Dilophosaurus wetherilli is a fairly recognizable dinosaur thanks to its memorable appearance in the Jurassic Park franchise – but unfortunately that also means the popular image of it is completely wrong.
Rather than a small frill-necked venom-spitting creature, this early theropod was actually rather large, reaching around 7m long (~23′), and along with its distinctive double crests it also had a narrow snout with large teeth and a distinctive notch at the front of its lower jaw.
It lived in North America during the early Jurassic, about 196-183 million years ago, and while it wasn’t venomous its notched jaws were probably capable of delivering powerful bites to small struggling prey, much like the similar-looking ornithosuchids in the Triassic. Some structural similarities to the skulls of spinosaurids suggest it may have primarily eaten fish.
Its two bony crests were probably used for visual display, with juveniles only having small crests that fully developed as they matured. They also may have had a more extensive keratinous covering, so it’s not clear what their actual shape and full extent was in life.
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.
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.
Between about 9 and 7 million years ago, the modern regions of Tuscany, Corsica, and Sardinia were once part of a single island in the ancient Mediterranean Sea.
And since evolution often goes in weird directions on isolated islands, it’s no surprise that some unusual species developed there.
One of which was a very odd duck.
From fig 4 in Williams, M. F. (2008). Cranio-dental evidence of a hominin-like hyper-masticatory apparatus in Oreopithecus bambolii. Was the swamp ape a human ancestor?. Bioscience Hypotheses, 1(3), 127-137. https://doi.org/10.1016/j.bihy.2008.04.001
Bambolinetta lignitifila lived during the Late Miocene, about 7.5 million years ago. Known from a single partial skeleton discovered in the mid-1800s, it was initially thought to be a fairly normal dabbling duck and wasn’t properly re-examined until 2014, when its strange features were finally recognized.
It was a medium-sized duck, probably around 50cm long (1’8″), but it had much chunkier wing bones than its relatives, with noticeably shortened forearms – looking much more like the wings of an auk or penguin, and suggesting that it was a similar sort of wing propelled diver. This is incredibly weird for a duck, since every other known diving species uses feet for propulsion instead, and so Bambolinetta may be the only known waterfowl to ever develop this type of underwater locomotion.
It’s not clear whether it was still capable of flying or not. There were few predators in its habitat, so it may well have become completely flightless – and that could also be the reason it later went extinct. Sea levels in the region began to drop around 7 million years ago, reconnecting the Tusco-Sardinian island to the European mainland, and Bambolinetta‘s high level of ecological specialization and its potential island tameness would have given it little defence against an influx of new unfamiliar predators.
Named after the Atlas Mountains of Morocco where its fossil remains were discovered, Atlasaurus lived during the mid-Jurassic period, around 168-165 million years ago. While it wasn’t the strangest–lookingsauropod by any means, compared to other species its body proportions still show a particularly bizarre combination of features, with a slightly bigger head, unusually short neck, and very long slender legs that made up nearly half of its 9m height (29’6″).
It’s sort of the uncanny valley of sauropods. Everything about it is just a tiny bit wrong.
And more shrinkwrapped depictions really don’t help with that. [image source]
Its tall shoulders and sloping back resemble the body plan of brachiosaurids so closely that it was initially thought to be an early member of that group, but more recent studies suggest it may have been part of an earlier evolutionary branch of sauropods known as the turiasaurs – which would mean its brachiosaur-like shape was actually the result of convergent evolution.
But what was it doing with such weird proportions?
…We really don’t know. Other short-necked sauropods seem to have been adapted for feeding on lower vegetation only a couple of meters off the ground, but Atlasaurus’ leggy build would have made it a high browser like the brachiosaurids it was mimicking. Its long legs may also have allowed it to move faster, or given it some advantage navigating over rough terrain, but since no other sauropod ever seemed to evolve this way it must have been doing something particularly unique.
Or perhaps it was just an evolutionary fluke. Maybe part of a lineage that had started adapting to short-necked low browsing, then moved back towards the high browsing niche – and happened to end up lengthening their legs instead of their necks to get the necessary height back.
Fragmentary fossils of huge azhdarchidpterosaurs 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.
Pseudosuchians – the evolutionary lineage whose only surviving modern representatives are crocodilians – first originated in the early Triassic and were once an incredibly diverse group. These croc-relatives experimented with fully erect limbs and bipedalism quite a few separate times, and on several occasions ended up evolving remarkably similar body plans to their distant cousins the theropod dinosaurs.
Living in Argentina during the Late Triassic, about 217-215 million years ago, Riojasuchus had a distinctive “hooked” upper jaw and two rows of osteoderm armor plates along its back.
It was only around 1.5m long (4’9″), much smaller than some of the other pseudosuchians and early theropod dinosaurs it lived alongside. Its front limbs were shorter than its hind limbs and it was probably a facultative biped – moving slowly on all fours, but getting up on just its hind legs for bursts of high speed running – which would have helped it avoid being eaten by those larger predators.
Like other ornithosuchids it had very strange ankles, with the bones in the joint articulating with each other the opposite way around compared to any other type of archosaur. The claws on its hind feet were also unusually tall and narrow, especially on the inner toes.
Its jaws were capable of delivering strong but somewhat slow bites, and the relative structural weakness of its narrow notched jaw would have made it difficult for it to deal with large struggling prey. It likely mostly hunted smaller vertebrates, and may also have been an opportunistic scavenger taking bites out of larger predators’ kills whenever it got the chance.
