the origins museum institute mesozoica origins museum institute presents mesozoica from the genesis...

The Origins Museum Institute

presents

Mesozoica From The Genesis Exhibit

THE TRIASSIC PERIOD

from 230 million to 195 million years ago

There were no flowers or grasses at the beginning of the Triassic

period (named for a tri-layered sequence of strata first discovered in

southern Germany). Surrounded by a vast ocean, the supercontinent

of Pangaea almost entirely circled the globe at the equator. Identical

fossil remains found as far apart as Africa and North America

suggest that the fauna of this period roamed freely across vast

expanses o land that are now separated by the oceans. The Triassic

marked the dawning of the Mesozoic (“Middle Life”) Era, or the

Age of Dinosaurs.

Because much of Pangaea lay along the equator, climates were

generally tropical, and warm, ferny swamps teemed with primitive

amphibians and crocodiles. In the arid desert regions, reptiles

flourished with the extinction of mammal-like reptiles, producing the

highly successful archosaur group which gave rise to crocodiles,

pterosaurs, and a new kind of animal gradually appearing in the Late

Triassic fossil record: the “Dinosauria” (“Terrible Lizards”), which

continued appear in increasing varieties for the next 140 million

years. The gradual breakup of Pangaea beginning at the end of the

Triassic globally separated dinosaur populations along with the first

true mammals, tiny burrowing descendants of the mammal-like

reptiles.

76. Class Reptilia,

Subclass Archosauria Euparkeria capensis

Early Triassic, South Africa

Crowding the archaic Permian protomammals out of their

dominant position in the competition for food, the rapidly evolving

Triassic reptiles known as thecodonts (“Socket Tooth”) were

distinguished by the development of remarkably open skulls,

hollow bones that were lightweight but very strong, and jaws lined

with individually socketed teeth. This group of ancestral

archosaurians (“Ruling Reptiles”) gave rise to the early

saurischians and ornithischians of the Late Triassic (collectively

known as the dinosaurs) as well as to crocodiles, birds, and the

extinct flying reptiles. Exemplifying this important parent group,

Euparkeria was a small creature that walked on 4 legs but, like the

modem crocodile, was capable of bipedal sprinting due to its

powerful hind leg muscles. A predator whose advantage over its

prey was its swiftness, Euparkeria was extremely close to the

immediate ancestry of the dinosaurs. This magnificent partial

skeleton is from the famous Karroo Formation. South African

Museum.

197. Class Reptilia,

Subclass Archosauria Eoraptor lunensis

Triassic, Argentina

The earliest known dinosaur, the “dawn raptor” preyed on insects

and small 4-legged animals. Although it was an efficient, bipedal

predator, its primitive jaws lacked the “hinged” flexibility of its

carnivorous successors. The Argentine Museum of Natural Sciences.


Subclass Archosauria Herrerasaurus

Triassic, Argentina

This early dinosaur was a primitive, bipedal carnivore with a flexible

jaw capable of entrapping its struggling prey. Argentine Museum of

Natural Sciences.


Subclass Archosauria Sharovipteryx mirabilis

Triassic, Kyrgyzstan

Formerly known as Podopteryx, this small gliding animal soared

from tree to tree like a flying squirrel. Its name means “Sharov’s

Wings.” It lived during the early Triassic period about 245 million

years ago in Asia. With hind legs supporting a flight membrane, it

appears to be an ancestor of the pterosaurs. From the Russian

Paleontological Institute.

77. Class Amphibia,

Order Temnospondyli Thoosuchus

Triassic, Russia

Still dependent on laying its eggs in water and undergoing a

larval stage with gills for breathing (as its fishlike ancestors did

when they first appeared during the Devonian Period), this small,

bottom-dwelling amphibian, its skull deeply grooved with nerve-

bearing canals, was only partially adapted to terrestrial life. Private

collection.

78. Class Amphibia,

Suborder Stereospondyla Aphaneramma

Late Triassic, Arizona

As a group, the Triassic stereospondyls, with their flat heads and

upward gazing eyes, were primarily bottom-dwelling predators.

Their weakly-limbed skeletons show an enigmatic regression in

development compared to those of their more sturdily-limbed

ancestors. Collected in the Moenkoepi Formation of Meteor Crater

by Charles Camp, Samuel Welles, and Frank Peabody in 1938.

University of California, Berkeley.

79. Class Amphibia,

Suborder Stereospondyla Hadrokkosaurus bradyi


This large amphibian from the Moenkoepi Formation has the

superficial appearance of a large frog. The pronounced indentation

between the eyes, the pineal opening, sensitive to light and shade,

was used as a “third eye” by early bottom-dwelling fish and

amphibians. Derived from an ancient lineage of marine ancestors,

the once photosensitive pineal body is still retained as a vestigial

organ within the brains of all modern vertebrates. University of

California, Berkeley.

80. Class Amphibia,

Suborder Stereospondyla Cyclotosaurus


Resembling a giant salamander, this amphibian spent most of its life

lying motionless on the murky bottoms of ancient lakes and rivers of

southwestern North America, its tiny limbs useless for support on

land. Often victims of drought, the fossilized remains of whole

populations are sometimes found desperately crowded together in

dried ponds. Derived from the labyrinthodonts of the Permian, they

were extinct by the end of the Triassic. University of California,

Berkeley.

81. Subclass Archosauria,

Order Thecodontia Aetosaurus ferratus

Late Triassic, Germany

Resembling the armored dinosaurs of a later age, Aetosaurus

(“Eagle Lizard”) actually belonged to the prolific thecodont group.

Although some of these archosaurs were small, bipedal carnivores,

others were broad, 4-legged herbivores with heavily armored

bodies for protection against predators. Sporting an ominous

battery of spikes and bony plates, the well-known Aetosaurus lived

along the fringes of the Triassic marshes of Central Europe.

Although closely related to the ferocious aquatic crocodilians and

phytosaurs of its time, as evidenced by this mummified skeleton

with a perfectly preserved hide, Aetosaurus was probably a passive

animal, devoted mostly to uprooting vegetation with its blunt,

upturned snout. Widespread throughout the northern hemisphere,

aetosaurs are also found in Triassic formations of North America.

Humboldt Museum.


Subclass Archosauria

Pachypleurosaurus edwardsi

Triassic, Switzerland

This perfectly preserved in-situ skeleton belonged to a small

nothosaur, a marine reptile originally descended from terrestrial

stock, and direct ancestor of the giant plesiosaurs of the Jurassic.

Private collection.

