A Colossal Mistake? De-extincting the dire wolf and the forgotten lessons of the Heck cattle

I am sure you have heard the news. In broad letters on its title page, Time Magazine presented an article in which they proudly declared that the dire wolf is no longer extinct and the same could be true for many new species to come. A biotechnology company called Colossal Biosciences, after having already made “woolly mice” based on the genes of woolly mammoths, claims to have created three dire wolf pups based on ancient DNA, named Romulus, Remus and Khaleesi (more on that particular naming choice later).

This has ruffled a lot of feathers, including mine, in fact so much that it is now bringing this blog back from hibernation. In the wake of this announcement, Time and various other news outlets, as well as social media, have spread some quite blatant misinformation and have not talked nearly enough about the ethical concerns, as well as the questionable conduct of Colossal in how they choose to present, or more accurately, market their projects. Moreover, I think there are many lessons from the past we are forgetting in this hype, for this is not the first questionable attempt at de-extinction and there are some remarkable parallels which bring to mind the cliché adage: Those who cannot learn from history are doomed to repeat it.

These are not dire wolves

First, I think it needs to be clarified that what Colossal has produced cannot be called dire wolves by most measures. The three pups they have made are not clones of dire wolves nor do they have any of the original DNA of that species in them. In fact, it is impossible with current technology to clone a long-extinct animal, because how cloning currently works is that the nucleus of a living donor cell is transferred to a host egg cell. While it is possible to sequence the complete genome of extinct animals like the mammoth from permafrost remains, you cannot actually get that DNA to code again without the intact cell-machinery of a living nucleus. Unless some major technological breakthrough is achieved, the only viable way of de-extinction is therefore to take a modern living animal and edit its genes to resemble the extinct counterpart. This is exactly what happened here. As per the Time article, Colossal took the genome of the modern grey wolf (Canis lupus) and made edits to only 14 genes out of 19’000 in order to create something with a few traits which they think resembles the dire wolf, such as larger size, more muscles and, for some strange reason we will get to, white fur. The resulting embryos were then carried out by surrogate dog mothers. If you have been following the Chickenosaurus project of Jack Horner, all of that may sound familiar to you and said project has received similar criticisms as you will read here. But to give Horner credit where credit is due, he never claimed to directly recreate Tyrannosaurus or Velociraptor but has always been pretty open about how the project would ultimately just result in a new breed of chicken that looks a bit dinosaury.

Fig 1.: A modern reconstruction of Aenocyon dirus (the big dogs feasting on the bison, not the small wolves) made by the great paleoartist Mauricio Anton. The reddish fur colour is in line with our modern recognition that these animals had more in common with jackals and dholes than with wolves.

The pups are therefore not clones, but imitations. Poor imitations at that. Aenocyon dirus has for a long time been thought to be a unique species of wolf, hence the outdated binomial Canis dirus, whose ancestors supposedly immigrated from Eurasia into North America. It has thus traditionally been depicted as a sort of uber-wolf. This old assumption was mainly based on the morphology of the bones. As of 2021, studies based on the genomes extracted from dire wolf bones, ironically the same data that Colossal should have based their work on, have shown a very different picture, which also has potential implications for the life appearance of the animal. They agree that the dire wolf was not a wolf at all, but instead a basal member of the Canini that lies wholly outside the genus Canis (Perri et al. 2021). In more simple terms, jackals and African wild dogs are more closely related to the grey wolf than Aenocyon is. Their last common ancestor lived as far back as 5.7 million years ago. The similarity of Aenocyon to wolves is merely due to convergent evolution and it likely represents a distinct lineage that evolved endemically in the Americas, similar to (though not directly part of) the cerdocyonines, like the South American maned wolf Chrysocyon, which looks more like a cross of a deer and a fox. In short, what this means is that Colossal’s choice of the grey wolf as a base genome is highly questionable. Most other species of canine would have been just as appropriate and some like jackals and dholes would have likely resulted in more accurate-looking results.

