Museum of Ancient Wonders presents

PALEO The Story of Life 4.6 billion years of fossil history

Drawn from the world’s foremost fossil collections, the unprecedented treasury of fossil casts known as PALEO The Story of Life, brings together into one exhibition some of the most exciting finds in the history of paleontology from over a century of worldwide excavations, exhibited as sculptural works of art.

Spanning 4.6 billion years in scope, from the earliest invertebrate marine life through the Triassic, Jurassic, and Cretaceous dinosaurs to mammals and prehistoric humans, this internationally acclaimed, comprehensive collection dramatically illustrates the awesome story of prehistoric life on Earth.

Displaying casts of rare fossils from the Americas, Europe, Asia, Africa, and Australia, this prestigious collection includes skeletons, skulls, claws, and eggs gathered from such revered museums as the Smithsonian Institution, the American Museum of Natural History, The Royal Ontario Museum, and the Carnegie Museum, as well as many others.

PALEO The Story of Life is proud to include casts of important fossils housed in the following venerable collections

UNITED STATES National Museum of Natural History (Smithsonian Institution) American Museum of Natural History Carnegie Museum Natural History Museum of Los Angeles County University of California, Berkeley University of California, Los Angeles Brigham Young University University of Texas, Austin University of Nebraska State Museum Harvard University Peabody Museum, Yale University Monroe Community College Page Museum Alf Museum Museum of the Rockies

CANADA Royal Ontario Museum Royal Tyrrell Museum of Paleontology National Museum of Natural Science

EUROPE AND GREAT BRITAIN Musee de l’Homme University of Bonn Humboldt Museum Bavarian State Institute of Geology and Paleontology Vienna Natural History Museum Swedish Museum of Natural history British Museum of Natural History Royal Scottish museum

ASIA ~ AUSTRALIA ~ AND THE MIDDLE EAST Beijing Institute of Vertebrate Paleontology and Paleoanthropology University of Adelaide Geological Survey of Pakistan

AFRICA Kenya National Museum South African Museum Transvaal Museum National Museum of Tanzania Cairo Geological Museum National Museum of Ethiopia

…and grateful to the following distinguished scientists.

ROBERT T. BAKKER LOWELL DINGUS STEPHEN JAY GOULD TOM GRAY JOHN R. HORNER NICHOLAS HOTTON DONALD JOHANSON JOHN KAPPELMAN WANN LANGSTON JAMES H. MADSEN, JR. JOHN MAISEY WADE MILLER WILLIAM R. MUEHLBERGER JOHN OSTROM TIMOTHY ROWE DALE RUSSELL J. WILLIAM SCHOPF SMILJANA MIMA STOJANOVIC

PRAISE FOR PALEO The Story of Life

“After 65 million years, they’re back. In a BIG way.” BOSTON HERALD

“Now underway at the World Trade Center in Boston…the entire story of life on Earth as represented by the fossil record.” THE TAUTON GAZETTE

“This fascinating presentation…has educated and enthralled all who have been fortunate enough to view it.” MASSACHUSETTS GOVERNOR WILLIAM F. WELD

“The only exhibit of its kind in the world… Paleomania makes no bones about theatrical approach… when it comes to drama, intrigue and excitement, it’s tough to beat the theater of life.” AUSTIN AMERICAN STATESMAN

“A window with a view into the most remote prehistory of man and animals…the unique feature of Paleomania is that the casts are displayed as sculpture…quite different from the paleontological exhibits one usually sees in museums…response from the public continues to be surprise and pleasure from lay people and scientists alike.” HILL COUNTRY LIVING

“To see the originals you would have to travel all over the world…an unprecedented collection of dinosaur fossil casts!” DISTINCT MAGAZINE

“A new breed of both art and science…it’s amazing to see…” WESTLAKE PICAYUNE

“It’s thrilling to see children get an idea of how really big…some of these creatures were…wonderful creations, almost works of art, because that’s what they look like at first glance.” HILL COUNTRY NEWS

“Without a doubt, this exhibit provides unmatched educational opportunities for its visitors. Children and adults alike have a unique chance to learn about the history and development of life on our planet, and to place themselves within the awesome scope of that development…a testament to what can be accomplished when the public and private entities work together for the benefit of everyone.” TEXAS GOVERNOR ANN RICHARDS

“This collection contains some very important finds which have added tremendously to our knowledge…From June until the Labor Day weekend, 200,000 people visited Atlanta’s Fernbank Museum of Natural History to view the highly acclaimed collection… such a remarkable presentation… so readily accessible.” GEORGIA GOVERNOR ZELL MILLER

PALEO The Story of Life 4.6 billion years of fossil history

Eskimo Nebula (NGC 2392 NASA Hubble photograph)

“Whenever I look at a bone, I always see the fingerprints of the god who amused himself with sculpting it.” Pablo Picasso

As art sometimes reflects nature, so, in turn, does nature occasionally reflect art. These bones, and teeth, and talons tell a story. A story of living molecules beginning to reproduce themselves in an ancient sea and gradually crawling out onto dry land. A story of dynasties of giant, complex creatures dominating land, sea and sky, descended from the tiniest and simplest of ancestors in an incredible chain of reproduction and diversification. A story of strength, ferocity and gentleness in titanic proportions, in other words, the story of the ingenious adaptability of life in the face of death. For in this struggle we see dramatic evidence of nature’s unrelentingly exploratory forces at work. Viewed as a progression of sculptures, one could say that a distinct style emerges early and gradually refines itself over millions of years, sometimes simple, sometimes quite baroque, and usually astonishingly practical. A story without words, cleft by humankind from stone.

THE PRECAMBRIAN ERA warm, shallow, offshore environments from 4.6 billion to 570 million years ago where complex living organisms first arose.

During the first 3 billion years of the 1. Kingdom Monera, planet’s existence there was no ozone layer Phylum Cyanophyta in the atmosphere to shield the land from the Collenia versiformis sun’s ultraviolet rays. Life on Earth began Early Precambrian, Minnesota in the dark ocean depths where these rays, destructive to the delicate DNA molecules The oldest known visible structures that are exclusive to living organisms, could produced by living organisms, stromatolites not penetrate. The early self-reproducing (“Cushion Stones”) are the fossilized one-celled organisms, known as remains of slimy mounds or mats formed by prokaryotes, were so primitive that they did the cementing (in distinctive layers) of not possess a distinct cell nucleus. About a calcium carbonate sediments to the filmy, billion years ago, these simple asexual cells gelatinous secretions of cyanobacteria, also gave rise to the more complex eucaryotes known as blue-green algae. Appearing in which possess a cell nucleus along with the the fossil record 2.5 billion years ago, these capacity for sexual reproduction, which primordial colonies of photosynthetic allowed for the exchange of genetic material microorganisms formed great reefs in the and, as a result, evolutionary variability warmer lakes and shallow seas of the between organisms. Precambrian. This sliced cross-section of the 2 billion-year-old stromatolite Collenia As some of these early microorganisms reveals an algae formation twisted by floods began producing oxygen, the oceans and the or volcanic activity. Private collection. atmosphere gradually became abundant with it. A reaction between lightning and the 2. Kingdom Monera, oxygen in the atmosphere slowly produced a Phylum Cyanophyta layer of ozone gas which, in turn, gradually Collenia tubiformis began to filter out enough of the harmful Late Precambrian, Montana ultraviolet rays to permit habitation of the shallower waters and, subsequently, the THE EDIACARA FAUNA land. Scattered throughout the world, the first In Western Australia the fossilized remains isolated communities of multicellular animal of simple microorganisms (such as bacteria) life in the oldest inhabited seas appear to have been found in rocks that are close to have developed around the oxygen enriched 3.5 billion years old. This was the Archean oases of algal colonies from 700 to 600 Era, also known as the Precambrian period, million years ago. Discovered in the which lasted until about 570 million years Ediacara Hills of Southern Australia by Sir ago. The earliest organisms visible to the Reginald Sprigg in 1947 and known as the naked eye did not appear until about 700 Ediacara fauna, these rare Precambrian life million years ago. During the Late forms are the most primitive known. With Precambrian, the formation of cells organized into actual tissue and Gondwanaland united the modern continents equipped with rudimentary vascular of the Southern Hemisphere, providing systems, they probably absorbed oxygen through their skin, tending to prevent their becoming too thickly-tissued, unlike any poisonous stinging cells capable of animals that have succeeded them. paralyzing prey on contact. Among the oldest and most primitive of such creatures Evidence of glaciations and a meteorite are the primordial medusa (or jellyfish) of impact correspond to the disappearance of the Precambrian, whose colorful modern this fauna from the fossil record, separating descendants are virtually unchanged. the Precambrian Era from that of the Although their soft structures consisted Paleozoic. Although these early animal mainly of water, some ancient jellyfish such prototypes did not survive into the as Rugoconites (the oldest known true Paleozoic, they appear to have produced a medusoid jellyfish) were durable enough to variety of survivors including segmented fossilize after washing onto the beach and annelid worms (the presumed ancestors of drying in the sun. Remarkably preserved, the arthropods), as well as the cnidarians this ancient impression is more than half a (jellyfish), and echinoderms (the presumed billion years old. ancestors of the chordates). The red coloration of the rocks containing the 4. Phylum Cnidaria, imprints of these dawn animals is attributed Class Cubozoa to the oxidation of iron in the sand of the Kimberella guadrata ancient tidal flats as a result of the growing Late Precambrian, South Australia abundance of the corrosive gas in the atmosphere. From the Late Precambrian Ediacaran deposits of Flinders Range, South Australia. University of Adelaide.