82. Dinosaur trackway

Grallator

Late Triassic, Connecticut

Left in the mud by one of the earliest dinosaurs, this footprint of an

ancient Triassic coelurosaur (“Hollow-Tailed Lizard”) gives no hint

of the gigantic proportions of its descendants which were to follow.

Ranging up to 10 feet in length, it ran on its hind legs

counterbalanced by a long tail. This little theropod (“Beast Foot”),

with its serpentine neck and lightweight, hollow bones, is believed to

have been swift and agile, chasing prey and tearing it with sharp

claws and teeth. Such behavior strongly suggests a warm-blooded

metabolism, a theory popularized by the revolutionary paleontologist

Robert Bakker. Among the first tracks to be found in North America,

they were discovered in the Connecticut Valley during the early 19th

Century by Edward Hitchock, who died convinced that he had found

evidence of prehistoric birds. When later compared to verified

Coelophysis tracks, they proved to be remarkably similar. Private

collection.

83. Subclass Archosauria,

Suborder Theropoda

Coelophysis bauri

Late Triassic, New Mexico

Among the earliest of the dinosaurs to appear in the fossil record,

Coelophysis (“Hollow Form”) was a long-legged, 3-fingered

predator armed with long, slender jaws lined with sharp, serrated

teeth. With grasping claws freed by its upright posture,

Coelophysis was a formidable hunter, suspected of cannibalistic

tendencies due to the presence of young skeletons found within the

body cavities of some adult individuals that evidently fed on their

own young. Inhabiting the Late Triassic coniferous forests, this

graceful forerunner of the giant theropod dinosaurs of later ages (as

well as the first birds) appears to have lived in wandering herds

throughout northern New Mexico. Ranging from 3 to 10 feet in

length and weighing up to 65 pounds, these sleek, swift creatures

are known primarily from the remains of what appears to have

been an entire herd that perished together, possibly in a sandstorm

or during a flood. This spectacularly exposed in-situ skeleton, with

the remains of a devoured juvenile, is from the famous Chinle

Formation of Ghost Ranch. American Museum of Natural History.

84-85. Order Crossopterygii,

Family Coelacanthidae Whitea

Triassic, British Columbia

For nearly 400 million years, these sluggish, passive creatures have

survived virtually unchanged. Derived from the primordial group

of freshwater fishes that produced the first terrestrial vertebrates

and distinguished by its primitive limblike fins, this ancient

carnivorous fish shows the preliminary bone structure that led to

amphibious walking on land. Well-known from ancient freshwater

and marine deposits, no fossil coelacanths (“Hollow Spine”) dating

less than 60 million years have been found. Formerly believed to

be long extinct, a rare extant species was discovered in 1938 off

the Comoro Islands in the Indian Ocean.

Inhabiting the ocean at depths exceeding 500 feet, these bright

bluefish swim with a peculiar synchronized rotation of the pelvic

and pectoral fins, which are capable of assuming nearly any

position. Possessing an elastic notochord instead of a segmented

backbone, the coelacanth, unlike most fish, bears its young live

rather than by laying eggs. Although their deep habitat appears to

be devoid of prey, dissected specimens reveal that they feed on fish

and squid, perhaps surviving between feedings by slowing their

metabolisms in the cold waters. Royal Tyrrell Museum of

Palaeontology.

86-87. Order Therapsida,

Infraorder Cynodontia

Thrinaxodon liorhinus

Early Triassic, South Africa

The transition from synapsid reptiles to mammals was gradual rather

than a quantum leap. Replacing gorgonopsids as the dominant

predators of the Early Triassic, cynodonts were small, fox-like

creatures with fewer reptilian characteristics than their ancestors.

Although exhibiting tiny pits in their skulls which appear to have

held whiskers and possessing a palate separating the nasal passages

from the mouth, distinctly mammalian features, the primitive

reptilian jaw structure of cynodonts retained certain prominent bones

that became greatly reduced in mammals and incorporated into the

inner ear.

Extremely close to the ancestry of the mammals, this group included

Thrinaxodon, an advanced therapsid of the forests of Antarctica and

the South African Karroo. Equipped with prominent canine teeth as

well as other dental features characteristic of early mammals,

Thrinaxodon is widely regarded as the original stock from which

they arose. In-situ skeleton and 2 skulls from the Karroo Formation.

University of California at Berkeley.

THE JURASSIC PERIOD


The Jurassic period, with its lush rainforests, derives its name from

an abundantly fossiliferous sequence of chalky deposits discovered

in the Jura Mountains bordering Switzerland and France. For the

70 million year duration of the Jurassic period, the supercontinent

of Pangaea was gradually being wrenched into 2 separate masses,

Gondwanaland (Africa, South America, Australia, India, Arabia,

and Antarctica) and Laurasia (Europe, Asia, Greenland, and North

America). Among the survivors of the Triassic extinction, tiny

primitive mammals began to diversify during the Early Jurassic.

By the dawning of the Late Jurassic (150 million years ago), the

Atlantic Ocean had formed and the drifting continents had barely

begun to resemble their present shapes. Gigantic dinosaurs that

cared for their young had evolved from their smaller Late Triassic

ancestors. Land bridges between the continents allowed the

thriving herds of dinosaurs to migrate across great distances. Palm-

like plants appeared and flourished throughout the warm, swampy

landscapes of the period, nourishing the largest creatures that ever

walked the Earth.

89. Suborder Theropoda,

Infraorder Coelurosauria

Compsognathus longipes

Late Jurassic, Germany

Of all the known fossils of adult dinosaurs, Compsognathus

(“Elegant Jaw”) has the distinction of being the smallest. Running

upright on its strong hind legs and stalking the underbrush for

smaller Reptiles along the forested seashores of Jurassic Germany

and France, Compsognathus was a swift and capable hunter, armed

with sharp claws and teeth. This tiny coelurosaur was a relative of

such giant creatures as the Tyrannosaurus rex of a later age. More

closely related to Archaeopteryx (the bird-dinosaur), this skeleton

shows that they shared a very recent common ancestor, suggesting

that birds may have inherited their warm-blooded metabolisms

from their dinosaur forebears. The smaller bones exposed within

the rib cage of this well-known specimen have been identified as

the undigested skeleton of Bavarisaurus, a tiny lizard that was

devoured just before the predator died. With its neck and tail bent

backwards, this Compsognathus (discovered in 1861) was long

thought to have died in agony, although its posture is now

attributed to the tightening of tissues as the carcass dried out prior

to fossilization. From the famous lithographic limestone of

Solnhofen. Bavarian State Institute for Paleontology and Historical

Geography.

