Flight on Niobrara Wings

Summary: In the Niobrara Formation, Western Interior Seaway, 85 million years ago in the Santonian age of the Late Cretaceous, a dominant Male Pteranodon goes off with his fellow kin on the annual Apsopelix run, a gathering where marine predators come to feed.

Cast: Pteranodon(Focus), Archelon, Baptornis, Claosaurus, Clidastes propython, Cretoxyrhina, Dolichorhynchops, Ectenosaurus, Elasmosaurus, Eonatator, Fumicollis, Geosternbergia/Pteranodon sternbergi, Hesperornis, Ichthyornis, Nyctosaurus, Parahesperornis, Platecarpus, Polycotylus, Selmasaurus, Squalicorax, Styxosaurus, Tylosaurus, Xiphactinus, Protostega, Parapuzosia, Ptychodus, Enchoteuthis, Apsopelix, Enchodus, Protosphyraena, Bonnerichthys, and Niobrarasaurus.

It starts on the second floor of the Natural History Museum of Los Angeles, Thomas stands behind a fossil display of skulls of two prehistoric flying reptiles, one has a larger crest than the other as he begins to speak, "Pterosaurs filled the skies of the Mesozoic era, they were the first of the back-bone vertebrate animals to evolve the ability of powered-flight. Pterosaurs were not dinosaurs. By definition, all dinosaurs belong to the group Dinosauria; Pteranodon belongs to the group Pterosauria. While not dinosaurs, pterosaurs such as Pteranodon form a clade closely related to dinosaurs as both fall within the clade Avemetatarsalia." Thomas brings out a cast model of the focus pterosaur. "This pterosaur is the most familiar Pteranodon. This was the most famous pterosaur, frequently featured in dinosaur media and strongly associated with dinosaurs by the general public. It was one of the largest known flying reptiles having a wingspan of over 6 m (20 ft). More fossil specimens of Pteranodon have been found than any other pterosaur, with about 1,200 specimens known to science, many of them well-preserved with nearly complete skulls and articulated skeletons. It was an important part of the animal community in the Western Interior Seaway. Behind me are two fossil skulls, the smaller one sporting a small crest representing a female while the larger skull has a long large crest representing the male, this is an example of sexual dimorphism. But what would its life be like flying over and fishing in the Niobrara Seaway in Kansas, North America?"

. . . . .

The Western Interior Seaway also called the Cretaceous Seaway, the Niobrara Sea, the North American Inland Sea, and the Western Interior Sea) was a large inland sea that split the continent of North America into two landmasses. The ancient sea, which existed from the early Late Cretaceous (100 million years ago) to the earliest Paleocene (66 Ma), connected the Gulf of Mexico, through the United States and Canada, to the Arctic Ocean. The two land masses it created were Laramidia to the west and Appalachia to the east. At its largest extent, it was 2,500 feet (760 m) deep, 600 miles (970 km) wide, and over 2,000 miles (3,200 km) long.

By Late-Cretaceous times, Eurasia and the Americas had separated along the South Atlantic, and subduction on the west coast of the Americas had commenced, resulting in the Laramide orogeny, the early phase of growth of the modern Rocky Mountains. The Western Interior Seaway may be seen as a downwarping of the continental crust ahead of the growing Laramide/Rockies mountain chain.

The earliest phase of the Seaway began in the mid-Cretaceous period when an arm of the Arctic Ocean transgressed south over western North America; this formed the Mowry Sea, so named for the Mowry Shale, an organic-rich rock formation. In the south, the Gulf of Mexico was originally an extension of the Tethys Sea. In time, the southern embayment merged with the Mowry Sea in the late Cretaceous, forming the "complete" Seaway, creating isolated environments for land animals and plants.

The Seaway was warm and tropical, with abundant calcareous planktonic algae. Remnants of these deposits are found in northwest Kansas. The Western Interior Seaway is believed to have behaved similarly to a giant estuary in terms of water mass transport. Riverine inputs exited the seaway as coastal jets, while correspondingly drawing in Tethyan waters from the south and Boreal waters from the north.

