credit: Mark Witton, https://commons.m.wikimedia.org/wiki/File:Hatzegopteryx.png

A wildlife safari to the island of Hațeg was going to be perfect they said. Warm sunny beaches, unspoiled wilderness and herbivorous dinosaurs small enough to ride like ponies. What could possibly go wrong!

But now the tourists are running for their lives through the fields of ferns, not daring to stop as the top predators of the island follow closely behind. They had been warned that they were dangerous, but their guide had said that they would be fine, they wouldn’t get too close and he would use his gun if they did. Sadly the guide had been eaten about fifteen minutes ago. The tourists keep going, trying to get as far away from the rasping squawks as they can. One of them is picked up of the ground, disappearing out of sight. Another suffers the same fate. Suddenly the last one trips and rolls forward. Coughing and spluttering he turns around, and sees one of the beasts towering over him. It regards him with its beady eyes before leaning its large head down and grabbing his leg with its beak. The beast leans its head back and with one final gulp the tourist joins his friends. The island once again belongs to its king.

The movie executives look up from the script they’d just read. “Okay who sent this in?”, one asks. “I think it was the same guy who sent in the one about the giant killer centipede, Arthro-something?” the other replied. With a sigh the first executive tosses the script onto a large pile in the corner.

Who needs alien monsters when prehistory keeps giving us animals to make movies about! First there was the giant creepy-crawlies of the Carboniferous, now this!

Hatzegopteryx (meaning “Hațeg basin wing”) was a wonder of the Late Cretaceous. It was first discovered only 17 years ago in 2002, and described from fragmentary remains of skull, humerus and femur. Initially these fossils were thought to belong to a large carnivorous dinosaur. However further study showed that they belonged to a flying reptile – a Pterosaur. Pterosaurs were a group of reptiles that dominated the skies during the Mesozoic era, going extinct sixty five million years ago at the end of the Cretaceous period. They had wings consisting of thin complex structures that stretched from their lower bodies to the end of an elongated fourth finger. Hatzegopteryx in particular belonged to the sub group of pterosaurs known as the azhdarchids. The azhdarchids appeared in the Late Cretaceous and grew to gigantic proportions even by pterosaur standards. They were the largest flying animals to ever live. Hatzegopteryx was no exception, with a wingspan of up to twelve metres long. Despite its large size (and some palaeontologists claiming that they had evolved to be flightless) such a large animal was able to fly because it was surprisingly lightweight. Even the largest azhdarchid pterosaurs have been estimated to weigh only 550 pounds. This is due to a combination of weight saving hollow bones and soft tissue air sacs, which also provided an oxygen reserve for powered flight. In flight azhdarchids such as Hatzegopteryx would have wasted little energy flapping, instead soaring on rising air currents like a modern day vulture. This allowed them to cover great distances, up to 10,000 miles in some estimates. Like almost all pterosaurs Hatzegopteryx would also likely have had a body covering of soft down known as pycnofibres. This down, while feather-like, was different to the feathers of birds and used in insulation rather than for display or flight.

Hatzegopteryx humorous bones from above (A) and from the side (B)
Image Credit: Mark Witton & Michael Habib, http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0013982

However despite being able to fly Hatzegopteryx would not have done its hunting whilst airborne. Instead, and rather unusually for a pterosaur, it hunted on the ground. When grounded Hatzegopteryx stood at a height of around five metres, which is as tall as a modern day giraffe! From this high vantage point Hatzegopteryx could survey the landscape, looking for any small dinosaurs it could catch. Able to comfortably stride across the landscape using all four limbs, Hatzegopteryx would pick up and swallow whole any small animals it could find while using its sharp beak to kill any larger individuals. Such a hunting strategy is not too dissimilar to that employed by modern day storks and hornbills, except on a much larger scale. Hatzegopteryx managed this hunting style because of its huge skull. At three metres long and half a metre wide it was the longest skull of any land based animal. This was a powerful beaked weapon that was supported by a relatively short but hugely muscular neck. This short neck is a relatively new discovery and stems from a 2017 paper written by Palaeontologists Mark Witton and Darren Naish. This skull and neck is different to other azhdarchids, such as Quetzelcoatlus and Cryodrakon, which tended to have longer necks and thinner skulls.

