pterosaur – Nix Illustration

Wukongopterus

Wukongopterus lii was a pterosaur that lived during the mid-to-late Jurassic, about 164 million years ago, in what is now northeastern China. It was fairly small, with a wingspan of around 70cm (~2’4″), and showed a mixture of anatomical features in-between the long-tailed short-headed ‘rhamphorhynchoids‘ and the short-tailed long-headed pterodactyloids.

Its long jaws were lined with tiny pointed conical teeth, suggesting it was adapted for primarily feeding on insects. It also had a very slight overbite, with the first two pairs of teeth in its upper jaw protruding almost vertically over the end of its lower jaw.

As a fully mature adult it would have had a low bony crest on its head that probably supported a larger cartilaginous structure – similar to other known wukongopterids – although the exact size and shape is unknown since the one confirmed specimen of Wukongopterus is missing that particular part of its skull. Another fossil nicknamed “Ian” may represent a second individual of this species, showing a different crest arrangement further forward on its snout, so I’ve made two different versions of today’s image to reflect that possibility.

Crystal Palace Field Trip Part 2: Walking With Victorian Dinosaurs

[Previously: the Permian and Triassic]

The next part of the Crystal Palace Dinosaur trail depicts the Jurassic and Cretaceous periods. Most of the featured animals here are actually marine reptiles, but a few dinosaur species do make an appearance towards the end of this section.

A photograph of a Crystal Palace ichthyosaur statue, posed hauled out of the water like a seal or crocodile. It's partially obscured by plant growth, and is in a state of slight disrepair – moss and lichen patches cover its sides, and a plant is growing out of a crack on its back. A moorhen can be seen in the water swimming towards it.

Although there are supposed to be three Jurassic ichthyosaur statues here, only the big Temnodontosaurus platyodon could really be seen at the time of my visit. The two smaller Ichthyosaurus communis and Leptonectes tenuirostris were almost entirely hidden by the dense plant growth on the island.

Two photographs of the Crystal Palace ichthyosaurs. On the left the island is clear of foliage and all three can be seen; and on the right is the current overgrown state. — Ichthyosaurs when fully visible vs currently obscured
Left side image by Nick Richards (CC BY SA 2.0)

Two photographs of the large Crystal Palace ichthyosaur, showing closer views of the eye, flipper, and tail fin. Int he background a second ichthyosaur can be seen through the foliage. A moorhen is pecking around near the flipper. — *Head, flipper, and tail details of the Temnodontosaurus. A second ichthyosaur is just barely visible in the background.*

Ichthyosaurs were already known from some very complete and well-preserved fossils in the 1850s, so a lot of the anatomy here still holds up fairly well even 170 years later. They even have an attempt at a tail fin despite no impressions of such a structure having been discovered yet! Some details are still noticeably wrong compared to modern knowledge, though, such as the unusual amount of shrinkwrapping on the sclerotic rings of the eyes and the bones of the flippers.

An illustration comparing the Crystal Palace depiction of an ichthyosaur with a modern interpretation. The retro version has long toothy jaws, very large eyes, a seal-like body, four scaly-looking flippers, and a small eel-like fin on its tail. The modern version is a much more dolphin-like animal with smaller eyes, smooth triangular flippers, a dorsal fin, and a vertical crescent-shaped tail fin.

Feilongus

Feilongus youngi was a pterosaur that lived during the early Cretaceous (~125 million years ago) in what is now northeastern China.

Known only from two skulls and a few neck vertebrae, its full body proportions are uncertain, but it’s estimated to have had a wingspan of somewhere around 2.4m (7’10”). As part of the ctenochasmatid lineage it was probably a wader specializing in snagging aquatic prey between its interlocking needle-like teeth.

It had two bony crests on its head – a long low one along its snout, and a backwards-pointing one at the very back of its skull – along with a distinct overbite at the front of its jaws. These structures are only seen in the larger of the two known specimens, suggesting that they either only developed towards full maturity or that this species was sexually dimorphic.

