What Sea Dragons Ate: Plesiosaur Diets Revised
An overzealousNakonanectes bites off more than it can chew. Art by Tosha Hollmann
By Tosha Hollmann, Christian Halliwell, and Elisandre Ardeo
Among the very first fossils to have been scientifically studied and recognized as belonging to extinct animals are the enigmatic plesiosaurs, withPlesiosaurus itself having been described based on fossils found by Mary Anning in December of 1823. Since that time, plesiosaurs have remained a source of continuous intrigue and fascination for both paleontologists and the general public alike. Their bones are so unlike anything we know today that it has always been a struggle to understand what these animals could have been like in life. Early artist depictions such as those of Thomas Hawkins strikingly envisioned them as voracious sea monsters, dragons, creatures of the Devil. Over the last two centuries, we have managed to slowly gain a much more complete understanding of the animals that they once were. They evolved a truly novel body plan and swimming style, which has not been replicated by any other aquatic vertebrate before or since. They were wildly successful, dominating the Mesozoic seas for nearly 140 million years, coexisting with and often outlasting numerous other groups of marine reptiles. We have uncovered fantastically preserved fossil specimens, many providing nearly complete skeletons, and some even showing the remnants of their organs, skin, and body shape.
Even so, there are still many gaps in our knowledge of plesiosaurs. And by far among the most poorly understood aspects of plesiosaur biology is their diet. Most plesiosaurs, with the exception of the apex-predatory pliosaurs (which are a topic of their own, and will not be discussed in this post), have long been seen as slow-moving, specialist predators of small fish or belemnites due to their proportionately small heads and interlocking teeth; their characteristic long necks suggested to be an adaptation for catching small and swift prey unawares while the rest of the body was far away. This concept has over time become heavily entrenched in both science and popular culture’s views of these animals, to the point that their ecology is often not discussed much further. However, in recent years, increasing evidence for the diet of plesiosaurs has come to light, including preserved stomach contents and bite marks on the bones of their prey, as well as more detailed studies into the implications of their anatomy.
Microcleidus displaying typical plesiosaur behavior…Or is it? Art by Tosha Hollmann
While the total body of evidence for plesiosaur diet remains quite small, some of these discoveries are increasingly painting an intriguingly different image of these animals to the prevalent view of them as specialist fish eaters. Many of these specimens are quite obscure and have been heavily overlooked. This post will provide a synthesis of what is known about the diet of non-pliosauroid plesiosaurs, and highlight how this impacts our understanding of these remarkable animals and their role in the ecosystems they were a part of. It will also establish how the concept of the small-fish specialist plesiosaur has over time become a persisting paleomeme, and why pigeonholing all plesiosaurs indiscriminately as such is not representative of the sheer diversity the fossil record is revealing.
Jurassic Dragons
The cryptoclididTricleidus capturing aSpathobatis ray. Illustration by Tosha Hollmann.
Some of the earliest plesiosaurs to appear in the fossil record are iconic plesiosauroids of the Early Jurassic Lias group, such asPlesiosaurus dolichodeirus andMicrocleidus homalospondylus. Considering these are some of the first extinct taxa to ever be formally described their historical significance cannot be understated. Despite this, research has been comparatively stagnant since their initial discovery in the 19th century. Fortunately the taxa are known from nearly complete skeletal remains excluding the rarely preserved fragile crania. These early plesiosaurs in many ways fit well the mould of the stereotypical plesiosaur, with long necks and small heads with small needle-like teeth. Unfortunately, we can only speculate on their dietary ecology as no gastric contents have yet been reported or published on for these animals. Considering their small size (about four metres in length) and needle-shaped teeth, it’s quite likely they did indeed feed upon smaller fish, and indeedMicrocleidus in particular shows what may be an intriguing specialization to this behavior. In contrast to the odd, upward staring eyes of most plesiosaurs,Microcleidus has forward facing orbits and binocular vision, which would have enabled it to better judge distance of fast swimming prey.