3. Kingdom Animalia, Phylum Cnidaria Rugoconites tenuriugosus Late Precambrian, South Australia

Beginning life as a tiny polyp attached to the underside of a rock, followed by metamorphosis into a medusa, this Among the first metazoans to arise from archetypic cubozoan (preserved in side protozoan ancestry were the coelenterates view) possessed an elongate, square-edged (“Hollow Entrails”), or cnidarians. From umbrella. Commonly known as sea-wasps, sea anemones and corals to jellyfish, these this extant form of deadly, long-tentacled marine organisms are known for their great jellyfish is the most venomous predator on beauty and diversity. As with modern Earth, capable of inflicting instantaneous forms, many primitive varieties possessed death. annelid worms presumably gave rise to the 5. Phylum Cniadria, segmented arthropods. Class Scyphozoa 7. Phylum Annelida, Ediacaria Flindersi Class Polychaeta Late Precambrian, South Australia Spriggina floundersi Late Precambrian, South Australia

Well-documented in the fossil record, Sprigginia attests to the diversity of the Long regarded as one of the earliest early annelids, whose descendants jellyfishes, the well-documented Ediacaria (including earthworms and leeches) are still may have lived a sedentary existence on the alive today. A flattened, segmented marine sea floor with its short tentacles extended worm, the extraordinary preservation of upwards, an assumption resulting from the most Spriggina specimens reveals a small, discovery of an anemone-like orifice on muscular creature with relatively simple some Ediacaria specimens. nervous and excretory systems. Owing to the enlargement of its head and other 6. Kingdom Animalia, physical similarities, it has been suggested Phylum Annelida that his annelid may have been ancestral to Dickinsonia costata the trilobites. Late Precambrian, South Australia 8. Kingdom Animalia, Phylum Echinodermata Tribrachidium heraldicum Late Precambrian, South Australia

A bizarrely flattened and discoidal segmented marine work indigenous to the primordial tidal flats of southern Australia, Dickinsonia was usually quite small, although on occasion some grew to extraordinary lengths. Already a diverse Representing the echinoderms in the group by the end of the Precambrian, the Precambrian community is the tiny, coin- shaped fossil known as Tribrachidium, though it is such a primitive form that it exhibits only 3 of the 5 symmetrical body sections that distinguish true echinoderms such as starfish, sea urchins, and crinoids. Within this group, the origin of the chordates, the soft-spined ancestors of the vertebrates, is theorized to have occurred. If Tribrachidium is an echinoderm, then it may be evidence of the presence of the ancestors of the vertebrates in the oldest known seas.

9. Phylum Cnidaria, Class Anthozoa Charniodiscus opositus Late Precambrian, South Australia

Sea pens, or Pennatulaceans, are soft corals that live a benthic existence attached to the sea floor. Those of the earliest inhabited seas were large, frondosa structures that lived by filtering tiny particles of food from the warm waters of the shallow tidal flats.

11. Phylum Cnidaria, Order Pennatulacea Glaessnerina grandis Late Precambrian, South Australia

Rising like delicate seaweed plumes from the bulbous holdfasts anchoring them to the substrate and swaying with the gentle currents, Pennatulaceans resembling Charniodiscus were widespread throughout the world, from Newfoundland to England and Australia. This group exhibits distinguishing characteristics that still persist in living Pennatulaceans.

10. Phylum Cnidaria, Order Pennatulacea Charniodiscus arboreus Late Precambrian, South Australia PALEOZOIC ERA from 570 million to 345 million years ago

Known as the Cambrian explosion, about 570 million years ago dense populations of complex sea creatures suddenly appeared, marking the beginning of the Cambrian period and of the Paleozoic era. First discovered in northern Wales (once known as Cambria), fossils of this period document the early establishment of all modern animal phyla, followed by the emergence of primitive, jawless fish in the Ordovician (500 million years ago), named for an ancient Celtic tribe of western Wales, the Ordovices, whose farms were built on rocks The last of such featherlike creatures to be rich in fossils. found in the Late Ediacaran deposits,

Glaessnerina was the nearest to modern Following the Ordovician, rich formations forms of sea pens. Because conditions found along the border of Wales and favorable to fossilization persisted past the England derive their name from the savage point of Glaessnerina’s disappearance from tribe of Silures that inhabited the region the Precambrian deposits, it is assumed that during the Roman occupation. Throughout they declined to the point of extinction. the Silurian (435 million years ago), plants

and insects invaded the land. In the 12. Phylum Cnidaria, Devonian (395 million years ago), Order Pennatulacea characterized by fossils first discovered in Cyclomedusa davidi Devon, England, advanced lobe-finned fish Late Precambrian, South Australia and tetrapod amphibians appeared in the

freshwater streams of the newly formed Old Red Sandstone Continent which united Greenland with Europe and North America. At the close of both the Ordovician and Devonian periods, Gondwanaland drifted over the south pole, triggering the onset of glacial episodes accompanied by mass extinctions of marine life.

Long regarded as ancestral jellyfish, the 13. Phylum Arthropoda, discoidal Cyclomedusae are now considered OrderAgnostida by the Australian scientists who have Ptychagnostus studied them for years to have been the Middle Cambrian, Utah holdfasts of other animals that lived attached to the substrate, the sea pens.

THE EARLY TO MIDDLE characteristic of echinoderms (the group which includes starfish and sea-urchins), the eocrinoids (“Dawn Crinoids”) of the shallow Cambrian seas were bottom-dwelling, bud- shaped creatures on elongated, tapering stems. Lacking the specialized respiratory structures of their more advanced descendants, these primitive marine animals

fed by transporting tiny, filtered food Already well-established by the dawn of the particles along their simple brachioles Cambrian, this ancient order of minuscule, (arms) to their mouths, which were located ancestral trilobites must have evolved in the on top of the bud, or theca. Although quite primordial seas of the Precambrian. rare, they persisted for over 200 million Although most agnostids (“Unaware Ones”) years, disappearing after the Silurian. were not equipped with eyes, these early creatures, less than half an inch in size, The origin of the first chordates (ancestors persisted for some 135 million years. of the vertebrates) appears to have occurred Ptychagnostus (“Folded Unaware One”), within the early echinoderm group, some of characterized by their minute size, lack of whose free-swimming larvae closely eyes and greatly reduced thoracic (mid- resemble the simplest living invertebrate section) segments, lived a planktonic, chordates, the acorn worms which live along drifting lifestyle in dark, murky marine the geothermal vents at the bottom of the environments which apparently were not sea. Private collection. conducive to vision. They became extinct around the close of the Ordovician. Private 15. Kingdom Monera, collection. Phylum Cyanophta Cryptozoon proliferum 14. Phylum Echinodermata, Late Cambrian, New York Class Eocrinoidea Gogia Kitchnerensis Middle Cambrian, Utah

Providing a variety of habitats for the sudden explosion of invertebrate life

throughout the planet at the dawn of the Appearing in the Early Cambrian and Cambrian, the stromatolite reefs all but exhibiting the pentameral symmetry vanished about 570 million years ago, presumably as a result of widespread grazing on the algae that formed them. Although fossilized algae is distributed throughout the world, exceedingly rare, living stromatolites are found only in such isolated places as the Bahamas and Australia where the currents are too swift or the waters to hypersaline to permit grazing. Exposed by glacial activity, this spectacular form of Cryptozoon (“Secret Life”) grew along the barrier reefs of an ancient island now known as the Adirondack Mountains. Monroe Community College.

THE BURGESS FAUNA

Discovered by Charles Doolittle Walcott in 1909, the Middle Cambrian deposits of the Burgess Shale of British Columbia represent the period of abundant genetic diffusion Preserved in exceedingly rare condition, which followed the initial explosion of with its soft-tissued antennae and limbs rapidly diversifying animal forms at the intact, including gills and chewing bases, dawn of the Cambrian. These extraordinary this small but widespread denizen of the “shadow fossils”, known as the Burgess ancient reef habitats is one of the oldest and fauna, are the filmy remains of creatures that best-known of the early spined trilobites. were buried alive about 530 million years Belonging to the corynexochid order, ago by a series of mudslides at the base of a Olenoides was characterized by eyes of massive algal reef, leaving an unparalleled medium size with a pygidium (tail) of record of the soft-bodied animal life smaller size than its cephalon (head). indigenous to a primordial sea that stretched Although its soft parts were protected by a from the Arctic Ocean to the Pacific of sturdy exoskeleton (which is periodically Southern California. Miraculously preserved shed as it grew), it was a passive and to the finest detail as reflective imprints of defenseless scavenger that lived by filtering carbonized film on black shale, these tiny particles of food from the muddy sea primitive marine organisms are startling floor. evidence of the presence of all existing animal phyla in the Middle Cambrian seas, 17. Phylum Arthropoda, alongside a number of extinct forms that Oder Limulavida defy classification in any known groups. Sidneyia inexpectans From the Middle Cambrian Burgess Shale of Middle Cambrian, British Columbia British Columbia. U.S. National Museum.

Swimming by means of a tail fan resembling 16. Phylum Arthropoda, those of crustaceans, this predatory Class Trilobita arthropod exhibits the combined Olenoides serratus characteristics of distinct family groups Middle Cambrian, British Columbia which have subsequently diverged (chelicerates and crustaceans). It fed by Although superficially shrimplike, this passing food from its rear limbs to its primordial marine creature is ranked among mouth, as do most marine arthropods, whose the unplaceable early arthropods of unique legs are outfitted with spiny teeth. The anatomical form. Among the most common digested remains of tiny trilobites have been of the Burgess arthropods and dwelling found in the guts of some specimens. almost exclusively on the shallow sea floor where it extracted small particles of food 18. Kingdom Animalia, from the muddy sediment, it was probably a Phylum Chordata weak swimmer and did not actively pursue Pikaia gracilens prey. Middle Cambrian, British Columbia TRILOBITES

The most commonly preserved creatures of the ancient Cambrian seas were the ubiquitous trilobites (“Three Lobes”). Comprising more than half of all known animal life at the time they shared the warmer waters with early jellyfish and sponges. Throughout the Silurian and The unlikely preservation of this tiny marine Devonian periods, as predatory eurypterid, organism supplies one of the most important early jawed fish, and amphibians appeared clues to the enigmatic origin of the and proliferated, the numbers of trilobites vertebrates. Despite its long standing dwindled, disappearing entirely at the close classification as an annelid worm, its of the Paleozoic Era some 245 million years profound reinterpretation in 1979 by Simon ago. Conway Morris and Harry Whittington revealed the distinguishing bands of muscles These vastly diversified primordial and dorsal notochord extending the length of invertebrates, exhibited in chronological its body which identify this swimming progression, comprise 8 distinct orders filtrator-feeder of the shallow seas as the (including the Agnostida) and represent oldest known chordate, a direct ancestor of every period of the Paleozoic Era from their the vertebrates. Outnumbered by vast sudden appearance in the Early Cambrian to varieties of arthropods and coelenterates, the their extinction in the Permian. From first proto-fishes appear to have been private collections. represented exclusively by this single species in the Cambrian seas of western 20. Order Redlichiida, Canada where this rare and important Family Olenellidae creature (along with its myriad descendants) Bristolia bristolensis once faced a very tenuous future in terms of Early Cambrian, California survival.

