Charmouth Mudstone Formation, England, 190 million years ago

For as long as it has existed, planet Earth has comprised two distinct worlds. The first is where life originally evolved: the ocean. This vast region of the globe is by far the most abundant, making up over 71% of the surface. Even in the Early Jurassic, this vast desert of flowing waves hides a wide diversity of organisms.

The second side of the natural world is what we recognize as land. Although a younger frontier for life, the creatures that call these stretches home are still widely varied. The terrains of this above-water realm are also distinguished by the many biomes that exist across the planet.

Between these drastically different domains are spaces where they collide: the coasts. Deep water becomes ever shallower, and dry land becomes ever more wet, a habitat transformed by elements of these distinct sides of our world.

One such shore lies on the edge of what is now England. In the modern day, the area features sizable coastal cliffs and exposed sedimentary rock layers. Sandy beaches stand between them and the waters of the English Channel. Its cool, Atlantic blue cuts the land away from current-day France.

With this being 190 million years in Earth's past, the region is heavily altered from what we recognize. Higher levels of greenhouse gases in the atmosphere contribute to a warmer, humid, more subtropical environment. These temperatures have also made it too warm for the ice caps to form, allowing sea levels to rise further.

For nearly 140 million years, the continents have been conjoined into a colossal stretch of land known as Pangea. Europe lies in the middle of the north half of this mass.

However, after the previous Triassic period ended, this great supercontinent started to show slow signs of splitting apart. In the process, two distinct land masses have begun to form. This northern region will be Laurasia, containing what is now Europe, Asia, and North America. Meanwhile, the southern half became Gondwana, containing what is now Africa, South America, Australia, Antarctica, and the subcontinent of India.

As the continents broke apart, Europe especially saw drastic changes. Salt water flooded much of the mainland, turning it into a series of islands scattered among a shallow sea. Thus, shoreline areas such as here in England have become a common sight.

Much of the land behind this coast is primarily green, made up of a plethora of ancient plant life. Seed ferns, cycads, and horsetails blanket a brown ground of dead leaves, twigs, roots, and moss. Numerous conifer trees tower above them all, casting thick shadows below as shining sunlight strikes them from above.

These patches of vegetation are alive with the sounds of many insects that populate them. Dragonflies, beetles, flies, wood gnats, snake flies, cicadas, damselflies, scorpion flies, and flying earwigs fill the air with many hums and buzzes as they dart and hover around. From the ground, grasshoppers and crickets add to this ambiance with their many chirps and stridulations. The only silent group of insects are the giant water bugs, patiently wading in the many freshwater estuaries for any small prey they can get their pincers onto.

One resident of this lush land is making its way through the greenery on a journey out of it. This type of animal is not an insect, but something much bigger. Honks, grunts, snorts, and groans from it permeate the soundscape with snaps and sifts of its footsteps. It belongs to a group of organisms that has only recently become the dominant life form on land, the dinosaurs.

Rustling through the foliage is a herd of nearly a dozen Scelidosaurus. This is one of the earliest members of the Thyreophora clade, the armored dinosaurs. These herbivores are rather small at only up to 13 feet long, but one day, their kind will paint the evolutionary path of much larger, living tanks such as Stegosaurus and Ankylosaurus.

Their wide, barrel-shaped bodies are shielded by arrays of hard, bony plates. Called "scutes," they greatly contrast in both shape and size. Some are larger and sharper along the flanks of these dinosaurs while others are smaller and more rounded. These pebble-like forms are much more common, running all across the topside of their bodies. Like their later, more well-known relatives, Scelidosaurus walk on four legs, yet have a different posture to them. The rear ones are longer and more muscular while the front ones are shorter but end in broad strong hands tipped with blunt claws. This arrangement allows them to easily switch between quadrupedal and bipedal stances. Thick, tapering tails counterbalance their forms, sporting the same armored scutes. The more jagged bony plates run on the sides of their sturdy necks, ending just under their small, wedge-shaped heads. Blunt, rounded snouts sport a short, beak-like tip used for clipping vegetation. Keen, warm amber eyes positioned to the sides of their heads give them a wide view of their surroundings. Even the tops of their skulls sport the same studded armor plating, including horn-like ones jutting from their cheeks and the back of their heads. Their scaly skin is primarily a dark-reddish brown mixed with the gray of their scutes and a cream underbelly.