A 3 metre long skull of Hatzegopteryx (Top) compared with the 1.5 metre long skulls of Spinosaurus (Bottom right) and Giganotosaurus (bottom left)
Image Credit: Wikimedia Commons, https://commons.m.wikimedia.org/wiki/File:Skulls_length_comparison_of_Hatzegopteryx,_Spinosaurus_and_Giganotosaurus.png. Based on images from Therrien & Henderson 2007 and Buffetaut, Grigorescu & Csiki 2002.

Hatzegopteryx was first discovered in Transylvania in Romania, in the same area that Bran Stokers Dracula lived (though I’m sure Hatzegopteryx would have eaten Dracula for lunch then eyed up Van Helsing as seconds!). 70 million years ago this area was an island, roughly the size of Ireland, known as Hațeg Island. Hațeg was a subtropical environment, consisting of broadleaf forests, open plains and a hot climate. If it were around today it would be heaving with tourists – Hatzegopteryx permitting. What makes the island uniquely interesting were the dinosaurs that lived there. Consisting of a mix of sauropods, hadrosaurs and small theropods, they were of a smaller size compared to their mainland counterparts. For example Magyarosaurus dacus, a species of titanosaur sauropod, had a maximum length of only six metres on Hațeg, compared to fifteen metres on mainland species. This is equivalent to finding an elephant the size of a donkey and is an example of “insular dwarfism”. This is when animals on an isolated island adapt to the limited resources by growing to smaller sizes. Hatzegopteryx on the other hand is an example of “island gigantism”, where in order to fill an empty ecological niche (in this case the role of “top predator” – there were no large carnivorous dinosaurs on Hațeg) an animal grows larger than usual. A modern day counterpart to Hațeg Island would be the Galapagos Islands, where we see similar diverged island evolutionary processes (e.g. the giant tortoise and numerous species of finches). Another example would be New Zealand, where in the absence of large mammals birds such as the Kiwi, the Moa and the Haast Eagle evolving to occupy the major ecological niches (the latter two only going extinct within the last 1000 years).

Hatzegopteryx would have been a marvel to witness flying. An extraordinary and complex achievement of natural aeronautical engineering, there has never been an animal quite like it. If Hatzegopteryx was alive today I’m sure the reptile/stork/giraffe hybrid would generate the same (if not more) fear as another famous blood sucking Transylvanian does.

EDIT: By a weird coincidence 3 days after this blog went up a new paper came out by (Solomon et. al. 2019) about the discovery of a new species from azhdarcid pterosaur from Transylvania! Known from fragments of beak and vertebrae and thought to represent a juvenile this new pterosaur has been named Albadraco tharmisensis. It has been estimated to have been only a little bit smaller than Hatzegopteryx and further illustrates the wide range of life that was present on Hațeg Island 70 million years ago!

References/Further Reading

Solomon et. al. 2019 paper on the new azhdarchid pterosaur Albadraco, which lived at the same place and time as Hatzegopteryx.

Solomon, A. A., et al. (2020). “A new species of large-sized pterosaur from the Maastrichtian of Transylvania (Romania).” Cretaceous Research 110: 104316.

A paper by Darren Naish and Mark Witton (Naish & Witton 2017) on Hatzegopteryx neck length and biomechanics

Naish D, Witton MP. 2017. Neck biomechanics indicate that giant Transylvanian azhdarchid pterosaurs were short-necked arch predators. PeerJ 5:e2908 https://doi.org/10.7717/peerj.2908

A paper, written by a team led by Michael Benton (Benton et. al. 2010), on the dwarf dinosaurs of Haţeg Island.

Benton, M. J., et al. (2010). “Dinosaurs and the island rule: The dwarfed dinosaurs from Haţeg Island.” Palaeogeography, Palaeoclimatology, Palaeoecology 293(3): 438-454.

An article, written by Elizabeth Martin-Silverstone and published on The Conversation website, on Azdarchid Pterosaur flight.

Martin-Silverstone, Elizabeth, “Pterosaurs should have been too big to fly – so how did they manage it?”, The Conversation, Jun. 30, 2016, theconversation.com/pterosaurs-should-have-been-too-big-to-fly-so-how-did-they-manage-it-60892

Another interesting paper, Yang et. al. 2018, on Pterosaur’s feather-like pycnofibres

Yang, Z., Jiang, B., McNamara, M.E. et al. Pterosaur integumentary structures with complex feather-like branching. Nat Ecol Evol 3, 24–30 (2019). https://doi.org/10.1038/s41559-018-0728-7

Megalosaurus: The Original Dinosaur


An Artist reconstruction of Buckland’s great lizard
Image Credit: LadyofHats Mariana Ruiz, https://commons.m.wikimedia.org/wiki/File:Megalosaurus_dinosaur.png

