Patagonian Plains - Collón Curá Formation

Patagonia, Argentina, during the Middle Miocene. A warm environment with open areas, few trees, and covered by low vegetation, such as the illustrated grasses and Amaranthaceae and Asteraceae flowers.

After the Age of Dinosaurs, once again the top of the food chain is occupied by a large terrestrial theropod: Kelenken guillermoi, the largest of the Phorusrhacidae, or "terror birds". This nickname is no exaggeration, as with a skull of ~70 cm armed with a curved, sharp beak, standing over 2 meters tall, powerful claws, and leg bones suggesting high speed and agility for a bird of this size, Kelenken indeed instilled terror in any animal it considered prey. Two individuals appear on the scene, each separately surrounding (they are not cooperating) their potential prey, the macrauquenid Theosodon sp., which can reach 2 meters in length and almost 1 meter in height at the shoulders. These camel-like mammals likely had a complex nasal structure resembling a "trunk", but incapable of grasping food (not a true proboscis, but rather a "prorhiscis", similar to animals like moose, saigas, and sea lions, what is inferred for its relative Macrauchenia). The herd feeds among Nothofagus sp. trees, using this denser forest area to try to elude the predatory birds, where they lose the advantage of running in open terrain.

On the nearest tree, a mother Neotamandua australis, with her baby clinging to her back, hangs on the trunk. Although this genus is considered close to the modern Myrmecophaga (giant anteater), the fossil found in the formation (a humerus) shows some similarity to Tamandua (southern and northern tamandua), suggesting it may belong to a different genus (it is considered that Neotamandua, as a whole, needs a revision of its species).

In the lower right corner, some small animals fight for a burrow. Two notoungulates, Protypotherium colloncurensis (a rather large and robust species for its genus), want to take over the burrow dug by a Peltephilus pumilus, an exquisite horned armadillo. It scares off several Panstrongylus sp. bugs that live in the hole, causing them to flee outside. Focused on their own fight, the Protypotherium and especially the Peltephilus do not notice a predator stalking dangerously close from behind: a Patagosmilus goini - a saber-toothed marsupial, relative of Thylacosmilus. The notoungulates, facing it, will notice in time and run away, while the armadillo will be attacked but, thanks to its armor, will manage to escape the initial bite and retreat into its burrow. Another Patagosmilus appears on the other side of the scene, in the left corner between the lake and the other entrance of the burrow, harassing and trying to attack a Neosteiromys tordillense, a giant porcupine. This Neosteiromys from Collón Curá is known from some smaller teeth than the type species, N. bombifrons, and its inclusion in the genus is uncertain.

Also in the right corner, a group of Astrapotherium guillei cools off in the water. These large mammals, about 4 meters long, catches the eye with their large tusks (bigger in males) and a trunk that likely helped them gather food. On the shore, several dung beetles take advantage of the feces left by the herd before they entered the lake. Behind them, some Podocarpaceae trees grow in this area near the water.

New artwork for Tales from the Phanerozoic, a project by João Macêdo. Check it out: https://sites.google.com/view/talesfromthephanerozoic/