90-92. Class Aves,

Subclass Archaeornithes Archaeopteryx lithographica


These small, feathered dinosaurs inhabited the Late Jurassic forests

of Central Europe 150 million years ago. Although adapted for

gliding and presumably for limited flight, these primitive ancestral

birds still retained efficient, grasping claws on each wing, as well as

a long bony tail and jaws lined with sharp archosaurian teeth.

perhaps the most famous fossil in the world, the spectacular “Berlin

specimen” was found in 1877. Owing to the faint preservation of its

flight feathers (overlooked for many years), the juvenile specimen,

known as the “Eichstatt specimen,” was long misidentified as a

Compsognathus.

The mounted skeleton, cast from the “London specimen” and

featured in a PBS Nova program, was discovered in 1861. These rare

specimens, the most complete ever found, are spectacular evidence

of an intermediate stage between Reptiles and birds. Because its

remains have only been found in deposits of shallow marine lagoons

rich in fossilized fish and squid, some believe Archaeopteryx

(“Ancient Wing”) was capable of diving for aquatic prey. Others

envision it darting along the ground bipedally, using its wings as

spoilers to increase its speed while chasing insects and small

Reptiles or for soaring from tree to tree. From the famous

lithographic limestone of Solnhofen. Berlin specimen from the

Humboldt Museum. Mounted specimen from the British Museum.

Juvenile specimen from the Jura Museum.

194. Class Aves,

Subclass Archaeornithes Cathayornis yandica

Jurassic, China

Roughly contemporary with the European Archaeopteryx, this

feathered theropod dinosaur from Asia more closely resembled

modern birds. Beijing Institute of Vertebrate Paleontology.

201. Class Aves,

Subclass Archaeornithes Confusciusornis sanctus

Jurassic, China

Possessing no tailbones, these early ancestors of modern birds lived

in Asia . About the size of ravens, their discovery revolutionized

long held concepts about the origins of birds. Beijing Institute of

Vertebrate Paleontology.

93. Superorder Archosauria,

Suborder Pterosauria Rhamphorynchus gemmingi


The first vertebrate creatures capable of flight, the ancient pterosaurs

(“Winged Reptiles”), were not on the evolutionary path that led to

birds. Descended from early Triassic archosaurs and divided into 2

distinct groups by certain physical characteristics, the older genera

were Distinguished by their long tails. Among the most primitive,

Rhamphorynchus (“Beak Snout”) had a slender tail that ended in a

kite- shaped membrane which presumably served as a rudder.

Growing to lengths of up to 2 feet, its average wingspan was about 4

feet. With an elongated, flexible neck and extended jaws lined with

sharp, forward- slanting teeth, this predator hunted along the same

reefs and shorelines as Pterodactylus. Coiling its neck for diving and

lunging at fish and squid, Rhamphorynchus speared its prey in the

intermeshing barbs of its teeth, which allowed for no escape.

Capable of sustained flight as well as aerial acrobatics,

Rhamphorynchus was probably furry and warm blooded. The

leathery wing membrane, extraordinarily preserved in this specimen,

was reinforced with a lacing of special tissue. From the lithographic

limestone of Solnhofen. Humboldt Museum.


Suborder Pterosauria

Pterodactylus kochi


Throughout the Jurassic, leathery-winged pterodactyls (“Wing

Finger”) would have been a common sight gliding on the tropical

breezes of the European coastal regions, catching up insects, small

fish, and squid in their long, sharply-toothed beaks. Pterosaurs

belong to the archosaur order, which also includes dinosaurs and

crocodiles. The first flying Reptiles to be discovered, the raven-sized

Pterodactylus, like all pterosaurs, was distinguished by its elongated

fourth finger which supported a powerful flight membrane. Their

hollow, lightweight bones enabled them to venture significant

distances over the shallower waters of the ancient German seas,

where a number of the remains have been recovered, exquisitely

preserved along with impressions of their furry coats. From the

lithographic limestone of Solnhofen. Humboldt Museum.


Suborder Pterosauria

Pterodactylus elegans


Once presumed to have been limited to gliding from high perches,

they are now believed to have been thoroughly agile in flight. They

were quite vulnerable to marine predators, judging by the numerous

pterosaur bones found in the stomachs of ichthyosaurs. The long,

narrow snout of Pterodactylus may have been an adaptation to

probing in the sand for burrowing worms. From the lithographic

limestone of Solnhofen. Humboldt Museum.

95. Superclass Chelicerata,

Subclass Xiphosura

Mesolimulus walchi


Related to arachnids and the extinct eurypterids, the xiphosurans

range from the Cambrian to the present. Derived from trilobites that

had invaded estuaries and streams and lost their antennae (along with

other specialized modifications), they are today represented by

“living fossils” known as horseshoe crabs. Virtually unchanged since

the Permian, these arthropods dig along the beaches for worms and

other small prey, often burying themselves in the sand. Possessing a

pair of compound eyes (as well as a pair of simple ones) and

equipped with a spiny telson for correcting its position when

overturned, horseshoe crabs undergo periodic molting. Reflecting

their ancient ancestry, in fetal form they resemble trilobites. During

the spring mating season, males cling to the telsons of the females as

they crawl along the sandy shores. Dramatic evidence of this same

behavior in ancient forms is provided by the well-documented

Jurassic Mesolimulus, whose trails sometimes lead to the remains of

the individuals that left them. From the lithographic limestone of

Solnhofen. Private collection.

96. Order Ornithischia,

Family Hypsilophodontidae Othnielia rex

Late Jurassic, Utah

Possibly the smallest of the horny-beaked hypsilophodonts (“High

Crest Tooth”) of Late Jurassic Colorado and Utah, Othnielia,

formerly known as “Nanosaurus rex” (“Dwarf Lizard King”) only

grew to a length of 3 to 4 feet. Agile sprinters when threatened or

chasing prey, the omnivorous hypsilophodonts possibly flourished

for longer than any other dinosaurs, about 100 million years. After

depositing their eggs in the sand, the females appear to have

carefully manipulated them into spiral clutches of regular depths and

even spacing. Although they probably remained with their herds

throughout adulthood, these dinosaurs (owing to their well-

developed limbs) apparently left their nests immediately upon

hatching, probably feeding first on adult feces, rich in fermentative

bacteria, and later progressing to plants and insects. As adults they

fed on everything from plants to small Reptiles and mammals.

“Nanosaurus” was renamed Othnielia in 1977, on the centennial of

its discovery by the great pioneer paleontologist Othniel C. Marsh.

