It Came From The Wastebasket

Taxonomy – the naming, description, and classification of living things – is one of the foundations of biology and ecology. We need to know what things are in order to properly understand them and their evolutionary relationships, and without that we can’t build up an accurate picture of the true diversity of life on Earth.

Taxonomy of living species is also vital for conservation efforts, recognizing unique species that would otherwise go unnoticed. Accidentally using the same name for multiple things can easily mask the decline and potential extinction of critically endangered populations – for example, if we’d just assumed all Galápagos giant tortoises were exactly the same we’d never have realized that Lonesome George was the last known individual of the Pinta Island subspecies, or made efforts to find living hybrid descendants of his kind.

Meanwhile the paleontological taxonomy of fossils helps us to understand where things came from, and to identify long-term trends of evolution, diversity, and extinction over time. The history of life shows us how different types of organisms coped with changing conditions in the past, so we can try to predict how current climate change will affect the biosphere in the present and future.

But sometimes species don’t neatly fit into our classification system. Maybe they’re rather “generic” or “primitive” examples of that type of organism and don’t really have many unique or specialized features, or maybe the scientists describing them just weren’t able to classify them more specifically at the time, but either way they often end up with the same fate: dumped into a wastebasket taxon.

A pencil sketch of a wire mesh waste-paper basket, tipped over on its side with crumpled pieces of paper spilling out. A whale's tail and a trilobite are poking out of the trash, while a bird-like feathered dinosaur and a shrew-like mammal peer around the sides of the toppled basket.

Wastebaskets aren’t natural lineages, just a default label for things that don’t seem to fit anywhere else, and they’re basically somebody else’s problem to sort out later. Sometimes they can even end up containing things that superficially look very similar to each other but later turn out to not even be closely related at all.

This can be especially bad in paleontology, where there’s often only poorly-preserved and fragmentary fossils to work with and usually no way to verify evolutionary relationships with modern genetic analysis. This can result in wastebaskets getting especially bad if left unchecked – like how for a while in the 19th and 20th centuries many fragmentary theropod dinosaurs were just dumped into Megalosaurus, resulting in over 50 dubious species that eventually needed to be carefully reevaluated, renamed, and reclassified.

Every weekday this October we’ll be looking at a different example of these sort of taxonomic tangles – so I’ll see you all on Monday with one the worst historical wastebaskets…

Spectember 2022 #04: Aquatic Brontotheres

Squeezing in one last bonus #Spectember post this year!

This one isn’t based on a specific prompt, but instead is a companion piece to a previous one.


While North American brontotheres were adapting to the spread of grasslands, some of their Asian cousins took a very different evolutionary path through the rest of the Cenozoic.

Continue reading “Spectember 2022 #04: Aquatic Brontotheres”

Spectember 2022 #03: Swimming Hummingbirds

Today’s #Spectember concepts come from three submitters: anonymous, Jonas Werpachowski, and Novaraptoria.

A digital illustration of a speculative future aquatic bird descended from hummingbirds, laying on its belly. It has a long beak with tooth-like serrations that give it a crocodilian appearance. Its body is penguin-like, with large flipper-wings, and it has relatively tiny webbed feet and a stubby tail. Its plumage is iridescent green and white, with a bright purple patch on its throat.
Humdertaker (Suchomergus pollinctor)

Despite having a convergent resemblance to penguins or gannetwhales, the humdertaker (Suchomergus pollinctor) is actually a distant descendant of modern hummingbirds.

Continue reading “Spectember 2022 #03: Swimming Hummingbirds”

Spectember 2022 #02: ‘Modern’ Brontotheres and Paraceratheres

Today’s #Spectember concept is a combination of a couple of anonymous submissions:

A digital illustration of two speculative hoofed mammals, descended from extinct brontotheres and paraceratheres. One resembles a hairy rhinoceros with an odd U-shaped horn on its nose and a fork-like bony "horn" on the back of its head. The other looks like a chunky camel with a moose-like bulbous nose and short downward-pointing protruding tusks.
Crowned brontothere (left) and woolly paracerathere (right)

These two animals are the descendants of brontotheres and paraceratheres, almost the last living representatives of their kinds, hanging on in the equivalent of modern-day times in a world similar to our own.