Strange Symmetries #12: Pterosaur Crossing

Rhamphorhynchus muensteri was one of the first pterosaurs known to science, and its snaggletoothed snout and long vaned tail have become classic features of many fictional “pterodactyls”. But despite its prevalence in pop culture depictions, it actually seems to have been quite a highly specialized pterosaur compared to its closest relatives – and a few specimens also seem to have an unusual little bit of asymmetry going on.

Living during the Late Jurassic, about 150-145 million years ago, around the warm shallow seas of what is now southeast Germany, Rhamphorynchus had a a wingspan of up to at least 1.8m (~6′), with larger fragmentary fossils suggesting a maximum of around 3m (~9’10”).

It had proportionally long wings, splaying intermeshing needle-like teeth, and a toothless beak at the tip of its jaws. The lower beak hooked strongly upwards, while the upper seems to have varied from upwards-curving to straight to downward-curving in different individuals – and some of these arrangements mean the keratinous beak tips must have crossed when the jaws closed, twisting to each side to asymmetrically pass each other similarly to modern crossbill birds.

Several specimens have been found with fish and cephalopod remains preserved in their guts, and along with the pointy intermeshing teeth this indicates Rhamphorhynchus was probably mainly piscivorous, occupying a similar ecological role to modern seabirds.

The different shapes of the toothless jaw tips may suggest there were several distinct populations of this pterosaur species exploiting slightly different food sources to each other, and the crossing beaks may have been an adaptation to pry the soft parts out of hard-shelled prey.

Noripterus

Noripterus complicidens was a pterosaur that lived in what is now Mongolia and northwest China during the early Cretaceous, about 140 million years ago.

It had a wingspan of up to 4m (~13′), with a head-and-body length of around 1.2m (~4′), and like other dsungaripterids it had a distinctively reinforced skull, with a toothless beak at the front of its jaws and strong widely-spaced teeth further back – an arrangement that was probably used to catch and then powerfully crack open hard-shelled prey.

Unlike other pterosaurs, however, Noripterus also had some very unusual feet.

All other known pterosaurs seem to have had plantigrade hindlimbs, standing and walking with the whole foot on the ground. But Noripterus had toe joints that looked more like those of theropod dinosaurs than other pterosaurs, with a higher level of upward flexibility and potentially a more digitigrade posture standing on just its toes.

With dsungaripterids already having fairly stout body proportions that suggest they spent a lot of time walking around on the ground, Noripterus may have been even more agile and adept at terrestrial locomotion. Digitigrady is generally more efficient for moving at higher speeds, so this pterosaur might have been a runner behaving similarly to modern ground birds, preferring to sprint away from threats on foot rather than launch itself into the air.

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.

Retro vs Modern #18: Pterodactylus antiquus

Pterodactylus antiquus was the first pterosaur ever discovered, and in popular culture the name “pterodactyl” has become commonly associated with the group as a whole.

1800s

The first known Pterodactlyus specimen came from southeast Germany, and was described (although not yet named) in the 1780s. The modern concept of extinction hadn’t yet been established, so at the time unknown fossil species were generally assumed to still exist alive somewhere in remote regions of the world. Initially it was unclear what type of animal this specimen represented, and it was interpreted as being aquatic because the oceans seemed like the best place for such a strange creature to hide undiscovered.

In 1800 it was recognized as instead being a flying animal, with naturalist Johann Hermann creating both the first known life restoration of a pterosaur and one of the first known examples of scientific paleoart in general. He depicted it as a bat-like mammal with extensive wing membranes, external ears, and a covering of fur, and made two different sketches of this interpretation. The first shows an odd rounded wing shape with the wing finger seeming to form a stiff “hoop” around to the ankles, but the second version has some interesting additions – showing an understanding of the wing finger being straightened and stretching out the membrane, and adding a very large colugo-like propatagium between the neck and the wrist.

In light of our modern understanding of pterosaurs this was an incredibly good attempt at a reconstruction, despite the total lack of soft tissue impressions and the mistaken mammal classification.

