Mimodactylus

Mimodactylus libanensis was a small pterosaur that lived in what is now Lebanon during the late Cretaceous, about 95 million years ago.

It was the latest-surviving known member of a group of pterosaurs called istiodactyliformes, closely related to the Chinese Haopterus.

The only known fossil specimen had a wingspan of around 1.3m (~4’3″) — but it was still a juvenile and the full adult size of Mimodactylus is currently unknown. Its long narrow wings were shaped much like those of modern seabirds, suggesting it used dynamic soaring over the shallow sea and scattered islands that covered the region at the time.

Its fairly broad snout and strong pointed teeth may have been used to forage for shrimp at the water’s surface similar to some modern albatrosses, a previously undocumented feeding style for pterosaurs.

Cambroraster

Cambroraster falcatus was a radiodont that lived during the Cambrian, about 508-505 million years ago, in what is now western Canada. Part of the hurdiid family of radiodonts, it reached sizes of up to 30cm long (~12″) – making it one of the largest animals known from the Burgess Shale fossil deposits.

Its distinctively-shaped massive head shield led to it being nicknamed “the spaceship” during collection and study of numerous fossil specimens. This was then referenced in its species name of “falcatus“, inspired by its resemblance to the fictional Millennium Falcon from the Star Wars franchise.

Its short frontal appendages bore long curved spiny blades that formed a basket-like structure. Originally these were thought to be used to sift through seafloor sediment, but more recently they’ve been proposed as filter-feeding structures instead.

Ptychotherates

Ptychotherates bucculentus was a herrerasaurian dinosaur that lived during the Late Triassic, about 205 million years ago, in what is now New Mexico, USA.

Probably around 2m long (~6’6″), it had a short deep skull and massive cheekbones – unusual features for an early saurischian, and convergently similar to those of some later theropods.

Along with its close relatives Tawa, Chindesaurus, and Daemonosaurus (a grouping collectively known as “morphoraptorans”) it represents one of the latest-surviving known herrerasaurians, suggesting that these early-diverging carnivorous dinosaurs persisted in low-latitude regions until much closer to the end of the Triassic than previously thought.

Esconichthys

The enigmatic Esconichthys apopyris lived during the late Carboniferous, around 308 million years ago, in a lush tropical estuary covering what is now Illinois, USA.

Up to about 8cm long (~3″), it had a prominent pair of eyes, two pairs of elongated external gills bearing long feathery projections, a slender limbless body lined with muscle segments, and a single low fin running along the underside of its tail.

There also seem to have been two different body types that might represent separate species: the “flathead” form with wide-set eyes, and the “snubnose” form with close-set eyes.

Often nicknamed “blades”, “ghosts”, or “grasshoppers” by fossil collectors, specimens of this little animal are the most common vertebrates found in the Mazon Creek fossil beds — and yet we don’t actually know what it is. In the past it was proposed to be a larval lungfish or amphibian, but its anatomy doesn’t quite fit any known group.

Galahadosuchus

Galahadosuchus jonesi was a small early crocodylomorph that lived during the late Triassic of what is now southwest England, around 215 million years ago.

About 60cm long (~2′), it had a fully upright quadrupedal posture, slender digitigrade limbs, a long tail, and a paired row of interlocking osteoderms running along its back.

Its habitat at the time was part of an archipelago of small tropical islands, in a forested karst environment full of sinkholes and caves. It would have been a fast and agile runner, and like its close relative Terrestrisuchus it was probably a generalist pursuit predator feeding on prey such as invertebrates and smaller reptiles.

Xenocranium

Xenocranium pileorivale lived during the late Eocene, about 35 million years ago, in what is now the Midwestern and Mountain states regions of the USA.

Despite its very mole-like appearance, this little mammal was a member of an extinct lineage known as palaeanodonts — and its closest living relatives are actually pangolins.