Later on in the Jurassic, these early plesiosaurs are displaced by a group known as cryptoclidids. These were an incredibly successful group, ranging from the Middle Jurassic up to the Early Cretaceous and known from most continents. Permanently etched into popular culture by the appearance inWalking With Dinosaurs,Cryptoclidusitself has become to many people the image of the generic plesiosaur. And it does indeed fit well with the traditional image of a plesiosaur, as this taxon, with its jaws lined with slender, interlocking teeth, is generally considered to have fed primarily on small and slippery prey such as fish. As a consequence, other cryptoclidids are often assumed to have been much the same, but in reality they show a great deal of diversity, and not all from this clade would have such stereotypical diets. A dramatic illustration of this may lie in the Middle Jurassic rocks of Switzerland. Numerous long, gutter-like furrows, some up to nine metres in length, formed along what was then seafloor. Similar traces are also known from Spain, dating to around the same time. These bizarre marks have been interpreted as feeding traces caused by marine reptiles, showing an animal sifting through the sand for crustaceans or other benthic animals.
A photograph of the gastroliths of an elasmosaur. Image from Oceans of Kansas.
The traces themselves cannot be referred to plesiosaurs specifically over other contemporary marine reptiles, such as ichthyosaurs, however there is further evidence to support the idea that plesiosaurs were utilizing benthic resources in this way. Plesiosaur stomach contents frequently contain gastroliths, or stomach stones. These stones have been reported from specimens of plesiosaurs from all manner of different lineages and likely also of very distinct ecologies, from cryptoclidids to elasmosaurs and polycotylids. This of course raises the question of just what it is plesiosaurs were doing with these gastroliths, and why consuming them was so important even for such disparate species. Several hypotheses have been put forth to explain their presence. Some believe that the gastroliths’ purpose was to aid in controlling buoyancy when swimming, others than gastroliths functioned primarily to break up food. The reality may be a bit of both, but as it goes, their true function is still a matter of uncertainty. What is clear though, is that these stones demonstrate that plesiosaurs were consuming objects from sediment, both from the seafloor and indeed in some cases from freshwater rivers and streams.
Expanding upon this, the morphology of some plesiosaur taxa may provide further support to this idea. The arctic plesiosaurOphthalmothulefrom the Agardhfjellet Formation of Svalbard is by all counts a very strange animal, with gigantic orbits suited towards a lifestyle in low light conditions of the polar seas and extremely slender teeth which protrude almost sideways from its jaw. Additionally, calculations of the mechanical advantage of its jaws indicate that it would have had a rather weak bite force. Seemingly ill suited to catching more abrasive food items like fish,Ophthalmothule instead appears to have been adapted for capturing small, soft-bodied prey items. The bizarre, protruding teeth also bear some resemblance to the condition seen in a highly unusual group of elasmosaurs known as the aristonectines, which will be discussed later in this post. As several of these aristonectines are suggested to be specialist benthic feeders, it seems likely that accordinglyOphthalmothule may too have been a benthic hunter. This is further supported by wear facets preserved on its teeth, which could be caused by a tight fit between the teeth or by abrasive sediment wearing into them as the animal fed. Many of these features are also shared to varying degrees with the relatedSpitrasaurus, known from earlier sediments in the same area, which could suggest an ongoing lineage that was specializing increasingly into this mode of feeding.
AnOphthalmothule foraging for food in the polar sponge reefs of Svalbard. Art by Tosha Hollmann.
