Cold Cretaceous - Prince Creek Formation

Late Cretaceous in what is now Alaska, at the highest paleolatitude (82–85 ºN) ever inhabited by dinosaurs. In a constantly foggy, cold setting, under a prolonged night lasting months, the aurora borealis lights up the prehistoric life of an environment facing its most challenging season of the year.

In this environment, the annual average temperature was around 6–7 ºC, but during the harshest months of the long winter, it could drop to about 2 ºC (sometimes falling below freezing and possibly reaching as low as -10 ºC for brief periods) and could even experience snow - which, in the illustrated moment, is still relatively light and does not fully cover the ground. Ferns and horsetails, which once dominated the landscape, are now dormant in their underground rhizomes, limiting the available food for herbivores (at least for those unable to dig them up). Some shrubs still persist, such as the angiosperm Hollickia quercifolia, along with deciduous conifers whose leaves have almost completely fallen. The local conifers were relatively small trees, with trunks about 20 cm in diameter and, according to more recent studies, of various species - unlike earlier notions that considered Parataxodium the dominant conifer in the region.

At the front of the scene, a classic clash between tyrannosaurids and ceratopsids: an adult Nanuqsaurus hoglundi, about 8 meters long, and her two young offspring charge at a herd of Pachyrhinosaurus perotorum. The large predator manages to seize one of the herbivore's babies in her jaws, while the younger tyrannosaurs distract the enraged Pachyrhinosaurus, preventing them from saving their calf in time. The theropods soon retreat, but the small reward from this hunt will belong only to the hungry mother.

The movement of the giants startles the small mammal Unnuakomys hutchisoni, who leaves its hiding place and tries to flee the chaos. Quickly, a hunger-driven Saurornitholestes langstoni takes the risk and approaches the irritated large dinosaurs to snatch the exposed Unnuakomys, then promptly flees with its prey in its jaws. Another small mammal, a Sikuomys mikros, remains still and safe at the base of the nearby tree. On the opposite side, another mammal, a pair of Cimolodon sp., also remains cautious on a tree branch. The potential threat doesn’t come from the tyrannosaurs, but from another theropod resting just below the branch: an Alaskan Troodon sp. (an animal that shows a considerable size for its group, possibly reaching 3.5 meters in length).

More dinosaurs appear in the scene: a small group of Alaskacephale gangloffi runs through the center, with some individuals observing the conflict ahead; a bit to the right, a female thescelosaurid is cleaning out her burrow while keeping an eye on a mysterious, larger figure among the nearby trees; in the background, moving into the forest, several ornithomimids look for food, seraching for the last conifer leaves within their reach - one even uses its arms to bend a young tree; in the far left, a herd of hadrosaurs once named Ugrunaaluk, but later reclassified within the genus Edmontosaurus, moves in search of food. When compared to fossils of similar age, the Alaskan Edmontosaurus cf. regalis appear to have been slightly smaller than their relatives, measuring about 8 meters in length (E. annectens and E. regalis from other localities easily reached 10 meters, with the largest specimens approaching 13 meters).

The scene includes some speculative presences, based on records from nearby formations that might justify such animals in the Prince Creek Formation: a therizinosaurid appears among the conifers in the far right of the scene, catching the attention of the thescelosaurid, and a large azhdarchid pterosaur is seen walking in the background, not far from the Edmontosaurus.

New artwork for Tales from the Phanerozoic, a project by João Macêdo. Check out the Late Cretaceous chapter here, with the backstory of the scene and detailed information about its environment and creatures: https://sites.google.com/view/talesfromthephanerozoic/the-mesozoic/four-month-darkness?authuser=0