Scelidosaurus are found all across England and parts of modern Ireland. They mostly feed on the abundant land vegetation, but now and then, they consume another source of food. This secondary source of food can only be found on the edges of their terrestrial world.

Here, the earth beneath their feet becomes softer as they step onto the pale beige sands. Thousands of grains make up this surface, along with the occasional stones and broken sea shells. The ground is largely dry closer to land, but is much wetter near water where it's constantly bathed by never-ending waves.

These same waves are what bring in the goal of the herd's beachcombing, algal plants. Normally, they'd appear across many parts of the sea floor, painting it in various shades of green. Now and then, they'd be broken loose and washed up on shores such as this. Piles of them are scattered atop the sands, appearing in many forms. Such shapes include branching stems, thin, leaf-like structures, thicker ones akin to lettuce, and ones that appear strangely like wet, green hair.

Their appearance matters not to the Scelidosaurus as all are considered food to them. Every one of these pieces of marine flora is full of minerals and nutrients not found inside inland plant life. Iodine, magnesium, and calcium along with higher levels of protein, salt, and Vitamins A, B, and C complement these herbivores' diets while adding other benefits. Their bone health improves along with their digestive systems and ability to fight off infections.

Undoubtedly, it's the many youngsters of the herd that benefit most from this part of their diet. Higher protein counts in each of these algal plants make them crucial for healthy growth. Since each of these little ones is only one-sixth the size of the adults, they'll need to eat a lot to one day reach their full stature. Although, this doesn't come without issues.

The baby Scelidosaurs have less experience eating this sea vegetation than what is found in the forests. Thus, they tend to struggle to maintain their grip on the slippery greens and bite through their tougher texture. Thankfully, with enough time, patience, and aid from their mothers, the youngsters eventually learn how to ingest such important meals better.

However, these sea plants aren't the only gift given by the tides. Other entities are commonly brought in from the sea, but never alive. The corpses of several fish as well as crustaceans like crabs and horseshoe crabs litter the sand in droves. Decayed algal plants blanket some while others are left exposed on the beach. If they're not already dead when being carried by the current, the fish would be dying, their bodies left to rot as life wilts away. Only the crustaceans would be lucky enough to avoid such a fate if they were still alive.

This stench of death lures other residents from further inland. Clouds of flies and beetles form around the many carcasses, slowly eating away at the moldering meat. Females will also lay their eggs inside the dead fish, allowing the larva a plentiful supply of food to ingest between hatching and becoming adults.

Another flyer—not an insect, but a reptile—is attracted to this seaside graveyard. Swooping onto and crawling on the littered sands is a gathering flock of Dimorphodons. These are early pterosaurs, the order of flying reptiles that, like the dinosaurs, started to bloom in diversity after the end of the Triassic.

Just like many other pterosaurs at this time, Dimorphodons are quite small, their compact, robust bodies growing scarcely more than three feet. Membranous wings stretch out over four feet in an elegant arc. Faint vascular patterns are visible on these smooth layers of tissue when backlit by the golden-white sun. Extended fourth fingers stretch out from the hands of their forelimbs, the ends acting as anchor points that connect their wings to the sides of their bodies. The back end of the thin veil of flesh to slender yet strong back legs ending in sharp curved claws. Unlike many of their later relatives, they have long stiff tails, tapering to a small, diamond-shaped tip. Short, muscular necks support disproportionately large, elongated, and boxy heads. They have sharp, narrowing snouts, large, deep brown eyes, and beaks filled with long, curved teeth in the front and shorter, stockier ones in the back. Primarily, their skin color is hidden by greenish-brown, hair-like pycnofibers. Their wing membranes lack this integument, exposing a solid gray color. Meanwhile, the beaks are also completely bald and are mostly a fiery red that shifts to a bright orange toward the tip.

Dimorphodons are the most common predators in the forests and coasts of this part of England. They primarily spend their days preying on the insects of the environment and scavenging the meat of any corpse they can find. Thus, this mass gathering on the beach has become an all-you-can-eat buffet.

Though, bugs, fish, and crustaceans aren't the only items on the menu here. While grounded, a few Dimorphodons start to dig into the beach. Their beaks toss up more and more sand by the second, deepening the holes even further.