There is no group of extinct life that enthrals the minds of the general public quite like dinosaurs. All palaeontologists both current and aspiring can claim to have at least been partially inspired by reading books and watching documentaries about dinosaurs, and from seeing their fossils and reconstructions in the many museums throughout the globe. Some dinosaurs have received vast amounts of media attention; the great Tyrannosaurus Rex; the three-horned Triceratops; and the long necked Brachiosaurus to name a few. However there is one dinosaur that can claim to be perhaps the most important of them all. Megalosaurus bucklandii is not as well-known as these other dinosaurs, which is quite surprising to me. However this medium-large sized theropod from the mid-Jurassic has every claim to live long in the history books.

Megalosaurus was the first dinosaur to be properly and scientifically described and the first animal to be referred to as a “dinosaur”. The first Megalosaurus fossils were discovered in the village of Stonesfield in Oxfordshire, England in the 18th century. These fossils came from a Mid-Jurassic (170-150 Million years old) deposit known as the “Stonesfield Slate”, a deposit that has also preserved the remains of other dinosaurs, pterosaurs, insects and plants of the time. The Megalosaurus fossils, originally described under the interesting name of Scrotum humanum, which was not formerly accepted by any scientific body, were passed on in 1824 to the geologist William Buckland, who in collaboration with the anatomist Georges Cuvier, identified the animal as a large extinct reptile. This animal was given the name Megalosaurus bucklandii, meaning “Buckland’s great lizard”. It was almost 20 years later in 1842 that Megalosaurus was referred to by Sir Richard Owen as a “dinosaur”. This discovery was quite unlike any living animal and captured the imagination of the Victorian public, with Megalosaurus making an appearance in the Charles Dickens novel Bleak House. This made it one of the first (but certainly not the last!) dinosaurs to appear in mainstream popular media.

A fossilised lower jaw and tooth of Megalosaurus. This jaw is one of the more iconic dinosaur fossils.
Image Credit: Wikimedia Commons, https://he.m.wikipedia.org/wiki/%D7%A7%D7%95%D7%91%D7%A5:Buckland,_Megalosaurus_jaw.jpg

Most of the Megalosaurus specimens that these early Victorian geologists had to go on were incomplete, with the only finds being a lower jaw, upper jaw, some teeth and a few thigh and leg bones. In addition this was really the first time anyone had attempted to reconstruct dinosaurs from their bones. So the Victorian scientists could only make educated guesses as to what this animal was like. While they knew, based on its tooth anatomy, that it was related to reptiles the first reconstructions of Megalosaurus were very different to what we believe today. Basing its design on modern lizards Megalosaurus was reconstructed as a massive, sluggish four legged animal, with its tail dragging along the ground and possessing a big hump on its shoulders. This interpretation can be seen in all its glory at the Crystal Palace Park in London. Unveiled in 1851 it is displayed stalking a group of equally lizard like Iguanodon, also inaccurate as Iguanodon would appear almost 40 million years after Megalosaurus (to name one inaccuracy!). It was only when further theropod remains were found a few decades later that a more accurate picture of Megalosaurus became clear. However during this time the Megalosaurus species was known as a “wastebasket taxon” where any newly discovered large theropod remains were all haphazardly lumped into the Megalosaur group, like somebody chucking different types of cutlery into the same drawer. Also the animal was portrayed, like other bipedal dinosaurs at the time, standing upright like a Kangaroo. This would only change nearly a whole century later, where research in the 1960s and 1970s led to all bipedal dinosaurs’ posture being altered to the more horizontally balanced forms seen today, where the head and body were counterbalanced by a long, lofted tail.

The Megalosaurus model at Crystal Palace park. This model, first revealed in 1851, shows us what Victorian Scientists thought it looked like.
Image Credit: Chris Sampson, https://commons.m.wikimedia.org/wiki/File:Crytsal_Palace_Megalosaurus.jpg