The name Pterodactylus was established for this animal by the late 1810s, and while it was correctly identified as a flying reptile by some early paleontologists, others also saw it as being more mammal-like or bird-like.

In this pre-Darwinian time there was no modern concept of evolutionary relationships, and pterosaurs were instead thought to be a type of bat positioned inbetween mammals and birds in the “chain of being“. This “bat model” became influential on the early study of pterosaurs, and some paleontologists depicted highly mammalian versions even as late as the 1840s.

(The aquatic interpretation also stuck around as a competing idea until at least 1830, with Pterodactylus‘ wings restored as huge penguin-like flippers.)

1850s-1970s

By the mid-19^th century the reptile interpretation had become standard but the bat influence remained, with pterosaurs commonly assumed to have been furry, warm-blooded, and quadrupedal and clumsy on the ground. Fossil evidence of hair-like fuzz had even been found on a specimen of Scaphognathus in the 1830s, but this was later disputed and was only confirmed as being real almost two centuries later.

British paleontologist Richard Owen disagreed with the bat model for pterosaurs, considering them to be scaly sluggish cold-blooded gliders, and in the 1850s oversaw the creation of the heavily-scaled and oddly goose-like Crystal Palace Pterodactylus statues – one of their first major portrayals to the general public, and influential in the popular perception of these animals at the time.

But even into the start of the 20^th century some paleontologists were still arguing for active warm-blooded pterosaurs, with the first popular book on the group in 1901 suggesting they were closely related to birds. German paleontologists continued to interpret pterosaurs this way into the 1930s, but in contrast English and American scientists largely lost interest in these animals over subsequent decades – and depictions of pterosaurs went the same way as non-avian dinosaurs during this period, descending into awkward evolutionary failures that could barely even fly, shown as scaly-skinned or naked, and hanging upside-down from trees and cliffsides like giant wrinkly bats.

2020s

The discovery of definite hair-like structures (known as pycnofibers) on Sordes brought pterosaurs into their own renaissance in the 1970s, and among a flood of new discoveries they were reinterpreted as active warm-blooded bird-like animals. Reconstructions sometimes went a bit too bird-like, though, attempting to distance themselves from the older saggy-repto-bat portrayals, with forced bipedal postures and much more slender wing membranes attaching to the waist.

But early 21^st century studies into biomechanics, soft-tissue remains, and trackways confirmed that some elements of the bat model had actually been right the whole time. Pterosaurs had flight membranes attached to their hind limbs and were quadrupedal when on the ground – but instead of being awkward bat-like sprawlers they were actually competent walkers and runners with an energy-efficient upright posture.

We now know Pterodactylus lived during the Late Jurassic, about 150-148 million, at a time when the region of southern Germany was part of an island archipelago in a shallow tropical sea. Fragmentary remains are also known from elsewhere in Europe and in Africa, suggesting this genus had a fairly wide range.

It was a fairly small pterosaur, with the largest adults having am estimated wingspan of around 1m (3’3″), and had long straight jaws lined with numerous pointed teeth. Most known specimens are juveniles, but fossils of larger adults preserve evidence of a soft tissue crest with a backwards-pointing “lappet”, and long mane-like pycnofibers on the back of the neck.

Like other pterosaurs it was fuzzy and warm-blooded, and it had hollow bird-like bones and air sacs lightening its body. Its wings were highly complex with layers of strengthening fibers and muscles that allowed the flight surface shape to be precisely controlled, and when walking on the ground it could fold up its wing fingers and stow the membranes well out of the way of its limbs.

It was probably a generalist carnivore, feeding mostly on small prey like invertebrates, and the shape of the sclerotic rings in its eye sockets suggest it was mainly active during the daytime.

Leptostomia

Leptostomia begaaensis here is a recently-discovered pterosaur that lived during the mid-Cretaceous period, around 100 million years ago.

Its fossil remains were found in the Kem Kem beds of Morocco – ancient river deposits famous for yielding some of the newer specimens of the bizarre aquatic dinosaur Spinosaurus – and consist of just a couple of small pieces of jaw bones.

But those fragments are rather weird for a pterosaur.