The choice of a white fur colour to differentiate the pups from their grey wolf template is also pretty puzzling. Aenocyon dirus is only known from bones, its coloration therefore remains mere guesswork. I have seen Colossal on social media claim that in their genetic research they found white to be the most likely coloration for the species, but they do not seem to have published those findings in any peer-reviewed journal. This is very suspect, because uncovering the coloration of an extinct mammal based on DNA fragments alone would be sure to generate headlines. It generally also does not make sense with what we know about the animal. Yes, Aenocyon lived during the ice ages, but that does not mean it was a permanent tundra dweller living in snowy environments, where white fur is the most advantageous. Fossils of these animals are conspicuously absent from northern latitudes, their northernmost range being southern Canada (Dundas 1999). The most famous locality of the dire wolf are the La Brea Tar Pits and Los Angeles was not a chilly place, even during the Ice Age. Fossils of Aenocyon have even been found as far south as Venezuela and Chile. In general, the animal seems to have preferred environments that resemble the modern American prairie or even the African savannah. Mere logic would therefore dictate that it likely had short fur and more earthy colours to better blend in with the dry vegetation. White, shaggy fur would have made these animals prone to overheating, too conspicuous to successfully sneak upon prey and also would have made them easy targets for other predators, including humans. If Colossal is right, maybe that’s why the dire wolf is extinct… but I think a wholly different aspect than scientific accuracy was chosen in making Romulus, Remus and Khaleesi white, one we will get to later.

Fig. 2: Modern genetic research recovers Aenocyon dirus (here still labelled  Canis dirus) as being outside of the true wolves and actually being intermediate somewhere between Andean foxes, jackals and African wild dogs.

This makes the claim of Beth Shapiro, CSO of Colossal Biosciences, that the pups should be considered dire wolves de facto because they share key anatomical traits, all the more dubious. They simply do not resemble what Aenocyon would have likely looked like. Moreover, Shapiro seems to be using a purely morphology-based approach to the definition of species, as per the Time article. This was what biologists used in the eighteenth century, before evolution or extinction was even known, and has long been supplanted by genetic and phylogenetic approaches to species definitions, as well as Ernst Mayr’s classic biological definition of interbreeding populations. Not even paleontologists, who often cannot work with genetic data, use purely morphological criteria to distinguish species anymore, but use complex cladistic computer-modelling and probability to determine if lineages can be considered distinct enough to warrant different names. I would bet money that if the DNA, skeletons or both of Romulus and Remus were fed into such a cladistic program, they would still be recovered as some type of Canis lupus or at least Canis, not Aenocyon. Speaking of Ernst Mayr, it is important to note that the same studies which recovered Aenocyon as a distinct lineage of American canine also found exactly zero evidence that it ever interbred with members of the genus Canis, once true wolves migrated to the Americas (Perri et al. 2021), showing that they were way too distinct to be able to hybridize. Romulus and Remus, however, still sharing 99.93% of their DNA with their grey wolf template, would no doubt still be able to father viable children with a wolf mother.

The story of the Nazi Mock-Aurochs

The idea of de-extinction is not quite as new as people may think. Ever since the infancy of vertebrate paleontology, people have been obsessed with seeing charismatic megafauna in the flesh again, such as when Thomas Jefferson asked Lewis and Clark to look out for any surviving mastodons on their westward expedition. The idea of using genetic engineering specifically to recreate extinct animals also goes farther back than one might expect, though back then it used to be called good, old-fashioned selective breeding. Beginning in the 1920s, the brothers Heinz and Lutz Heck, living in Weimar Germany, attempted to recreate the extinct aurochs, Bos primigenius, by crossbreeding various types of cattle until they ended up with a breed that they thought looked and behaved sufficiently primitive enough. The original goal was to preserve the memory of the species, because the brothers feared that too many people were mistaking historical mentions of the aurochs with the still-living wisent (the European bison).

Fig. 3: Modern specimens of the Heck cattle.

With the fall of the Weimar Republic and the takeover of Hitler, the project saw support by the Nazi regime. Lutz Heck appealed to them by proposing that the aurochs could be used as an instrument of their Lebensraum-Politik, as rewilding it into the primordial forests of Eastern Europe would, in their eyes, authentically recreate the original primitive homeland of the Germanic people (Driessen & Lorimer 2016). This was not done out of any ecological interest, but rather because the Nazis dreamt of a scenario where their freetime consisted of recreationally hunting aurochs for sport like their ancestors supposedly did. Hermann Göring took an especial liking to the Heck cattle, seeing the aurochs as a symbol of German Urkraft and in a sense using them as tools of colonization during the conquest of Eastern Europe. He released the first specimens in 1938 in his personal hunting range in the Romincka Forest, which is today in Kaliningrad. The next batch was released in 1941 in the Polish Białowieża Forest, after displacing and killing numerous local villagers in order to expand this nature preserve (Driessen & Lorimer 2016). Further plans were only halted by the collapse of the Eastern Front and the advance of the Soviets.