Whilst Megalosaurus has a long and important story about its discovery, and how it changed scientific thinking forever, what was this dinosaur actually like when it was alive? Well, Megalosaurus belonged to a group of theropods known as the Megalosauridae. This group were the main land predators of the early to mid-Jurassic period, dominating the landscape until their numbers declined during the late Jurassic 150 million years ago. Megalosaurus had many of the features that are typical of theropod dinosaurs; big hind legs, saurischian (lizard-like) hips, arms ending in non-pronated wrists, sharp claws and robust jaws filled with razor sharp teeth suitable for cutting and biting into the flesh of its prey. The powerful legs of Megalosaurus would have enabled it to reach speeds of up to 20 miles per hour, equivalent to a modern day Grizzly Bear and easily fast enough to chase down its prey. Once caught Megalosaurus would have attacked its prey with a powerful bite, its skull built for heavy impact by having a framework of slightly loose bones that, through flexing on impact were able to absorb the forces involved in biting and holding large struggling prey. Reaching up to nine metres long, three metres tall and weighing nearly one and a half tonnes it was the undisputed top predator of mid-Jurassic England, hunting large herbivorous dinosaurs, such as the long necked sauropod Cetiosaurus. However it would have needed to be an unfussy eater. During the Mid Jurassic, the UK was broken up into small islands, with Megalosaurus probably swimming from island to island and combing the beaches for any food it could find, including any marine reptiles, crabs and pterosaurs that had been beached. It is also possible, like a lot of other theropods, that Megalosaurus could have been at least partially feathered. Evidence for this comes from another megalosaurid called Sciurumimus. Found in the Late Jurassic of Germany this juvenile megalosaur was found preserved with a filamentous coating of feathers. While this isn’t direct evidence of feathers on Megalosaurus the fact that it is present on a close relative means that it is likely that it too possessed a similar coating, making it look a bit less like a scaly lizard and a bit more like a fluffy carnivorous bird. This new finding, put forward in a 2014 study by Rauhut et. al., would certainly have startled William Buckland, Richard Owen and the other Victorian scientists that first named this remarkable beast a “dinosaur”.

So, just as the 2008 film “Iron Man” was the start of the Marvel Cinematic Universe, and the Benz Patent Motor Car was the origin of today’s cars, the discovery of Megalosaurus was the genesis of dinosaur research. While T-Rex and others get the spotlight nowadays without this first description and reconstruction of this Mid-Jurassic Megalosaur from Oxford, dinosaurs would not have captured the public imagination in quite the way that they have. The field of palaeontology would perhaps have never evolved into the science it is today, and who knows, in that world I may have become an archaeologist!

References/Further Reading

Rauhut et al 2014 paper about feather filaments in the Megalosaur Sciurumimus

Rauhut, O. W. M., et al. (2012). “Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany.” Proceedings of the National Academy of Sciences 109(29): 11746-11751.

The Friends of Crystal Palace Dinosaurs page on the Megalosaurus model at Crystal Palace park, including comparisons with how the Victorian scientists thought it looked and behaved compared with modern interpretations

“Megalosaurus”, Friends of Crystal Palace Dinosaurs, cpdinosaurs.org/visit/statue-details/megalosaurus

More Information on Megalosaurus and other animals of the Stonesfield slate from the Oxford University Museum of Natural History website

“The Oxfordshire Dinosaurs”, Oxford University Museum of Natural History, oumnh.ox.ac.uk/megalosaurus-and-oxfordshire-dinosaurs

The Legend of the Sea Serpent Mosasaurus

Mosasaurus as it may have looked when it swam in Earth’s seas 70-65 million years ago.
Image Credit: Dmitry Bogdanov, https://commons.m.wikimedia.org/wiki/File:Mosasaurus_beaugei1DB.jpg

The idea of a large, serpentine like animal living in the depths of the ocean and battling heroes of legend has been a favourite tale of a whole host of myths and legends. Since early human history people seem to have been attracted to the idea of such an animal, quite unlike anything that lives today. Even in recent times this is a concept that has people enthralled. Just ask anybody who is convinced that there is a plesiosaur like animal living in Loch Ness. However while a large sea serpent probably doesn’t exist today (not counting real life sea snakes) there was a similar beast that ruled the seas of the Late Cretaceous period 70 million years ago. Its full scientific name, is Mosasaurus hoffmanni (Meaning “Hoffmanns Meuse Lizard”).

Mosasaurus was discovered back in 1764 near the town of Maastricht in the Netherlands. This was a time when the word “dinosaur” hadn’t been spoken yet, and proper scientific research on fossils was in its infancy. The fossil itself was a disarticulated skull, a cast of which is on display in the Sedgwick Museum in Cambridge. This fossil went through an eventful journey before it was first scientifically examined in the early 19th century, which includes being hidden from French occupation and being traded (allegedly) for 600 bottles of wine! Scientists of the time, including the famous French naturalist Georges Cuvier, correctly deduced that this animal was a reptile. Now “Meuse Lizard” may seems like a weird name to give an animal like this, but it was named after the Meuse River which runs through Northern Europe close to Maastricht.

