Prehistoric Wild: Life in the Mesozoic

First Flight (110 MYA)

Romualdo Formation, Brazil, 110 MYA

For nearly 30 million years, the continents of Africa and South America have been drifting apart. For much of the Mesozoic era, they were joined by Antarctica, Australia, and the Indian subcontinent to form Gondwana. Thanks to the continuous shifting of tectonic plates, the southern continents have been progressively moving away to form their land masses.

Between the biggest continents of the southern hemisphere is an ever-growing stretch of seawater, the beginnings of the South Atlantic Ocean. Such a dramatic change in the continental status quo has created coastal areas on both landmasses. The land of what is now northeastern Brazil is just one of many such areas.

Here, ocean waves slide and retreat along the sandy, algae-litter sands. Some parts of this shore are eclipsed by tower rocky cliffs, hundreds of feet high. The scorching mid-day sun radiates heat onto the arid land on top while casting a shadow on most of the beach below.

The beach extends past the initial coast, creating tidal flats in some parts. Batches of moist sea mud of varying sizes rest interspersed along the shallower ends of the seaboard. Groups of barnacles attach themselves to the many, differently shaped rocks in these flats. Flies buzz around the air here, gathering in massive clouds. Their days are spent primarily feasting on the carcasses of fish and other marine animals that wash up on the shore.

This coast is also the feeding ground of a much larger animal. Stalking the tidal flats is an Irritator, a Brazilian member of the spinosaur family of two-legged theropods. Despite being 26 feet long, it's small compared to most of its relatives. Its robust body sports a short, half-oval-shaped sail and ends in a long, rigid tail. Sharp claws grow from the end of each of the three fingers on its robust arms. Like its relatives, its head is elongated and shallow with a slender snout lined with straight, unserrated, conical teeth. Dangling from its lower jaw to its throat is a fleshy, magenta pouch. A thin, sagittal crest runs atop its head. Its scaly skin is primarily burnt umber with vertical, beige stripes along its back and an underbelly of the same color.

Leisurely, the Irritator approaches the edge of the seawater, leaving three-toed prints in the mud behind it. Flies start to buzz and hover around its face and body, attempting to bite its skin. Throughout this, it repeatedly shakes its head and grumbles lowly. It then snaps at the flies several times, causing many of them to scatter away.

The buzzing insects quickly retreat as soon as the Irritator enters the water. Now hip deep into the sea, it focuses through the clear blue waves. Through the surface, it's able to glimpse a part of the world that lies beneath. Crabs crawl across the beige, silty floor, sometimes even being buried by it. Young sea turtles float by, flapping their flippers in the water.

Out of all that swims through here, one lifeform catches its attention the most, fish. Several of these ray-finned, scaly animals tread the waters here in mass. Their size and growth stages range from 1-foot adults to 4-inch youngsters.

Upon seeing the assortment of fish, the Irritator lunges its head toward the water. A splash rises from the surface as its jaws snap into it. It immediately pulls out, its mouth filled with many fish. Both its pouch and its widening lower jaw allow it to hold much of its favorite prey. The further pulling back of this structure also pushes out any excess salt water. Now the piscivore is free to swallow its catch directly, an act made easier thanks to its widening lower jaw also expanding its throat.

Upon ingesting its catch, the Irritator glances back down at the water below. Now that he has struck, the fish that he missed have completely swum away. Thus, the predator treads along the coast, searching for more of his prey.

Quickly it spots something swimming across the liquid blue. It appears different from the other fish but will serve as an excellent meal, nonetheless. With no hesitation, snaps its jaws onto the animal before abruptly tugging it out.