Dicynodonts were a group of herbivorous animals with toothless beaks and protruding tusks, part of the synapsid lineage and much closer related to mammals than to reptiles. They were some of the most successful and widespread land vertebrates from the Late Permian to the Middle Triassic, with one genus even briefly taking over the world in the aftermath of the End-Permian mass extinction event.

And it turns out some of them got very big.

Fossils of a surprisingly large dicynodont were first reported in 2008, but it wasn’t until just recently (in late 2018) that this giant creature was finally given an official name – Lisowicia bojani.

Close in size to a modern elephant, at around 2.6m tall (8′6″) and 4.5m long (14′9″), it was by far the largest known example of its kind to have ever lived. And while most other dicynodonts had upright hindlimbs and sprawling forelimbs, Lisowicia seems to have developed a fully upright posture much more similar to that of quadrupedal dinosaurs and modern mammals.

It was also one of the very last of its kind, living during the Late Triassic of Poland, about 208 million years ago (although there was a possible later survivor in Australia). This was around the same time that early sauropod dinosaurs were likewise first starting to experiment with gigantism, suggesting that both groups were convergently evolving to exploit newly-available ecological niches.


Enaliarctos mealsi, an early seal from the Late Oligocene and Early Miocene of California, USA (~23-20 mya).

Measuring about 1.5m long (5′), it was a transitional form between modern seals and their more otter-like ancestors. It was well-adapted for swimming with a flexible spine and flipper-like limbs, but unlike most modern pinnipeds it probably used both its front and hind flippers for propulsion.

Its teeth also still resembled those of terrestrial carnivores, with slicing carnassials at the back of its jaws. This suggests that it had to drag larger prey items back to shore in order to tear them apart and eat them, similar to the behavior of modern otters.


Ocepechelon bouyai, a sea turtle from the late Cretaceous of Morocco (~70-66 mya). Closely related to the modern leatherback turtle and the pug-nosed Alienochelys, it’s only known from a single 70cm-long skull (2′4″) – and while its body proportions aren’t known for certain it was probably very big, possibly up to 4m long (13′).

Unlike any other known turtle it had a unique narrow tube-shaped snout. This is thought to be an adaptation for suction feeding, vacuuming up tiny fish, squid, and jellyfish in a similar manner to modern pipefish or beaked whales.