Today, the Heck cattle survive merely as curiosities in some European zoos and wildlife parks. The few Göring specimens that survived the Red Army were all later killed by Polish farmers, due to being aggressive and dangerous. The only wild populations today are documented in the Netherlands and Latvia, where the animals have trouble surviving, due to still being domestic cattle and therefore not being adapted to cope well with winters and wolves. The Heck cattle project has been described by historians as misguided from the very beginning, even before being retooled by Nazi ambitions. The Heck brothers worked off inaccurate and idiosyncratic assumptions of the aurochs’ life appearance and so all experts today do not deem the Heck cattle an accurate reconstruction of the extinct animal (Van Vuure, 2005). Various southern European domestic breeds, especially Spanish fighting bulls, are seen as being genetically and morphologically closer to the aurochs than the Heck cattle ever were. Both ecologically and scientifically they are therefore close to worthless.

Fig. 4.: Graphic showing the notable differences between the extinct aurochs (top) and the modern mock recreation of the Heck cattle (bottom).

I hope some of the parallels are clear here, though the Heck cattle are arguably closer to their intended goal than the Colossal wolves, because domestic cattle are at the very least still direct descendants of the aurochs. The methodology and standards used by Colossal Biosciences in bringing back the dire wolf are really not too dissimilar to what the Heck brothers tried to do. As there is no ancient DNA directly involved in its creation, the phenotype Colossal wanted to create could have theoretically also been produced just as well by selectively breeding grey wolves for desired traits. Gene-editing with CRISPR is simply a faster way to get the same results. And that result would still be an unusual grey wolf, not a resurrected dire wolf. Add to that the fact that, again, said phenotype is not actually accurate to what we know from palaeontological and genetic data, and you are instead very quickly looking at dire consequences.

Granted, Colossal is obviously not as sinister as the Nazis, because they claim that they want to rewild the dire wolf and various other extinct animals, like the mammoth and thylacine, as a form of ecological restoration and also claim this is paying back nature for the negative impact humans have made. But the results would still look the same, even if their “dire wolves” were 100% accurate to the real thing. If Colossal indeed were to rewild a viable breeding population of their mock wolves into the Americas, they would not magically fill out the ecological niche Aenocyon once occupied. That niche simply does not exist anymore. Its whole ecosystem does not exist anymore. The end of the Pleistocene saw the extinction of 35 genera of mammals alone in North America (Faith & Surovell 2009), most of which were megafauna that the dire wolf relied on for its diet. Without recreating that ecosystem, the dire wolves would instead be forced to compete for the same prey animals as regular wolves and coyotes, negatively impacting the ecology of those two species and their prey. Just like the Heck cattle, they would also come into conflict with farmers, hunters and poachers, quickly leading to their second extinction. In the most likely and optimistic case, however, due to their aforementioned genetic similarity, the Colossal wolves would simply bond and interbreed with populations of regular grey wolves, which in turn means that their genome and phenotype would stop being a distinct entity and just become part of the wider grey wolf gene pool.

Similar problems can be imagined for a variety of other hypothetically rewilded extinct animals. What life would a mammoth herd in modern Siberia or Alaska realistically live now that climate change is destroying the permafrost? What ecological changes would such large and destructive animals create that would bring them into conflict with the local humans? What prospects does a thylacine realistically have in an Australia that is now overrun by dingoes, cane toads and, worst of all, Australians?

As per the Time article, in addition to their de-extinction programs, Colossal is also cloning the extant red wolf in hopes of preserving the species and introducing more genetic variety into the population. This is in theory more defensible, but cloned animals are on average much less healthy than regular-born individuals, so in the end this does not seem nearly as effective as regular wildlife preservation methods (such as those employed in preserving the cheetah), which mainly focus on keeping the habitats of the animals intact and free from disturbance, so that genetic variety can recover on its own. This all opens up the question of why even bother? I have various reasons to believe that ecology is not at the forefront of Colossal’s concerns, despite their claims.