The Western Interior Seaway was a shallow sea, filled with abundant marine life. Along the coastal floodplains of Laramidia, some dinosaurs lived next to the ocean. Herds of hadrosauroids known as Claosaurus, a primitive hadrosaurian dinosaur that was small by hadrosaurian standards as it was nearly the length of a rhinoceros (some of the more advanced later hadrosaurs were around 3 to 5 times larger). An analysis in 2008 found that Claosaurus was outside of the hadrosaurid clade, making it the closest not-hadrosaurid relative of true hadrosaurids within the clade Hadrosauria. The Claosaurus walk along the sand of the beaches, some individuals bend down to feast on salt-enriched kelp washed up on the beach, licking the salt-encrusted rocks, skeletons, and driftwood logs for minerals, and occasionally snacking on crabs. The herd arrives at an estuary to feed on the vegetation growing nearby and wallowing in the shallows, some individuals feed on water plants on occasion, their broad beaks would be great for cropping seaweed or aquatic plants. The hadrosaurians are often accompanied by one or a few Niobrarasaurus, nodosaurid ankylosaurs alongside feeding on the washed-up seaweed and plants growing on the dunes.

They are often landing pads for smaller creatures, a few Ichthyornis land on the Nodosaurs' back to rest and peck bugs off the ankylosaur. These birds are the Cretaceous equivalent of gulls, petrels, skimmers, opportunistic hunters, and scavengers often resorting to stealing from others. Ichthyornis has been historically important in shedding light on bird evolution. It was the first known prehistoric bird relative preserved with teeth, and Charles Darwin noted its significance during the early years of the theory of evolution. Flocks of Ichthyornis fly above the beach looking for any opportunity, from washed-up dead carcasses or anything they see as food.

A few landed on the beach during low tide dabbing their beaks in the sand for meiofauna like bivalves (clams and cockles), gastropods (snails), sand crabs, hermit crabs, and annelid worms searching for close to a nest covered with sand and seaweed, a few approached the nest, and they are suddenly chased off by its protectors. A female Pteranodon gallops and honks fiercely at the birds as they fly away, This is the mother and she'll guard her nest from eggs. She is just one of many in this colony, this stretch of sand-covered beach and neighboring cliffs are filled with pterosaurs.

The females are small with small, rounded head crests that are small and triangular, they come here to lay their eggs and raise their young. The size and shape of these crests varied due to several factors, including age, sex, and species. They are quite numerous in fact, the gender ratio is mostly females outnumbering males. In the center of the flock standing on a rock among the females and their young, is a large proud Male. Adult Male Pteranodons are twice the size of the females, and he has a large narrower, more backward-projecting crest. His crest is brightly colored during the breeding season to attract the females, Pteranodons live primarily in offshore rookeries, where they can nest away from land-based predators and feed far from shore; being polygamous, this male protects and guards his harem of females. In other groups, there are small bachelor groups who would challenge the dominant males through beak wrestling and dogfight aerial battles. Younger males are sneaks resembling the females in appearance and having a short crest, they could mate with the females behind the Dominant Males' backs.

Pteranodons aren't the only pterosaurs and flying creatures here, the cliff tops and rocky shores are home to Geosternbergia. The males of these pterosaurs have a more vertical crest with a broad forward projection alongside Pteranodon; it was among the largest pterosaurs, with the wingspan of most adults ranging between 3 and 6 meters (9.8 and 19.7 ft). It is debated whether it should be considered a species within the Pteranodon Genus or its own species. There are also Nyctosaurus, Males who possess an extraordinarily large antler-like cranial crest. It was once thought it could have a sail of skin before it was disproven.