19. Kingdom animalia, Pylum Arthropoda Waptia fieldensis Middle Cambrian, British Columbia

Middle Cambrian, Utah

An early member of the olenellid family, representative of the redlichiid order, with large, crescent-shaped eyes. Among the oldest and most primitive of trilobites, a A member of the ogygopsid family, a spined, bottom-dwelling scavenger capable variant form of corynexochid, characterized of both swimming and crawling. by medium-sized eyes and a broad, fused pygidium, well-developed for burrowing. 21. Class Trilobita, Order Corynexochida 23. Class Trilobita, Olenoides superbus Order Corynexochida Middle Cambrian, Utah Wanneria walcottana Late Cambrian, Pennsylvania

A late representative of the dwindling

corynexochids which died out by the close A common representative of the widespread of the Cambrian, characterized by its corynexochid order, characterized by its medium-sized eyes and spiny pleura (ribs). medium-sized eyes and enlarged pygidium A scavenger adapted for crawling on the (tail). muddy sea floor.

22. Order Corynexochida, 24. Class Trilobita, Family Ogygopsidae Order Odontopleurida Hemirhodon amphipyge Eoceraurus trapezoidalis Ordovician, Oklahoma have aided in surface flotation and drifting with the current.

26. Class Trilobita, Order Ptychopariida Amphyxina bellatula Ordovician, Missouri

The spines of these peculiar trilobites were special adaptations for the widest possible distribution of body weight on the soft sea floor, where its life was spent crawling in the mud. From the Orodovician of Tiny, gregarious examples of the Oklahoma. Excellently preserved along ptychopariids, an extremely diverse order with the partial remains of a juvenile of the which gave rise to most of the trilobites that same species, this rare, early phacopid appeared after the Cambrian, descended belonged to a diverse new order from the older, extinct redlichiids, which distinguished by its highly complex eyes. their earliest representatives resembled. 25. Class Trilobita, 27. Order Ptychopariida, Family Raphiophoridae Family Trinucleidae Lonchodomas mcgeheei Cryptolithus laelus Ordovician, Oklahoma Ordovician, Pennsylvania

An elegant, pyritized example of the vast order of ptychopariids, this tiny, sightless member of the widespread trinucleid family This unusual and highly specialized member possessed a broad, perforated brim along the of the raphiophorid family was a sightless, cephalon (head) and elongated genal spines, lightly built swimmer, protected from which supported its body on the soft, muddy predators by its long spines which also may sea floor on which it lived. Silurian, New York 28. Order Phacopida, Family Dalmanitidae Kanoshia kanoshensis Late Ordovician, Utah

A typical example of trilobite behavior, this early form of phacopid, ancestral to the later A large and splendid example of the diverse dalmanitid family and distinguished by its order of lichids, a broad, flattened form well distinctively flared pygidium, commonly suited for a life spent crawling on the sea protected itself from danger by rolling up floor, filtering organic food particles from when threatened. the mud. 29. Class Trilobita, 31. Order Phacpida, Order Proetida Family Calymenidae Fragiscutum glebalis Diacalymene clavicula Silurian, Oklahoma Silurian, Oklahoma

A tiny and uniquely specialized member of the longstanding proetid order, capable of enrolling and distinguished by its unusual A member of the abundant calydmenid eyes positioned at the ends of short stalks. family, a variant form of phacopid with smaller, simpler eyes than its more 30. Class Trilobita, specialized relatives, and typically found Order Lichida enrolled. Arctinurus boltoni prickly spines extending from every part of 32. Order Phacopida, its body, an effective defense against the Family Dalmanitidae growing number of marine predators. Huntonia oklahomae Early Devonia, California 34. Class Trilobita, Order Odontoplurida Leonaspis williamsii Early Devonian, Oklahoma

An unusually specialized phacopid, this long-snouted member of the widespread With tiny eyes positioned on the tips of dalmanitid family was well-adapted for short, stiff stalks, this small, bizarrely plowing in the sand and burrowing, lying barbed trilobite was among the last with only its head exposed, watching with representatives of the rather spiny order of its compound eyes and waiting for tiny prey odontopleurids, which had persisted from to crawl or drift by. the Late Cambrian.

33. Class Trilobita, 35. Order Proetida, Order Lichida Family Phillipsidae Dicramurus hamatus Breviphillipsia sampsonii Early Devonia, Oklahoma Mississippian, Missouri

A member of the diverse phillipsid family, This rare, exotic form of lichid was representative of the far-ranging proetid equipped with a pair of horns and elongate, order which flourished from the Ordovician to the end of the Paleozoic. 38. Phylum Arthropoda, Class Trilobita 36. Class Trilobita, Homotelus bromidensis Order Proetida Ordovician, Oklahoma Ditomopyge parvulus Pennsylvanian, Oklahoma

This cluster of tiny, pyritized proetids may represent moltings rather than the actual remains of the animals themselves, which periodically shed their exoskeletons as they Presumably evolved from segmented grew. Precambrian annelid worms, these primitive arthropods, distinguished by their simple 37. Class Trilobita, eyes and enlarged cephalons and pygidia, Order Proetida were simple scavengers, dwelling on the Delaria antiqua muddy sea bottoms and grubbing for food, Permian, Texas periodically shedding their sturdy exoskeletons as their softer internal parts outgrew them. A gentle and gregarious creature, Homotelus (“Same End”) derives its name from the similarity between its anterior and posterior sections. This spectacular cluster of 30 ptychoparlid trilobites perished together 500 million years ago in the ancient sea of Oklahoma, preserved in a mass burial along with cast- off moltings, in beautiful mosaic detail. Private collection. Descended from the primitive ptychopariids of the Early Cambrian and characterized by 39. Class Trilobita, its large eyes and pygidium and the ability to Order Phacopida enroll, this late proetid was among the very Dalmanites last of the trilobites. Early Silurian, Tennessee

Though some trilobites were sightless, most Widespread throughout the Paleozoic Era, were equipped with either single-lens or these giant water scorpions were particularly compound eyes. With an almost abundant during the Silurian Period (465 to hemispherical field of vision to aid them in 415 million years ago) when they ranged their hunt for food on the muddy ocean from marine environments to brackish bottoms, trilobites were the first creatures on streams and estuaries. The sharp telson, or Earth to develop complex eyes, some of tailspike of Eurypterus (“Wing Fin”), which were composed of over 10,000 primarily useful for correcting its position individual lenses. when stranded upside down on the seafloor,

may have been armed with a venomous Although compound eyes were not stinger. Two individuals of one species and uncommon among the diminished groups of a smaller individual of another species are trilobites that survived the Ordovician dramatically preserved together with yet extinction, this progressive order of early another species of eurypterid prominent at phacopids had eyes equipped with an the bottom of the slab. Armed with pincers advanced type of lens structure that enabled and a spiked fantail Pterygotus was a them to see better in the deeper, darker ferocious predator. Numerous fossilized waters and at night. Inhabiting the offshore trilobites bear scars left by the fearsome marine environments of the Silurian, this pincers of such creatures. rare and giant form of Dalmanites may have been nocturnal. Burrowing with its Descended from trilobites (whose enormous diminutive telson (tail spike) into the soft populations they helped to decrease), these sand until only their heads were exposed, impressive invertebrates possessed an they would lie in wait for tiny drifting prey. elongated, segmented body and were Private collection. equipped with a pair of compound eyes as

well as a pair of simple ones. Sometimes 40. Phylum Arthropoda, growing to lengths of as much as 10 feet Class Erypterida these early arthropods were the direct Eurypterus remipes antecedents of the first creatures to leave the Eurypterus lacustris aquatic environment to inhabit dry land: the Pterygotus macrophthalmus scorpions. Private collection. Late Silurian, New York

41. Phylum Arthropoda, Class Arachnida Palaeoscorpius devonicus deltas and intertidal estuaries of central Late Devonian, Germany Europe with the sole exception of Palaeoscorpius, a formidably large example known exclusively from deep marine deposits. From the University of Bonn.

42. Superclass Agnatha, Order Osteostraci Cephalaspis Lyelli Early Devonian, Scotland

Among the very first creatures to abandon the aquatic environment and invade the land, an event which took place during the Late Silurian, were the scorpions. Derived from eurypterid, the earliest true scorpions were marine creatures. Pressured by the rise of Ancestral to the first true fish, the Agnatha predatory fishes and eurypterids, the (“Jawless Ones”) are the oldest fossil appearance of amphibious scorpions, vertebrates. Of this early group of marine capable of surviving in a terrestrial and freshwater creatures, Cephalaspis environment for limited visits, presumably (“Shield Head”} was the most successful led to the establishment of completely and enduring. Ranging throughout the Late terrestrial, air breathing varieties. Silurian rivers, lakes, and estuaries from Asia to Germany, it had spread as far as Related to spiders, these ferocious predatory eastern Canada by the end of the Devonian. arachnids possess a venomous stinger on the tip of the tail, with which they are capable of With its head encased in a bony, armored disabling their prey. Unlike the tiny, carapace (or shell), Cephalaspis was primitive Silurian scorpions, the amphibious vulnerable to very few predators other than Devonian forms were adapted to feeding out eurypterid. Presumably a bottom dweller, it of water. External digestion, or liquid fed by filtering particles of food from mud feeding, is not possible in an aquatic sucked into its small, jawless mouth. environment, where ingestion of solid food Between its 2 upward-looking eyes lay the is necessary. The Devonian scorpions pineal body, or “Third eye,” a photosensitive exhibit a definite landward trend along the organ which distinguished light from shade. Networks of nerves, preserved in a number of fossil specimens, extended from its simple brain to sensory dorsal plates. Once considered to be electrical organs, these sensitive plates probably served to monitor such things as temperature and water pressure as well as vibrations. They became extinct some 365 million years ago. From the Royal Scottish Museum.

43. Class Trilobita, Order Phacpida Derived from the earlier Agnatha, the Phacops africanus Devonian placoderms were among the first Devonian, Morocco ancestral fish to develop jawbones and paired fins. Growing to about 1 foot in length, these primitive vertebrates were equipped with a bony armored carapace which covered the front part of the body, the exposed trunk and tail presumably covered with scales. Also found in Antarctica, the widespread Bothriolepis (“Trench Scale”) reached North America near the end of the Devonian, inhabiting freshwater lakes and streams.