Featured in the 1993 Universal Studios film Jurassic Park, this

spectacularly exposed in-situ skeleton is from the Morrison

formation of Emery County, Utah. Brigham Young University.

97. Subclass Ichthyopterygia,

Order Ichthyosauria

Stenopterygius quadricissus

Jurassic, Germany

Flourishing throughout the Mesozoic, the ichthyosaurs (“Fish

Reptiles”) appeared during the Early Triassic. Growing up to 15 feet

in length, they apparently evolved from land-dwelling creatures,

possibly the pelycosaurs. From the limbs of their terrestrial ancestors,

the ichthyosaurs evolved their strong, broad paddles. Stenopterygius

was Distinguished by its paddles, which contained more joints and

fewer digits than those of other species. This magnificent specimen

is preserved with an epidermal silhouette. Humboldt Museum.

98. Class Reptilia,

Subclass Ichthyopterygia

Ichthyosaurus megacephalus

Jurassic, Germany

Typifying these classic marine Reptiles, Ichthyosaurus was

Distinguished by the presence of extra digits with fewer joints in its

paddle. From other fossils, these air-breathing, dolphin-like creatures

are known to have fed on pterosaurs and fishes and, rather than

laying eggs, gave birth to live young. This rare and extremely young

Ichthyosaurus appears to have died at birth, although the

displacement of its vertebra could easily have occurred after its death.

Private collection.

99. Coprolites

Ichthyosaur

Jurassic, Mexico

Found in deposits rich in ichthyosaur remains, these coprolites

(“Dung Stones”) are the fossilized excrement of large, dolphin-like

marine predators. When examined microscopically, coprolites can

reveal not only the fibers of the digested matter, but also the

fossilized remains of bacterial parasites that inhabited the digestive

tracts of the hosts millions of years ago. From the Jurassic of

Chihuahua, Mexico. Private collection.

100. Subclass Euryapsida,

Order Sauropterygia

Plesiosaurus macrocephalus

Jurassic, Scotland

Derived from small Triassic nothosaurs similar to Mesosaurus, these

gigantic marine Reptiles, ranging from 6 to 40 feet in length,

flourished throughout the Jurassic Period in the oceans of Europe

and North America. Their small heads were equipped with a battery

of needle-like teeth for catching fish, with elegantly long, serpentine

necks capable of darting and striking. Adapted for “underwater

flight”, these formidable predators glided through the water by

flapping their winglike paddles up and down in the manner of

penguins. Originally descended from terrestrial stock, plesiosaurs

(“Ribbon Reptiles”) were air-breathing and had to haul their heavy

bodies onto the beaches to lay their eggs. First appearing in the Late

Triassic, plesiosaurs gradually tapered to extinction by the end of the

Cretaceous. This rare, in-situ juvenile specimen is from the Jurassic

of Lyme-Regis, England and was found by Mary Anning. Royal

Scottish Museum.

101. Order Saurischia,

Suborder Sauropodomorpha Apatosaurus ajax

Late Jurassic, Utah

The regal, long-necked sauropods were by far the largest land

animals that ever lived. With a long, sloping skull and a single

nostril situated on top of its skull, Apatosaurus (“Mystery Lizard”)

was a member of the diplodocid family, shorter in length but much

heavier than the closely related Diplodocus. Measuring 70 ft. in

length and weighing 33 tons, these gigantic herbivores possessed

long, serpentine necks and even longer whiplike tails.

Because the first skeletons discovered were not found associated

with any skulls, this dinosaur was originally described as

“Brontosaurus” (“Thunder Lizard”), a name which persisted until the

genus was finally correctly identified as Apatosaurus, previously

known only from a skull that had been named before the discovery

of the headless Brontosaurus skeletons, hence its name prevails. For

a long time some museums continued to traditionally exhibit their

Apatosaurus skeletons with the heads of Camarasaurus. Known

only from North American specimens, they lived in vast herds that

ranged throughout Utah, Wyoming, Colorado, and Oklahoma. This

classic leg bone was recovered from the famous Morrison Formation.

Brigham Young University.


Suborder Sauropodomorpha

Camarasaurus lentus

Late Jurassic, Utah

Herds of Camarasaurus (“Chamber Lizard”), a heavy sauropod

(“Lizard Foot”), with a shorter neck and tail and a blunter snout than

Apatosaurus, thrived in the Late Jurassic Colorado, Oklahoma, Utah,

and Wyoming. Unique among the sauropods, the large nasal cavities

on top of its head, similar to those found in elephants and tapirs,

suggest the possibility o a flexible trunk. They grew to 60 feet in

length and weighed about 20 tons. Discovered ill 1877 by the

pioneer palaeontologist Edward Drinker Cope, these giant animals

were once presumed to have been semi-aquatic swamp dwellers, too

heavy to walk about on dry land. Camarasaurs and other sauropods

are now believed to have avoided such murky places in favor of the

drier plains, possibly migrating across vast distances. Sauropod

footprints indicate that these gentle herbivores cared for their young,

guarding them on all sides as they wandered together, feeding on the

highest tree branches. Found in the famous Cleveland Lloyd Quarry.

Carnegie Museum.


Suborder Sauropodomorpha Hypselosaurus priscum

Cretaceous, France

This 40 foot long sauropod, characterized by its short, blunt head

and small teeth, laid the largest eggs known, about 12 inches in

length. The folded embryo within would have hatched to a size

twice the length of the egg. Larger eggs probably would have

required a shell too thick for hatching. Hypselosaurus (“High

Crested Lizard”) is the only sauropod dinosaur that has ever been

found in association with its eggs. Private collection.

105. Gastroliths

Sauropod

Late Jurassic, Utah

Because their teeth were adapted for cropping but not for chewing

the tons of plants they required daily, sauropods and other dinosaurs

deliberately swallowed stones to help grind food to a digestible pulp

in their gizzards. Smoothly polished gizzard stones have been found

to originate from rock sites as much as 15 miles from their final

resting place among the bones of a dead dinosaur, suggesting that

these creatures, were somewhat particular about the types of rocks

they ate. Private collection.


Suborder Stegosauria Stegosaurus stenops

Late Jurassic, Utah

Discovered in Colorado in 1877, Stegosaurus (“Plate Lizard”) grew

to a length of up to 30 feet and weighed up to 2 tons. The bony

armored plates guarding the neck, back, and tail of the huge Jurassic

herbivore were attached to powerful skin muscles, and were

probably capable of being raised and lowered to protect the spine or

the flanks. Honeycombed with capillaries, they may also have

served as a heat exchange for warming (or perhaps cooling) the

animal’s bloodstream, although their actual placement and function

remain an enigma.