On the cliffs, the Ichythornis make their nests on the cliff sides to raise their chicks on the calm shoreline of lagoons is a flock of strange birds. The Hesperornis, Baptornis, Fumicollis, and Parahesperornis resemble loons but have no wings. Like many other Mesozoic birds such as Ichthyornis, Hesperornis had teeth as well as a beak. Like loons, the legs were probably encased inside the body wall up to the ankle, causing the feet to jut out to the sides near the tail. This would have prevented them from bringing the legs underneath the body to stand, or under the center of gravity to walk. Instead, they likely moved on land by pushing themselves along on their bellies, like modern seals. However, more recent studies on hesperornithean hindlimbs suggest they were more functionally similar to those of the still-upright walking cormorants.

Coming from the oceans are large female sea turtles, Archelons, and Protostegas. The females have come to the beach to lay their eggs at the place where they were hatched. They would lay about 110 eggs they would dig with their back flippers creating a large body pit for their eggs. Once buried, the adults would return to the ocean and the eggs incubate in the warm sand for about 60 days. The temperature of the sand determines the genders of baby sea turtles, with cooler sand producing more males and warmer sand producing more females. Once hatched, only a few will survive to adulthood and when they do hatch they would become a feast to many predators from birds, pterosaurs, fish, and marine reptiles.

Occasionally the pterosaurs take off from land to fish along the coast joined by the Hesperornithes diving in the waters. Like other pterosaurs, they take off from a standing, quadrupedal position. Using their long forelimbs for leverage, they would have vaulted themselves into the air in a rapid leap. Almost all of the energy would have been generated by the forelimbs. The upstroke of the wings would have occurred when the animal cleared the ground followed by a rapid down-stroke to generate additional lift and complete the launch into the air. The Pterosaurs dive into the water to catch, although they must avoid thieves, a Pteranodon sternbergi is being mobbed by a flock of Ichthyornis, One Pteranodon is being chased by a Nyctosaurus which flew similar to modern-day soaring birds such as albatrosses, which consisted of flying very long distances and rarely flapping.

Our Dominant Male Pteranodon is being chased by others of his own species, but one of them has been caught by a Selmasaurus who breaches out of the water to catch the flying reptile. Selmasaurus was a small predatory mosasaur at approximately 3–5 meters in length. It possesses a relatively low number of teeth for a mosasaur, the lowest of any known species at the time of its discovery. But Selmasaurus is unique among the mosasaurs in that its skull is unusually akinetic, meaning that it is incapable of widening to swallow large prey. Most mosasaurs have skulls that possess "coupled kinesis" (mesokinesis and streptostyly), that is, parts of the jaw can open widely to accommodate large prey.

Another victim is grabbed by a tangle of tentacles, a large ammonite called Parapuzosia. This ammonite is the largest of these cephalopods known to have lived, with a shell possibly over 3 meters in diameter. Parapuzosia is thought to of been a pelagic predator, feeding on other oceanic organisms. These may have included fishes, other cephalopods (including squids and even other ammonites), as well as possibly even smaller marine reptiles even pterosaurs if they could catch them. When a Parapuzosia has a prey item such as a fish or a Pteranodon within its tentacles, the prey would have been manipulated and positioned near the mouth. This would have been a strong, very tough beak that could slice flesh as well as crush shells and bones.

The coasts are filled with dangers with many predators patrolling the shores. Mosasaurs use these areas to give birth to their young which will grow up until adulthood, but some smaller species remain here. Clidastes, agile swimmers preying upon cephalopods, fish, and other small vertebrates in shallow water and may occasionally have entered freshwater, just like modern sea snakes. Clidastes was one of the smallest of the mosasaurs (the smallest known being Dallasaurus), averaging 2–4 meters (6.6–13.1 ft) in length, with the largest specimens reaching 6.2 meters (20 feet) long. The name refers to how the vertebral processes allow the proximal heads of the vertebrae to interlock for stability and strength during swimming. Even though the vertebrae lock together, the living animal would have still had a range of motion in the horizontal plane that is sufficient to allow for the high quality of swimming in shallow waters. Additionally, the strengthening of the tail, and entire backbone, allowed for muscle attachments to help it swim. It possessed a delicate and slim form with an expansion of the neural spines and chevrons near the tip of the tail and this enabled it to chase down the fastest of prey.