Although trilobites began to decline after the The development of jaws in these fish, close of the Cambrian, probably as a result though rudimentary, increased their capacity of increased predation from the rapidly for hunting and feeding. Their paired and growing numbers of fish and other marine spiny pectoral appendages may have served life, they enjoyed a temporary resurgence of as anchors against currents as they gleaned diversity in the Devonian, giving rise to the for food on the muddy river bottoms. The 2 largest and most grotesque forms known. In pockets stemming from the throat may have dwindling numbers, these once common served as lungs, temporarily allowing creatures survived into the Permian before Bothriolepis to breathe air when stranded on vanishing from the fossil record. This giant shoals by the tide. This exquisitely phacopid trilobite, with its excellently preserved school of placoderms represents preserved compound eyes, each composed some of the earliest of true fish. American of over 100 individual lenses, is Museum of Natural History. characterized by its large eyes, a granularly decorated glabella (face), and the ability to 45. Class Placodermi, enroll. Private collection. Order Arthrodira Dunkleosteus terrelli 44. Class Placodermi, Devonian, Ohio Order Antiarchi Bothriolepis canadensis Late Devonian, Canada

As the Late Devonian freshwater streams and ponds shrank or dried up during periods of drought, the primordial, lobe-finned lungfish of the period developed The earliest known giant vertebrate, rudimentary adaptations to the hostile Dunkleosteus (“Dunkel’s Bones”) grew to environment of land before spreading into lengths of over 16 feet and weighed up to 5 the seas. Special bone features that enabled tons. Like all placoderms, its massive head them to crawl on their fins evolved not for was protected by an armor of bony plates the purpose of escaping the aquatic while its scaly trunk was exposed. environment, but as a means of reaching Possessing no teeth, its powerful jaws were fresher water when shrinking pools became equipped with razor-sharp blades of bone crowded and putrid or the streams became which enabled it to slash and crush the too muddy. armor of its prey. Also known as Dinichthyes, this monstrous fish hunted A formidable predator resembling the everything from sharks and other modern pike and perfectly preserved with its placoderms to large invertebrates throughout fins and scales intact, this elongated the Devonian oceans of North America and freshwater fish was highly adapted to the Europe. Their extinction coincides with severe climatic fluctuations (often daily) of evidence of widespread tidal waves which the Devonian. With tear ducts to keep its appear to have devastated the majority of eyes moist and lungs derived from a simple marine life along the seashores at the end of air bladder originally employed to keep the the Devonian period about 365 million years bodies of fish right side up, Eusthenopteron ago. Private collection. (“Good Strong Fin”) was able to breathe out of the water during times of drought and stagnation while other fish suffered 46. Order Crossopterygii, asphyxiation. Some of the descendants of Suborder Thipidistia this ruggedly adaptive crossopterygian fish Eusthenopteron foordi gave rise to tetrapod amphibians, the others, Late Devonian, Canada to saltwater coelacanths. The apparent progenitor of all terrestrial vertebrates, it was extinct by the dawn of the Permian. Royal Ontario Museum. 47. Class Amphibia, Subclass Labyrinthodontia Ichthyostega Late Devonian, Greenland record, Ichthyostega is known only from incomplete remains. Skull reconstruction courtesy of the Swedish Museum of Natural History.

THE LATE PALEOZOIC ERA from 345 to 250 million years ago

Inundated by the inland invasion of the seas throughout the Mississippian (345 million years ago), the first division of the Carboniferous period, immense tropical forest regions were fossilized into deep carbon bands in the Earth’s crust. During the Pennsylvanian (310 million years ago), the remaining division of the period, reptiles diverged from their amphibious ancestors and began to proliferate on the land.

The origin of terrestrial vertebrate life By the Permian (280 million years ago), appears to have begun in Greenland with the named for the discovery of fossils near the appearance of the first tetrapod amphibians. region of Perm in Western Siberia, Among the earliest of these creatures, mammal-like reptiles (synapsids) had Ichthyostega (“Fish Plate”) inhabited appeared, characterized by developments freshwater lakes and streams during the Late that would ultimately distinguish them from Devonian and Early Carboniferous. Derived their reptile ancestors and lead to a new from crossopterygian fish, this air-breathing class of animals. predator still retained many of the primitive fishlike structures of its ancestors. Although All of the continental land masses of the it possessed scales and a long tail fin, it also Cambrian collided during the Permian, had a sturdy backbone and 4 short limbs, forming the supercontinent of Pangaea. A each equipped with 7 digits, enabling it to series of devastating ice ages were triggered waddle about on dry land for limited periods by the encroachment of the supercontinent of time before having to return to water. on both poles. The resulting widespread Unlike the amphibians that were to follow, extinction that ended the Permian period and Ichthyostega lacked notches for ears, an the Paleozoic Era was of such massive indication that it had no auditory sense. Its proportions that it has never been equaled, direct relation to crossopterygian fish is over 90 percent of all species vanishing. evidenced by their virtually identical tooth The decimation of the once dominant patterns, a distinctive characteristic with multitudes of mammal-like reptiles provided ichthyostega passed on to the varied an ecological niche that favored the generations of labyrinthodont amphibians surviving reptile groups. which it produced. In fact, this important creature is believed to have given rise to all 48. Paleozoic Sea Floor of the diverse and prolific groups of reptiles, Crinoids birds, and mammals which followed. Brachiopods Although well-documented in the fossil Coral Actinocrinites gibsoni Trilobite Dorycrinus gouldi Trilobite trackway Taxodrinus coletti Mississippian, Indiana Sarocrinus nitidus Agaricocrinites americanus Late Mississippian, Indiana

Dominated by a fossilized crinoid and flecked with tiny brachiopod shells, coral, and even a half-buried trilobite, this exquisite slab has preserved a cross-section of a once thriving marine ecosystem. The Early Paleozoic crinoid gardens were sparse compared to the vast varieties of the Trace fossils preserving the activities of Mississippian period, known as the Age of trilobites are not uncommon. Digging Crinoids. Most of the crinoids died out at furrows into the sand with their jointed the close of the Paleozoic; however a few limbs (or endopodites), many left tiny trails species still survive today. Preserved in that dried and hardened before they could be beautiful detail, these 6 crinoid species were washed away. Fossilized burrows indicate rendered in bouquet. Private collection. that trilobites apparently laid their eggs in pits carefully dug in the sea floor, afterwards leaving them to be covered by drifting sand 50. Phylum Cnidaria to protect them from predators. These traces Class Scyphozoa of an ancient journey were left on the Essexella asherae shallow sea floor by a small marine Pennsylvanian, Illinois arthropod. Private collection.

49. Phylum Echinodermata Class Crinoidea Ulrichcrinus coryphaeus Silurian period) was able to circulate water and nutrients to the cells of its highest leaves by means of its advanced root and vascular systems. Unlike the more primitive true ferns which reproduce from spores, these large, non-flowering, tree-like plants were crowned with seed-bearing fronds.

Supported by rigid trunks that often reached heights of as much as 10 feet, this common seed fern proliferated in the dense swamps Swimming by rhythmic contractions of their and forests of the Late Paleozoic during a gelatinous bodies, these medusoid jellyfish time when coastal areas were often preyed on small creatures that became inundated by the intermittent rising of the entangled in the poisonous, dangling seas. Deeply buried under accumulated tentacles. Lacking a central nervous system, organic debris, the remains of these early these simple marine organisms are actually plants did not decay but instead turned to colonial animals composed of hundreds of peat which in time became coal. Private specialized individual creatures, each collection. fulfilling a separate function such as flotation, stinging, feeding, or digestion. 52. Phylum Arthropoda, From the famous Mazon Creek deposits. Class Insecta Private collection. Urogomphus giganteus Late Jurassic, Germany 51. Kingdom Plantae, Class Lyginopteriodopsida Neuropteris rodgersi Pennsylvanian, Pennsylvania

As evidenced by their distinctly segmented bodies, insects are the direct descendants of the early aquatic arthropods. Appearing in the Middle Devonian, primitive wingless insects gradually gave rise to such Presumably evolved from Precambrian one- magnificently winged creatures as the celled algae, primitive plants existed long ancestral dragonflies with 30 inch before the appearance of the first animals. wingspans that subsequently inhabited the Neuropteris, an ancient seed fern of the coal coal swamps from the Pennsylvanian forests of 300 million years ago (derived throughout the Triassic. Distantly related to from early terrestrial plants of the primordial these ancient insects, Urogomphus (“Bolt Tail”), a true dragonfly, was a formidable for over 280 million years, cockroaches are predator, using its spiny legs for capturing close to the common ancestry of such prey. From the Humboldt Museum. diverse groups as crickets, beetles, wasps, ants, and moths. Private collection.

53. Class Insecta 54. Class Reptilia, Order Orthoptera Order Cotylosauria Mylacris Cephalerpeton ventriarmatum Pennsylvanian, Kansas Pennsylvanian, Illinois

One of the very oldest vertebrates to be recognized as a reptile, Cephalerpeton belonged to the most primitive group, the anapsids, which began with the suborder Captorhinomorpha. Descended from labyrinthodont amphibians, the early “stem reptiles”, or cotylosaurs, were the ancestral stock of all Reptilia, distinguished by their revolutionary ability to deposit their eggs on The most successful group in the animal dry land, bypassing the gilled larval stage of kingdom, insects proliferated with the their immediate ancestors. As the first spread of the Carboniferous forests. The vertebrates to become entirely independent development of folded wings from thoracic of the water, their ability to exploit the flaps enabled the more advanced varieties of terrestrial habitat led to a rapid radiation of the terrestrial arthropods to escape diversely specialized reptile groups which predation. Unlike the dragonflies, whose included the ancestors of birds and primate, outstretched wings made hiding mammals. From the Mazon Creek deposits. from predators difficult, these newly Yale Peabody Museum. evolved insects with wings that folded backwards rapidly flourished. 55. Subclass Labyrinthodontia, Order Anthracosauria Inhabiting the damp ground of humid, Seymouria baylorensis swampy forests, some Pennsylvanian Early Permian, Texas cockroaches such as the gigantic Mylacris commonly grew to lengths of 3 to 4 inches. Unlike insects whose larval forms differ radically from their adult forms, cockroaches undergo incomplete metamorphosis, hatching into nymphs that differ very little from adult forms. Enduring and New Mexico 260 million years ago. Eryops was largely an aquatic creature like the modern alligator. Unlike the early fish, these amphibians were able to listen for their prey due to their well-developed eardrums, evolved from degenerate skull bones inherited from their fish ancestors.