Burrowing further reveals the secret of what lies beneath: eggs. They were laid by horseshoe crabs only a week or so prior. Sandy beaches like this are common nesting sites for the ancient crustaceans, providing the right mixture of moisture and salinity until the young hatch before being swept out to sea.

Being buried in the sand also allows the baby horseshoe crabs to remain hidden from predators while they develop. However, some like Dimorphodons will occasionally dig these nests up to feast on them. For horseshoe crabs, this loss is minimal as 10s of thousands of these eggs have lain across many clusters on this one beach alone. To the pterosaurs, this makes it a highly abundant, nutritious snack. Though other burrows are bound to have these meals in larger supply, occasionally causing these squabbles with one another. These often start as hissing and frantic wing flapping before turning into biting.

One Dimorphodon finds a drastically different clutch in the sifted sands. These eggs aren't soft and transparent, but hard and opaque. They also appear bigger and ovular at around 2 inches in length. Horseshoe crabs didn't lay this batch, but the reptile cares not. Either way, it's still food.

But before the Dimorphodon can get its jaws around any of the eggs, a loud splash turns its attention away. Its head darts to his left, finding the abrupt emergence of another creature on the coast. Unlike anything else seen on this beach, it's not of the land or air, but of the water.

This is a fearsome, 6-foot-long, female Turnersuchus. She's an early member of the thalattosuchians, a group of distant crocodilian relatives adapted to life at sea. The body of this marine reptile is much like what's seen on modern crocs, but much sleeker and more streamlined. Armor is present like in its extant relatives too, but much smoother. Four slender limbs sprawl out, each ending in web-toed feet with small, curved claws. Her form tapers to the end of a lengthy, powerful tail, tipped with a small, fish-like fluke. From the body, a muscular, slightly arched neck flows seamlessly into a long, narrow head. The snout is smooth and thin with jaws filled with sharp, conical teeth. A pair of large, forward-facing eyes sit high upon her skull. Her skin is primarily a grayish-blue with a darker shade along the spine and a lighter gray underbelly.

From the edges of the ocean waters, the Turnersuchus charges at the Dimorphodons, filling the air with the sound of her loud hissing. Startled, the small pterosaurs immediately turn around, throwing their bodies away from the sea croc. They lift their legs and force themselves upward while extending their wings. Frantic cries erupt from them as they scatter across the air. Within seconds, they've completely abandoned the littered sands.

Alone at last, the sea croc treads towards the dug-up whole of eggs. As she does, she starts to hear the sounds of faint chirps. Upon arriving, she shovels away more of the sand, exposing the full clutch of over 20. She peers at the nest, finding small bits of movement. This transitions into cracks forming along the shells and peeks of skin showing through.

For a moment, the Turnersuchus lies completely still, sitting like a statue as it peers down at the hatching eggs. In the blink of an eye, this ends as she thrusts her jaws into the nest. Repeatedly, she snaps her jaws before lifting her head back up, sending the breaking eggs further back into her mouth.

From there, the Turnersuchus reenters the shimmering blue waters, her snake-like movements leaving a trail of ripples in her path. It only takes mere seconds until she reaches a point where her feet don't touch the soft, submerged sands below. As she does, the sea croc's jaws become increasingly agape, revealing what lies inside... babies.

Each of them is scarcely more than an inch and a half long, a small fraction compared to their mother. Their heads are proportionately bigger with much larger eyes and a shorter snout. Even their skin color is different, having a more greenish-yellow hue to it.

While inside their mother's mouth, the young Turnersuchus crawl and squirm all about as they continue chirping, none too dissimilar to the young of modern crocodiles and alligators. Once entering a small pool guarded by rings of stone, the adult sinks her head, prompting the newborns to leave the safety of her jaws. Their swimming is a near-perfect reflection of their mothers only appearing faster, more frantic, and occurring in shorter bursts.

One day, later relatives of these marine crocs will reach the point where they'll no longer lay eggs on the beach. Instead, they'll transition to giving live birth, a method used by nearly every aquatic reptile of this time and even some terrestrial ones in the present day. For now, the roots of Turnersuchus still lie on the land, where afterward, mothers will take their offspring to nursery pools such as these. Here, they'll grow and hunt smaller prey before transitioning into the deeper parts of their environment as they get older.

But the mother's job still isn't over. Even over 10 feet away, she can hear the distinctive calls of what's left of her young on the beach. Thus, the female Turnersuchus heads back, ready to take her newborns to join their many siblings. Even as she travels away, her eyes remain fixated on her spawns who've made it to their nursery pools.