Clidastes represent one of the first properly marine predatory forms alongside other early hydropedal genera like Tylosaurus and Platecarpus. This mosasaur has a long, down-turned tail with a large dorsal lobe on it, steering flippers, and jaws lined with conical teeth which were less robust, suggesting that they fed on smaller (or softer) prey such as small fish and squid. It swam like a shark in a form of movement known as carangiform locomotion. The downturned caudal vertebrae of Platecarpus suggest it had a crescent-shaped tail fluke. At the point of the tail where the fluke begins the vertebral centra are shortened and disk-like. Their reduced size likely allowed for greater flexibility in an area that would have experienced high stresses during swimming. The neural spines of these vertebrae also have grooves for the insertion of interspinal ligaments and dorsal connective tissues which would have aided in lateral movement of the fluke. The ligaments were probably made of collagenous fibers that acted as springs to move the tail back into a resting position after energy was stored in them. These types of ligaments work in some living fish to conserve energy during repetitive bending of the tail. While the fluke and back of the tail were undulated in the Platecarpus, the base of the tail remained stable.

Platecarpus would have occasionally visited freshwater as well, these small mosasaurs swimming about ignore the pterosaurs they help in the hunt by chasing the fish towards the pterosaurs, they pose no threat to adults, but would go after fledging pterosaurs who attempt to fly. One Nyctosaurus victim was a fledgling who got stranded on the water and tried to swim back to shore only to be pounded by the waves and grabbed by another small mosasaur, Ectenosaurus. But these small mosasaurs are prey to the larger Tylosaurus and other larger ocean predators, An Eonatator taking a breath of air is grabbed by a larger mosasaur that attacks from the side, It was a Tylosaurus, the Sea Rex, one of the largest mosasaurs of all time, measuring at 8–9 meters (26–30 ft) long and weighed around 1.1–1.8 metric tons (1.2–2.0 short tons). It was the top predator of the Western Interior Seaway preying on a wide range of prey from birds, pterosaurs, dinosaurs, sea turtles, fish, sharks, plesiosaurs, and even other mosasaurs including their own species. The dead remains are left to the Crow Sharks known as Squalicorax to feed on nothing here is wasted.

Mosasaurs might be one danger, but another danger is sharks like Cretoxyrhina, the "Ginsu Shark." Measuring up to 8 meters (26 ft) in length and weighing over 4,944 kilograms (4.866 long tons; 5.450 short tons), Cretoxyrhina was one of the largest sharks of its time. Having a similar appearance and build to the modern great white shark, it was an apex predator in its ecosystem and preyed on a large variety of marine animals including mosasaurs, plesiosaurs, sharks, and other large fish, pterosaurs, and occasionally dinosaurs. Its teeth, up to 8 centimeters (3 in) in height, were razor-like and had thick enamel built for stabbing and slicing prey. The dominant Pteranodon dove down to catch another fish after losing it to the thieves, unfortunately, he's now a target coming towards him a 'Ginsu shark.' Cretoxyrhina was also among the fastest-swimming sharks, with hydrodynamic calculations suggesting burst speed capabilities of up to 70 kilometers per hour (43 mph). It has been speculated that Cretoxyrhina hunted by lunging at its prey at high speeds to inflict powerful blows, similar to the great white shark today, and relied on strong eyesight to do so. The Pteranodon takes off to the surface of the water just as the shark breaches the water, but it misses and the pteranodon lives to fly another day. Despite its failure, as an apex predator, Cretoxyrhina played a critical role in the marine ecosystems it inhabited.

. . . . .

A few weeks passed, and a special event was about to happen. The predators of the Niobrara had known it for many generations. Soon the Pteranodons longiceps and sternbergi including the adult male alongside Nyctosaurus and Ichthyornis take to the skies flying to sea. Baptornis, Fumicollis, Hesperornis, and Parahesperornis dived into the shores while the mosasaurs, Clidastes propython, Platecarpus, Ectenosaurus, Selmasaurus, Eonatator, and Cretoxyrhina, Ginsu Shark swim towards open ocean. An annual migration is coming and this is what almost every predator of the Western Interior Seaway depends on.