Genetic Engineering and Extinct Animals in the Age of Capitalism

I have purposefully not brought up Jurassic Park until now, because it simply is cliché and not really a comparable situation. The story’s Ingen company was at least honest about the fact that their products could not live in the wild without causing major damage to ecology and human life and therefore had to be restricted to an artificial theme park. Instead, I would like to draw attention to another science fiction novel. Authored by Stephen Baxter in 2002 and simply titled Evolution, the book is a retelling of human evolution from the earliest primates in the Cretaceous all the way until the far future. A little creative project on my Patreon is heavily inspired by it, but also written in opposition to its cynical tone. The frame story Baxter uses is that of Joan Useb, a paleontologist from Kenya, and primatologist Alyce Sigurdardottir, who in the year 2031 are invited to a conference in Rabaul, where scientists of many different fields meet to discuss solutions to climate change as well as societal and ecological collapse. There they meet star geneticist Alison Scott, as well as Scott’s daughter Bex, a genetically enriched designer-child with blue hair and orange eyes. During the course of the conference, the following happens:

Alison Scott was talking to the camera. She was a tall, imposing woman. ‘… My field is in the evolution of development. Evo-devo, in tabloid speak. The goal is to understand how to regrow a lost finger, say. You do that by studying ancestral genes. Put together a bird and a crocodile and you can glimpse the genome of their common ancestor, a pre-dinosaur reptile from around two hundred and fifty million years ago. Even before the end of the twentieth century one group of experimenters were able to “turn on” the growth of teeth in a hen’s beak. The ancient circuits are still there, subverted to other purposes; all you have to do is look for the right molecular switch…’

Joan raised her eyebrows. ‘Good grief. You’d think it was her event.’

‘The woman’s work is show business,’ Alyce said with cold disapproval. ‘Nothing more, nothing less.’

With flourish, Alison Scott tapped the box beside her. One wall turned transparent. There was a gasp from the pressing crowd – and, beyond that, a subdued hooting. Scott said ‘Please bear in mind that what you see here is a generic reconstruction, no more. Details such as skin colour and behaviour have essentially had to be invented…’

‘My God,’ said Alyce.

The creature in the box looked like a chimp, to a first approximation. No more than a metre tall, she was female; her breasts and genitalia were prominent. But she could walk upright. Joan could tell that immediately from the peculiar sideways-on geometry of her hips. However right now she wasn’t walking anywhere. She was cowering in a corner, her long legs jammed up against her chest.

Bex said, ‘I told you, Dr. Useb, you don’t have to go scraping for bones in the dust. Now you can meet your ancestors. 

Despite herself, Joan was fascinated. Yes, she thought: to meet my ancestors, all those hairy grandmothers. That is what my life’s work has really been all about. Alison Scott evidently understands the impulse. But can this poor chimera ever be real? And if not- what were they really like?

Bex impulsively grasped Alyce’s hand. ‘And, you see?’ Her crimson eyes were shining. ‘I did say you didn’t have to be upset about the loss of the bonobos.’

Alyce sighed. ‘But, child, if we have no room for the chimps, where will we find room for her?’

The mock australopithecine, terrified, bared her teeth in a panic grin. (Baxter 2002, p. 285 – 286)