With a sturdy, terrestrial-type skeleton characteristic of reptiles and a skull exhibiting prominent ear notches characteristic of amphibians, Seymouria was long regarded as a primitive reptile and the closest link to their amphibian ancestry. Because related forms document the passage of a gilled larval stage, a characteristic thoroughly eliminating them from the reptilian class, Seymouria is now placed among the anthracosaurs (“Coal Reptiles”) by most authorities, thus including this distinctly terrestrial amphibian in the group A true amphibian, Eryops laid its eggs in of Permian labyrinthodont. Although water, its young passing through a larval Seymouria (named for the town of Seymour, stage, with gills for breathing, before Texas, where it was discovered) differed reaching maturity. Armed against predators very little from the Pennsylvanian ancestors with bony nodules in its skin and growing to of the reptiles, it left no known descendants. about 6 feet in length, this extremely This exquisite skeleton is from the U.S. common swamp creature presumably preyed National Museum. on fish and other amphibians. Hunted, in turn, by the fierce Dimetrodon, Eryops was 56. Class Amphibia, extinct by the close of the Permian, although Subclass Labyrinthodontia its survivors gave rise to the peculiar Eryops megacephalus stereospondyl amphibians of the Triassic. Early Permian, Texas Collected by Kenneth W. Craddock. Private collection. Throughout the Carboniferous and Early Permian periods, the evolving groups of 57. Class Amphibia, primitive amphibians, collectively known as Subclass Lepospondyli labyrinthodont (due to the labyrinthine Diplocaulus magnicomis wrinkles in their tooth enamel, derived from Early Permian, Texas their crossopterygian antecedents) are exemplified by Eryops (“Drawn Out Face”) Among the most bizarre of the Permian which inhabited the lush deltas along the lepospondyl amphibians is Diplocaulus edge of the ancient sea of Texas, Oklahoma, (“Two-Tail”), a flattened, bottom-dwelling predator of the Late Pennsylvanian to Early 58. Subclass Synapsida, Permian streams and ponds. Ranging from Order Pelycosauria 1 to 3 feet in length and lying in wait in the Dimetrodon limbatus murky bottom, Diplocaulus fed by Early Permian, Texas ambushing its prey, its upward-looking eyes positioned on top of its grotesquely boomerang-shaped head.

The aggressive, carnivorous Dimetrodon With tiny legs for its overall body length and (“Dual Sized Tooth”), distinguished by a a body too flattened to bear the musculature prominent dorsal fin along its back, prowled necessary for swift locomotion, Diplocaulus the upland regions of the swampy delta of was probably not a very strong swimmer northern Texas along the edge of a shallow, despite speculations regarding the drifting sea. The dominant predator of this hydrodynamic properties of its oversized area, Dimetrodon fed without competition head. Unable to see each other except by on an abundant population of large touch due to the placement of their eyes, the defenseless amphibians. Belonging to the widely extended corners of these creatures’ archaic order of finback pelycosaurs, these skulls may have provided advantages in early cold-blooded synapsids were ancestral intimidating displays of head-butting during to the mammal-like reptiles of later Permian mating competition, gradually producing a times. Dimetrodon was equipped with a genetic favoring of those with the greatest ferocious arcade of palatine teeth in addition range. Private collection. to the sharp teeth that lined their jaws. Incapable of sustaining an extended chase, they probably hid in the lush vegetation, as on smaller, slower reptiles and waiting for unsuspecting prey to stray too amphibians. close to escape a quick surprise attack. Although undoubtedly cold-blooded, The creature’s impressive dorsal “sail” because of their specialized bone structure provided a large surface area for warming the archaic synapsid reptiles are considered the blood when exposed to sunlight and to be the ancestors of the therapsids, the cooling it when in the shade, although such later and more advanced reptile group that spectacular features may evolve more subsequently gave rise to warm-blooded rapidly for the purpose of mating displays mammals. Some scientists have also noted than for thermal functions. By the Middle affinities between the Early Permian Permian, when the climate along the delta pelycosaurs and the later Permian freshwater became too dry to sustain them anymore, the mesosaurs, the possible forerunners of the Dimetrodons disappeared quite suddenly air-breathing, marine ichthyosaurs. from the fossil record. Brigham Young Collected by Charles Camp and Samuel University. Welles in 1928 and identified by Wann Langston and Robert Reisz in 1981, this 59. Class Reptilia, cluster of Early Permian specimens also Subclass Synapsida contains the dissociated bones of various Aerosaurus wellesi other reptiles and amphibians including an Early Permian, New Mexico Eryops and an Edaphosaurus. University of California at Berkeley.

60. Class Reptilia, Subclass Anapsida Mesosaurus brasiliensis Early Permian, Brazil

The most primitive of the early synapsid reptile groups, the pelycosaurs may have led A small freshwater reptile of the lakes and a somewhat amphibious existence, similar to estuaries of Permian South Africa and South that of alligators. Catching and killing its America (when the 2 continents were still prey in jaws lined with an extraordinary joined), the slender Mesosaurus (“Middle number of sharp teeth, Aerosaurus (“Air Reptile”) grew to a length of 3 feet and had Lizard”) was apparently an aggressive jaws lined with needle-shaped teeth for predator. Equipped with an unusually long catching fish. The earliest known and flat swimming tail, this young aquatically adapted animal descended from pelycosaur probably preyed on fish as well terrestrial ancestors, its broad limbs were adapted for swimming and appear to have Permian times than it is now. In order to been web-footed. survive the severe Karroo winters, they may have evolved some kind of furry insulation. Although mesosaurs are believed by some to be a transitional stage between the later Although they were probably the first ichthyosaurs and their early land-dwelling successful group of herbivores among the ancestors, due to their extremely primitive vertebrates, equipped with horny beaks and aquatic adaptation, there are no actual tusk-like upper canines, by the end of the affinities between the two animal groups to Permian Period to the Middle Triassic, the support this supposition. Because the herds of Dicynodons (“Double Dog Tooth”) remains of this creature have been found had dwindled to extinction, survived by a only in Brazil and South Africa, Mesosaurus few relatives which evolved into early is one of the very strong links in the chain of mammals. From the famous Karro evidence for shifting continents. University Formation. University of California, of California, Los Angeles. Berkeley.

61. Class Reptilia THE TRIASSIC PERIOD Subclass Therapsida from 230 million years to 195 million Dicynodon grimbeeki years ago Middle to Late Permian, South Africa 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 of 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 For about 10 to 15 million years, great herds equator, climates were generally tropical, of these fat, little mammal-like therapsids and warm, ferny swamps teemed with inhabited South Africa, Russia, Scotland, primitive amphibians and crocodiles. In the Asia, and the Americas, apparently arid desert regions, reptiles flourished with reproducing at an extraordinarily prolific the extinction of mammal-like reptiles, rate. Found in the red beds of the South producing the highly successful archosaur African Karroo Formation, these 3 group which gave rise to crocodiles, specimens are the remains of creatures that pterosaurs, and a new kind of animal once flourished throughout a region that was gradually appearing in the Late Triassic considerably closer to the South Pole during fossil record: the Dinosauria (“Terrible Lizards”), which continued to appear in and ornithischians of the Late Triassic increasing varieties for the next 140 million (collectively known as the dinosaurs) as well years. The gradual breakup of Pangaea as to crocodiles, birds, and the extinct flying beginning at the end of the Triassic globally reptiles. Exemplifying this important parent separated dinosaur populations along with group, Euparkeria was a small creature that the first true mammals, tiny burrowing walked on 4 legs, but, like the modern descendants of the mammal-like reptiles. crocodile, was capable of bipedal sprinting due to its powerful hind leg muscles. A 62. Class Reptilia, predator whose advantage over its prey was Subclass Archosauria its swiftness, Euparkeria was extremely Euparkeria capensis close to the immediate ancestry of the Early Triassic, South Africa dinosaurs. This magnificent skeleton is from the famous Karroo Formation. South African Museum.

63. 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.

64. Class Reptilia, Subclass Archosauria Herrerasaurus Triassic, Argentina

This early dinosaur was a primitive, bipedal carnivore with a flexible jaw capable of entrapping its prey. Argentine Museum of Crowding the archaic Permian Natural Sciences. protomammals out of their dominant position in the competition for food, the 65. Class Amphibia, rapidly evolving Triassic reptiles known as Suborder Stereospondyla thecodonts (“Socket Tooth”) were Hadrokkosaurus bradyi distinguished by the development of Late Triassic, Arizona remarkable open skulls, hollow bones that were lightweight but very strong, and jaws This large amphibian from the Moenkoepi lined with individually socketed teeth. This Formation has the superficial appearance of group of ancestral archosaurians (“Ruling a large frog. The pronounced indentation Reptiles”) gave rise to the early saurischians 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 between the eyes, the pineal opening, verified Coelophysis tracks, they proved to sensitive to light and shade, was used as a be remarkably similar. Private collection. “third eye” by early bottom-dwelling fish and amphibians. Derived from an ancient 67. Order Therapsida, lineage of marine ancestors, the once Infraorder Cynodontia photosensitive pineal body is still retained as Thrinaxodon liorhinus a vestigial organ within the brains of all Early Triassic, South Africa modern vertebrates. University of California, Berkeley.

66. Dinosaur trackway Grallator Late Triassic, Connecticut

The transition from synapsid reptiles to mammals was gradual rather than a quantum leap. Replacing gorgonopsids as the Left in the mud by one of the earliest dominant predators of the Early Triassic, dinosaurs, this footprint of an ancient cynodonts were small, fox-like creatures Triassic coelurosaur (“Hollow-Tailed with fewer reptilian characteristics than their Lizard”) gives no hint of the gigantic ancestors. Although exhibiting tiny pits in proportions of its descendants which were to their skulls which appear to have held follow. Ranging up to 10 feet in length, it whiskers and possessing a palate separating ran on its hind legs counterbalanced by a the nasal passages from the mouth, distinctly long tail. This little theropod (“Beast mammalian features, the primitive reptilian Foot”), with its serpentine neck and jaw structure of cynodonts retained certain lightweight, hollow bones, is believed to prominent bones that became greatly have been swift and agile, chasing prey and reduced in mammals and incorporated into tearing it with sharp claws and teeth. Such the inner ear. Extremely close to the behavior strongly suggests a warm-blooded ancestry of the mammals, this group included Thrinaxodon, an advanced therapsid of the forest 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. Two skulls from the Karroo Formation. University of California at Berkeley.