The closest living relatives to modern flamingos are, surprisingly, the grebes. But this relationship is especially ancient, with their last common ancestor probably living sometime between the end of the Cretaceous and the early Eocene.
Such an ancestor is thought to have been a highly aquatic swimming bird, more grebe-like than flamingo-like, but there are few fossils of intermediate forms between that and the modern wading flamingos – with the exception of a group known as the palaelodids.
Palaelodus ambiguus here lived about 29-12 million years ago in Europe, from the early Oligocene to the mid-Miocene. It was similar in size to a small flamingo at about 80cm tall (2’7″), but had proportionally shorter legs and appears to have been capable of both wading and swimming in different depths of water, leading to its nickname of “swimming flamingo”. (Even though modern flamingos do occasionally swim too!)
Its straight pointed beak also suggests it had a much less specialized diet than its modern cousins, probably feeding on small aquatic animals like snails, insect larvae, and fish.
Various other palaelodid species have been found all around the world – even as far as New Zealand – so they seem to have been incredibly common and successful birds during their time. The last definite remains of this group come from the late Miocene, about 7 million years ago, although one Australian fossil may represent a late-surviving relict population that existed until just half a million years ago in the mid-Pleistocene.
Fossils of pterosaurs are already rather rare due to their fragile hollow bones — and they’re especially scarce in Australia, with only a handful of fragments known.
Ferrodraco lentoni (“Lenton‘s iron dragon”) is named after the ironstone that the fossils were found in, and while it’s known only from a partial skull, some pieces of its neck and wings, and various teeth, it’s still by far the best pterosaur specimen ever found in Australia.
Living during the mid-Cretaceous, somewhere between 94 and 90 million years ago, it had a 4m wingspan (~13′) and was also one of the very last of its kind. It was a member of the ornithocheirids, a group characterized by rounded crests at the tips of their long toothy jaws, which were previously thought to have all gone extinct by that time.
Many of Australia’s Cretaceous animals were close relatives of those found in South America, due to an earlier land connection via Antarctica, but surprisingly Ferrodraco wasn’t particularly closely related to any South American ornithocheirids. Instead it seems to have been part of a lineage known from halfway around the world in Europe, suggesting that these pterosaurs were capable of crossing long distances over oceans to disperse between continents.
Originating from Japanese monster movies like Godzilla, the word “kaiju” is now often used to refer to giant creatures in general – and so it was only a matter of time before a huge sauropod dinosaur was named after the concept.
Kaijutitan maui* was a titanosaur living in Argentina during the Late Cretaceous, about 89-86 million years ago. It’s only known from fragmentary remains, so its full size is difficult to estimate, but it was probably somewhere in the region of 20m long (66′). Nowhere close to the largestsauropod, but possibly one of the heaviest since it does seem to have been rather chunkily built, with stout limbs and an estimated weight of 40-60 tonnes (44-66 US tons).
* Not named for the Polynesian hero, apparently, but for the initials of the Museo Argentino Urquiza.
The Mediterranean island of Crete had very few predators during the Pleistocene, with most being birds of prey. And with the terrestrial carnivore niches in the ecosystem left vacant, it was a semi-aquatic mammal and an owl that ended up taking advantage of that opportunity.
Neither were large enough to threaten the dwarf elephants and hippos, and don’t even seem to have habitually eaten even the smallest of the miniature giant deer. Instead these Cretan predators focused much more on the smaller land vertebrates on the island, preying on birds, shrews, rodents, amphibians, and reptiles.
Lutrogale cretensis
Lutrogale cretensis (previously known as Isolalutra cretensis) was a close relative of the modern smooth-coated otter. It was about the same size as its living cousin, around 1m long (3’3″), but had stronger jaws and chunkier limbs.
Its skeleton shows features associated with walking and running more than swimming, and it seems that this was something of a “land otter” — still able to swim, but spending most of its time on land similar to the modern small-clawed otter.
Shellfish were likely still the main part of its diet, indicated by its crushing teeth. But it probably also regularly ate whatever small terrestrial vertebrates it could catch, since more aquatic otters are already known to prey on those types on animals when they can.
Athene cretensis
Athene cretensis was yet another weird island owl, but this time not a descendant of a Strix or Tyto species. Instead this owl was descended from the Eurasian little owl — except it had become much much larger.
It stood around 60cm tall (2′), over three times bigger than its living relative. Its legs weren’t quite as long as those of the modern burrowing owl, but they were still proportionally much longer than those of little owls and show adaptations for terrestrial movement. Little owls already sometimes chase down prey on foot, and Athene cretensis was probably even more of a ground-based hunter, convergently similar to the Hawaiian stilt-owls and the Cuban terror owls.
Preserved pellets show that it ate small mammals and birds, mainly large mice.
Its wings were still quite large, and it was probably also a good flier — and may even have spread over to some of the Dodecanese islands to the east of Crete, since a wing bone closely resembling that of Athene cretensis has been found on Armathia.
Both of these predators seem to have disappeared around the end of the Pleistocene, at the same time as many of the other native Cretan species about 21,500 years ago. Much like the situation with Candiacervus, this may have been a result of a combination of a rapidly shifting climate and the presence of humans disrupting the already fragile island ecosystem.