A mock Australopithecus is more outrageous than a mock Aenocyon, but we are seeing today basically the same situation play out in real life. Just like the unfortunate ape, there is no place or chance for the wolf pups to live outside of an artificial environment. This is outright admitted in the Time article: Due to the way they had to be raised, the “dire wolves” and even the cloned red wolves do not actually know how to survive in the wild and are therefore destined to live out their fate in captivity. How the company plans to solve this obvious problem to their rewilding efforts, I have not been able to deduce. The sole reason these organisms exist for now, and maybe forever, is for showmanship. In the story, Alison Scott uses the modified chimpanzee merely to showcase the versatility of her genetic research, with the main purpose being to modify humanity itself into a new species capable of withstanding all of the current troubles (with a sinister hint that she maybe intents to divide our species into castes to stop social unrest, à la Brave New World). Colossal does something similar by proposing genetic de-extinction as an easy solution to all of the current ecological problems we are facing. It is no big deal that the red wolf is critically endangered, we can just clone it back. It is no big deal that the quoll is going extinct due to cane toads, we can just make them resistant to the amphibians’ poison. It is not too dissimilar from tech bros proposing that general AI, libertarianism or Mars colonization will be our saviours, despite all of these also being just pipedreams. The modern world is facing complex problems that cannot be solved with a holy grail, they all require a coordinated group-effort on multiple fronts. Often, private companies are actually opposed to such efforts, because it means they cannot have the monopoly on selling you the solution to the problem that the system they inhabit has caused. A snake oil salesman would rather you buy his homeopathic globuli for your cancer rather than you undergoing surgery.

In my view, it is all just marketing, aimed to generate financial support from shareholders and a public easily wooed by headlines. Marketing using living designer organisms. This is especially obvious by Colossal’s social media presence. Did you know that they have a Reddit account? And that account is the moderator of r/deextinction? A day ago, said account posted this image on r/gameofthrones:

Fig. 5.: "George RR Martin said we could post this here—the Colossal dire wolves sitting on the Iron Throne", the image caption reads. I see how it is George, you'd rather let ethical horrors beyond human comprehension happen in your name before finishing Winds of Winter.

I do not know about you, but I find it very concerning to see these supposedly scientifically important organisms, merely a few months old, being used for a kitschy photoshoot meant to generate online clicks and upvotes due to the association with a popular TV show. It is no less gut-wrenching than a mock australopithecine cowering in a glass box for all eyes to oggle at. But now so much makes sense. Why one of the pups is named Khaleesi, why they used grey wolves as the genetic template, why they made their fur white. They did not want to create real Aenocyon dirus. They wanted to make something people would recognize from Game of Thrones, where the dire wolves are portrayed by CGi-enhanced Utonagan dogs and where the most prominent individual, Jon Snow’s pet Ghost, is white. In this sense, and really only in this instance, Colossal is really pulling a Jurassic Park, but in particular the one scene from Jurassic World where Dr. Wu admits: “You didn’t ask for reality, you asked for more teeth.”

There are two ways to frame this story. The most charitable is that Colossal is truly concerned about wildlife preservation and that projects such as the red wolf cloning are the main focus. In this case, all that marketing circus around de-extinction is a way to keep shareholders interested and keep funds flowing into the actually important projects. But this would still be at the ethical expense of creating organisms merely for marketing stunts that can afterwards not live out an authentic life. All in service of a capitalist hellscape that does not see inherent value in ecology.

The more cynical view is that the de-extinction truly is the main (and vain) focus, which makes it even more questionable what the point is, seeing, as we have discussed, that there is no realistic prospect of these animals being successfully reintroduced into the wild. Seeing all the “brand synergy” with Game of Thrones, the obvious appeal the company wants to make to nerd culture and remembering the story of the Heck cattle, one fears more sinister motives. Just like the Nazis wanted a formidable hunting target in form of the aurochs, could you not as easily see Colossal in the near future try to sell their mock dire wolves as exotic pets to rich nerds? You can already imagine the marketing lines: “Get your own Ghost! Feel like a true Stark! Winter is coming!”

They would make fine additions to chickenosaurs, woolly mice, quollacyines, dovedodos and whatever else may be cooked up in the lab that will resemble actual prehistoric life about as much as David Peters reconstructions. Pugs and chihuahuas will look quaint in retrospective, we are maybe about to see the new age of GMO pets as living accessories and commodities shaped solely to chase pop culture and social media trends.

If you liked this and other articles, please consider supporting me on Patreon. I am thankful for any amount, even if it is just 1$, as it will help me at dedicating more time to this blog and related projects. Patrons also gain early access to the draft-versions of these posts and my art.

Related articles:

• What really are the Jurassic Park Raptors supposed to be?

