Coastal Feast - Pisco Formation

Not far from the shore of a beach in Peru during the Late Miocene, the search for food and the struggle to not get eaten drive the life underwater. This marine fauna includes not only creatures somewhat strange to our eyes, but also some genera and species that continue to exist today.

At the front of the scene, a female Odobenocetops leptodon and her calf feed on Anadara sp. bivalves that they find on the bottom. This peculiar animal, related to today’s beluga and narwhal, draws attention for having the shortest snout among cetaceans, as well as a pair of small backward-facing tusks (in males, only one side bore an extremely long tusk, up to 1 m). Although it is not known from complete skeletons, the proportions of its vertebrae indicate an animal 3 m long. The mother swims covering the calf, as if instinctively protecting it from a nearby danger. Besides the Anadara, the cetaceans end up scaring away the Chlamys sp. scallops, which reveal a rare ability among bivalves: at the sign of danger, they are able to swim.

The bottom also attracts some herbivores, and the ground sloths Thalassocnus natans gather to devour the seagrasses Zosteraceae. These 2.5 m xenarthrans, being semiaquatic, show yet another adaptation to such a different niche within their group, which contrasts with the small arboreal sloths of today. Near them, starfish Luidia magellanica attack sea urchins Loxechinus sp., and rays Myliobatis sp. search through the sand for bivalves. In the lower left corner, some sea cucumbers Isostichopus fuscus bury themselves in the sand, keeping only their tentacles exposed to collect food particles. Some individuals are outside the sand and on a rock, which also shelters an Octopus vulgaris (common octopus), which camouflages itself. Far away, in the right corner, some Lessonia sp. algae grow, and above them, in the upper corner and more distant towards the sea, there is an Architeuthis sp. (giant squid), whose presence in this period is speculative. For some reason driven by its weakened health, the large cephalopod is shown leaving its deep-water habitat and reaching the coast (a tragic phenomenon, but one that occurs even today and allows us to better know this elusive animal).

While feeding, the Odobenocetops and Thalassocnus may become the next meal of another animal approaching from the open sea: a group of Acrophyseter robustus, ~4.5 m hunters. These cetaceans possessed large and strong teeth, indicating that they hunted prey of considerable size, such as other marine mammals. They are part of the superfamily Physeteroidea, which includes the modern sperm whales - Acrophyseter and some other Miocene species are even called “macropredatory sperm whales” due to their adaptations for subduing large animals.

The main dish of the scene, a spectacle that draws many hungry mouths, is a school of Sardinops sp. These ~40 cm long silver fish seek safety in numbers, but face simultaneous attacks that disrupt their defensive formation. Two species of penguins, the smaller Spheniscus humboldti (Humboldt penguin), coming from the beach, and the larger one with a proportionally longer and more robust beak, Spheniscus megarhampus, coming from the open sea, attack in their flocks and end up unintentionally coordinating their strikes, which pierce the school. Piscobalaena nana whales also try to fill their filter-feeding mouths with the Sardinops, but they are not as terrifying a predator to the fish as one might imagine when thinking of modern whales - this species reached “only” 4-5 m. The classic marine hunter, the shark, marks its presence with an Isurus oxyrinchus (mako shark), but, it leaves the area before it can catch a prey, having been startled by a large crocodilian approaching just below, the Piscogavialis jugaliperforatus (which may have reached 8 m). In a skillful movement, an Acrophoca longirostris snaps up a Sardinops separated from the school, and in the sky some Pelagornis sp. (large birds with ~6 m wingspans) wait for their opportunity to capture any fish that appears at the surface.

New artwork for Tales from the Phanerozoic, a project by João Macêdo. Check out the Late Miocene chapter here, with the backstory of the scene and detailed information about its environment and creatures: https://sites.google.com/view/talesfromthephanerozoic/the-cenozoic/strange-sea