THE JURASSIC PERIOD from 195 million to 140 million years ago

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 55 million year duration of the Jurassic period, the supercontinent of Pangaea was gradually being wrenched into 2 separate masses, Of all the known fossils of adult dinosaurs, Gondwanaland (Africa, South America, Compsognathus (“Elegant Jaw”) has the Australia, India, Arabia, and Antarctica) and distinction of being the smallest. Running Laurasia (Europe, Asia, Greenland, and upright on its strong hind legs and stalking North America). Among the survivors of the underbrush for smaller Reptiles along the Triassic extinction, tiny primitive the forested seashores of Jurassic Germany mammals began to diversify during the and France, Compsognathus was a swift and Early Jurassic. capable hunter, armed with sharp claws and teeth. This tiny coelurosaur was a relative By the dawning of the Late Jurassic (150 of such giant creatures as the Tyrannosaurus million years ago), the Atlantic Ocean had rex of a later age. More closely related to formed and the drifting continents had Archaeopteryx (the bird-dinosaur), this barely begun to resemble their present skeleton shows that they shared a very shapes. Gigantic dinosaurs that cared for recent common ancestor, suggesting that their young had evolved from their smaller birds may have inherited their warm- Late Triassic ancestors. Land bridges blooded metabolism from their dinosaur between the continents allowed the thriving forebears. herds of dinosaurs to migrate across great distances. Palm-like plants appeared and The smaller bones exposed within the rib flourished throughout the warm, swampy cage of this well-known specimen have been landscapes of the period, nourishing the identified as the undigested skeleton of largest creatures that ever walked the Earth. Bavarisaurus, a tiny lizard that was devoured just before the predator died. With 68. Suborder Theropoda, its neck and tail bent backwards, this Infraorder Coelurosauria Compsognathus (discovered in 1861) was Compsognathus longipes long thought to have died in agony, although Late Jurassic, Germany its posture is now attributed to the tightening of tissues as the carcass dried out prior to specimen,” was long misidentified as a fossilization. From the famous lithographic Compsognathus. These rare specimens are limestone of Solnhofen. Bavarian State spectacular evidence of an intermediate Institute for Paleontology and Historical stage between Reptiles and birds. Geography.

Because its remains have only been found in deposits of shallow marine lagoons rich in fossilized fish and squid, some believe 69-70. Class Aves, Archaeopteryx (“Ancient Wing”) was Subclass Archaeornithes capable of diving for aquatic prey. Others Archaeopteryx lithographica envision it darting along the ground Late Jurassic, Germany bipedally, using its wings as spoilers to increase its speed while chasing insects and These small, feathered dinosaurs inhabited small Reptiles or for soaring from tree to the Late Jurassic forests of Central Europe tree. From the famous lithographic 150 million years ago. Although adapted for limestone of Solnhofen. Berlin specimen gliding and presumably for limited flight, from the Humboldt Museum. Juvenile these primitive ancestral birds still retained specimen from the Jura Museum. efficient, grasping claws on each wing, as well as a long bony tail and jaws lined with 71. Class Aves sharp archosaurian teeth. Perhaps the most Subclass Archaeornithes famous fossil in the world, the spectacular Cathayornis yandica “Berlin specimen” was found in 1877. Jurassic, China Owing to the faint preservation of its flight feathers (overlooked for many years), the juvenile specimen, known as the “Eichstatt 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 Roughly contemporary with the European specimen, was reinforced with a lacing of Archaeopteryx, this feathered theropod special tissue. From the lithographic dinosaur from Asia more closely resembled limestone of Solnhofen. Humboldt modern birds. Beijing Institute of Museum. Vertebrate Paleontology. 73. Superorder Archosauria, 72. Superorder Archosauria, Suborder Pterosauria Suborder Pterosauria Pterodactylus kochi Rhamphorynchus gemmingi Late Jurassic, Germany Late Jurassic, Germany

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 Throughout the Jurassic, leathery-winged Snout”) had a slender tail that ended in a pterodactyls (“Wing Finger”) would have kite-shaped membrane which presumably been a common sight gliding on the tropical served as a rudder. Growing to lengths of breezes of the European coastal regions, up to 2 feet, its average wingspan was about catching up insects, small fish, and squid in 4 feet. With an elongated, flexible neck and their long, sharply-toothed beaks. Pterosaurs belong to the archosaur order, streams and lost their antennae (along with which also includes dinosaurs and other specialized modifications), they are crocodiles. The first flying Reptiles to be today represented by “living fossils” known discovered, the raven-sized Pterodactylus, as horseshoe crabs. Virtually unchanged like all pterosaurs, was distinguished by its since the Permian, these arthropods dig elongated fourth finger which supported a along the beaches for worms and other small powerful flight membrane. Their hollow, prey, often burying themselves in the sand. lightweight bones enabled them to venture significant distances over the shallower Possessing a pair of compound eyes (as well waters of the ancient German seas, where a as a pair of simple ones) and equipped with number of the remains have been recovered, a spiny telson for correcting its position exquisitely preserved along with when overturned, horseshoe crabs undergo impressions of their furry coats. periodic molting. Reflecting their ancient ancestry, in fetal form they resemble Once presumed to have been limited to trilobites. During the spring mating season, gliding from high perches, they are now males cling to the telsons of the females as believed to have been thoroughly agile in they crawl along the sandy shores. Dramatic flight. They were quite vulnerable to marine evidence of this same behavior in ancient predators, judging by the numerous forms is provided by the well-documented pterosaur bones found in the stomachs of Jurassic Mesolimulus, whose trails ichthyosaurs. The long, narrow snout of sometimes lead to the remains of the Pterodactylus may have been an adaptation individuals that left them. From the of probing in the sand for burrowing worms. lithographic limestone of Solnhofen. Private From the lithographic limestone of collection. Solnhofen, Humboldt Museum. 75. Order Ornithischia, 74. Superclass Chelicerata, Family Hypsilophodontidae Subclass Xiphosura Othnielia rex Mesolimulus walchi Late Jurassic, Utah Late Jurassic, Germany 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 Related to arachnids and the extinct females appear to have carefully eurypterids, the xiphosurans range from the manipulated them into spiral clutches of Cambrian to the present. Derived from regular depths and even spacing. Although trilobites that had invaded estuaries and they probably remained with their herds throughout adulthood, these dinosaurs land-dwelling creatures, possibly the (owing to their well-developed limbs) pelycosaurs. From the limbs of their apparently left their nests immediately upon terrestrial ancestors, the ichthyosaurs hatching, probably feeding first on adult evolved their strong, broad paddles. feces, rich in fermentative bacteria, and later Stenopterygius was distinguished by its progressing to plants and insects. As adults paddles, which contained more joints and they fed on everything from plants to small fewer digits than those of other species. reptiles and mammals. This magnificent specimen is preserved with an epidermal silhouette. Humboldt Museum.

77. Class Reptilia, Subclass Ichthyopterygia Ichthyosaurus megacephalus Jurassic Germany

“Nanosaurus” was renamed Othnielia in

1977, on the centennial of its discovery by Typifying these classic marine reptiles, the great pioneer paleontologist Othniel C. Ichthyosaurus was distinguished by the Marsh. Featured in the 1993 Universal presence of extra digits with fewer joints in Studios film Jurassic Park, this its paddle. From other fossils, these air- spectacularly exposed in-situ skeleton is breathing, dolphin-like creatures are known from the Morrison Formation of Emery to have fed on pterosaurs and fish, and County, Utah. Brigham Young University. rather than laying eggs, and gave birth to

live young. This rare and extremely young 76. Subclass Ichthyopterygia, Ichthyosaurus appears to have died at birth, Order Ichthyosauria although the displacement of its vertebra Stenopterygius quadricissus could easily have occurred after its death. Jurassic, Germany Private collection.

78. Coprolites Ichythyosaur Jurassic, Mexico

Flourishing throughout the Mesozoic, the ichthyosaurs (“Fish Reptiles”) appeared during the Early Triassic. Growing up to 15 feet in length, they apparently evolved from Found in deposits rich in ichthyosaur name prevails. For a long time some remains, these coprolites (“Dung Stones”) museums continued to traditionally exhibit are the fossilized excrement of large, their Apatosaurus skeletons with the heads dolphin-like marine predators. When of Camarasaurus. Known only from North examined microscopically, coprolites can American specimens, they lived in vast reveal not only the fibers of the digested herds that ranged throughout Utah, matter, but also the fossilized remains of Wyoming, Colorado, and Oklahoma. This bacterial parasites that inhabited the classic leg bone was recovered from the digestive tracts of the hosts millions of years famous Morrison Formation. Brigham ago. From the Jurassic of Chihuahua, Young University. Mexico. Private collection. 80. Order Saurischia, 79. Order Saurischia, Suborder Sauropodomorpha Suborder Sauropodomorpha Camarasaurus lentus Apatosaurus ajax Late Jurassic, Utah 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 This juvenile skull specimen, its body length but much heavier than the closely measuring 17 feet in length, is considered related Diplodocus. Measuring 70 ft. in one of the most perfectly preserved length and weighing 33 tons, these gigantic sauropods ever to be recovered. Sauropod herbivores possessed long, serpentine necks footprints indicate that these gentle and even longer whiplike tails. herbivores cared for their young, guarding them on all sides as they wandered together, Because the first skeletons discovered were feeding on the highest tree branches. Found not found associated with any skulls, this in the famous Cleveland Lloyd Quarry. dinosaur was originally described as Carnegie Museum. “Brontosaurus” (“Thunder Lizard”), a name which persisted until the genus was finally 81. Order Saurischia, correctly identified as Apatosaurus, Suborder Sauropodmorpha previously known only from a skull that had Hypselosaurus priscum been named before the discovery of the Cretaceous, France headless Brontosaurus skeletons, hence its 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.

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 Aiding in the precision of the movement of have hatched to a size twice the length of the the enormous hind-quarters and spiked tail, egg. Larger eggs probably would have an enlargement of the spinal cord at the required a shell too thick for hatching. pelvis, much larger than the creature’s brain, Hypselosaurus (“High Crested Lizard”) is was long believed to be its “second brain.” the only sauropod dinosaur that has ever For its bulk, Stegosaurus had the smallest been found in association with its eggs. skull of any dinosaur, with a brain no larger Private collection. than a walnut. Its front legs, only half the length of its back legs, indicate that it 82. Order Ornithischia, probably evolved from a 2-legged ancestor Suborder Stegosauria and could easily have reared on its strong Stegosaurus stenops hind limbs to feed on the higher tree Late Jurassic, Utah 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.

