145 — 66 Ma

Cretaceous

Flowering plants transform the landscape until an asteroid impact ends the age of dinosaurs.

Northern Hemisphere

Late Cretaceous European chalk sea floor with Micraster urchins

In the warm, shallow chalk seas of Late Cretaceous Europe, about 100–66 million years ago, the seafloor was blanketed by fine white carbonate mud made largely from coccolithophore remains. Scattered across this pale bottom are heart-shaped Micraster sea urchins and broad shells of the giant bivalve Inoceramus, while a loose school of small teleost fishes glides through the milky turquoise water above. This scene captures the calm epicontinental seas that once covered much of northern Europe, whose accumulated sediments later formed the famous chalk deposits of Britain and France.

Tylosaurus hunting Placenticeras in Western Interior Seaway

In the warm waters of North America’s Western Interior Seaway, about 80–75 million years ago in the Late Cretaceous, a giant mosasaur, Tylosaurus proriger, surges through a flashing school of small clupeomorph fish toward a ribbed Placenticeras ammonite. Below, fang-toothed Enchodus patrol the dimmer water above a soft muddy seafloor scattered with shell debris. This scene captures the rich marine food webs of the Campanian inland sea, where apex reptiles, predatory bony fish, and cephalopods thrived in a vast shallow seaway that split the continent in two.

Late Cretaceous European lagoon with rudist bivalve reef

In a warm, shallow lagoon on a Late Cretaceous European carbonate platform, dense clusters of rudist bivalves such as Hippurites and Radiolites rise from rippled lime sand like short stone horns, surrounded by green calcareous algae and a few small coral patches. Tiny decapod crustaceans shelter among the shells while deep-bodied pycnodont fishes glide through the clear, sunlit water. Scenes like this, roughly 100–66 million years ago, show how rudists—not modern reef corals—often formed the main reef-building communities in parts of the ancient Tethys Ocean.

Tyrannosaurus rex confronting Triceratops on Late Cretaceous riverbank

On the coastal plains of western North America at the very end of the Cretaceous, about 67–66 million years ago, a massive Tyrannosaurus rex edges toward a defensive Triceratops horridus on a shrinking oxbow-lake sandbar. The predator’s deep skull, heavy-scaled body, and small forelimbs contrast with the ceratopsian’s lowered horned head, broad frill, and powerfully braced stance, capturing a likely high-risk encounter in the Hell Creek ecosystem. Around them lie trampled wetland plants, muddy tracks, and storm-darkened floodplain sediments that evoke the rich riverine landscapes of Late Maastrichtian Laramidia, just before the end-Cretaceous extinction.

Velociraptor ambushing Protoceratops in Late Cretaceous Mongolian dunes

In the arid dune fields of Late Cretaceous Mongolia, about 75–71 million years ago, a feathered Velociraptor mongoliensis launches an ambush on the stocky ceratopsian Protoceratops andrewsi, echoing the famous predator-prey association preserved in Djadokhta Formation fossils. The scene shows a harsh desert world of wind-rippled red sand, sparse low shrubs and conifer-like plants, and blowing dust, where agile dromaeosaurs and beaked herbivores lived in a burial-prone landscape that could rapidly entomb animals in combat.

Edmontosaurus herd crossing Hell Creek river plain wetlands

In the final million years of the Cretaceous, about 67–66 million years ago, herds of the duck-billed dinosaur Edmontosaurus annectens moved across the humid river plains of the Hell Creek Formation in western North America. This scene shows adults and a juvenile wading through a muddy channel bordered by taxodiaceous conifers, early broadleaf flowering trees, ferns, and horsetails—vegetation typical of a warm, seasonally wet Late Maastrichtian floodplain on Laramidia. Their horizontal posture, deep tails, and broad beaks reflect the anatomy of these large herbivores, which were among the most common dinosaurs living just before the end-Cretaceous mass extinction.