Continue reading “Spectember 2022 #02: ‘Modern’ Brontotheres and Paraceratheres”

Spectember 2022 #01: Arboreal Ornithopod

Despite some minor delays, it’s time once again for #Spectember – when I dive back into the big pile of speculative evolution concepts that you all submitted to me in 2020, and try to get through a few more of the backlog.

(…There’s still over 50 of them left. This is going to take a while.)

So today’s concept comes from an anonymous submitter, who requested an arboreal ornithopod dinosaur:

Continue reading “Spectember 2022 #01: Arboreal Ornithopod”

Retro vs Modern #23: Spinosaurus aegyptiacus

Spinosaurid teeth were first found in the 1820s in England, but were misidentified as belonging to crocodilians. It wasn’t until nearly a century later that Spinosaurus aegyptiacus was discovered and recognized as a dinosaur – and it would be another century after that before we really started to learn anything about it.


1910s

The first fossils of Spinosaurus were discovered in Egypt in the 1910s. With only a few fragments of its skeleton known it was an enigma right from the start, hinting at a large and very strange theropod dinosaur with crocodile-like teeth, an oddly-shaped lower jaw, and elongated neural spines on its vertebrae that seemed to be part of a huge sail.

A few possible extra fragments were found in the 1930s, but overall these few pieces were all that was known of Spinosaurus for a long time.

The fossils were kept in the Paleontological Museum in Munich, Germany,a building that was severely damaged during a bombing raid in World War II. Many important specimens were destroyed, including Spinosaurus, and only the published drawings and descriptions of the bones remained.

So for the next several decades Spinosaurus remained a very poorly-understood mystery. During this period it was generally depicted as a generic “carnosaur“, often modeled on something like Megalosaurus, in the standard-for-the-time tripod pose and with a Dimetrodon-like sail on its back.

Interestingly a 1930s skeletal reconstruction shows Spinosaurus with an unusually long torso and fairly short legs, details that are surprisingly modern despite the retro posture.


1990s

In the 1980s some partial snout bones from Niger were recognized as having similarities with the jaw of Spinosaurus. Around the same time the fairly complete skeleton of Baryonyx was discovered, and along with further spinosaurid discoveries in the mid-to-late 1990s a decent idea of what Spinosaurus might have looked like began to emerge.

It was reconstructed with a long kinked crocodilian-like snout, a ridged bony crest in front of its eyes, an S-curved neck, and large thumb claws on its hands – an interpretation that was heavily popularized by Jurassic Park III in the early 2000s, bringing this enigmatic dinosaur to public attention and portraying it as a fearsome super-predator bigger than Tyrannosaurus.


2020s

Despite attempts to locate more complete Spinosaurus remains, only fragments continued to be found, and it remained a frustratingly poorly-known species even into the early 2010s.

Finally, in 2014, almost a full century after it was first described and named, Spinosaurus started to reveal its secrets with the announcement of the discovery of the most complete skeleton so far, discovered in the Kem Kem fossil beds in Morocco. Its body was still only partially represented, but it included skull fragments, part of a hand, a complete leg and pelvis, some sail spines, and several vertebrae from the neck, back, and tail.

And nobody was expecting what these pieces revealed.

It had a very long torso and proportionally short stumpy legs, and was reconstructed with a huge distinctive “M-shaped” sail on its back. Its feet had flat-bottomed claws and its “dewclaw” toe was enlarged into an extra weight-bearing digit – adaptations for spreading its weight over soft muddy ground, and suggesting its feet may also have been webbed. Initially it was also presented as possibly being quadrupedal, due to how far forward its center of mass seemed to be, reviving an odd idea from the late 20th century.

Along with its long crocodile-like head and conical teeth, this was interpreted as evidence it was a semiaquatic fish-eating swimming animal – potentially making it the first known semiaquatic non-avian dinosaur. Spinosaurids had been suggested to be specialized piscivores before, especially since Baryonyx had been found with fish scales in its stomach, but they were generally assumed to be more like modern grizzly bears, wading into water to hunt but not being habitual swimmers. Spinosaurus’ weird croco-duck proportions, however, seemed like they might be much more suited to watery habitats than to the land.

Since Spinosaurus had become a popular dinosaur with the general public by that point, the discovery was big news – and a big controversy for a while. It was so bizarre that some paleontologists were skeptical of the radical new interpretation, wondering if the measurements of the skeleton were correct or if the short legs were even from the same individual or the same species as the rest of the bones.