83. Order Saurischia, Suborder Theropoda Allosaurus fragilis Late Jurassic, Utah Discovered in Colorado in 1877, Stegosaurus (“Plate Lizard”) grew to a Its massive, yet open, lightweight skull a length of up to 30 feet and weighed up to 2 marvel of engineering, the fearsome tons. The bony armored plates guarding the Allosaurus (“Different Lizard”) was the neck, back and tail of the huge Jurassic predominant carnivore in North America herbivore were attached to powerful skin during the Late Jurassic, and probably fed muscles, and were probably capable of on such herbivorous dinosaurs as Apatosaurus (Brontosaurus) and Stegosaurus, its flexible skull capable of expanding to accommodate oversized chunks of food.

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 While some believe that they were too huge agile than its hypsilophodontid ancestors. and clumsy to hunt, scavenging on carrion Short but sturdy, its 5-fingered forelimbs instead, others believe them to have been were adapted to bearing weight, although agile runners and swimmers, capable of fossilized footprints indicate that it was also hunting in packs for large prey. Trackways thoroughly capable of walking bipedally on found in Texas indicate that such predators its 4-toed hind legs. Found in the Cleveland indeed chased herds of much larger Lloyd Quarry. dinosaurs, and Apatosaurus vertebrae, scarred by the teeth of an Allosaurus, have THE CRETACEOUS PERIOD been unearthed. from 140 million to 65 million years ago

Sporting strong, 3-fingered claws at the ends Marking the appearance of flowers, the of its short arms, this creature grew to 36 fertile Cretaceous period was named for vast feet or more in length and weighed 1 to 2 deposits of chalk (creta in Latin), rich in tons, possibly reaching full maturity in as fossils and widely distributed throughout the little as 5 years. Although they have been world. The distribution of the continents found in Africa, Australia, and perhaps even was beginning to resemble that of the Asia, Allosaurus are most common in North present, although a great shallow sea America, some 40 individuals coming from flowing from Canada to the Gulf of Mexico a single quarry (possibly having perished separated the supercontinent of Laurasia into together). Found in the Cleveland Lloyd Asiamerica (East Asia and Western North Quarry. America) and Euramerica (Europe and Eastern North America). Marked by a rich 84. Order Ornithischia, emergence of advanced dinosaurs, the Late Family Camptosauridae Cretaceous, 75 million years ago, was a time Camptosaurus browni of tremendous volcanic upheaval as Late Jurassic, Utah mountain ranges and new islands were being process by choking on prey too large to formed. swallow. Unlike more primitive fish with primarily cartilaginous skeletons, such as The drifting of the continents toward the sharks and lobe-fins, the early teleosts polar regions brought on significant changes possessed fully ossified internal skeletons. in the seasonal weather. No longer able to From the famous Santana Formation of roam between the continents, many of the Brazil. Private collection. later dinosaurs evolved exclusively in Asiamerica. The dominant creatures of the 86. Infraorder Denonychosauria, period, most species lasted no more than 5 Family Dromaeosauridae million years before disappearing from the Dromaeosaurus albertensis fossil record, often followed by more Late Cretaceous, Canada 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. . 85. Infraclass Teleostei Order Leptolepiformes Cearana Early Cretaceous, Brazil

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 The appearance in the fossil record of the Brown, this rare and highly specialized heterogeneous group of leptolepids marks group of theropods was not fully understood the arrival of the modern teleost, or bony, until the discovery by John Ostrom in 1964 fishes, which now dominate the world’s of Deinonychus, an early dromaeosaur aquatic environments. Armed with a succeeded in the Late Cretaceous by mouthful of small, sharp teeth, these Dromaeosaurus (the first such dinosaur to elongate, tapering fish became widespread be discovered), and the Mongolian throughout the Late Jurassic and Early Velociraptor. Cretaceous. Spectacularly preserved in mud concretions, Cearana is a well-documented Because Dromaeosaurs (“Running variety known to have preyed on its own Reptiles”) display a striking affinity to birds, species, some individuals having died in the 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 crested Corythosaurus (“Helmet the most dangerous of the dinosaurs. Royal Lizard”), with its short muzzle and tall, Tyrrell Museum of Paleontology. hollow crest, lived in herds throughout the

forests of western Canada where it browsed 87. Order Ornithischia, on tree leaves and pine cones. Equipped Family Hadrosauridae with strong, bulging cheeks, it was capable Anatosaurus annectens of chewing a mouthful of food while storing Late Cretaceous, Montana 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 sense of vision, hearing, and smell served to warn them of approaching danger. Females and immature individuals had smaller crests. Like other crested duckbills, when This fibular fragment with a splendidly Corythosaurus called to each other the preserved skin impression is from a partially sound resonated through the long air mummified duckbilled dinosaur found in the passages of their nostrils (which extended Hell Creek Formation. Private collection. into their hollow crests) producing a far- reaching, bugle-like honk. Linked with 88. Order Ornithischia blood vessels, such extended nasal passages Family Hadrosauridae also may have evolved for the purpose of Corythosaurus casuarius warming the arctic air before its arrival into Late Cretaceous, Alberta the lungs. From the Royal Ontario Museum.

These coprolites were discovered in association with the fossilized remains of duck-billed dinosaur nests in Saskatchewan. Private collection. 88. Order Ornithischia, Family Hadrosauridae 90. Order Saurischia, Maiasaura peeblesorum Suborder Theropoda Late Cretaceous, Montana Oviraptor philoceratops Late Cretaceous, Mongolia 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 In Mongolia in 1922, an Expedition from the feet, appear to have returned to these nesting American Museum of Natural History led by sites year after year. Roy Chapman Andrews set out to find remnants of early humankind. Instead they Browsing on their hind legs among the tree discovered several nests of Oviraptor (“Egg branches or cropping the undergrowth on all Thief”) eggs, the first dinosaur eggs ever fours, these peaceful herbivores were located, in what must have been a large defenseless against the ferocious weapons of nesting ground. Because skeletons of the their predators. Migratory hadrosaurs such small, frilled dinosaur Protoceratops were as Maiasaura appear to have fed and found in association with the nests, the eggs protected their young until they were old were long attributed to them. More recent enough to join the herd. Discovered in 1976 expeditions have uncovered a fossil female by John R. Horner. Museum of the Rockies. Oviraptor (a small, beaked, and toothless theropod) actually sitting on a clutch of 89. Coprolites unhatched eggs, revealing that Hadrosaur Protoceratops was the intruder. From the Cretaceous, Canada historic Roy Chapman Andrews Gobi Expedition. Alf Museum. these herbivorous grazers have been found 91. Order Ornithischia, in Alberta, New Mexico, and Texas. Suborder Ceratopsia Though not as well-equipped as its Protoceratops andrewsi descendant, Triceratops (“Three horned Late Cretaceous, Mongolia Face”), Chasmosaurus was capable of warding off attacks by fierce tyrannosaurs. Regarded as the earliest known horned Females of the genus are distinguished by dinosaur (although it only possessed small their diminutive horns. This impressive crests where the great horns of its giant creature was one of the first dinosaurs to be descendants would be), this exquisite skull found along with an impression of its skin, of an adult individual is from the Polish- the patterns of its large mosaic scales Mongolian expedition. suggesting contrasting color patterns.

92. Order Ornithischia, 93. Order Ornithischia, Suborder Ceratopsia Family Pachycephalosauridae Chasmosaurus belli Stegoceras validus Late Cretaceous, Alberta Late Cretaceous, Alberta

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.

Among the rarest of dinosaur remains, the enigmatic boneheads are known mostly from fragments of skulls and skeletons, making their relationships to other ornithischians 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 Large openings in the frill reduced the insects, fruits, and leaves. Roaming in herds weight of the bone mass. It had 2 small that ranged throughout the hills of eastern horns over the brows and one on its parrot- Asia and western North America, the beaked snout. Living in large, migrating boneheads apparently had lifestyles similar herds and measuring over 16 feet in length, to those of modern sheep and goats. Distinguished by thickly domed skulls remnant of its 3-fingered Jurassic ancestors. rimmed with bony spikes, rival males are Royal Tyrrell Museum of Paleontology. believed to have established dominance over their herds through fierce contests of head- 95. Superorder Archosauria, butting. This supposition is further Suborder Pterosauria evidenced by their neck and backbones, Quetzalcoatlus northropi which were specially reinforced with strong Late Cretaceous, Texas 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.

94. Suborder Theropoda, Family Tyrannosauridae Albertosaurus sarcophagus Named for the ancient Mexican feathered Late Cretaceous, Alberta serpent-god Quetzalcoatl, the giant Quetzalcoatlus was estimated at twice the Sometimes known as Gorgosaurus, size of the largest known pterosaurs known Albertosaurus (“Alberta Lizard”) was a at the time, the Pteranodons of the Kansas smaller, slender tyrannosaur (“Tyrant Chalk. Only one wing was found, indicating Lizard”) that only grew to a length of about a wingspan of 36 to 39 feet with a weight of 26 feet and a weight of 2 tons. Despite its 190 to 220 pounds, making it the largest size in comparison to its larger relatives, it known flying creature. With a low, narrow was a ferocious predator that probably crest and a long, sharp, toothless beak, this hunted the herbivorous horned and armored giant is better known from smaller, more dinosaurs of the Late Cretaceous lowland revealing specimens found in the same forests of Alberta. Presumably descended region, which were either younger from a small, Late Triassic theropod and individuals or a smaller species. Although named for the province in Canada where it they were dynamically suited for fishing was discovered, Albertosaurus was also over the sea, their remains are not found in common in Montana just before the end of marine deposits or even near any sizeable the Mesozoic Era. freshwater lakes, but are instead found in the silts of the vast floodplain of an ancient Various names have been given to the inland system of stream channels over 250 dozens of Albertosaurus skeletons miles from the nearest sea, suggesting the discovered during the past century, but only possibility of their having been scavengers recently has their relation to each other been of carrion instead. Similar discoveries in recognized. Like all tyrannosaurs, Canada and Israel indicate the possibility of Albertosaurus only has 2 fingers on each a wide distribution. Their colossal humerus, claw, the vestigial third finger a useless discovered in 1971 by Douglas A. Lawson and Wann Langston, Jr., belonged to one of the last of the flying reptiles. Texas reduced forelimbs which could not even Memorial Museum. reach their mouths, others consider these creatures the most fearsome hunters ever to 96-98. Suborder Theropoda, have existed, balanced for swift running by Family Tyrannosauridae their long tails. Tyrannosaurus rex Late Cretaceous, Montana

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 Presumed to have dealt mostly with the much as 50 feet, towering 20 feet high and animal’s senses, the brain of Tyrannosaurus weighing 5 to 7 tons. Their heads alone rex was not small for a dinosaur although measured 4 to 5 feet, sporting jaws lined compared to the size of the creature’s body with long, saw-edged teeth, each one it was remarkably diminutive. This cranial supported by ranks of replacements. endocast preserves the size and shape of the Reaching maturity within 5 years, the life brain of a Tyrannosaurus rex. spans of these enormous creatures may have surpassed 100 years.