Feathered Caudipteryx in Early Cretaceous Jehol forest ecosystem

In the Early Cretaceous Jehol ecosystem of northeastern China, about 125 million years ago, feathered Caudipteryx forage along an ash-dusted lakeshore beneath ginkgoes, conifers, cycads, and tree ferns, while small enantiornithine or other early birds perch in the branches above. On the forest floor, the robust mammal Repenomamus searches through fern cover, illustrating the surprising diversity of this volcanic woodland preserved in the Yixian Formation. The scene reflects a cool-temperate landscape shaped by frequent ash falls, with early flowering plants present only as low shrubs rather than a modern-style forest canopy.

Juvenile hadrosaurids in Late Cretaceous Arctic polar forest

In the polar forests of Arctic Alaska some 70–68 million years ago, juvenile hadrosaurids forage along a dark, peaty stream beneath the low midnight sun of a Late Cretaceous summer. Deciduous conifers resembling Metasequoia, scattered ginkgos, ferns, horsetails, and early flowering shrubs formed cool-temperate high-latitude woodlands on the northern edge of Laramidia, where dinosaurs endured months of continuous daylight and winter darkness. This scene reflects a surprisingly lush Arctic ecosystem, showing that duck-billed dinosaurs thrived far north of the Arctic Circle in a moist, seasonal world unlike the icy polar regions of today.

Equatorial Zone

Sarcosuchus ambush in Early Cretaceous Niger floodplain

On a seasonal floodplain of the Elrhaz Formation in what is now Niger, about 125–100 million years ago in the Early Cretaceous, the giant crocodyliform Sarcosuchus imperator lies half-submerged in a shrinking muddy channel, its armored back and long, broad snout barely breaking the surface. Nearby, small basal ornithopod dinosaurs edge cautiously toward the remaining water while lungfish and other stranded aquatic life signal the harsh dry season. This scene captures a predator-rich tropical river system of equatorial Africa, where conifers, horsetail-like plants, and patchy fern cover lined channels that periodically swelled and then contracted under a strongly seasonal climate.

Paralititan sauropods browsing African coastal delta in Cenomanian

In the Cenomanian of northern Africa, about 95 million years ago, a herd of the giant titanosaur Paralititan stromeri wades across a muddy coastal delta under towering monsoon clouds. These enormous sauropods browse among ferns, horsetails, cycads, bennettitaleans, and early flowering plants, while small ornithocheiroid pterosaurs glide overhead above sediment-choked channels and brackish pools near the southern margin of the Tethys Sea. The scene captures a hot equatorial greenhouse world, where floodplain wetlands supported some of the largest land animals of the Cretaceous.

Spinosaurus hunting fish in North African Cenomanian river

In the blazing midday heat of Cenomanian North Africa, about 95 million years ago, a giant Spinosaurus aegyptiacus wades chest-deep through a muddy river, using its long crocodile-like snout and powerful, paddle-like tail to pursue fish in a predator-rich floodplain ecosystem. Nearby, the saw-bearing fish Onchopristis numidus cuts through the sediment-laden water while freshwater turtles bask on sandy bars among sparse ferns, cycads, and conifers. This scene reflects the Kem Kem-style river systems of the mid-Cretaceous, where semi-aquatic theropods, large fishes, and reptiles thrived under intensely hot equatorial conditions.

Late Cretaceous tropical understory with flowering angiosperm blossoms

In a humid equatorial forest of the Late Cretaceous, about 100–66 million years ago, towering araucarian and podocarp conifers rise above a shaded understory of early flowering plants, tree ferns, cycads, and moss-covered fallen logs. Small, pale blossoms on magnoliid-grade angiosperms attract beetles, wasps, lacewings, and primitive bee-like pollinators, reflecting the expanding ecological role of flowering plants during this interval. The scene captures a transitional tropical ecosystem, where ancient gymnosperm-dominated canopies still prevailed even as angiosperms were rapidly diversifying below.