After a while the new proportions were accepted as fairly accurate, and over the next few years attention turned to instead figuring out just how this animal worked and how aquatic it actually was. An earlier isotope analysis of its teeth supported a semiaquatic lifestyle similar to crocodiles and turtles, but a buoyancy study argued that it might not have been able to dive below the water suface and its sail made floating unstable – but also found that its center of mass was closer to its hips than previously calculated, suggesting it could walk bipedally after all.

Then in 2020 came another surprise: more of the tail of the new specimen had been found, and it was just as weird as the rest of Spinosaurus. Its tail was a huge vertically flattened paddle-like fin supported by long thin neural spines and chevrons, resembling a giant eel or newt more than a dinosaur and also giving some more weight to the idea that it was a swimmer.

Our modern view of Spinosaurus is still evolving, and likely to be full of even more surprises in the future as we discover more about this unique dinosaur. But we at least know it lived in what is now North Africa during the Late Cretaceous, about 99-93 million years ago, and whether it was a swimmer or wading generalist predator it was one of the largest known theropods to ever live, estimated to have reached around 16m long (~52ft).

While the “M-shaped” sail reconstruction has been popularized by the recent discoveries, the exact shape of this structure is still unknown. Like with other sailbacked animals it’s also not clear what it was for, with ideas including temperature regulation, visual display, supporting a fatty hump, and a potential hydrodynamic adaptation.

EDIT: And while I was working on this entry (late March 2022) I missed that another study had just come out with more anatomical support for swimming Spinosaurus!

Retro vs Modern #22: Tyrannosaurus rex

Probably the most famous and popular dinosaur of all time, Tyrannosaurus rex is also the only species commonly known by both its full scientific name and its abbreviation T. rex.


1900s-1960s

Fragments of what we now know are Tyrannosaurus fossils were first found in the Western United States in the 1870s, but it wasn’t until the early 1900s that a couple of partial skeletons were discovered and recognized as belonging to a new species of huge carnivorous theropod.

With its charismatic and memorable name meaning “tyrant lizard king” it was an immediate hit with the general public, portrayed as the “king of the dinosaurs” in pop culture and as the dramatic nemesis of Triceratops.

Like other bipedal dinosaurs of the time it was depicted in an upright kangaroo-like tripod pose, cold-blooded and lizard-like. Sometimes it was also shown with three-fingered hands, since its arms were poorly known for a long time – and while the closely-related tyrannosaurid Gorgosaurus was known to have had just two fingers, this wasn’t confirmed for Tyrannosaurus until the late 1980s.


1990s

During the 1970s and the early Dinosaur Renaissance it became obvious that bipedal dinosaurs like Tyrannosaurus couldn’t have stood so sharply upright without dislocating their hips and tail vertebrae.

Jurassic Park was influential in introducing this new corrected posture to the general public in the early 1990s, presenting a powerful and active predator with a more bird-like horizontal stance and its tail acting as a counterbalance. Reconstructions inspired by this portrayal became standard for Tyrannosaurus during the 1990s (although the old-style tripod remains in public consciousness even decades later), and while it didn’t tend to get as heavily shrinkwrapped as some other species it was still common for a while to push its belly ribs in as much as possible to make its bulky body look skinnier and more “athletic”.

The 1980s and 1990s were also a time when discoveries of new Tyrannosaurus specimens began to become much more frequent, improving knowledge of the species’ anatomy, biology, and life history. Some, like Sue, Stan, and the Dueling Dinosaurs, would also unfortunately end up becoming highly controversial, tied up in legal disputes for years and sold for multi-million-dollar prices.


2020s

After the explosion of feathered non-avian dinosaur specimens from China in the mid-1990s, eventually the small feathered tyrannosauroid Dilong was discovered in the early 2000s, followed by the much larger-bodied Yutyrannus in the early 2010s.

While these tyrannosauroids weren’t particularly closely related to Tyrannosaurus itself, the question of potential tyrant fuzz still began to loom, and for a while in the 2010s highly fluffy T. rex interpretations were popular in paleoart. But in the late 2010s a study of known skin impressions from Tyrannosaurus and several of its closer relatives showed that small pebbly scales were known from various parts of the body, and suggested that these particular dinosaurs were most likely primarily scaly. Sparser fluff was still possible on parts of the body, however, similar to the hair on modern elephants, and it’s also possible that juveniles were much fuzzier.

