Anomalochelys angulata, a terrestrial turtle from the mid-Cretaceous of Hokkaido, Japan (~100-94 mya).
Measuring around 60cm long (2′), it had a pair of large forward-facing horn-like spikes at the front of its shell – the function of which isn’t clear, but they may have been useful for defense if it was incapable of fully retracting its head into its shell.
It was part of a family of turtles from Asia and North America known as nanhsiungchelyids, a group that adapted to live fully on land and ended up convergently closely resembling modern tortoises. Other members of this group included the larger Nanhsiungchelys (which was also recently found to have possessed “horns” on its shell!) and the very flat Basilemys.
They were also a rare example of a turtle family that didn’t survive through the end-Cretaceous mass extinction, with no known remains from the Cenozoic.
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.
Alienochelys selloumi, a sea turtle from the Late Cretaceous of Morocco (70-66 mya). Although only known from a single skull, it was probably around 2-2.5m long (6′6″- 8′2″), and was closely related to both the modern leatherback turtle and the giant Archelon – and so it wouldn’t have had a solid shell but instead a leathery skin-covered carapace.
But that one skull was also incredibly weird. While most turtles have pointed beaks, Alienochelys had a blunt squared-off face, sort of “pug-nosed”, with its nostrils set high up between its eyes. It seems to have been specialized for crushing hard-shelled prey between the wide flat grinding surfaces of its beak, more similar to the jaws of rays than those of other turtles.
It also lived alongside another bizarre-jawed turtle, but that’s a subject for another time.