This sea faring animal was very much the top predator of its day, reaching up to 15.2 metres long and weighing 15 tons. While there were other formidable hunters around (one example being Xiphactinus, a 5 metre long predatory fish known for swallowing prey whole!) there was no other marine predator that could rival it. Mosasaurus was an opportunistic hunter, eating almost anything that it could fit its powerful jaws around. This included a whole range of marine animals, from fish to squid, other marine reptiles and even smaller species of Mosasaurs! Mosasaurus was also quite different from other marine reptiles in that its lizard ancestors took to the water at a much later date than other marine reptiles such as Ichthyosaurs and Plesiosaurs. Also, unlike its lizard ancestors Mosasaurus gave birth to live young instead of laying eggs (just like modern day sea snakes). However Mosasaurus, along with the rest of its family, could not survive the asteroid that struck the earth 65 million years ago, dying out alongside the dinosaurs. They are survived by their closest living relatives; monitor lizards and snakes. Which funnily enough makes the sea serpent comparison even more fitting!

The fossilised head of Mosasaurus, showing its frightening battery of teeth!
Image Credit: Tim Evanson, https://www.flickr.com/photos/timevanson/9322551651

In the last couple of years Mosasaurus has been getting attention both in film, where it steals the show in the film Jurassic World, and in the world of paleontological research. This research has changed our understanding of how Mosasaurs both looked and behaved, with the following three studies being particularly insightful:

First. A study carried out by Johan Lindgreen, Hani Kaddumi and Michael Polycin in 2013 discovered a new anatomical feature in Mosasaurs. Previously it had been thought that they powered their long bodies through the water with a broad, straight tail, moving in a undulating manner like a modern day sea snake. However, after examining a fossil Mosasaur, named Prognathodon, from Jordan in Africa the palaeontologists noted that the outline of its skin had been fully preserved. This impression clearly showed a tail fluke like those of sharks or Ichthyosaurs, albeit with the upper fluke being smaller than the lower fluke. This tail, a product of convergent evolution, would have enabled mosasaurs to perform fast, powerful strokes to catch prey by surprise.

Second. A study in 2014, carried out by a team of palaeontologists based at Lund University in Sweden (which also included Lindgreen and Polycin, among others), gave us our first look at the colour of a mosasaur. This was an exciting find as evidence of colour is very rarely preserved in extinct animals and had never before been seen in a marine animal. The study looked at tiny blob like structures on the skin of an 85 million year old fossil mosasaur named Platecarpus tympaniticus. These had previously been thought to be bacteria. However as it turns out these blobs were actually melanosomes, the cells that produce skin colour. The structure of these preserved melanosomes showed that this mosasaur, and by extension other mosasaurs such as Mosasaurus, had what is known as “countershading”. Countershading is a colouration pattern that consists of a dark upper body and a light lower body (an example of this being the colouration of a modern day Killer Whale). This has a few advantages; it provides camouflage against the dark ocean depths (when looked at from above) and against the sunlight lit surface (when looked at from below). The dark upper surface also allows the mosasaur to absorb more heat from the sun when it surfaces for air and gives it protection from UV light when at the surface.

Third. A recent study conducted at the University of California, and only published in September 2019, looked in detail at how Mosasaurs swam. What they found was that Mosasaurs could perform a “breaststroke” like action with their front flippers. In conjunction with powerful beats of their tails, this would have allowed them to achieve great bursts of speed through the water. This is interesting because it was thought that marine animals swim using either their tails or their fins, but not both at the same time. As a result this swimming style is unlike any other known animal and makes mosasaurs even more remarkable.

And so, thanks to studies both old and new, we have a detailed picture of Mosasaurus, and its family, as one of the most unique sea faring animals ever. It further proves that the world of paleontological research is still capable of putting fresh spins on iconic animals of the past!

Mosasaurus enjoying a dinosaur dinner!
Image Credit: Jonagold2000, https://commons.m.wikimedia.org/wiki/File:Mosasaurus_hoffmanni_life.jpg

References/Further Reading

Lindgren, Kaddumi & Polcyn 2013 paper about Mosasaur tail flukes.

Lindgren, J., Kaddumi, H. & Polcyn, M. Soft tissue preservation in a fossil marine lizard with a bilobed tail fin. Nat Commun 4, 2423 (2013). https://doi.org/10.1038/ncomms3423

Lindgren et. al. 2014 paper about Mosasaur coloration. This study also discovered the colour of a 55 million year old turtle (which had the same colour as a modern day leatherback turtle) and a 200 million year old Ichthyosaur (which was a dark colour).