***

Traveling away from the drier shore reveals a deeper, underwater world. Though the levels of salt water aren't as high as what's seen much further in the open oceans, life thrives here in many unique ways. These spots between land and sea are the shallows.

Like the waves of the surface above, sunlight quivers across the floor. Much of it is a series of coal-black stones, formed into a myriad of shapes and sizes throughout hundreds, thousands, and even millions of years. Between them are parts of an underwater desert of smooth sand, some grains being lightly carried away by the flow of the current. Batches of algal plants are lightly back and forth here too, appearing more colorful and fuller of life than they do washed up on the coast.

Towering above them is a strange organism sparsely scattered across the ocean bed. They appear like plants as they have long stems rooting them to the ground. Yet this and the wavering bristled branches growing from the top are an entirely bright orange, standing out from the greens of the marine plants around them. These are in fact, crinoids, or "sea lilies" as they're most commonly named. They're not plants, but rather members of the echinoderm phylum, also containing urchins, starfish, sand dollars, and sea cucumbers. As they remain glued to the sea sand, their bristled arms slowly reach toward the center, eating up any plankton, algae, or other small particles they feed on.

The sands, rocks, and swaying algal fields teem with life, each crevice and corner bustling with activity. Across the sea floor, crustaceans like crabs and horseshoe crabs crawl and scuttle along in search of food. Small fish float and swim, filter-feeding on any small organisms like plankton and algae. Larger fish, including young sharks, feast on their more diminutive contemporaries and any other meaty creatures they can get their jaws onto.

Among them are a group of animals that are highly ancient and widely different. Cephalopods have been on earth for hundreds of millions of years, even before the dinosaurs ever appeared. Their recognizable forms are the squid and octopus of today's oceans. However, they have yet to evolve this early on in the Jurassic.

Instead, their roles are filled by their most iconic, prehistoric relatives: ammonites. They're highly similar to their present-day brethren with their many tentacles hiding a sharp, parrot-like beak. What sets them apart are the coiled, almost snail-like shells that house their fleshy bodies.

Many species are present in these English waters, sharing the same general shape yet are varied in size and other small differences. Most have shells that are smooth with bigger gaps between their rings like Asteroceras. Others like Uptonia have smaller spaces between bands, making them rougher in texture. Phricodoceras stand out among their contemporaries as the bands of their shells protrude into jagged edges.

These many forms of shelled cephalopods share these shallows with ones that only just entered the world. Baby ammonites, no larger than a thumbnail, drift in shimmering clouds through the turquoise water, their translucent bodies quivering as they pulse their tentacles in rhythmic bursts. Having just hatched from eggs laid by their mothers two months ago, they still have an entire lifetime of growth and learning ahead of them.

Similar to their relatives, these baby ammonites have white, almost transparent bodies. Their eyes are proportionately larger and their tentacles are drastically smaller. The shells they're born with are much smoother, destined to become much rougher as they grow into adulthood.

Ammonites aren't the only icons of the Jurassic seas to use this cove as a nursery. Something much bigger and faster visits here every year. Nicknamed the "dolphins of the Mesozoic," they rush through the waters at blistering speeds, regularly breaching the surface with skyrocketing springs.

These are Ichthyosaurus, the namesake of the famous order of fish-like marine reptiles. Their bodies are compact, blubbery, and muscular, built for rapid acceleration and sustained swimming. Like fish, they have short, gently-curved, paddle-like fins, allowing them exceptional control when maneuvering through their aquatic environment. They also have an extra fin set halfway along their backs. Flukes at the end of their tails help to form a crescent shape at the very end. Long, perfectly hydrodynamic heads end in narrow snouts brimming with sharp, conical teeth. Large, expressive eyes dominate the sides of their skulls, shimmering with a dark, glassy sheen. Their smooth, scaleless skin, insulated by a layer of blubber underneath, is primarily a glistening silvery-gray. A darker, almost black shade runs along the top of their forms while a lighter shade is present on their underbellies.

Despite such fame associated with their name, Ichthyosaurus are rather small compared to most in this famous group of reptiles, only reaching up to 11 feet in length. They're also joined by newborn calves, only a fifth the size of their mothers. This discrepancy in measurement makes them highly vulnerable to potential large predators.