However, it would appear that some cryptoclidids were feeding on much larger things. Some of the best dietary evidence for these plesiosaurs comes from the Sundance Formation of Wyoming. During the mid-Jurassic, this region was part of a shallow, inland seaway, known as the Sundance Sea. Though not as well studied as some of the more famous contemporary European formations, such as the Oxford Clay, the Sundance is already known to have been home to a number of marine reptiles, and some specimens have even been preserved with stomach contents, including those of two cryptoclidid plesiosaurs. Firstly, a specimen ofPantosauruswas discovered with an embryonic ichthyosaur as stomach contents, which implies either that it came across a random voided embryo or scavenging of the carcass of a pregnant ichthyosaur, resulting in consumption of the embryo. This is also the only known evidence thus far of predation upon ichthyosaurs by non-pliosaurid plesiosaurs.
The bizarreTatenectes, also from the Sundance,on the other hand was found with hybodont teeth and spines as stomach contents implying it was capable of hunting sharks. Although the hybodont in question was relatively small (~40cm), this is still fairly impressive consideringTatenectes itself is only around three metres in length, making the shark significantly larger than the plesiosaur’s head and accordingly much bigger than what such an animal would generally be thought to consume. Despite their apparent ecological diversity the cryptoclidids would eventually go extinct during the early Cretaceous. The combined effort of climate fluctuations with rising and falling sea levels forced this group to go extinct, allowing other, much weirder, plesiosaurs to take their place.
Lords of the Shallows
APolycotylus in pursuit of aHesperornis. Art by Tosha Hollmann.
In stark contrast to the cryptoclidids, the short necks and large, elongate skulls of the leptocleidians make them look superficially like miniature pliosaurs, however they are actually closer to cryptoclidids and elasmosaurs than to any true pliosaur, making them a remarkable example of convergent evolution. They were a highly successful group, being present in shallow seas and brackish and freshwater environments around the world for the majority of the Cretaceous. They include two different plesiosaur families, the widespread but comparatively poorly understood Leptocleididae and the more common Polycotylidae. The leptocleidids are an interesting topic in their own right, as many of them seem to have had a strong preference for brackish lagoon and freshwater environments, but unfortunately we do not have much direct evidence for what it is that these animals ate.
By contrast, we do have direct dietary information for the other group of leptocleidians: the polycotylids (though still limited to only a couple of specimens). Made famous in popular culture by the 2007 IMAX filmSea Monsters,Dolichorhynchops more than any other is the animal which has most informed the general view of polycotylid plesiosaurs. Known from four species spanning more than 20 million years, this was a highly successful genus in the shallow Western Interior Seaway that filled central North America during the Late Cretaceous. The distinctive long, slender, gharial-like jaws ofDolichorhynchops and other related polycotylids have largely been seen as evidence that they were specialist predators of small, swift fish and cephalopods. This kind of lifestyle is quite strongly correlated among living animals with similarly slim jaws, so this would appear to be a rather reasonable conclusion to draw. As well as this, a 1998 thesis by Elizabeth Nicholls documents a specimen ofDolichorhynchops bonnerifrom Manitoba which contained teeth belonging to the aulopiform fishApateodus as a gastric residue, which provides further support to this notion.
However, a remarkable specimen of the marine birdHesperornis, described in 2016, tells a rather different tale. The tibiotarsus (shin bone) of the bird bears a series of tooth marks, caused by an attack from a marine reptile. Bite marks from marine reptiles are not uncommon in the fossil record, but the vast majority of those known from the Late Cretaceous of North America have been attributed to mosasaurs, which occupied most of the large predatory niches in marine ecosystems at the time. The teeth of mosasaurs, however, did not match the spacing of the tooth marks on theHesperornis, nor did those of large predatory fish likeXiphactinus which were also around at the time. By contrast, the spacing perfectly matched the jaws of a smallDolichorhynchops. Even more intriguing, the specimen shows that the injuries had healed and slightly stunted the growth of the bone on that side. This indicates that theHesperornisin question was likely attacked when younger, but managed to escape and then grew to skeletal maturity before dying of unrelated causes. Additionally, an overgrowth of bone around the joint is also evidence that the injury eventually led to the development of osteoarthritis in the bird’s leg.