Lindgren, J., Sjövall, P., Carney, R. et al. Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles. Nature 506, 484–488 (2014). https://doi.org/10.1038/nature12899

A paper, written by Kiersten Formoso and published in September 2019 (Formoso 2019), on new theories on Mosasaur swimming motions.

Formoso, Kiersten K., Reassessment of the Mosasaur pectoral girdle and its role in aquatic locomotion, Geological Society of America Abstracts with Programs. Vol. 51, No. 5, (2019), doi: 10.1130/abs/2019AM-333823

Further information, from the FossilEra website, about Mosasaur size, diversity, lifestyle and history of discovery

FossilEra “Mosasaurus & Mosasaurs”, FossilEra, fossilera.com/pages/about-mosasaurs

Get the all new Spinosaurus while stocks last!

The skeleton of an ancient river monster!
Image Credit: Mike Bowler, https://commons.m.wikimedia.org/wiki/File:Spinosaurus_swimming.jpg

Let me tell you a story. Three time travellers meet in a bar. They decide that they want to journey back to Mid Cretaceous North Africa, around 95 million years ago. They plan to have a dinosaur safari, just like the safaris that are conducted across the modern day Serengeti. However the area is dangerous as there are plenty of dangerous dinosaurs roaming around, some big enough to take out the jeep faster than the time travelling tourists can say “holy cow is that a dinosaur!” So they come up with a plan. Instead of going by jeep, they will use a river boat. “It’s perfect!” they say, “no dinosaur will be able to reach us as we are on the water and because it’s inland there’s no need to fear any sea faring marine reptiles”. After some time planning the time travellers undertake their boat journey. They marvel at the herds of the huge sauropod Paralititan and see an impressively large Carcharodontosaurus watching the herd hungrily. However as they are distracted by what they are seeing they don’t notice a large object moving in the river. Suddenly one of them hears the sound of rushing water and turns round to see a large sail poking out of the water like Jaws’ fin and heading right towards the boat. In five minutes, the time travellers will have seen their last dinosaur….

The unidentified river monster in this story is not a fish, nor a crocodile. It is instead the largest of all theropod dinosaurs: Spinosaurus aegyptiacus (meaning “Egyptian spine lizard”). The first Spinosaurus fossils were discovered in Egypt by German palaeontologist Ernst Stromer in 1912, however sadly these remains were destroyed during allied bombings raids on Munich during World War Two. Spinosaurus has gained more attention in recent years as new research has shown that this theropod had a lifestyle unlike any other dinosaur. The research suggests that Spinosaurus is the first known aquatic dinosaur.

There are certain anatomical features that support this interpretation. One area is the shape and design of the skull. The teeth were long and conical, well suited for gripping and holding on to slippery prey such as fish. The nostrils were placed high on its snout so it could hold it submerged in water while still being able to breath. It’s also thought that holes at the end of Spinosaurus’ snout contained pressure sensors, similar to those seen in modern crocodiles, which are used to detect disturbances in the water. The water based adaptations don’t stop there; one specimen of a Spinosaurus upper jaw has a barb embedded in it that belonged to a species of giant swordfish called Onchopristis. This suggests that Onchopristis was one of Spinosaurus‘ main sources of food. So taking all these adaptations together it suggests that Spinosaurus had a mostly fish based diet (however it is still possible that it ate meat as well).

An illustration of the head of Spinosaurus. Note the distinctive long, crocodile like jaws, conical teeth and small head crest.
Image Credit: Steveoc 86, https://commons.m.wikimedia.org/wiki/File:Spinosaurus_skull_steveoc.jpg

All these adaptations are well and good, however the biggest evidence for Spinosaurus‘ aquatic lifestyle was detailed in a paper released in 2014, written by a team of palaeontologists led by Spinosaurus expert Nizar Ibrahim. The paper examined and described a new 11.3 metre long specimen (that wasn’t fully grown, Spinosaurus could reach a maximum length of 15 metres) that is the most complete Spinosaurus skeleton ever found. Examination of the hind limb bones and pelvic girdle showed that they were much shorter than previously thought. These hind limbs were so short that Spinosaurus could not have walked on two legs for long periods of time as its legs couldn’t support its massive, front heavy bulk. This meant only one thing, Spinosaurus walked on all fours (at least occasionally). This is certainly very different to the bipedal, T-Rex killing beast that terrorised Alan Grant and the Kirbys in the 2001 film Jurassic Park 3. This new discovery also fits with the theory of a mostly aquatic based Spinosaurus. Short hind legs reduce drag when swimming and diving through water and is something that other aquatic and semi-aquatic animals, such as crocodiles and otters, exhibit today. These hind limbs were also solid and dense, helping with buoyancy control, and it has been speculated that feet would have been webbed to further aid in swimming. This means that Spinosaurus would have been comfortable and manoeuvrable in water, and a somewhat clumsy walker on land!