Aiding in the precision of the movement of the enormous hind-

quarters and spiked tail, an enlargement of the spinal cord at the

pelvis, much larger than the creature’s brain, was long believed to be

its “second brain.” For its bulk, Stegosaurus had the smallest skull of

any dinosaur, with a brain no larger than a walnut. Its front legs, only

half the length of its back legs, indicate that it probably evolved from

a 2-legged ancestor and could easily have reared on its strong hind

limbs to feed on the higher tree branches. The deadly spikes attached

to the tip of its powerful tail were used as a defense against predators

in Late Jurassic Colorado, Oklahoma, Utah, and Wyoming. Found in

the Cleveland Lloyd Quarry. U.S. National Museum.


Suborder Theropoda Allosaurus fragilis

Late Jurassic, Utah

Its massive, yet open, lightweight skull a marvel of engineering,

the fearsome Allosaurus (“Different Lizard”) was the predominant

carnivore in North America during the Late Jurassic, and probably

fed on such herbivorous dinosaurs as Apatosaurus (Brontosaurus)

and Stegosaurus, its flexible skull capable of expanding to

accommodate oversized chunks of food. While some believe that

they were too huge and clumsy to hunt, scavenging on carrion

instead, others believe them to have been agile runners and

swimmers, capable of hunting in packs for large prey. Trackways

found in Texas indicate that such predators indeed chased herds of

much larger dinosaurs, and Apatosaurus vertebrae, scarred by the

teeth of an Allosaurus, have been unearthed.

Sporting strong, 3-fingered claws at the ends of its short arms, this

creature grew to 36 feet or more in length and weighed 1 to 2 tons,

possibly reaching full maturity in as little as 5 years. Although they

have been found in Africa, Australia, and perhaps even Asia,

Allosaurus are most common in North America, some 40 individuals

coming from a single quarry (possibly having perished together).

Found in the Cleveland Lloyd Quarry.


Suborder Sauropodomorpha “Ultrasaurus”

Late Jurassic, Utah

This massive vertebra of a giant brachiosaur is from the upper neck

of one of the largest sauropod dinosaurs ever found, a gentle

herbivore. Brigham Young University.


Family Camptosauridae Camptosaurus browni

Late Jurassic, Utah

A primitive ornithopod (“Bird Foot”), ranging in length from 12 to

23 feet and weighing up to 1000 pounds, Camptosaurus (“Bent

Lizard”) was much larger and less agile than its hypsilophodontid

ancestors. Short but sturdy, its 5-fingered forelimbs were adapted to

bearing weight, although fossilized footprints indicate that it was

also thoroughly capable of walking bipedally on its 4-toed hind legs.



Family Camptosauridae Camptosaurus browni

Late Jurassic, Utah

Cropping low plants with its beaked jaws, this peaceful grazer lived

in western North America and Europe from the Late Jurassic to the

Early Cretaceous, suggesting a former connection of the 2 continents.

The ancestor of the famous Iguanodon, this important animal is

believed to have given rise to the diffuse groups of duckbilled

dinosaurs which spread throughout the world in Cretaceous times.


THE CRETACEOUS PERIOD


Marking the appearance of flowers, the fertile Cretaceous period was

named for vast deposits of chalk (creta in Latin), rich in fossils and

widely distributed throughout the

world. The distribution of the continents was beginning to resemble

that of the present, although a great shallow sea flowing from

Canada to the Gulf of Mexico separated the supercontinent of

Laurasia into Asiamerica (East Asia and Western North America)

and Euramerica (Europe and Eastern North America). Marked by a

rich emergence of advanced dinosaurs, the Late Cretaceous, 75

million years ago, was a time of tremendous volcanic upheaval as

mountain ranges and new islands were being formed.

The drifting of the continents toward the polar regions brought on

significant changes in the seasonal weather. No longer able to roam

between the continents, many of the later dinosaurs evolved

exclusively in Asiamerica. The dominant creatures of the period,

most species lasted no more than 5 million years before disappearing

from the fossil record, often followed by more advanced descendants.

This period lasted until 65 million years ago, ending with a

catastrophic mass-extinction second only to that of the Permian.

Nearly half of all the Cretaceous plants and animals, both marine and

terrestrial, suddenly vanished. Among them were the dinosaurs.

110. Infraclass Teleostei,

Order Leptolepiformes

Cearana

Early Cretaceous, Brazil

The appearance in the fossil record of the heterogeneous group of

leptolepids marks the arrival of the modern teleost, or bony, fishes,

which now dominate the world’s aquatic environments. Armed with

a mouthful of small, sharp teeth, these elongate, tapering fish became

widespread throughout the Late Jurassic and Early Cretaceous.

Spectacularly preserved in mud concretions, Cearana is a well-

documented variety known to have preyed on its own species, some

individuals having died in the process b):: choking on prey too large

to swallow. Unlike more primitive fish with primarily cartilaginous

skeletons, such as sharks and lobe-fins, the early teleosts possessed

fully ossified internal skeletons. From the famous Santana Formation

of Brazil. Private collection.

111. Phylum Mollusca,

Class Cephalopoda Texanites texanum

Late Cretaceous, Texas

Gregarious creatures, the ammonoids lived in large schools near

the bottom of deep seas, avoiding areas occupied by seaweed,

clams and snails. Preying on fishes and invertebrates (including

other ammonoids) captured with their tentacles, they fed through a

beak resembling that of a parrot. Related to octopus and squid,

their chief defense against predation was to squirt ink in the faces

of their predators, which included large crabs, fish, and marine

reptiles. In the deeper seas that once extended westward from the

Gulf of Mexico, ammonoids were plentiful, although gigantic

fossil forms such as Texanites and even larger varieties are

extremely rare. These long enduring creatures disappeared abruptly,

along with the dinosaurs, at the end of the Cretaceous Period 65

million years ago. From the famous Austin Chalk of Texas. Private

collection.