References:

• Baxter, Stephen: Evolution. A novel, London 2002.
• Driessen, Clemens & Lorimer, Jamie: Back-breeding the aurochs. The Heck brothers, National Socialism and imagined geographies for nonhuman Lebensraum, in: P. Giaccaria and C. Minca (Hrsg.): Hitler’s Geographies. Chicago 2016, p.138-157.
• Dundas, Robert: Quaternary records of the dire wolf, Canis dirus, in North and South America, in: Boreas, 28, p. 375 – 385.
• Faith, Tyler & Surovell, Todd: Synchronous extinction of North America's Pleistocene mammals, in: Proceedings of the National Academy of Sciences of the United States of America, 106, 2009, p. 20641–20645.
• Kluger, Jeffrey: The Return of the Dire Wolf, in: Time Magazine, April 7, 2025.
• Perri, Angela; Mitchell, Kieren; Mouton Alice; et al.: Dire wolves were the last of an ancient New World canid lineage, in: Nature, 591, 2021, p. 87 – 91.
• Van Vuure, Cis: Retracing the Aurochs. History, Morphology and Ecology of an extinct wild Ox, Chicago 2005.

Image sources:

• Fig. 1: National Geographic
• Fig. 2.:  Perri et al. 2021.
• Fig. 3.: Wikimedia
• Fig. 4.: Wikimedia   
• Fig. 5.: This Reddit post
  

Classic Paleoart but with Donkey Kong 64 music

Classic Paleoart but with Donkey Kong Country 3 music

 

Classic Paleoart but with Donkey Kong Country 2 music

 

Classic Paleoart but with Donkey Kong Country Music

 

The Amazing Diversity of Swiss Ichthyosaurs

An ichthyosaur, drawn by me, originally for my book. Based on Ichthyosaurus communis, which was originally thought to have lived in Switzerland, but the specimen in question is now more likely to have been Protoichthyosaurus, which had a noticeably upward-curved lower jaw..

 

Well, it has finally happened. I am now a co-author on a peer-reviewed paleontological paper. I guess you could say I am something of a scientist myself now. The paper in question is Swiss Ichthyosaurs: a review, published in the Swiss Journal of Paleontology, headed by Christian Klug and co-written by six other authors. 

It is open access and can be read Here.

The following images and information are all taken from the paper.

Fig. 1 of the paper, showing the phylogeny of the Ichthyosauria and where Swiss specimens can be placed on the family tree. As you can see, Swiss ichthyosaurs come from almost all major points of the whole clade.

It is pretty much what the title says: A comprehensive view of all notable ichthyosaur material that has been found over the centuries in Switzerland. While most of this is a compilation of already existing literature, we were also able to incorporate brand new data and assessments, including a new genus that was described just this year, and reclassify some questionable taxa. We also included state-of-the-art photos and illustrations of important specimens, so this paper should prove to be a major anchoring point in all future research on the topic. My main contribution to this paper were the making of initial taxa-lists, compiling literature on the topic and researching the history behind some of the specimens.

Geographic distribution of ichthyosaur finds in Switzerland.

The important results of this review are that Switzerland truly was an ichthyosaur country. Multiple species and specimens from all three periods of the Mesozoic are known across the country, from almost all the major families of the clade, including members which sat at important points of evolutionary transition.

Triassic

The greatest diversity of Swiss ichthyosaurs is found in the Middle Triassic, thanks largely to the famous Konservat-Lagerstätten of Monte San Giorgio. Among the taxa we recognize on a named basis are:

• Wimanius odontopalatus
• Mixosaurus cornalianus
• Mixosaurus kuhnschnyderi
• Phalarodon sp.
• Cymbospondylus buchseri
• Besanosaurus leptorhynchus

 

Skeletal of Mixosaurus cornalianus, by Beat Scheffold.

 

These can be grouped into three types: Phalarodon and Mixosaurus are small, streamlined and fast swimmers, already very suggestive of the ichthyosaur types that would become prominent in the Jurassic. Soft-tissue preservation has shown that Mixosaurus already possessed a prominent dorsal fin, something that paleoartist Beat Scheffold told me he has already speculated on before it was even discovered. Besanosaurus and possibly Wimanius were shastasaurids, which were giant ichthyosaurs, albeit with long, slender snouts, possibly adapted towards sucking up cephalopod prey. Cymbospondylus was a large marine predator, likely hunting fish and other reptiles of the time. The specimen from Monte San Giorgio is a 6m long juvenile. Based on what we know from other Cymbospondylus species, adults may have grown up to 17 metres long.