While it’s hard to tell for certain from such meagre remains, Leptostomia might have been part of the azhdarchoid lineage, related to both the elaborately-crested tapejarids and the terrestrial-stalking giants like Quetzalcoatlus. And if it was indded an azhdarchoid it was an especially tiny one, possibly the smallest known member of the whole group. Based on the proportions of its relatives it would have stood just 30cm tall (1′) with a wingspan of 60-70cm (2′-2’4″), roughly comparable in size to a modern pigeon.

And it had an incredibly long beak that tapered to a thin delicate tip, resembling the beaks of modern probe-feeding shorebirds more than any other known pterosaur. It may have been specialized for the same sort of ecological niche, poking around in mud and shallow water for small invertebrates and snapping them up, possibly detecting its hidden prey using super-sensitive nerve endings in the tip of its beak.

Weird Heads Month #01

It’s been a whole four years since Weird Backs Month, so we’re long overdue for a companion series:

Weird Heads Month!

Ever since heads first evolved as a defined body part, over 500 million years ago, evolution has been experimenting with them. There are many modern examples of animals that have modified parts of their heads and faces in a variety of strange-looking ways – elephants, deer, narwhals, hornbills, sawfish, bats, stalk-eyed flies, hammerheads, barreleyes, and star-nosed moles, to name only a few – and species in the fossil record were just as diverse and weird.

So let’s start off with…

Weird Heads Month #01: Wacky Flying Headgear

One of the most immediately recognizable examples of extinct animals with strange head structures are the pterosaurs, almost always depicted in pop culture with a large Pteranodon-like head crest.

But that wasn’t anywhere near as weird as pterosaur crests got.

Nyctosaurus gracilis here had an absolutely ridiculous elaborate crest, sporting an enormous antler-like structure on the back of its skull that grew to lengths longer than its own body.

Living around the Western Interior Seaway of the Midwestern United States during the Late Cretaceous, around 85 million years ago, it was a fairly small pterosaur standing about 40cm tall without the crest (1’4″) and with a 2m wingspan (6’6″). Its wings were long and narrow, and had completely lost the three small clawed fingers seen on other pterosaurs, suggesting it may have been less capable of moving around on the ground. It’s thought to have been a specialized soaring flier that spent most of its life on the wing at sea, much like a modern albatross.

Made up of two long thin spars arising from a common base, Nyctosaurus‘ crest has sometimes been reconstructed with a large sail-like membrane of skin – but since there’s no evidence at all of soft-tissue attachment on the bones, this seems unlikely. Juveniles were crestless, with only fully mature adults developing their spectacular headgear, so it was probably some sort of display structure.

It’s also not clear whether there was any sexual dimorphism in Nyctosaurus, since well-preserved skulls with intact crests are incredibly rare. But as with most other crested pterosaurs it’s likely that all mature individuals had crests, just with a difference in size and shape between sexes.

Cryodrakon

Fragmentary fossils of huge azhdarchid pterosaurs have been found in Canada since the early 1970s, and for a long time they were assumed to belong to Quetzalcoatlus. But more recently these remains were re-examined and shown to actually represent an entirely new genus and species.

Cryodrakon boreas – an excellent name meaning “icy dragon of the north wind” – was officially described in late 2019. With a wingspan of around 10m (32’10”) it was similar in size to its close relative Quetzalcoatlus, but it dates to about 10 million years earlier making it one of the oldest azhdarchids ever found in North America.

It lived about 76 million years ago in Alberta, with its fossils coming from the Dinosaur Park Formation, an area that at the time would have been a coastal plain near the northern parts of the Western Interior Seaway. Despite Alberta being located somewhat closer to the Arctic Circle than it is today, the climate was warm-temperate and temperatures rarely dipped below freezing, with short nights in the summers and only a few hours of daylight in the winters.

Like other azhdarchids Cryodrakon would have spent a lot of its time on all fours on the ground. While moving like that it would have been almost 5m tall (16’5″), similar in size to a modern giraffe, stalking smaller animals and eating whatever it could catch and fit into its mouth.