It is the run of a small fish called Apsopelix, which spend their lives around coastal open waters feeding on plankton. Every late spring to summer, these anchovy-like fish come here to spawn in the cool waters along the coastline containing millions of individual fish. Their sheer numbers create a feeding frenzy for the predators. It is believed that the water temperature has to drop below 21 °C for the migration to take place, Conditions require Decreasing sea surface temperature, Calm current conditions, Light north-westerly land breezes, and Stable atmospheric conditions. Water temperature has an inverse and highly significant influence. This is consistent with the preferred temperature range of Apsopelix. Sea currents have a significant effect, with calm current conditions most favorable for Apsopelix presence and moderate current speeds from north to south most detrimental. As Apsopelix movement during the run is northwards, this counter-current effect is expected.

The ocean predators of the coasts are later joined by other marine predators joining the masses, long-necked plesiosaurs like Elasmosaurus and Styxosaurus, and short-necked plesiosaurs like Dolichorhynchops and Polycotylus. There were sharp-toothed fish like the pug-faced Gillicus, schools of Enchodus, and its larger relative, Xiphactinus. Xiphactinus is a glutton that eats other fish from small Apsopelix to Gillicus, birds like Hespronis, small marine reptiles, sharks, and even cannibalism on their own species. There are even swordfish like Protosphyraena, averaging 2–3 meters in length, which have become part of the great sea feast.

The ocean floor has strange inhabitants like the shark Ptychodus which has a massive arrangement of crushing plate teeth. A Ptychodus jaw contains many teeth, up to 550 teeth, 220 of which are on the lower jaw and 260 in the upper jaw. These teeth were enormous as well—Paleontologists believe that the largest tooth plate measured 55 centimeters in length and 45 centimeters in width. There are two distinct formations of tooth plates between the genus; one being juxtaposed, non-overlapping tooth rows, and another being imbricated tooth rows. It is believed that the shape coincides with the diet of the species and their geographic locations, but the time it lived has a big part as well. Giant Sea turtles like Archelon and Protostega spend their time here to feed on benthic marine organisms, one of them is the strange cephalopod like Enchoteuthis, which is more closely related to octopus than squid. Before a Protostega can approach one, the Enchoteuthis squirts a cloud of black ink to distract the Sea Turtle for the cephalopod to make its getaway escape.

Soon the predators arrive at the school, and the Apsopelix group together when they are threatened. This instinctual behavior is a defense mechanism, as lone individuals are more likely to be eaten than when in large groups. The Elasmosaurus, Styxosaurus, Dolichorhynchops, and Polycotylus use their bodies and necks to swim around the fish to create a bait ball, the long-necked plesiosaurs retract their necks to launch a strike or use side-swipe motions to stun or kill prey with their laterally projected teeth. The Sharks, Protosphyraena, Large fish, and small Mosasaurs join in to herd the fish, Gillicus, schools of Enchodus, and its larger relative, Xiphactinus mouth their mouths to swallow the small fish whole. The Protosphyraena charge at high speeds through forage fish schools, slashing with their pointed upper snouts to kill or stun prey. The Mosasaurs and sharks use their tails and dorsal fins to corral them and stun their prey to consume them at the top, while the Hesperornithe birds maneuver to chase the fish using their paddle-like feet to swim at high speeds and Dolichorhynchops and Polycotylus herd the fish to the surface, this is what the flying animals were waiting for.

With the Big Male taking the lead diving head first, The Pteranodons dive down to the ocean for their take on the hunt, The head, neck, and shoulders of Pteranodons were as heavily built as diving birds, and suggested that they could dive by folding back their wings like the modern gannet. They swim using their wings to catch the fish before swimming back up to the surface. The Nyctosaurs and Ichthyornis snatch the fish that leap out of the surface. Then a big surprise, when a large fish swims from out of the depths taking a big gulp of Apsopelix, Bonnerichthys. It grew to at least 5 meters (16 ft) in total body length, One of the most significant features of Bonnerichthys is the recognition that it was a filter feeder, living on plankton. But during an event like this, it would feed on the small fish.