Skeletals of Cymbospondylus (top) and Besanosaurus (bottom), by Beat Scheffold.

Among the specimens that cannot be clearly identified are also an indeterminate mixosaurid and shastasaurid from Laufenburg and Schleitheim respectively and, more importantly, gigantic teeth, ribs and vertebrae from shastasaurids in the Kössen Formation of Kanton Graubünden. These bones have become quite famous, as their size is suggestive of animals that may have grown up to (maybe even exceeding) 20 metres in length, making them possibly some of the largest marine reptiles of all time.

Jurassic

The end of the Triassic saw the extinction of many of the more archaic forms and the proliferation of the remaining clades of the Neoichthyosauria, mainly Parvipelvia. Most of the Swiss specimens come from the Early Jurassic of the northern part of the country. These are:

• Protoichthyosaurus cf. applebyi (formerly identified as an Ichthyosaurus communis)
• Temnodontosaurus sp.
• Eurhinosaurus longirostris
• Hauffiopteryx typicus (formerly identified as a Leptonectes tenuirostris)
• Stenopterygius sp.

Hauffiopteryx material from the Unterer Hauenstein (Solothurn). Note the very large orbit and scleral rings.

Stenopterygius sp. from Teysachaux in Kanton Fribourg.

Again, there is an interesting diversity of forms here. Protoichthyosaurus and Stenopterygius can be imagined as fairly “standard” ichthyosaurs, meaning compact, fast swimmers that likely hunted fish and cephalopods. Temnodontosaurus on the other hand was a very large (up to 15 metres in length) predator of other marine tetrapods, likely filling out the role previously occupied by forms like Cymbopospondylus and later the pliosaurs and mosasaurs. Eurhinosaurus and Hauffiopteryx meanwhile were more specialized beasts. Eurhinosaurus is quite famous for the length of its upper jaw exceeding that of the lower one, readily inviting comparisons to modern swordfish and spearfish (the extinct whale Eurhinodelphis, funnily enough also known from Switzerland, had the same configuration too). It has become doubtful, however, if Eurhinosaurus used its long snout to strike at fish like a marlin. It may have instead used it to probe sediments for burrowing invertebrate prey. Hauffiopteryx was an elongated parvipelvian with ridiculously huge eyes, suggesting perhaps an adaptation towards deep waters or nocturnal activities. The odd thing about this specimen’s taphonomy is that its snout was vertically piercing through three ammonite zones, which would suggest that it somehow died while ramming head-first into the ground, almost like a scene from the Looney Tunes. 

Skeletal of Argovisaurus, by Beat Scheffold. The name refers to Argovia, a latinization of Aargau, while the species name honors Marta Fernandez, known for her work on marine reptiles.

From the Middle Jurassic of Aargau is instead known Argovisaurus martafernandezi, a basal ophthalmosaurian with a 1.3 metre-long skull. It was first described just in March of this year! The only notable specimen from the Late Jurassic of Switzerland is one dubbed the “Bornsaurier”, a platypterygiine from Solothurn whose genus cannot be conclusively determined but was probably something similar to Brachypterygius/Grendelius. The remains of this animal sat in the Naturmusem Olten since 1905, where they had originally been mislabelled as belonging to a marine crocodylian (thalattosuchian). Otherwise known from the Late Jurassic are only a few indeterminate ophthalmosaurians.

Cretaceous

No clearly identifiable taxa of ichthyosaurs are known form the Cretaceous of Switzerland. This may be both due to the depositional environment, local ecology as well as the fact that ichthyosaurs were slowly losing diversity during this time, until eventually going extinct on their own in the Cenomanian.

Vertebra of a Cretaceous ophthalomsaurine from La Presta in Kanton Neuchatel.

However, we do still know that ichthyosaurs lived here during this time thanks to isolated teeth and vertebrae, which come from the Aptian of St. Gallen and Neuchatel. These were historically assigned to Platypterygius, but are not further identifiable than as indeterminate ophthalmosaurians.