(While this is disappointing for fans of huge fatbird T. rex, it’s also a great example of the scientific process. The skin impressions hadn’t ever been properly described before this point, and the scaly interpretation had mostly been an assumption. Speculative fluffiness prompted all the skin evidence to actually be consolidated, and now we know a lot more about Tyrannosaurus’ potential outward appearance than we did before.)

Arguments about lips in theropod dinosaurs also went back and forth during the 2010s, with interpretations ranging from tight-skinned crocodilian-like snouts with exposed teeth to fleshy lizard-like lips similar to modern Komodo dragons. There’s not really a consensus yet, but since most non-beaked tetrapods do have lips the safe bet is still that dinosaurs like Tyrannosaurus would have had them too. 

Our modern view of Tyrannosaurus is a much chunkier animal than older interpretations, with  more extensive soft tissue, properly-positioned belly ribs showing that it had a barrel-shaped pot-bellied body, and its tail being thicker-muscled than previously thought.

Living across western North America – then the island continent of Laramidia – during the very end of the Cretaceous, about 68-66 million years ago, it was one of the largest terrestrial carnivores to ever live. The very biggest known specimens are estimated to have been as much as 13m long (~43′), with the proportionally large head making up around 1.5m of that (~5′).

Its skull was boxy at the back but narrow along the snout, allowing its forward-facing eyes to have hawk-like stereoscopic vision. Large fenestrae and a “honeycomb” of air spaces reduced the weight of the skull, while reinforced fused bones strengthened it, and Tyrannosaurus is estimated to have had an incredibly powerful bone-crushing bite force.

It had a highly developed sense of smell, and its hearing was geared towards low-frequency sounds. The texture of its skull bones suggests it may also have had thick toughened keratinous skin and bumps over its face, which might have been involved in head-shoving and headbutting behaviors.

Although proportionally tiny for its overall size, its arms were still rather beefy, with large areas for muscle attachment with “meathook” claws that may have been used to hold onto struggling prey.

As a heavily-built bulky carnivore it probably wasn’t especially fast, and its legs were adapted for energy-efficient walking rather than running. It may have been a long-distance stalker, only using short bursts of speed in a final ambush – and like most large carnivores it would have also opportunistically scavenged on carcasses, too.

Specimens once argued to belong to a separate smaller species of tyrannosaur, Nanotyrannus, are now generally accepted as actually being juvenile Tyrannosaurus. They show a surprising amount of physical change as these animals aged, starting out leaner-built with longer legs more suited for speed, slender more delicate snouts, and only developing the characteristic chunky adult proportions during a huge growth spurt in their mid-to-late teens.

Meanwhile, the latest big controversy over this dinosaur as of March 2022 (because there’s always something) is a study proposing splitting Tyrannosaurus into three separate species: T. rex, T. imperator, and T. regina. It doesn’t seem to be going down well, but much like the feather situation it probably at least means we’re going to see a lot of further investigation over the next few years.

Retro vs Modern #21: Deinonychus antirrhopus

Deinonychus antirrhopus was one of the most significant dinosaur discoveries of the 20th century, kicking off the Dinosaur Renaissance and the recognition of the evolutionary link between maniraptoran theropods and modern birds.


1960s

The first remains of this species were discovered in North America in the 1930s, but at the time the fossils weren’t officially described or named. It wasn’t until the 1960s that more specimens were found in Montana, representing at least three preserved individuals, and paleontologist John Ostrom recognized that there was something very special about this dinosaur.

In contrast to the prevailing view at the time that theropods were all upright tail-dragging “sluggish lizards” this was clearly a highly specialized and active predator, with a huge sickle-shaped claw on each foot and a long stiff tail for balance – inspiring its scientific name’s meaning of “counterbalancing terrible claw”.

And while the very first reconstruction of Deinonychus might seem retro to modern eyes, at the time it was revolutionary and it went on to become an iconic representation of the species for the next couple of decades. Drawn by Robert Bakker, who was Ostrom’s student at the time, it depicted a lizard-like creature with its body held in a horizontal pose and its tail held out straight behind it. Its head was portrayed as more domed than we now know Deinonychus’ skull to have been, and its neck was up in an alert posture while the animal ran at full sprint, with its sickle-claws held up away from the ground to keep them sharp.

A few years later further discoveries showed a highly bird-like pelvis and hands very similar to those of Archaeopteryx, triggering the Dinosaur Renaissance reinterpretation of dinosaurs as active warm-blooded animals, and the revival of the 19th century idea that they were the ancestors of birds.


