Prehistoric Wild: Life in the Mesozoic

Midnight Cove (88 MYA)

Itombe Formation, Angola, 88 Million Years Ago

    Daylight collapses on the Late Cretaceous horizon. Fading remnants of its reddish light glistens across the waters of the West African coast. The sea appears endless when looking beyond, yet it's only a small part of the early South Atlantic. With the night approaching, the surface of the seawater appears dark and translucent.

    Hiding within the darkness below is an ecosystem untouched by the world above. Peering light reveals a plethora of oceanic fish of many shapes and sizes. Their darting and gliding add to the bubbling and rushing heard in the water, which otherwise would be silent.

A massive field of flowing greenery blankets the muddy, rock-infested floor. It appears like a collective of underwater vegetation, yet are plants formed by green algae. They take many forms such as leaves connected to narrow stalks, thin blades like grass or even misty green clouds clumped onto rocks. As with any plant on land, this sea foliage rests on the submerged ground soaking up light from above. This process aids in photosynthesis allowing these clumps of algae to grow and multiply.

    However, there are other organisms here that prevent the overspreading of this field of green. Black, spike-covered sea urchins inch across the floor between all the sea plants. They only move at a snail's pace, but large groups can clear away 30 feet of these underwater plants in nearly a month. Even now, bits and pieces of the greenery are being chewed away by these spiny invertebrates.

    These urchins too have an adversary controlling their populations. Hovering through the greenery are several Angolachelys, a type of ancient sea turtle. Much like their modern counterparts, they sport a hard shell and four flipper-like limbs. These shells are primarily dark green, the same as the algae, with lines of beige forming hexagonal shapes. The skin on their bodies has the same beige color but with hard, hexagonal scutes whose color matches their shell.

    Another trait Angolachelys share with modern sea turtles is a hard beak on their mouths. These hard, sharp structures are perfect for shearing apart their primary food source, the sea urchins. Normally, the long spines of these small creatures would deter many predators from even touching them. However, the turtles simply bite off these structures, clearing them away before crunching down onto the shells of the urchins. Not only do the Angolachelys get a constant food source, but the field of algae plants gains a reduced risk of being entirely depleted.

    Of course, this feeding isn't entirely constant. As reptiles who evolved on land, the turtles still have lungs and thus need air to breathe. So, now and then, they'd float up to the surface to draw oxygen into their gaping mouths before diving back down.

    Other forms of life lie concealed under the beds of flowing green, slowly feeding off of it. Clams bury themselves in the sand, occasionally consuming passing particles of algae. Barnacles suctioned to the rocks repeatedly open and close their mouths as green specs are sucked in. Marine snails slither across the floor and rocks, vacuuming up whatever they can of the bloom.

    In the greenery, a predator emerges to feast on the snails. A crab, bright red on its top while the rest is a creamy beige. It's none too dissimilar to the crabs seen in our modern waters as they are part of a lineage that goes as far back as the Triassic. Using their claws, they grasp and compress their prey, before nibbling at what's left over.

    This feasting gradually pauses as the crab stares upward. A wavering display of glowing white and dark green flashes above it. Captivated by the moving patterns, the ancient crustacean crawls toward it. The mass of glimmering color seems to grow larger as it approaches the dazed decapod. Suddenly, four, long tentacles spring from the mass and pull the crab toward it. The flashing stops as the appendages encapsulate the hard-shelled animal while four others flow loosely.