Around 15cm long (~6″), Xenocranium was highly adapted for a subterranean burrowing lifestyle, with an upturned shovel-shaped snout bearing a pad of thickened skin, and short powerful limbs with large digging claws. Its eyes were very reduced, functionally blind, and may not have even been visible in life. Its sense of hearing was also specialized for the sort of low-frequency sounds that carry well through the ground.

It was probably a head-lift digger, using upward motions of its snout and downward strokes with its forelimbs to excavate tunnels while foraging for worms and underground insects.

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…April fools! Let’s turn that text the right way around:

April Fools 2026: The Backwards Elasmosaurus

In 1869, American paleontologist Edward Drinker Cope published a description and reconstruction of a newly-discovered plesiosaur, Elasmosaurus platyurus.

But there was a big problem: the head was on the wrong end.

It also didn’t have hind flippers, since no limb material had been found and Cope assumed the long “tail” was the primary means of propulsion.

By the next year the mistake had been recognized, pointed out by Cope’s mentor Joseph Leidy (and not his Bone Wars rival Othniel Charles Marsh, despite later retellings). Cope hurriedly published a corrected edition with the same title and date, and it seems he was embarrassed enough to attempt to cover up the whole affair, even recalling and replacing most of the preprint copies he’d sent out to colleagues around the world.

Tanyka

Tanyka amnicola was a tetrapodomorph closely related to both the baphetoids and true tetrapods, living in what is now northeastern Brazil during the Permian around 278 million years ago — making it one of the latest-surviving known stem-tetrapods.

Although only known from lower jaw remains it was likely about 1m long (~3’3″), and would have resembled a large chunky salamander.

Those jaws were particularly unusual, having a distinct twist in the bone that made the teeth towards the front stick out sideways when its mouth was closed. However, this twisting brought a different set of teeth into alignment with the upper jaw — “pavements” of many small denticles on the inner side of the lower jaw, which may have been used to rasp up aquatic plants or grind small invertebrates.

Tanyka’s highly specialized feeding adaptations suggest that late-surviving stem-tetrapods in Permian Gondwana weren’t just evolutionary relics but were instead actively exploring new niches, and that the extinction of these animals wasn’t quite as simple as just being outcompeted by more “advanced” tetrapods.

Saniwa

Saniwa ensidens was a varanid lizard that lived during the Eocene, about 49 million years ago, in what is now Wyoming, USA.

Closely related to monitor lizards, it would have grown to about 2m long (~6’6″) and looked very similar to modern forms, with a pointed snout, well-developed limbs, and a proportionally long tail.

But it also had something not seen in any other jawed vertebrate — a total of four eyes.

Many lizards have a single prominent parietal “third eye” on the top of their heads, which are light-sensitive and involved with both regulating circadian rhythms and hormone production for thermoregulation. However, Saniwa ensidens had two of these structures, with one formed from the parapineal gland like in other lizards, and the second positioned behind it formed by the pineal gland. The only other vertebrates with this arrangement are the jawless lampreys, suggesting that Saniwa somehow re-evolved a pineal eye hundreds of millions of years after its distant ancestors had lost it.

It’s not clear what this extra eye was used for. It would have increased the pineal complex’s sensitivity to blue-wavelength light, and may have been involved in orientation and navigation using polarized light similar to some modern lizards — or possibly magnetoreception-based navigation similar to some modern newts.

Haikouichthys

Haikouichthys ercaicunensis was one of the earliest known vertebrates, living in what is now southwestern China during the Cambrian, around 518 million years ago.

About 2.5cm long (~1″), it had a streamlined body with a long fin along its back and tail. It lacked limbs and jaws, but it did have a flexible “upper lip” that could potentially have been used to manipulate food particles, either engulfing them on the seafloor or stirring them up into the water for filter-feeding.

And a recent study revealed a big surprise — it had four eyes! Along with its already-known large sideways-facing pair of eyes, it also had another smaller upwards-facing pair in the middle of its face, giving it a much wider field of vision and the ability to watch out for predators from multiple angles at once.

The extra pair of eyes may be the evolutionary precursors to the pineal complex in later vertebrates — represented in modern forms by the pineal gland and the parietal eye.