1980s-1990s

As the “birds are dinosaurs” idea began to gain acceptance with increasing amounts of anatomical evidence, some paleontologists in the 1980s began to also suspect that highly bird-like dromaeosaurids like Deinonychus might have also been feathered. Some reconstructions during this time showed this to varying degrees, particularly those drawn by Bakker and by Gregory Paul – but it didn’t really catch on more widely at first, for one very big reason:

Jurassic Park happened.

Dromaeosaurs hadn’t been well-known dinosaurs to the general public before that point, but the 1993 JP “raptors” were an instant hit in pop culture. Physically based much more on Deinonychus than on Velociraptor, and exemplifying the renaissance view of dinosaurs in major media for the first time, the movie’s fully scaled and oversized version of these animals dominated popular depictions for years afterwards. Even the most rigorous and anatomically accurate artwork showcasing their bird-like features still usually kept them completely naked to retain that familiar reptilian appearance.

Most 1990s attempts at any feathering tended towards being as sparse as possible – often along with the shrinkwrapping typical for the era – at best being decent for the time but what we’d now deride as “half-assed”, and at worst being “a few token quills on the back of the head”.

Deinonychus fossils found in association with Tenontosaurus were also interpreted as being evidence of cooperative pack hunting behavior during this time, and it became a common paleoart meme to depict the large herbivore being constantly swarmed by ravenous raptors.


2020s

The mid-1990s discovery of fully-feathered dinosaurs like Sinosauropteryx in China, followed a few years later by raptors with wing-feathered arms like Sinornithosaurus, gradually began to put the fluff back onto dinosaurs like Deinonychus.

(…At least in reasonably scientific paleoart. The much much stronger and ongoing resistance from popular culture is far too big a subject to get into here. But maybe, just maybe, we’re finally hitting a turning point there?)

Early attempts at properly feathering dinosaurs were a bit awkward, usually looking rather like a bunch of scruffy greasy hair glued onto a scaly raptor, a dinosaur wearing fuzzy pajamas, or like the old “bird-lizard” depictions of Archaeopteryx. Even into the early 2010s some paleoart memes were still common in depictions of dromaeosaurs, but increasingly better understanding of their anatomy and plumage arrangements over the last decade or so has brought us to a much more birdlike interpretation of these animals – with paleoartists like Emily Willoughby being especially influential in popularizing the modern view of dinosaurs like Deinonychus.

We now know Deinonychus lived during the Early Cretaceous, about 115-108 million years ago, in what is now the Mountain West and South Central United States. Up to around 3.4m long (11′), it stood about 1m tall (3’3″), similar in size to a large dog.

It had blade-like teeth in its jaws, and forward-facing eyes with stereoscopic vision. Its three-fingered arms would have been covered by wing-like feathers, and its tail probably had feathers all the way along its length and was stiffened but not totally inflexible.

It may have used the sickle-claws on its feet to pin down struggling prey, eating it alive while flapping its wings and waving its tail for balance. And while often depicted as an extremely fast-runner, its leg proportions and foot anatomy suggest it was actually built more for walking and had an especially strong grip strength in its feet, trading speed for power and probably being more of an ambush predator – often being compared to a “giant ground-hawk”.

Pack hunting has been called into question recently, too, arguing that the Tenontosaurus sites may actually represent crocodile-like or Komodo dragon-like behavior with mobs of scavenging individuals congregating at a carcass. But other evidence from trackways and Utahraptor does offer potential support for pack behavior in raptors, so it’s still open to interpretation.

Retro vs Modern #20: Deinocheirus mirificus

Discovered in Mongolia in the mid-1960s, and named in 1970, Deinocheirus mirificus was a famous paleontological mystery for over 40 years.


1970-2000s

For a long time all that was known of this dinosaur was a few fragments and an enormous pair of arms – some of the largest of any known theropod at 2.4m long (7’10”) – inspiring its name meaning “wonderful terrible hands”.

Initially it was classified as a new type of carnosaur (which was something of a wastebasket group at the time), but similarities with the “ostrich-mimic” ornithomimosaurs were soon noted in the early 1970s. And despite some paleontologists trying to link Deinocheirus to the similarly big-armed therizinosaurs over the decades, the ornithomimosaur interpretation seemed to have won out by the early 2000s.