This reconstruction, which has commonly been dubbed “new Spinosaurus“, has caused quite a stir in the palaeontology community, Not everyone is on board with the idea and a few have even written articles and papers questioning the findings of the Ibrahim et al. 2014 paper. For example palaeontologist Scott Hartman questioned the length measurements of Spinosaurus’ hind limbs and Donald Hendersons 2018 paper questioned its buoyancy. However both these counter papers have their own issues; for example the Henderson paper based their buoyancy calculations on bone density data from other theropods and birds, except Spinosaurs have been shown to have proportionately thicker bones than these animals. The debate is still ongoing to this day, and so it is still not known for certain whether Spinosaurus truly was a quadruped or a biped.

So let us rejoice in the quadrupedal walking, gracefully swimming, humongously sized, sail-backed fish eater that Spinosaurus has become! Proof that during their 170 million year reign there were few habitats that the dinosaurs couldn’t reach.

UPDATE: Spinosaurus reconstructions continue to change with every new paper! A new study was published on the 29th April 2020 in the journal nature. Written by a team led by Nizar Ibrahim, has revealed that Spinosaurus had unusually tall neural spines and elongated chevrons on its tail vertebrae. These special vertebrae supported a flexible, paddle-like tail and it’s theorised that Spinosaurus used it to swim through the water! The image below illustrates what most palaeontologists now think Spinosaurus aegypticus looked like.

The most up to date (as of 29th April 2020) look of the river monster that our time travelling tourists had the misfortune of encountering!
Image Credit: Gustavo Monroy-Becerril, https://en.m.wikipedia.org/wiki/File:Spinosaurus_aegyptiacus_underwater.png

EDIT: One key piece of evidence, that I missed when writing this blog (my apologies!), from the Donald Henderson 2018 paper is that Spinosaurus’ centre of mass was located closer to its hips than to its torso. This is further evidence that Spinosaurus was a biped, walking on its short stubby legs (almost like a duck!). At the time of writing this Nizar Ibrahim has yet to publish his latest research on Spinosaurus so the two legged/four legged debate rages on. But currently the common consensus, at time of writing, is that Spinosaurus was a biped.

References/Further Reading

Ibrahim et al. 2014 paper, published in Nature, describing “New Spinosaurus

Ibrahim, N., et al. (2014). “Semiaquatic adaptations in a giant predatory dinosaur.” Science 345(6204): 1613-1616.

Henderson et. al. 2018 paper countering the Ibrahim et. al. 2014 paper

Henderson DM. 2018. A buoyancy, balance and stability challenge to the hypothesis of a semi-aquatic Spinosaurus Stromer, 1915 (Dinosauria: Theropoda) PeerJ 6:e5409 https://doi.org/10.7717/peerj.5409

Nizar Ibrahim’s response to Scott Hartman, published on Scott Hartman’s Skeletal Drawing.com.

Ibrahim et. al., “Aquatic Spinosaurus – The authors respond”, Scott Hartman’s Skeletal Drawing.com, Sept. 18, 2014, skeletaldrawing.com/home/aquatic-spinosaurus-the-authors-responsd9182014

An article in Smithsonian Magazine on the history of Spinosaurus research

Smithsonianmag.com, “Cracking the Code of Spinosaurus”, Smithsonian Magazine, Apr. 19, 2017, smithsonianmag.com/sponsored/spinosaurus-lost-dinosaur-paleontology-new-discovery-great-courses-plus-180962953/

New Ibrahim et. al. 2020 paper on the structure of Spinosaurus’ tail (USED FOR UPDATE)

Ibrahim, N., Maganuco, S., Dal Sasso, C. et al. Tail-propelled aquatic locomotion in a theropod dinosaur. Nature (2020). https://doi.org/10.1038/s41586-020-2190-3

