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.