Mid-Cretaceous anoxic sea with dark organic mud

A calm, plankton-rich equatorial sea during a mid-Cretaceous Oceanic Anoxic Event is shown in partial cutaway, with bright turquoise surface waters fading downward through a murky chemocline into dark, oxygen-starved depths above a seafloor of black organic mud. Scattered shells of inoceramid bivalves rest on the nearly lifeless bottom, while only a few ammonites and fish occupy the better-oxygenated upper water. Such episodes, common in parts of the Tethys and proto-Atlantic around roughly 120–90 million years ago, helped generate the laminated black shales that record times of exceptional marine productivity and deep-water stagnation.

Late Cretaceous ammonites drifting above equatorial carbonate shelf

In the warm equatorial seas of the Late Cretaceous, about 100–94 million years ago, ribbed ammonites such as Acanthoceras drift above a carbonate shelf margin alongside smoother-shelled Puzosia, while schools of the predatory fish Enchodus flash through the sunlit water. Below them, a crow shark, Squalicorax, patrols the shell-strewn fore-reef slope, where rudist debris and sponge mounds mark a tropical limestone platform of the Tethyan realm. This scene captures a rich marine ecosystem from a greenhouse world, when ammonites, teleost fishes, and lamniform sharks thrived in warm shallow seas.

Late Cretaceous Tethyan reef crest of rudist bivalves

In the warm, shallow seas of the Late Cretaceous, about 100–66 million years ago, equatorial Tethyan reef crests were often built not by corals but by dense thickets of rudist bivalves such as Hippurites, Radiolites, and Toucasia. This scene shows their pale, horn-like shells rising from a carbonate seafloor, with smaller patches of Actinastrea coral and purple-red calcareous algae filling the spaces between them. Deep-bodied pycnodont fishes weave through the reef while spiny cidaroid sea urchins cling to the substrate, illustrating the distinctive structure and ecology of a rudist-dominated Cretaceous reef.

Globidens mosasaur crushing shells in Late Cretaceous lagoon

In a warm, shallow sea along the equatorial Tethys during the Late Cretaceous, about 100–66 million years ago, a stocky Globidens mosasaur patrols above a carbonate lagoon floor littered with rudist reef rubble and broken shells. Its short, powerful jaws and rounded crushing teeth were specialized for durophagy, allowing it to crack hard-shelled prey such as ammonites and bivalves. Around it lie characteristic inhabitants of these tropical shelf habitats, including oysters, high-spired Nerinea gastropods, and small crabs among the sunlit lime sands and shell beds.

Southern Hemisphere

Late Cretaceous Rudist Bivalve Reefs in Tethys Lagoon

In a shallow tropical lagoon of the southern Tethys during the Late Cretaceous, roughly 100–66 million years ago, dense thickets of rudist bivalves such as Hippurites and Radiolites rise from bright carbonate sand, forming reef-like frameworks in place of modern coral reefs. Nestled among them are low colonial corals including Actinastrea and Thamnasteria, while small teleost fishes flicker through the clear water and Mecochirus lobsters creep between shells and coral heads. This scene reflects the warm greenhouse seas fringing Madagascar or the drifting Indian plate, where rudist-dominated carbonate platforms were among the most important shallow-marine ecosystems of their time.

Giant Mosasaur Kaikaifilu Hunting in Late Cretaceous Chile

In the cool-temperate waters off Late Cretaceous Chile, about 70–66 million years ago, the giant mosasaur Kaikaifilu hervei lunges upward from the dim offshore slope, scattering a school of Enchodus while a strange paperclip-shaped Diplomoceras drifts nearby. This scene captures a southern Pacific ecosystem along the active Gondwanan margin, where marine reptiles hunted above muddy, shell-strewn seafloors influenced by volcanism and deepening forearc basins. Kaikaifilu was among the apex predators of these seas, part of a diverse Maastrichtian marine fauna that also included teleost fishes, ammonites, and other open-ocean invertebrates.