Deinocheirus: The tale of the horrible hands

When I was a young boy who was madly into palaeontology and had significantly less adult responsibilities, I remember walking through the ever popular dinosaur exhibition in the Natural History Museum in London. Among the many displays, which ranged from models of dinosaur nests to the big skeleton of the Triceratops, there was one that always stood out to me. It was a pair of huge arms, complete with hands tipped with large claws. Unlike the proportionately tiny arms of Tyrannosaurus Rex, (I say proportionately as T-Rex arms were still as long as a humans) or the backwards facing stump like arms of Carnotaurus these arms were long with highly developed “hands”, displayed in such a way that it seemed like they could either give you a large hug or grab you and carry you away into the night. These arms, discovered in 1965, belonged to a dinosaur known as Deinocheirus mirificus; meaning “terrible hand which is unusual”. Quite a fitting description for a giant pair of arms! This beast lived in Mongolia 70 million years ago during the Late Cretaceous. At the time I first saw this fossil palaeontologists still didn’t really know what kind of dinosaur it was as no other fossils had been found except for the arms. It was a tricky task, how can you build up the image of an animal from just its arms. Imagine trying to construct what a human looked like, how we behaved, what we ate and what our social lives were like from just our arms. From this incredible looking fossil palaeontologists were able to deduce that it was a species of theropod dinosaur, but apart from that it was only guesswork.

That is, until new fossilised material was discovered in 2009 by a team from South Korea’s Institute of Geoscience and Mineral Resources in Kigam, lead by a palaeontologist named Yuong-Nam Lee. These were not only more giant arms, but also two nearly complete skeletons that finally solved the almost 50 year mystery.

It was much weirder than anything my younger self could have imagined. For starters, it was not a vicious giant carnivore like other large theropods such as Giganotosaurus. Instead it was an omnivore, using its duck-like beak to eat vegetation with a helping of small fish on the side. Deinocheirus was a slow, lumbering giant stretching to eleven metres in length, and weighing up to 6 tonnes. To add to the weirdness, it also possessed back spines that may have formed part of a hump like structure on its back, and it may also have even been covered in feathers. The end of its tail bones were fused together into a pygostyle. This same structure is seen today in modern birds and is used to support long tail feathers, so it’s possible that Deinocheirus also had a feathery tail fan! The large arms were probably used to gather out of reach plants closer to its mouth, rather like a giant panda grabbing bamboo, or as a defence against predators, such as the tyrannosaurid Tarbosaurus whose bite marks are seen on the bones. The fossils did confirm that it was a theropod dinosaur and part of the ornithomimids, a group of dinosaurs which also included Gallimimus of Late Cretaceous North America. However Deinocheirus is very bizarre even when compared to other ornithomimids. Other species were smaller, with slender bodies and legs built for speed (not too dissimilar in lifestyle to the modern day Ostrich).

So as it turns out, Deinocheirus is not the terrifying monster that I thought it was when I saw those fossil arms all those years ago. Instead, in looks and lifestyle, it seems like the result of a group of mad scientists genetically splicing a T-Rex, a duck and an ostrich together to see what they get. However this new depiction, in my view, is just as fascinating and awe inspiring, and shows how diverse dinosaurs really were.

The Horrible hands, along with the rest of Deinocheirus!
Image Credit: Johnson Mortimer, https://commons.m.wikimedia.org/wiki/File:Deinocheirus_by_johnson_mortimer-d9npnef.jpg

References/Further Reading

Lee et al 2014 paper, published in the journal Nature, describing new fossil material of Deinocheirus

Lee, Y., Barsbold, R., Currie, P. et al. Resolving the long-standing enigmas of a giant ornithomimosaur Deinocheirus mirificusNature 515, 257–260 (2014). https://doi.org/10.1038/nature13874

An article on National Geographic, written by Ed Yong, on the 2014 study of Deinocheirus that revealed its true form

Yong, Ed “Deinocheirus Exposed: Meet The Body Behind the Terrible Hand”, National Geographic, Oct. 22, 2014, nationalgeographic.com/science/phenomena/2014/10/22/deinocheirus-exposed-meet-the-body-behind-the-terrible-hand/

An article on NewScientist, written by Jeff Hecht, about the re-discovery of a fossil Deinocheirus‘ head and feet, which had been previously smuggled out of Mongolia!

Hecht, Jeff. “Stolen dinosaur head reveals weird hybrid species” NewScientist, May. 12, 2014, newscientist.com/article/dn25551-stolen-dinosaur-head-reveals-weird-hybrid-species/