112. Infraorder Deinonychosauria,

Family Dromaeosauridae Dromaeosaurus albertensis

Late Cretaceous, Canada

Popularly known as a “Raptor”, this ferocious creature was armed

with one lethal, sickle-shaped claw on each foot, held in a retracted

position when it walked and extended for slashing the bellies of its

victims with multiple kicks of its powerful hind legs. Discovered in

1914 by Barnum Brown, this rare and highly specialized group of

theropods was not fully understood until the discovery by John

Ostrom in 1964 of Deinonychus, an early dromaeosaur succeeded in

the Late Cretaceous by Dromaeosaurus (the first such dinosaur to be

discovered), and the Mongolian Velociraptor. Because

Dromaeosaurs (“Running Reptiles”) display a striking affinity to

birds, particularly the Jurassic Archaeopteryx, there is little doubt

that they were warm-blooded. Its brain had unusually large cerebral

hemispheres for a dinosaur, suggesting complex behavior more

birdlike than reptilian. Of the few fossilized battles between

dinosaurs that have ever been found, two involved Dromaeosaurs,

providing spectacular evidence of their behavior. One find in

Montana indicates that they hunted in packs, while a one-on-one

battle to the death with a Protoceratops was discovered in the Gobi

Desert. Their combination of intelligence, swiftness, and the sickle

claw places these creatures among the most dangerous of the

dinosaurs. Royal Tyrrell Museum of Palaeontology.


Family Dromaeosauridae Velociraptor mongoliensis

Late Cretaceous, Mongolia

This small but extremely vicious Chinese dromaeosaur, armed

with the lethal sickle-claw, has been found preserved in deathlock

combat with the early ceratopsian dinosaur Protoceratops. From

the Polish-Mongolian Expedition and From the Russian

Paleontological Institute.


Family Dromaeosauridae Deinonychus antirrhopus


These large, swift, dinosaurs slashed their prey with sharp, sickle-

like toe claws. The small Mongolian Velociraptor was followed

by the larger North American Deinonychus. From the Harvard

Museum.


Family Hadrosauridae Prosaurolophus maximus

Late Cretaceous, Alberta

This Late Cretaceous duckbilled dinosaur, with its broad, flat

muzzle and its small nasal crest, is presumed to have been an

ancestor of Saurolophus (“Crested Reptile”), the forerunner of the

prominently crested Parasaurolophus (“Beside Saurolophus”) of

North America. These skull crests, both large and small, might

have served as resonators for bellowing and honking during mating

competition. Living in herds, the 26 foot long Prosaurolophus

(“Early Crested Reptile”) was herbivorous and may well have fed

and looked after its young. Royal Ontario Museum.


Family Hadrosauridae Parasaurolophus walkeri


Unlike the earlier hadrosaurs, whose skulls were distinguished by

small crests of solid bone, this advanced duckbill sported a

prominent hollow crest extending from the back of its head by as

much as 6 feet. This tubular crest, which may have been connected

to the creature’s back by a fleshy frill, is believed to have functioned

as a resonating chamber for mating calls and warnings. With

chambers connecting to the nasal passage, the crest was long

regarded as a snorkel for the storage of air while the animal was

submerged, however a better understanding of the habitats of

Parasaurolophus, a forest-dwelling dinosaur, has dispelled its

popular image as a swamp dweller. Although the function of its

spectacular crest is not fully understood, It is unlikely to have been

used for defense due to its hollow structure. Ranging up to 33 feet in

length, Parasaurolophus was indigenous to New Mexico, Utah, and

Alberta. Royal Ontario Museum.


Family Hadrosauridae

Edmontosaurus regalis


This classic hadrosaur, with its massive skull, was among the

largest of the duckbilled dinosaurs. Royal Ontario Museum.


Family Hadrosauridae

Anatosaurus annectens

Late Cretaceous, Montana

There were numerous species of Anatosaurus (“Duck Reptile”), also

known as Edmontosaurus and Trachodon, that flourished up until

the very end of the Cretaceous Period. Rare mummified hides of

some of these classic duckbilled dinosaurs have preserved parts of

their skin in minute detail. An unprecedented discovery in Alaska

yielded the frozen, unfossilized remains of a related variety long

buried in the permafrost, providing possible DNA samples as well as

evidence that the present tundra region was once a subtropical,

swampy home to these gentle dinosaurs. This rare skin impression of

the underbelly from the mummified remains of an Anatosaurus was

found in the famous Hell Creek Formation. American Museum of

Natural History.


Family Hadrosauridae Anatosaurus annectens


This fibular fragment with a splendidly preserved skin impression is

from a partially mummified duckbilled dinosaur found in the Hell

Creek Formation. Private collection.


Family Hadrosauridae Corythosaurus casuarius


The crested Corythosaurus (“Helmet Lizard”), with its short muzzle

and tall, hollow crest, lived in herds throughout the forests of

western Canada where it browsed on tree leaves and pine cones.

Equipped with strong, bulging cheeks, it was capable of chewing a

mouthful of food while storing another. Growing to lengths of 33

feet and weighing over 4 tons, these peaceful herbivores ranged

north of the Arctic Circle in search of food and migrated south

during the long winters, which were less cold in Late Cretaceous

times than they are now. Known for protecting and feeding their

young, these duckbills may have relied upon their prominent head

crests for recognition during their mating season.

Although they possessed no significant defense against predators,

their keen senses of vision, hearing, and smell served to warn them

of approaching danger. Females and immature individuals had

smaller crests. Like other crested duckbills, when Corythosaurus

called to each other the sound resonated through the long air

passages of their nostrils (which extended into their hollow crests)

producing a far-reaching, bugle-like honk. Lined with blood

vessels, such extended nasal passages also may have evolved for

the purpose of warming the arctic air before its arrival into the

lungs. From the Royal Ontario Museum.

119. Coprolites

Hadrosaur

Cretaceous, Canada

These coprolites were discovered in association with the fossilized

remains of duck-billed dinosaur nests in Saskatchewan. Private

collection.


Family Hadrosauridae Maiasaura peeblesorum


These gentle duckbilled dinosaurs left in the fossil record a very

detailed picture of their way of life. Herds of Maiasaura (“Mother

Lizard”) appear to have nested together in vast colonies along the

shores of Cretaceous rivers of Montana. Juveniles and hatchlings of

varying ages have been found in these nests, exhibiting evidence of

prolonged parental care. The eggs were carefully arranged in regular

patterns in large, dug-out mounds, each an adult body length from

the next. Adults, which grew to lengths of 30 feet, appear to have

returned to these nesting sites year after year.

Browsing on their hind legs among the tree branches or cropping the

undergrowth on all fours, these peaceful herbivores were defenseless

against the ferocious weapons of their predators. Migratory

hadrosaurs such as Maiasaura appear to have fed and protected their

young until they were old enough to join the herd. In situ juvenile

skeleton. Private collection. Nestling discovered in 1978 by John R.