Antarctic Elasmosaur Morturneria Hunting Late Cretaceous Ammonites

In the cold, green-grey waters of the James Ross Basin at the end of the Cretaceous, about 70–66 million years ago, a broad-skulled elasmosaurid, Morturneria seymourensis, glides beneath the dim Antarctic sun among drifting ammonites. Ribbed Maorites and smoother Gaudryceras fill this high-latitude sea, reflecting the rich marine ecosystems of a polar Antarctica that was cool and seasonal but still free of permanent ice. The animal’s long neck, four powerful flippers, and unusual flattened snout hint at a specialized feeding style in one of the last marine worlds before the end-Cretaceous mass extinction.

Armored Saltasaurus Titanosaurs on the Late Cretaceous Patagonian Plain

On a semi-arid floodplain in Late Cretaceous Patagonia, a herd of armored titanosaurs, Saltasaurus, moves beside a shallow braided river under hot, dusty skies. These compact sauropods—about 12 m long and notable for their pebble-like osteoderms embedded in the skin—browse among ferns, cycads, and scattered araucarian conifers, reflecting the open, seasonal landscapes of southern Gondwana around 72–66 million years ago. The scene captures a characteristic South American dinosaur ecosystem, where titanosaurs thrived on broad red-bed river plains along the tectonically active western margin of the continent.

Horned Carnotaurus Crossing Late Cretaceous Patagonian Mudflats

In the seasonally dry floodplains of Patagonia’s Neuquén Basin, about 72–69 million years ago in the Late Cretaceous, an adult Carnotaurus sastrei crosses a cracked mudflat bordered by low dunes and sparse conifer scrub. Its short, deep skull, prominent brow horns, and tiny forelimbs mark it as one of the most distinctive abelisaurid predators of southern Gondwana, while distant juvenile titanosaurs hint at the giant herbivores that shared this semi-arid landscape.

Isisaurus Titanosaurs Amidst Volcanic Eruptions in Ancient India

At the close of the Cretaceous, about 66 million years ago, India’s drifting island continent was engulfed by eruptions of the Deccan Traps, as fresh basalt lava spread across ash-choked floodplains beneath a dim red dawn. In this scene, a small group of Isisaurus—long-necked titanosaur sauropods known from Late Cretaceous India—moves warily among fern margins, horsetails, charred conifer trunks, and steaming fissures. The image captures a moment of environmental crisis, when volcanism, ash fall, and sulfur-rich haze were transforming landscapes just before the end-Cretaceous mass extinction.

Small Ornithopod Dinosaurs in Cretaceous Australian Polar Forests

In the cool-temperate polar forests of southeastern Australia during the late Early Cretaceous, about 110 million years ago, small ornithopod dinosaurs such as Leaellynasaura amicagraphica and Qantassaurus intrepidus dart through fern thickets beneath towering podocarps and araucarians. The scene evokes a high-latitude floodplain woodland under the low summer sun, with horsetails, mossy logs, and tannin-stained streams but no flowering plants or grasses, reflecting a time when Australia lay much closer to the South Pole. These agile herbivores were adapted to life in a seasonal polar environment that experienced long summer days and extended winter darkness, yet remained free of permanent ice.

Predator Majungasaurus Scavenging During Late Cretaceous Madagascar Drought

In the drought-stricken floodplains of Madagascar’s Maevarano Formation, about 70–66 million years ago in the latest Cretaceous, a stocky Majungasaurus crenatissimus confronts the carcass of the titanosaur Rapetosaurus krausei while the small, armor-backed crocodyliform Simosuchus clarki lurks nearby. The scene captures a seasonal semi-arid ecosystem of dusty river channels, conifer woodland, and scattered early flowering shrubs, where abelisaurid theropods and titanosaurs dominated the island’s unusual fauna. Towering storm clouds on the horizon hint at the dramatic wet-and-dry cycles that shaped this Late Cretaceous Malagasy landscape.

Cretaceous Seas

Tylosaurus hunting Enchodus in Western Interior Seaway

In the warm green-blue waters of the Western Interior Seaway about 80 million years ago, a giant mosasaur, Tylosaurus proriger, rushes through the midwater in pursuit of a school of Enchodus, the fang-toothed predatory fish often called “saber-toothed herrings.” Nearby, a striped Scaphites ammonite drifts above a soft seafloor of chalky carbonate mud and marl, typical of this broad inland sea that once split North America. The scene captures a Campanian marine ecosystem shaped by high sea levels, abundant plankton, and formidable reptilian predators.