Depictions of Deinocheirus during this time period were highly speculative and reflected the uncertainty over its evolutionary relationships, varying from giant carnosaurs to therizinosaur-like forms to “Gallimimus but bigger” – or sometimes simply showing a hilarious pair of monster-arms reaching in from out-of-frame. Many popular dinosaur books just gave up entirely and only illustrated the known fossil material unreconstructed, and an iconic photograph of Mongolian paleontologist Altangerel Perle standing between the arms was commonly used to emphasize the sheer scale of the bones.


2020s

In the early 2000s attempts to find more fossil material at the original discovery site had only turned up a few additional fragments, including some belly ribs with evidence of having been bitten by a Tarbosaurus – suggesting that the specimen represented the scattered dismembered bits left behind by a feeding carnivore, and that the rest of the carcass might not even have fossilized.

But then between 2006 and 2009 a team of international paleontologists working in Mongolia found a couple of unusual partial skeletons at sites that had been looted by fossil poachers. While parts like the skulls and feet had been taken, the two specimens were still fairly complete and one still had enough arm material left to clearly identify it as Deinocheirus.

When the discovery was announced at the 2013 Society of Vertebrate Paleontology conference it was massive surprise to most of the paleontological community, confirming that Deinocheirus was indeed an ornithomimosaur, and that it was an incredibly weird one. Heavily-built, it was a much chunkier animal than its other relatives, and most surprising of all it had a humped “sailback” formed by long neural spines on its back vertebrae.

Then things got even better.

And stranger.

A “weird skull” had been spotted in the private fossil trade in Europe in 2011, along with some hand and foot material that perfectly matched the missing pieces of one of the new Deinocheirus specimens. The fossils were acquired and donated to a Belgian museum, and then finally were repatriated to Mongolia in 2014, filling in the rest of Deinocheirus’ appearance with a suitably surprising head to go with the rest of its body.

We now know Deinocheirus lived about 70 million years ago during the Late Cretaceous, in what is now the Gobi Desert but at the time was a river-delta-like environment with numerous river channels, shallow lakes, and mudflats.

It grew up to about 11-12m long (~36-39′) and had a long narrow skull with a wide beak and a deep lower jaw – resembling a hadrosaur more than an ornithomimosaur – and it had a rather small brain for a theropod of its size, proportionally closer to that of a sauropod. Its fairly weak jaw muscles suggest it mainly fed on soft vegetation, possibly foraging for aquatic plants in bodies of water like an enormous duck. Gastroliths in its gut helped to grind up its food, and the remains of fish in its stomach suggest that it was also somewhat omnivorous.

Its characteristic huge arms were actually one of the least strange things about it, and were actually proportionally smaller compared to its body size than other ornithomimosaurs. They were heavily muscled, though, with large curved claws, and may have been used to dig up food from mud and soft soil or to pull clumps of vegetation closer.

Its skeleton was highly pneumatized, full of lightening air sacs, but it was still a very big and bulky animal with relatively short legs that suggest it was rather slow-moving. Its feet resembled those of both hadrosaurs and tyrannosaurs, with blunt claws and adaptations for heavy weight-bearing in a bipedal stance.

The large sailback may have been a display structure, and the tip of its tail resembled a pygostyle and so may have sported a fan of feathers. The rest of its body was probably feathered similar to what’s known from other ornithomimosaurs, although potentially more sparsely due to its huge size.

Retro vs Modern #19: Quetzalcoatlus northropi

Named after an Aztec deity and often called “the largest animal to ever fly”, Quetzalcoatlus northropi is probably the most famous large pterosaur after Pteranodon – but despite its popularity for a long time we actually knew very little about it.


1970s

Discovered in Texas in the United States during the early 1970s, the first known fossils of Quetzalcoatlus were just a few giant wing bones, along with several partial skeletons of smaller individuals which at the time were thought to be juveniles.

But although it was given its charismatic name in 1975, the fragmentary nature of the find and it only being given a brief non-formal description meant it was very poorly understood at the time. Worse, the known fossil material was notoriously difficult for other paleontologists to study for several decades afterwards, with the museum housing it often refusing access requests entirely or demanding promises of total secrecy from anyone who was actually allowed to see it.