Homer. Museum of the Rockies.


Family Ornithomimidae Struthiomimus altus

Late Cretaceous, Canada

Prowling along the Cretaceous riverbanks of Southern Alberta and

New Jersey, herds of predacious Struthiomimus (“Ostrich Mimic”)

may have hunted everything from fruit and insects to eggs and small

animals. Its toothless beak resembling that of a bird, Struthiomimus

had sharp 3-fingered claws that were capable of grasping as well as

digging. Although large, it was slender and built for swift running on

its powerful hind legs, balanced by a long tail. Commonly known as

ostrich dinosaurs, the ornithomimids ranged from North America to

Mongolia. Equipped with unusually large brains, these creatures

were among the more intelligent of the dinosaurs. Their particularly

large eyes imply that they were highly adapted to hunting at night,

when the small rodentlike mammals emerged from their hiding and

other dinosaurs were hampered by the darkness. The ostrich

dinosaurs are exemplified by Struthiomimus, whose strong hands

appear to have been the most powerful of this widespread group.

Because of their formidable digging abilities they are largely

regarded as nest-robbers, feeding on the buried eggs of other

dinosaurs and occasionally on tender hatchlings. Royal Ontario

Museum.


Suborder Theropoda Oviraptor philoceratops


In Mongolia in 1922, an Expedition from the American Museum

of Natural History led by Roy Chapman Andrews set out to find

remnants of early humankind. Instead they discovered Museum.

several nests of Oviraptor (“Egg Thief”) eggs, the first dinosaur

eggs ever located, in what must have been a large nesting ground.

Because skeletons of the small, frilled dinosaur Protoceratops

were found in association with the nests, the eggs were long

attributed to them. More recent expeditions have uncovered a fossil

female Oviraptor (a small, beaked, and toothless theropod)

actually sitting on a clutch of unhatched eggs, revealing that

Protoceratops was the intruder. From the historic Roy Chapman

Andrews Gobi Expedition. Alf Museum.


Suborder Ceratopsia

Psittacosaurus


This small, swift plant eater had a narrow beak and short horn-like

bumps on its cheeks. The name of this primitive, early

ceratopsian meant “Parrot Lizard.” Ancestral to the giant horned

dinosaurs, it lived in Mongolia during the early Cretaceous period

between 120 and 98 million years ago. From a private collection.


Suborder Ceratopsia

Protoceratops andrewsi


This in-situ egg nest was found in association with the small frilled

dinosaur, a social, sharply-beaked herbivore ancestral to the giant

horned dinosaurs. From the Polish-Mongolian Expedition.


Suborder Ceratopsia

Protoceratops andrewsi


Regarded as the earliest known horned dinosaur (although it only

possessed small crests where the great horns of its giant descendants

would be), this adult skull and exquisite mounted skeleton of a rare

nestling are from the Polish-Mongolian Expedition.


Suborder Ceratopsia

Chasmosaurus belli


Of the long-frilled ceratopsian dinosaurs of the Late Cretaceous,

Chasmosaurus (“Ravine Reptile”) is the earliest known. Extending

from the back of the creature’s head, a sturdy, spiked frill protected

its neck and part of its back. Large openings in the frill reduced

the weight of the bone mass. It had 2 small horns over the brows and

one on its parrot-beaked snout. Living in large, migrating herds and

measuring over 16 feet in length, these herbivorous grazers have

been found in Alberta, New Mexico, and Texas. Though not as well-

equipped as its descendant, Triceratops (“Three Horned Face”),

Chasmosaurus was capable of warding off attacks by fierce

tyrannosaurs. Females of the genus are distinguished by their

diminutive horns. This impressive creature was one of the first

dinosaurs to be found along with an impression of its skin, the

patterns of its large mosaic scales suggesting contrasting color

patterns.

Despite their obvious abundance throughout the Late Cretaceous, the

ceratopsians, along with the rest of the dinosaurs, disappeared

entirely at the end of the Cretaceous Period, 65 million years ago.

Colossal skull from the Royal Ontario Museum.


Family Pachycephalosauridae Stegoceras validus


Among the rarest of dinosaur remains, the enigmatic boneheads are

known mostly from fragments of skulls and skeletons, making their

relationships to other ornithischian groups difficult to prove.

Growing to lengths of over 6 feet and weighing up to 120 pounds,

Stegoceras (“Horny Roof”) had keen vision and an acute sense of

smell. Possessing sharp teeth, this slow-moving bipedal creature is

believed to have fed on insects, fruits, and leaves. Roaming in herds

that ranged throughout the hills of eastern Asia and western North

America, the boneheads apparently had lifestyles similar to those of

modern sheep and goats.

Distinguished by thickly domed skulls rimmed with bony spikes,

rival males are believed to have established dominance over their

herds through fierce contests of head-butting. This supposition is

further evidenced by their neck and backbones, which were specially

reinforced with strong ligaments for absorbing and distributing

severe shocks to the head. Ancestral to the larger and more advanced

Pachycephalosaurus of North America, Stegoceras may have

evolved from an ancestor of such horned dinosaurs as Triceratops

and migrated from Mongolia before the continents divided. Royal

Ontario Museum.


Suborder Ceratopsia

Triceratops horridus

Late Cretaceous, Wyoming

These horn cores belonged to a Triceratops, the last and the largest

of the many frilled, horned dinosaurs. Private collection.


Family Tyrannosauridae Albertosaurus sarcophagus


Sometimes known as Gorgosaurus, Albertosaurus (“Alberta

Lizard”) was a smaller, slender tyrannosaur (“Tyrant Lizard”) that

only grew to a length of about 26 feet and a weight of 2 tons.

Despite its size in comparison to its larger relatives, it was a

ferocious predator that probably hunted the herbivorous horned

and armored dinosaurs of the Late Cretaceous lowland forests of

Alberta. Presumably descended from a small, Late Triassic

theropod and named for the province in Canada where it was

discovered, Albertosaurus was also common in Montana just

before the end of the Mesozoic Era.

Various names have been given to the dozens of Albertosaurus

skeletons discovered during the past century, but only recently has

their relation to each other been recognized. Like all tyrannosaurs,

Albertosaurus only had 2 fingers on each claw, the vestigial third

finger a useless remnant of its 3-fingered Jurassic ancestors.

Spectacularly complete in-situ skeleton of an extremely rare

juvenile individual. Royal Tyrrell Museum of Palaeontology.