Photo of a false gharial taken by Zig Leszczynski.
This specimen indicates that in spite of the slender jaws ofDolichorhynchops as well as stomach contents proving predation on fish, these animals may not have been as restricted in their dietary preference as is generally imagined. Rather than being specialist piscivores like gharials, this situation more strongly parallels that observed in the extant crocodylian genusTomistoma, also known as the false gharial. LikeDolichorhynchops,Tomistomahas very elongate and slender jaws, and accordingly was believed in the past to be a specialist predator of small fish. Yet in recent years, increasing evidence has come to light demonstrating that false gharials predate not only upon fish, but also on a variety of larger animals, such as monkeys, deer, domestic cattle, and even, in some rare instances, humans. This generalist ecology is further supported by a polycotylid specimen from Hokkaido which features the jaws of several ammonites in its stomach contents. The ammonites in question are estimated to have been small in size and possibly swallowed whole by the plesiosaur.
Of further interest of note is that polycotylids are also less homogenous in terms of their morphology than may often be realized. While many of them do indeed have generally similar proportions and skull shape toDolichorhynchops, there are several outliers. Particularly among the earlier polycotylids, as opposed toDolichorhynchops and its relations which were among the latest surviving members of the group, there seems to have been a lot more evolutionary experimentation in morphology. This may also indicate that early polycotylids filled a greater variety of niches than the latest forms, epitomized by taxa such asEdgarosaurus, which has extremely robust jaws and teeth in comparison to other polycotylids and may have been focusing on larger bodied prey items in general, andThililua, which has a much longer neck than those of the rest of its group.
The Last of a Dynasty
The early elasmosauridLagenanectes seizing a sea star from the seafloor. Art by Tosha Hollmann.
Finally we come to perhaps the most iconic plesiosaurs of all, the elasmosaurs. Elasmosauridae is one of the longest lived and most diverse groups of plesiosaurs known, lasting from around 130 million years ago all the way until the abrupt end of the Cretaceous 64 million years later. In spite of their apparent diversity as well as their extreme success on a global scale, elasmosaurs in particular are subject to several persisting misconceptions. Most relevantly to the subject of this post, they are often all (with the exception of the remarkably odd aristonectines) lumped indiscriminately into the fish specialist barrel without much further regard for the differing ecologies that seem to have been present within the group. Fortunately, and unusually by plesiosaur standards as you may have noticed by now, there are actually numerous specimens of elasmosaurs with preserved stomach contents. Much of this evidence, however, is remarkably obscure and not well known among paleoartists or those otherwise interested in paleontology.
It is important to recognize that there are in fact several different lineages within the Elasmosauridae, and that elasmosaurs are not at all monotonous in their anatomy and by extension would not all be the same ecologically. The most famous of these lineages, and the ones which most people think of when they picture an elasmosaur, are the styxosaurines. This is the predominant elasmosaurid group known from the Late Cretaceous Western Interior Seaway of North America, and curiously there does not seem to be much evidence for their presence anywhere else. The styxosaurines include some of the largest and most well known genera of elasmosaurs, such asStyxosaurus,Albertonectes, and of courseElasmosaurusitself. These animals took the already extremely elongate necks of elasmosaurs to new levels, withAlbertonectes in particular having the longest neck among plesiosaurs, nearly seven metres in length and comprised of a record 76 vertebrae, the highest number known for any animal.
One of the best-known insights into elasmosaur diet comes from a nearly complete specimen of the extensively studied taxonStyxosaurus snowii. This specimen, uncovered in the Sharon Springs Member of the Pierre Shale of Kansas, preserves the remains of numerous small teleost fish in its stomach contents, including the genusEnchodus. Additional evidence for predation of small fish by elasmosaurs is provided by the only known specimen ofElasmosaurus, which also contains the remains of numerous teleost fish. Another specimen from South Dakota, described in brief by Barnum Brown in 1904, similarly contains “great numbers” of fish vertebrae. All of these specimens taken as a whole seem quite consistent with the idea that small fish comprised a significant portion of styxosaurines’ diet. However, Brown’s specimen also provides a far more curious clue to elasmosaur behaviour. In addition to the fish vertebrae, its stomach contents also contain seven of the heteromorph ammoniteScaphites and “several pterodactyl bones, broken in small sections”. The identity of the pterosaur in question is not remarked on further, however the only pterosaur which is documented from the Pierre Shale thus far isPteranodon sternbergi, which makes this a likely candidate.