Most pterosaurs at the time were thought to be soaring seabird-like fish-eaters, but this huge species had been discovered in an inland environment. So Quetzalcoatlus was interpreted as being a huge vulture-like scavenger, with early reconstructions based on this idea ending up highly speculative due to the lack of good anatomical information. A common paleoart meme in the 1970s and 1980s depicted it with a long snake-like neck, a bizarrely tiny head, snaggly teeth, and a small nub-like crest.


1990s

In the mid-1980s Quetzalcoatlus was recognized as belonging to the newly-discovered azhdarchid lineage, a group with extremely long necks, toothless beaks, and long legs – although these pterosaurs were also rather poorly-known until more complete specimens were found in the mid-to-late 1990s.

Reconstructions during this period were considerably less demonic, reflecting the changing ideas about pterosaurs at the time. Quetzalcoatlus became sleeker and more bird-like, depicted with long narrow wing membranes, its neck held in an S-curve, its legs sticking out straight behind it in flight, and sometimes pycnofiber fuzz on parts of its body.

(…And sometimes there was excessive shrinkwrapping.)

During the early 1990s Quetzalcoatlus was also often shown with a blunt chunky beak based on fossil jaws found in west Texas, but in 1996 these remains were determined to belong to a different pterosaur. At the same time more material of the “juveniles” suggested they actually represented an entire second species of Quetzalcoatlus, about half the size of Quetzalcoatlus northropi, with partial skulls showing evidence of a bony crest on the head.

Quetzalcoatlus was also interpreted as a skim-feeder during this time, thought to fly along just above bodies of water with its lower jaw trawling over the surface, snapping up any fish it contacted.


2020s

The skimming hypothesis was widely accepted until 2007, when a detailed study showed that it was physically impossible for any pterosaurs to have actually fed that way. Based on their anatomy and known habitats azhdarchids like Quetzalcoatlus were subsequently reinterpreted as highly terrestrial predators, spending a lot of their time stalking around on all fours snagging prey in their huge beaks like a stork with the proportions of a giraffe.

A full technical description of the known fossil material had been promised since the early 1980s, but decades had passed and by the 2010s it still hadn’t been published. The specimens continued to be inaccessible, information was still under heavy embargo, and what little had been published in the 1970s and 1990s was argued to be sparse enough and undiagnostic enough that it was starting to be genuinely unclear if Quetzalcoatlus northropi was even a valid species name at all.

Finally, finally, after over 40 years, a whole collection of papers about this pterosaur were released in 2021 – and in a refreshing contrast to the many years of secrecy and hoarding they were all free and open access. The second species finally got a name, Quetzalcoatlus lawsoni, and the genus as a whole is now properly and officially defined, instantly going from dubious and almost unknown to one of the most complete azhdarchids so far.

The study isn’t without its issues or controversy, particularly in regards to some of its retro-seeming interpretations of Quetzalcoatlus’ posture, proportions, and launch mechanics. But since the publication means that the fossils are finally unrestricted to other researchers, there’s probably going to be plenty more studies and arguments and new discoveries about it in the future.

While Quetzalcoatlus northropi is still only known from fragments, the new knowledge about its smaller relative means we now have a much better idea of what it was probably like. It lived at the very end of the Cretaceous period, about 68-66 million years ago, and is currently known just from Texas – but it probably ranged much further than that, since azhdarchids are thought to have been able to fly for potentially thousands of kilometers at a time using energy-efficient thermal soaring.

It was one of the largest animals known to have been capable of powered flight, but not necessarily the largest ever. Some past Quetzalcoatlus wingspan estimates got ridiculously over-enthusiastically huge, in some cases up to to 21m (69′), but modern estimates based on better knowledge of azhdarchid proportions suggest something shorter-winged and much closer to 10m (33′) – and some other azhdarchids are now thought to have had similar or possibly even slightly larger wingspans.

Still, Quetzalcoatlus was very big, and when standing on all fours it was probably similar in size and shape to a modern giraffe, about 6m tall (~20′) with at least half of its height just being its neck. It had limb proportions more like an ungulate mammal than most other pterosaurs, suggesting it was highly adapted for walking and running around on the ground – but it could also catapult itself up into the air using its powerful forelimbs to take flight.

It would have been a ground-stalking predator similar to some modern storks and ground hornbills, using its long sharply pointed beak to snatch up any smaller animals it could fit into its mouth. Since its Texan habitat was a semi-arid “fern prairie” dominated by the titanosaur Alamosaurus, hatchlings and small juveniles of this sauropod may have made up a major part of Quetzalcoatlus’ diet.