Suborder Pterosauria Quetzalcoatlus northropi

Late Cretaceous, Texas

Named for the ancient Mexican feathered serpent-god Quetzalcoatl,

the giant Quetzalcoatlus was estimated at twice the size of the largest

pterosaurs known at the time, the Pteranodons of the Kansas Chalk.

Only one wing was found, indicating a wingspan of 36 to 39 ft. with

a weight of 190 to 220 lbs., making it the largest known flying

creature. With a low, narrow crest and a long, sharp, toothless beaks,

this giant is better known from smaller, more revealing specimens

found in the same region, which were either younger individuals or a

smaller species.

Although they were dynamically suited for fishing over the sea, their

remains are not found in marine deposits or even near any sizable

freshwater lakes, but are instead found in the silts of the vast

floodplain of an ancient inland system of stream channels over 250

miles from the nearest sea, suggesting the possibility of their having

been scavengers of carrion instead. Similar discoveries in Canada

and Israel indicate the possibility of a wide distribution. This

colossal humerus, discovered in 1971 by Douglas A. Lawson and

Wann Langston Jr., belonged to one of the last of the flying reptiles.

Texas Memorial Museum.


Suborder Pterosauria Pteranodon sternbergii

Late Cretaceous, Kansas

Among the last of the pterosaurs, this small-crested female

individual had a 12-foot wingspan. Gliding over the inland sea,

these creatures were adapted for fishing. This mounted skeleton is

from Lane County, Kansas. Private collection.

129-132. Suborder Theropoda,

Family Tyrannosauridae Tyrannosaurus rex


One of the largest known predators to have walked the Earth (the

females distinctly larger than the males), this invincibly massive,

ferocious carnosaur of Late Cretaceous western North America and

Asia was discovered in 1902 by the adventurous collector Barnum

Brown.

Surpassed in size only by the South American carnosaur

Giganotosaurus, Tyrannosaurus rex (“Tyrant Lizard King”) grew to

lengths of as much as 50 feet, towering 20 feet high and weighing 5

to 7 tons. Their heads alone measured 4 to 5 feet, sporting jaws lined

with long, saw-edged teeth, each one supported by ranks of

replacements. Reaching maturity within 5 years, the life spans of

these enormous creatures may have surpassed 100 years.

Fossil evidence of their actual metabolism is magnificently

preserved in the sequential rings of growth-spurts which scar the

teeth. While strictly regarded by some as nothing more than

scavengers, owing to their greatly reduced forelimbs which could

not even reach their mouths, others consider these creatures the

most fearsome hunters ever to have existed, balanced for swift

running by their long tails.

Presumed to have dealt mostly with the animal’s senses, the brain

of Tyrannosaurus rex was not small for a dinosaur although

compared to the size of the creature’s body it was remarkably

diminutive. This cranial

endocast preserves the size and shape of the brain of a

Tyrannosaurus rex. This gigantic foot, discovered in the famous

Hell Creek Formation, is from the Natural History Museum of Los

Angeles County. This isolated maxilla, once the largest known, is

from the University of California, Berkeley. This spectacular skull,

from one of the largest skeletons ever found, is from the Museum

of the Rockies.


Family Tyrannosauridae

Tarbosaurus bataar (Tyrannosaurus bataar)


First appearing in Central Asia around 74 million years ago, the

tyrannosaurid family subsequently spread to North America where

they flourished until the end of the Mesozoic Era. Smaller and more

ancient than Tyrannosaurus rex, the Asian species is often assigned

its own genus Tarbosaurus (“Alarming Reptile”). Discovered in

1955 in the Bataar region of Mongolia, it was immediately named

Tarbosaurus, but owing to the minimal differences between its

features and those of Tyrannosaurus rex, its name has frequently

been assigned to that genus instead. Because of the immense size of

these creatures, paleontologists also disagree about whether these

fierce dinosaurs were active predators or strictly scavengers.

Defending her nest of eggs (exceedingly rare fossils discovered in

association with the species) this spectacular mounted skeleton is

from the Polish-Mongolian Expedition.

152. Insects in Amber

Early Miocene,

Kenya, Colombia,

Domenican Republic

Trapped in resin that oozed from the trunks of ancient conifer trees

before hardening into amber, fossil insects are found throughout the

world, preserved to the tiniest bristles, including their last

exhalations and excretions. Related to the petroleums, amber is

usually clear and yellow in color. Lumps containing insect inclusions

provide an important record of the prehistoric faunas of the locales

and geological periods in which they are found. Formerly thought to

contain only impressions of the decomposed remains of insects,

amber in fact contains the actual preserved remains of its hapless

victims. In 1992 revolutionary researchers at the University of

California, Berkeley and the American Museum of Natural History

in New York successfully recovered and cloned DNA from 30-

million-year-old insects preserved in amber. Suspended in amber for

over 20 million years, these termites and tiny flies are from the

Miocene of Colombia and the Domenican Republic. Private

collection.

133. Dinosaur footprint

Carnosaur

Late Cretaceous, Utah

This foot impression of a Cretaceous carnivore was found in the

ceiling of a Utah coal mine. By measuring the height of the leg and

the length of the stride, paleontologists are able to calculate from

trackways of such footprints the speed at which the creatures may

have been traveling, often indicating high, warm-blooded,

metabolisms. Private collection.

134. Meteorite

Meteor Crater, Arizona

Since 1978, the extinction of the dinosaurs has largely been

attributed to cosmic intervention in the form of an enormous

meteorite impact on the Earth 65 million years ago. Discovered by

scientists Walter and Luis Alvarez, Frank Asaro, and Helen Michel,

a thin layer of the exceedingly rare element iridium (commonly

found in meteorites) forms a boundary worldwide between

Cretaceous deposits and those of the Tertiary period, apparently the

global fallout from a devastating collision with a large

extraterrestrial body. Heat trapped on the planet’s surface by the

dense atmospheric debris may have raised global temperatures,

killing off the majority of land and sea organisms in a single

catastrophic event. The gigantic Xixulub crater in Yucatan, Mexico

was blasted by such an impact around the time of the Cretaceous

extinction.

Most meteorites come from the vicinity of the asteroid belt, the

orbiting fragments of metal and rock which are the remnants of a

failed planet and of the actual creation of our solar system some 4.6

billion years ago. About 22,000 years ago this meteorite, composed

of 95% pure iron, left a crater over 3,600 feet wide and 525 feet deep.

A fragment of the original meteorite, this pristine relic of the

formation of the solar system was found in the famous depression of

Meteor Crater, Arizona. Private collection.

the origins museum institute mesozoica origins museum institute presents mesozoica from the genesis...

Documents