Rudist bivalve reef in Tethyan Ocean lagoon

In a shallow lagoon of the Tethyan Ocean during the mid- to Late Cretaceous, roughly 100–70 million years ago, dense stands of rudist bivalves such as Hippurites and Radiolites rise from bright carbonate sand beneath clear turquoise water. Low colonies of the coral Actinastrea and crusts of red coralline algae fill the spaces between these unusual reef builders, while small deep-bodied pycnodont fishes and brachyuran crabs move through the sheltered habitat. Unlike most modern tropical reefs, many Cretaceous reef systems were built primarily by rudists—specialized clams that became some of the dominant framework organisms in warm shallow seas.

Late Cretaceous chalk seafloor with Micraster urchins

On the Late Cretaceous chalk seafloor of Europe, around 84–66 million years ago, a pale blanket of coccolith ooze stretches across a quiet offshore shelf beneath softly clouded blue water. Scattered across this white seabed are heart-shaped Micraster and rounded Echinocorys sea urchins, along with large shells of the bivalve Inoceramus and delicate bryozoan colonies. Such chalk seas formed from the accumulation of microscopic calcareous plankton, creating one of the most distinctive marine environments of the Campanian–Maastrichtian world.

Giant Deinosuchus waiting in Cretaceous coastal estuary

In a muddy Late Cretaceous estuary along the Gulf Coastal Plain, a giant Deinosuchus lies half-submerged beside oyster-encrusted driftwood, waiting in ambush as fish scatter across the turbid surface. On the far bank, a small herd of hadrosaurids approaches the water’s edge, underscoring the scale and danger of one of North America’s largest crocodyliforms. Scenes like this would have unfolded about 82–73 million years ago near the margins of the Western Interior Seaway, where warm, brackish channels linked rivers, coastal wetlands, and the shallow inland sea.

Cretaceous coastal forest with conifers and angiosperms

On a humid Late Cretaceous shoreline about 100–70 million years ago, towering araucarian conifers and swamp cypresses rise above a dense coastal understory of cycads, ferns, horsetails, and early broad-leaved angiosperms. The muddy, low-gradient plain is cut by brackish channels and backwaters that lead to a warm shallow epicontinental sea, reflecting the greenhouse climate and high sea levels of the Cretaceous. This scene captures a transitional coastal ecosystem in which ancient gymnosperm-dominated forests still flourished while flowering plants were becoming an increasingly important part of terrestrial vegetation.

Late Cretaceous storm over Western Interior Seaway

Under storm-darkened skies, the shoreline of North America’s Western Interior Seaway is lashed by wind-driven waves that wash ammonite shells, inoceramid fragments, and driftwood onto broad muddy flats. This scene captures the Late Cretaceous, roughly 100–66 million years ago, when a warm shallow inland sea split the continent and bordered swampy lowlands of conifers, cycads, bennettitaleans, and ferns. The ribbed ammonites and soft marl-rich sediments reflect the distinctive fossil-rich coasts of this epicontinental sea, one of the great marine environments of the age of dinosaurs.

Pteranodon soaring over Late Cretaceous chalk cliffs

Along a warm Late Cretaceous shoreline, several Pteranodon longiceps ride the updrafts beside brilliant white chalk cliffs while much smaller Ichthyornis dart and wheel over the surf below. This scene evokes the great chalk seas of about 86–84 million years ago, when high sea levels flooded broad epicontinental seaways under a greenhouse climate. Pteranodon, a giant toothless pterosaur with a wingspan of roughly 6–7 metres, was built for efficient soaring, whereas Ichthyornis was an early seabird whose jaws still retained teeth—a striking reminder that modern-style birds had already evolved alongside pterosaurs.

Next Period

Paleogene