As this continues, with all marine species working together the bait ball becomes smaller and smaller and soon there are some survivors left for them to spawn in the coastal cool waters. The stun dead fish missed by the predators float down for the scavengers like Sea Turtles and Cephalopods to feed on. Soon all the marine predators depart on their separate ways with the pelagic predators returning to the open ocean while the pterosaurs including the Big Male and the coastal predators swim and fly back to the coast. This has been an event that the Big Male Pterosaur will never forget and he will be around for many years to come in the oceans of the Niobrara Seaway of our Primeval Planet.

Trivia/References:

-Claosaurus eating crabs is based on a recent discovery of crab shells found along with plant remains in the coprolite (fossil dung) thought to be from a hadrosaur from Campanian age Utah, showing that these dinosaurs would've fed on crustaceans for protein in addition to vegetation, based on a Walking with Dinosaurs, Claosaurus Profile artwork by TrefRex.

-The Mosasaur nursery grounds along the coast are based on fossil evidence.

-Pterosaur parental care is based on a recent discovery on the wing growth wings of youngsters, meaning the young of larger species rely on the adult's protection and guidance to food by the adult.

-The First Pteranodon hunting scene is based on the Rite of Spring Segment from Fantasia.

-The Parapuzosia catching a Pteranodon with its tentacles is based on a video of a Giant Pacific Octopus when it tries to prey on a bald eagle, as well as this video with an octopus dragging a seagull underwater, which is based on an artwork by Olmagon, titled "Ammonite Attack."

-Hesperornis and relatives' nesting behavior is based on cormorants, loons, and grebes.

-The Pterosaur colony is inspired by seabirds, evidence of pterosaur guano particularly in Oregon, and artwork by Taliesaurus called "PALEOART- PTERANODON RESTING ON SHORELINE."

-The Pterosaur fishing pose is also based on an artwork from Taliesaurus, "PALEOART- Pteranodon fishing."

-The Tylosaurus and Cretoxyrhina stalking the pterosaurs and the Cretoxyrhina leaping out of the water to catch the male is based breaching great white sharks and on two artworks by WildandNatureFan, "Escape from Cretaceous Shark" and "Patience Until Ambush."

-The Pteranodon/Geosternbergia sternbergi being mobbed by a flock of Ichthyornis is a reference to the Egg Travels Scene in Disneys' Dinosaur.

Speculative Behaviors:

This story is inspired by an Artwork project titled, "Pteranodon: King of the Sky [SpecDoc idea]," CYCreon. Which include the following scenes and behaviors:

-Niobrarasaurus accompanying the Claosaurus herd and a landing pad to Ichthyornis, which is also based on a Walking with Dinosaurs Profile Page on Niobrarasaurus by TrefRex.

-The Claosaurus feeding on aquatic plants like a moose is based on an artwork "All Yesterdays Fan-art 12," by Boverisuchus.

-Ichthyornis mobbing the pterosaurs, stealing prey from them, and trying to hunt pterosaur eggs, But also finding prey in the sand and nesting on cliff sides is based on, of course, Gulls. But Pterosaurs also have to prevent their prey from being stolen by other pterosaurs from Nyctosaurus being similar to frigatebirds and even members of their own species.

For all you Readers out there please Review my stories!

You can suggest ideas for stories for the other creatures and can suggest dialogues, scenes, and natural or speculative behaviors for the prehistoric animals.

Comments and positive feedback are helpful to make this story more complete, but negative, hateful, and spam comments are not allowed and will be reported.

The Next Story is "Morrison Trek," inspired by an accurate style of the Land Before Time, which sees the journey of a young juvenile male Apatosaurus and his unlikely companions as they travel to find their herds in the intense drought of the Dry Season.

This is WildExpert24 signing off.