Skeleton ofElasmosaurus, a classic example of a styxosaurine. Photo by University of British Columbia.
The presence of pterosaur material is certainly not consistent with the traditional idea of elasmosaurs, and indeed neither are the ammonites. Even more tantalizing, however, is a brief, obscure reference to yet another Pierre Shale elasmosaur specimen in the 1872 volume of the Proceedings of the Academy of Natural Sciences of Philadelphia, which was in the possession of Edward Drinker Cope. The elasmosaur in question is remarked by Cope to represent a new species, which he refers to as being most closely related toElasmosaurus platyurus. Discovered beneath the vertebral column of the plesiosaur were several vertebrae of a small mosasaur (which Cope believed to belong to the genusClidastes). It is noted that the vertebrae of the mosasaur were “about three-quarters the length and one-fourth the diameter of those of the plesiosauroid”, suggesting that the mosasaur would have been a reasonably large prey item for the elasmosaur, and certainly larger than many of the other animals styxosaurines are known to have consumed. So in spite of the overwhelming prevalence of fish in styxosaurine stomach contents, this specimen, as well as the fragments of pterosaur bones present in Brown’s elasmosaur, suggest that styxosaurines were likely more generalist than often thought. Further support for this idea may also come from an upcoming study on the feeding ecology of the mosasaurs of the Bearpaw Formation by Femke Holwerda, which finds that the isotope values ofMosasaurus missouriensis, a taxon known to have been predating fairly large prey items, are very similar to those of elasmosaurs.
Outside of the Styxosaurinae, there is much less direct evidence available. For some time all there was to go on was a specimen of the American elasmosaurThalassomedon, found with fragmented ammonite shells in the stomach region, which seems fairly consistent with the stomach contents of the later styxosaurines of the same region, as well as an undescribed elasmosaur from Japan which was found with the beaks of vampyromorph octopods inside its rib cage. However, a more recent discovery of even older elasmosaurs has surprising implications for the diversity of elasmosaur diet. Two partially articulated Aptian-Albian aged elasmosaurid specimens from Australia collected by the Queensland Museum were reported by McHenry et al. in 2005, both of which contain the remnants of the animals’ stomach contents. These specimens were not referred to any genus in particular, however bothWoolungasaurusandEromangasaurus are known to have inhabited Australian waters around this time frame. Their stomach cavities included a diverse array of numerous prey items, with the younger of the two, from the Albian Allaru Formation, containing the intact carapace of a decapod crustacean, as well as more fragmentary crustacean remains and an isolated fish scale.
The second specimen is even more informative. Within it were found the fragmentary remains of a teleost fish, as well as a wide variety of invertebrates, including the shells of bivalves, gastropods, fragments of a crinoid, and the guards of belemnites. In addition to these, the specimen also contains a bromalite (the fossilized remains of the animal’s fecal matter), which also contains yet more belemnite, gastropod, and bivalve material. Of particular note is that the proportions of bivalve and gastropod remains in both the bromalite and the stomach contents of both specimens far outnumber those of nektonic or free-swimming animals, like the fish and belemnites. It would seem that at least for these elasmosaurs, benthic prey was a very significant, if not the most significant, portion of their diet, likely acquired by raking through the seafloor. This very different to the emphasis on nektonic prey items like fish, cephalopods, and small marine reptiles that we see in styxosaurines’ dietary remains, as well as those ofThalassomedon, and suggests a notably different ecology and feeding strategy for these Australian elasmosaurs (which in some ways is much more similar to that proposed for some of the cryptoclidids mentioned earlier).