However, that's where coves such as these come on. Mother Ichthyosaurus, as well as their many relatives, migrate to these spots yearly to give birth. Many of the carnivores that stalk the open oceans are too large to traverse such shallow waters. Therefore, the young fish lizards can be reared safely until they are old enough to head out into the sea beyond. Though these natural nurseries offer protection for the calves, their mothers remain ever watchful, even as their offspring swim and play together.

Outside of these lush, more active parts of the shallows, there are areas closer to the edge of the sea that are more vacant. Fewer algal plants, no crustaceans, no fish, no Ichthyosaurus, and no ammonites. These aren't the havens for such animals, but rather a stage. The performers are the largest and most different of residents of the shallows. Their unmistakable frames cast a shadow against the sunlit surface as they leisurely swim through.

These are Attenborosaurus, one of the earliest members of the long-necked plesiosaur order of marine reptiles. In our modern day, tales of similar aquatic creatures plague many lakes across the world, often being dubious. However, these are the real Nessies.

Their robust, streamlined bodies are perfectly designed for carving through the aqua. Four flat, prolonged flippers move in synchronized motions, rippling through the water as they propel the creatures with effortless grace. Their tails are remarkably short, ending in a small fluke that aids in steering. Long, sinuous necks flow elegantly from their bodies to their sleek, elongated heads. These streamlined skulls taper to a pointed snout sporting jaws filled with needle-sharp teeth. Their eyes are large and face forward, a single faint, white strip tracing over each of them.

Primarily, the smooth skin of these 14-foot-long plesiosaurs is mainly a dark bluish gray with a white underbelly, blending them in their oceanic environment. However, one group of them easily stands out from the rest: the males. From their heads down to their necks, they sport a vibrant mosaic of greens, purples, and golds.

Only one event in the year causes these colorations to appear on male Attenborosaurus: the mating season. Subsequently, they gather in these aquatic arenas in the hopes of attracting females. This phenomenon lures dozens of these marine reptiles out from the ocean, something quite rare for a normally solitary animal.

During this courtship, the females gently swim through the amassing swarm of males. They assess the bachelors by observing their elegant dancing displays, consisting of spins, flips, and orbits around the females. These suitors are also sure to attract attention to head and neck colorations, allowing the beaming sunlight to bounce and glitter off their iridescent skin. A few males take the extra mile, occasionally breaching through the surface halfway before diving back under with an erupting splash. Doing so, creates clouds of rising bubbles around their bodies, enhancing their already fluid ballets.

The many combinations in these displays allow the males to show off their fitness. But with so many Attenborosaurus gathered here in the shallows, it will take a lot for each of these potential bachelors to stand out. After all, only the most eye-catching males will be able to mate.

Already, one has succeeded despite only recently arriving. His name is David and at 15 feet in length, he's exceptionally large for his kind. He also easily has the brightest colors of any male here, creating the biggest of sparkles and glimmers along his head and neck.

Instantly, David gravitates to one lone female in the middle of the arena. He begins twirling his body around, circling her as they gently drift through the liquid blue. The female only stops upon finding the large male upside down in front of her.

For a moment, they simply stare into one another's eyes. This soon turns their noses gently tapping together before twirling together in sync. In their rotating rise to the surface, both Attenborosaurus grow ever closer to each other, a sign that the courtship spectacle has been a success.

Now receptive, the female touches her underside with that of David. Subsequently, they also place their flippers around one another in a hug-like embrace. Once reaching the surface, the pair bob above the water, maintaining their hold on each other. As they do, David begins to impregnate the female. The act is brief and the Attenborosaurus separate not long after.

Males serve no part in raising their offspring, thus the process will be left to the female. Now expecting, she swims further into the shallows where her spawn will be raised alongside the other aquatic residents. Meanwhile, David remains, continuing his display with the other males. If he's lucky, he may find himself another mate.

In these little worlds between land and sea, many species live harmoniously off of the benefits they provide. Terrestrial animals like Scelidosaurus and Dimorphodon reap the rewards brought to them by the tide. More aquatic types such as Turnersuchus, Ichthyosaurus, and ammonites use the depthless waters as a refuge to foster the next generation. For the Attenborosaurus, it's proven to be a perfect staging ground for their chance to forge more of their kind. These are just some of the many cycles that take place year-round in places such as the shallow sanctuary.