Deleted Bits: Mystery Marine Reptiles

One part of my research did not make it into the final publication, but that decision was fairly reasonable, as it did not really relate to ichthyosaurs but rather to other marine reptiles of the time, namely plesiosaurs. From historical records of the 19th century are known three rather mysterious specimens of marine reptiles which have not been examined again since their original description. My original hope in including these in early drafts of the paper was that this could spark future research on these neglected specimens, which may uncover new species and insights into the Cretaceous marine reptile diversity of the country. This is especially important as, compared to ichthyosaurs, the record of plesiosaurians in Switzerland is exceedingly rare. At least mentioning them here in this blogpost may have the same effect and perhaps I will do the necessary research myself somewhen in the future.

Some of the following information was gathered through personal communication with Dr. Adam S. Smith of the Plesiosaur Directory, to whom I am very thankful.

«Polyptychodon sp.» 

• Location: Sainte-Croix (Waadt)

• Time: Early Cretaceous, Hauterivian («Middle Neocomian» in sources)

• Remarks: A single tooth. Polyptychodon is regarded today as a nomen dubium, which is why all that can be said about this specimen is that it likely comes from an unknown pliosaur of the type Pliosaurus or Kronosaurus. That pliosaurs lived in Switzerland is well known, thanks to a humerus from Brugg. The original tooth was housed in the private collection of Gustave Campiche.

• References: Pictet & Campiche 1860, Jaccard 1869.

«Plesiosaurus neocomiensis» 

• Location: Sainte-Croix (Waadt)

•  Time: Early Cretaceous, Hauterivian («Early to Middle Neocomian» in sources)

•  Remarks: Known from two neck vertebrae, three dorsal vertebrae, rib bones, hips and a jaw fragment. Pictet and Campiche classified these in a new species “Plesiosaurus neocomiensis”, but were open to discuss the possibility that the bones from the early and middle Nèocomien may respectively be separate species. Casts of these bones were presented by Campiche in 1866 at the Natural History Museum of London (the lectotype is in the NHM database). In the following years additional British fossils were added to this taxon. Said British specimens were then however reassigned by Richard Lydekker and Per Ove Persson to Cimoliasaurus cantabrigensis, who also rejected Plesiosaurus neocomiensis as a valid taxon. The Swiss specimens were ignored during this reassessment, which leaves them in an interesting taxonomical limbo. Obviously, they cannot be actual Plesiosaurus, as that is a genus from the Early Jurassic that was sometimes used as a wastebasket taxon, but they likely are also not Cimoliasaurus (Smith, pers. comm.). A new examination could therefore be fruitful. Either Campiche’s bones cannot be further identified than Plesiosauria indet. or there may be a chance here to uncover a brand new taxon native to Switzerland. The original bones were in Campiche’s collection and should therefore be traceable to a modern museum collection in Vaud.

• References: Pictet & Campiche 1860, Jaccard 1869, Persson 1963.

«Mosasaurus grosjeanni» 

• Location: Court, Bern

• Time: Late Jurassic, Kimmeridgian

• Remarks: A large tooth found by a pastor named Grosjean at the Mont-Girod. Greppin described it as a contemporary and “imitator” of “Megalosaurus meriani” (today the sauropod Amanzia greppini), by which he seems to have simply meant that it was a large, predatory reptile. Greppin’s original classification as a mosasaur is surely wrong, as those do not appear until the Late Cretaceous. Possible bearers of the tooth may have been large plesiosaurs/pliosaurs, marine crocodylians or perhaps even an ichthyosaur. Teeth of large theropod dinosaurs are also known from the Kimmeridigian of Switzerland.

• References: Greppin 1867, Heer 1883.

References:

• Greppin, Jean-Baptiste: Essai géologique sur le Jura suisse, Délémont 1867.
• Heer, Oswald: Die Urwelt der Schweiz, Zürich 1865 (2. Ausgabe 1883).
• Jaccard, A.: Description du Jura Vaudois et Neuchatelois, in: Matériaux pour la carte géologique de la Suisse, 6, 1869, S. 1 – 340.
• Persson, Per Ove: A Revision of the Classification of the Plesiosauria with a Synopsis of the Stratigraphical and Geographical Distribution of the Group, in: Lunds Universitets Arsskrift, 59, 1963.
• Pictet, François Jules; Campiche, Gustave: Matériaux pour la Paléontologie Suisse, 1860.