Unfortunately, for the majority of elasmosaurs, we still do not have preserved stomach contents or feeding traces to directly inform our understanding of their diet. However, elasmosaurs actually display a huge amount of diversity, particularly in terms of their skulls, more than in nearly any other group of plesiosaurs. This strongly suggests that there was also a great variety of lifestyles and that the prey preferences would have been much more varied than the few specimens we have with preserved stomach contents indicate. While styxosaurines (and primarilyStyxosaurus snowii itself) have certainly informed the general image of these animals, they are not the only elasmosaur lineage which is worthy of discussion. Some of the others evolved in ways which are decidedly stranger.
Weddellonectines: The Elasmosaurs’ Final Hurrah
Skulls ofStyxosaurus browniiandZarafasaura oceaniscompared with a human head by Tosha Hollmann. Abandon all hope, you who enter here.
While the long-necked styxosaurines likeElasmosaurus andStyxosaurushave received fame and extensive media attention over the many years since their discovery, other clades of elasmosaurs have remained relatively obscure, in part due to the fact that there was until recent comparatively little research into elasmosaurs from outside North America. The weddellonectines are a poorly known and relatively newly identified clade, first appearing at the beginning of the Maastrichtian, the final stage of the Late Cretaceous. Weddellonectia was defined by O’Gorman and Coria (2016) as includingAristonectes, Kaiwhekea, Morenosaurus, Vegasaurus, Kawanectes,their most recent ancestor, and all descendants. Even the most well-known weddellonectines, the aristonectines, aren’t fully understood. What is clear is that weddellonectines were still diversifying well into the Maastrichtian, and the unique jaw and skull morphologies displayed attest to this fact. Aristonectines and other members of the clade cast a light on a greater variety of diets of elasmosaurs. Due to the inconsistent nature of elasmosaurid phylogeny, Weddellonectia is often poorly recovered so some taxa that may or may not actually belong in Weddellonectia have been included in this post.
Non-aristonectine weddellonectines seem to have developed a variety of unique morphologies that have often been overlooked.Zarafasauraoceanis is an unusual taxon known from the Ouled Abdoun Basin of Morroco, recently recovered as a weddellonectine in several phylogenies by Sachs et al. (2020).Zarafasaura is notable for its extremely unusual skull, not just for elasmosaurs but even for plesiosaurs as a whole. The front of the skull is shortened to an extreme extent, producing an especially robust snout. The skulls of even less robust elasmosaurs, such asLibonectes, have been found to be quite stress resistant, so it is logical to assume the shorter and deeper snout of Zarafasaurawas capable of enduring higher stresses still. The back end of the skull is also heavily changed from the standard elasmosaur bauplan; the supratemporal fenestrae have greatly lengthened and expanded. Araújo & Polcyn (2013) concluded that selective pressures to expand the supratemporal fenestrae were strictly myological, meaning the large fenestrae seen inZarafasaura were solely to accommodate larger muscles, especially the adductor muscles. They also found thatLibonectes generated most of its bite force with the adductor mandibulae externus, pseudotemporalis, and adductor mandibulae posterior rather than the pterygoideus muscle, so the large adductor muscles and deep skull of Zarafasaura are consistent with adaptations for a higher bite force and indicate the animal was well adapted for the pursuit of larger or tougher prey.
Another bizarre animal often recovered as a basal member of Weddellonectia isHydrotherosaurus alexandrae. The incredibly complete remains of this animal, some of the best known for any elasmosaur, come from the Moreno Formation of Fresno County, California. Dating to the Late Maastrichtian,Hydrotherosaurus, likeZarafasaura, is one of the latest known plesiosaurs in the fossil record, from right around the K-Pg extinction event. It is notable for its proportionately tiny head (only 33 centimetres in length, compared to a total length of 8 metres) lined with proportionally very long teeth (the longest teeth in the jaw being 4.6 centimetres), long enough to extend below the jaws when they were closed. The teeth of Hydrotherosaurusare also notable for have very prominent striations, indicating little wear. Comparatively little wear could indicate a diet of softer prey and its long and thin teeth would be perfect for piercing fast and slippery prey, which could support a diet of mainly cephalopods for this animal, similar to that proposed for some pliosaurids, such asSimolestes.
Aristonectesfiltering prey from the sediment while halisaurine mosasaurs pursue crabs disturbed in its wake. Art by Tosha Hollmann.
The aristonectines themselves are perhaps some of the most bizarre plesiosaurs to ever evolve. They are most notable for their unique feeding habits but are also unique in their postcranial anatomy, including a secondarily shortened neck, proportionally huge flippers (3-metre-long forelimbs inAristonectes quiriquinensis), and in some cases a truly impressive size, including among their number the largest known elasmosaur and the largest non pliosaurid-plesiosaur in general. However, what really sets these animals apart from all other elasmosaurs is their skulls. Wide and hoop-shaped jaws, a multitude of small homodont teeth, and an expanded and cavernous palate show a shocking convergence with baleen whales and betray a filter-feeding lifestyle, something otherwise unheard of among marine reptiles. Aristonectine skulls have a fleet of adaptations in the jaw and palate designed to help the animal gulp in large volumes of water, and teeth perfectly suited to straining out tiny prey. These adaptations were taken to a particular extreme inMorturneriaseymourensis,which has an expanded palate drooping down past many of its teeth, a feature also seen in modern day mysticetes as an adaptation for greater suction power.
While the exact method of filter feeding in aristonectines is not definitively known and is likely variable, the relatively complete skeletons ofAristonectes help shed light on the exact habits of the aristonectines. Otero et al. (2018) suggest thatAristonecteswas a benthic filter feeder, based on morphological features like adaptations in the neck for having the head of the animal being positioned below its body as well as poor speed and high maneuverability and several points of convergence with extant whales. The environmentAristonectes lived in seemingly had a low number of bony fishes, but a high amount of benthic marine invertebrates to provide ample food forAristonectes,painting a clear picture of these massive animals occupying a niche similar to that of modern grey whales in the terminal Cretaceous seas of the Southern Hemisphere.
Final Remarks
What we begin to see now is that the image of plesiosaurs that is increasingly coming to light as more and more evidence is found is not that of the specialist hunters of small fish and squid, but rather an incredibly diverse group that managed to coexist with and indeed outlast many of their competitors by filling a wide variety of niches. Far from an evolutionary experiment doomed to failure by their specialization, they represent one of the greatest success stories in the long history of marine reptiles, and indeed also that of marine tetrapods as a whole. Their unusual and alien body plan, far from being a hindrance, was a generalized tool that allowed them to exploit almost every imaginable niche and a huge variety of prey for the better part of 200 million years. Only when we set aside the age-old preconceptions about their behaviour can we begin to see them for the amazing and versatile animals that they truly were.
Acknowledgements
Huge thanks to Tosha Hollmann for their textual and artistic contributions to this post, please go and check out their work at@fishboy86164577 on Twitter.
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Published byEshanahan
Undergraduate at UMW dealing with Biological sciences.Email edmundshan4@gmail.com for any questions/inquiries.View all posts by Eshanahan
3 thoughts on “What Sea Dragons Ate: Plesiosaur Diets Revised”
Nice article though it leaves me a with a feeling of deja vu….
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Fantastic blog post!
One thing, though: didn’t O’Gorman (2020) synonymize Styxosaurinae with Elasmosaurinae? I don’t claim to understand the intricacies of plesiosaur phylogeny (wish I did!) but I thought I should bring it up.
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