This isolated maxilla, once the largest known, is from the University of California, Berkeley. This spectacular skull, from one of the largest ever found, is from the Museum of the Rockies.

99. Meteorite Fossil evidence of their actual metabolism is Meteor Crater, Arizona 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

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 CENOZOIC ERA from 65 million years ago to the present 100. Phylum Tracheophyta A series of glaciations distinguishes the era Class Gymnospermida that includes the present. By the time the Gingko adiantoides dust settled on top of the last Cretaceous Paleocene, South Dakota sediment, another era had dawned, the Cenozoic ("Recent Life"), giving rise to rapidly diversifying groups of mammals. No longer relying on their diminutive size for survival in a world dominated by giants, the mammals immediately assumed the roles of chief competitors for supremacy over the newly abundant territory left by the passing of the dinosaurs, producing such giants of their own as the great wooly mammoths of the Ice Age.

As the early mammals diversified throughout the Paleocene ("Ancient Recent") and the subsequent Eocene ("Recent Dawn") epochs, from 64 to 36 million years ago, many of the modern mammal groups began to appear in the fossil record. Of these early mammals, several The earliest gingkoes, or maidenhair trees, became extinct as rainforests retreated from appeared in the Permian. Their the frost during the Oligocene ("Few characteristic fan-shaped leaves did not Recent"), which ended 26 million years ago. grow on the tree in totally uniform shapes, The Miocene ("Less Recent"), which exhibiting combinations of the differing followed, lasted until 6 million years ago. ancestral forms from which they were Along with the appearance of large, new derived. The unmatching leaves in this mountain ranges, the spreading of grasslands specimen probably came from the same tree. during this period gave rise to a vast Sexually distinct, these ancient trees radiation of grazing animals. reproduce through pollenation by males of the pitted ovules grown by females. A As the climate became colder throughout the nourishing group throughout the Mesozoic, Pliocene ("More Recent"), from 6 to 1.6 gingkoes reached their peak during the million years ago, numerous mammals Jurassic and were long thought to be extinct became extinct while modern plants and until a single surviving species was animals appeared, including early discovered in China, preserved in some humankind. During the Pleistocene ("Most temple gardens. Found in the same rocks as Recent") epoch, from 1.6 million to 10,000 fossil palms, this Gingko is evidence of the years ago, vast continental glaciers spread subtropical climates in North America at the and receded as over half of the giant dawn of the Cenozoic. Private collection. mammals became extinct following the appearance of modern humans. 101. Class Mammalia, Order Insectivora Icaronycteris index famous Green River Formation. Yale Early Eocene, Wyoming Peabody Museum.

102. Class Aves, Family Scolopacidae Rhynchaeytes messelensis Eocene, Germany

The disappearance of toothed birds at the Derived from the Late Cretaceous tree- end of the Mesozoic was followed by the dwelling insectivores and surviving virtually appearance of nearly half of the modern bird unchanged except for the adaptation of the groups which, in early Cenozoic times, were forelegs for flight, bats first appeared in the less diverse and specialized. Insulated by Early Eocene. Employing echolocation as a feathers derived from the scales of their navigational aid, the earliest of these flying theropod ancestors, these warm-blooded insectivores had highly evolved wings that creatures are the only surviving descendants were reinforced by the finger bones. In of the dinosaurs. search of insects over the ancient lakes of

Wyoming, some invariably drowned and Wading along the beaches of central Europe became fossilized in the fine-grained lake- at low tide and digging for prey in the sand, bottom sediments. the long-limbed snipe Rhynchaeytes was

specially adapted to life as a shorebird. This The last of only 4 animal groups to develop beautifully preserved fossil snipe is from the the power of flight, the early bats gave rise fossiliferous oil-shales of Messel. Private to fruit-eating varieties equipped with collection. powerful vision and unreliant upon echolocation. Exemplified by this perfectly 103. Subclass Actinopterygii preserved type specimen, Icaronycteris is Family Clupeidae one of the oldest known bats. From the Knightia humilis continents separated from North America Eocene, Wyoming during the Eocene. Like its immediate ancestor, Eohippus, Propalaeotherium's 4- toed front and 3-toed hind feet (each with a small hoof), as well as its low-crowned teeth, suggest a life of browsing on the lush undergrowth of the Eocene rainforests of 45 million years ago.

With an arched back and elevated Descended from the primitive Agnatha of hindquarters, this diminutive ancestor of the the Paleozoic and distinguished by their horse probably lived in small herds, running bony internal skeletons and symmetrical in leaps like a deer, with most of its weight tails, these are among the most advanced of resting on the padded soles of its feet rather fossil fish. First appearing in the Early than on the hoofs. The diversification of the Cretaceous, this group of teleost fish, which horse family took place largely during the includes anchovies and sardines, is typified subsequent Oligocene and Miocene epochs by the herring. From the Green River as some took to the rapidly spreading Formation. Private collection. prairies while others remained in the forests. From a rare juvenile specimen unearthed in 104. Class Mammalia the famous fossil deposits of Messel. Order Perissodactyla Humboldt Museum Propalaetherium messensis Middle Eocene, Germany 105. Class Mammalia Order Artiodactyla Merycoidodon culbertsoni Late Eocene, South Dakota

Among the earliest known descendants of Eohippus ("Dawn Horse"), this tiny ancestral horse only reached the size of a These gentle little sheeplike creatures, with fox. Close to the ancestry of rhinoceroses their short limbs and 4-toed feet, roamed the and tapirs as well, it also gave rise to the forests and plains of North America in great extinct giant palaeotheres ("Ancient Beasts") herds 25 to 30 million years ago. Except for of Western Europe and Asia when the their prominent canines, the teeth of Merycoidodon ("Cud Chewing Tooth") were about 70 million years ago. Equipped with similar to those of present day deer, premolars and vertical front teeth, Adapis indicating that they probably spent most of ("Adjustable One") was somewhat more their time browsing on low shrubs. The advanced than other early primates. Its thousands of fossils found in the White forward-facing eyes, evolved for focusing River badlands of South Dakota make this on single objects, enabled it to leap from primitive cloven-hoofed animal, related to branch to branch with an accuracy of depth camels and swine, one of the most abundant perception superior to that of earlier and well-known of the early North mammals. Flourishing throughout forests of American mammals. First appearing in the Europe and North America some 40 to 50 Late Eocene about 38 million years ago, million years ago, these long-tailed, cat- their herds were quite common throughout sized creatures were agile quadrupedal the Oligocene. They belonged to a climbers that presumably fed on fruits and successful group of even-toed ungulates insects. Restricted to arboreal life (living in called Oreodonts, believed to have been trees) by competition with the growing ruminants, or cud chewers. This exposed in- number of ground-dwelling rodents, this situ skeleton is from the South Dakota primitive ancestor of lemurs and tarsiers, Badlands. Private collection. with its 5-digited, grasping hands and feet, is believed to have indirectly given rise to the 106. Class Mammalia, higher primates. Private collection. Order Primates Adapis parisiensis 107. Order Primates, Middle to Late Eocene, France Family Omomyidae Rooneyia viejaensis Early Oligocene, Texas

Apparently derived from the lemur-like adapids, early prosimians known as omomyids appeared in North America and Europe at the dawn of the Eocene. Diverse throughout the period, particularly in North Among the oldest groups of placental America, only a few genera survived into mammals, the first primates evolved from the Oligocene. Resembling tarsiers, earlier primeval insectivores (possibly tree shrews) species appear to have been insectivorous, whereas the relatively late Rooneyia was as Proconsul. From the famous Fayum probably a frugivore. The position of the eye Depression. Cairo Geological Museum socket suggests a distant link between these basal primates and living anthropoids. The . lone representative of its species, the large- 109. Order Primates, eyed Rooneyia was a contemporary relative Subfamily Proconsulidae of the first prosimians to appear in Africa. Proconsul africanus University of Texas. Miocene, Africa

108. Order Primates, Family Pliopithecidae Aegyptopithecus zeuxis Middle Oligocene, Egypt

Along with the shrinking of the prehistoric Tethys Sea, the extinct early apes probably spread from Africa to Europe and Asia when the continents were once again linked. As the climate shifted and grasslands replaced the forests, some primates spread to the savannas, learning to stand upright and evolving cooperative societies for protection In Egypt's Sahara, the exposed remains of a from the dangers that lurked in the tall grass. lush 33 million-year-old tropical rainforest Sometime during the Miocene epoch (from have yielded rare fossils of Aegyptopithecus 24 to 6 million years ago) the ancestral line ("Ape From Egypt"), perhaps the oldest of the hominids (the family that includes the known direct ancestor of the great apes and great apes and humankind) diverged from humankind. Commonly known as the that of the apes. With limbs adapted for "Dawn Ape", this tiny tree dwelling primate, crawling through trees, the quadrupedal no longer than a cat, probably fed on insects, Proconsul (named for a chimpanzee once fruit, and nuts. Possessing a short tail and popular in the London Zoo) is largely primitive snout, its forward-facing eyes and regarded as being ancestral to apes and 32 teeth link it with such later Miocene apes hominids, possessing characteristics of both. Larger than monkeys, this tailless capable of the unique thrusting action of its dryopithecene ("Oak Ape") inhabited the modern survivors, which helps prevent its fringes of the forests and savannas of prey from making last-moment escapes. Miocene Africa from 22 to 15 million years Private collection. ago, possibly living and hunting in 111. Insects in Amber primitively cooperative groups like the Early Miocene, modern chimpanzee, although no evidence Kenya, Columbia, Dominican Republic of this behavior has ever been found. Discovered in 1948 by Mary Leakey. National Museum of Kenya.

110. Class Chondrichthyes, Family Isuridae Carcharodon megalodon Miocene, South Carolina

Trapped in resin that oozed from the trunks of the ancient conifer trees before hardening into amber, fossil insects are found throughout the world, preserved to their tiniest bristles, including their last exhaustions 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 Descended from primitive Devonian sharks, geological periods in which they are found. true sharks appeared during the Jurassic. Formerly thought to contain only Characterized by their streamlined bodies, impressions of the decomposed remains of powerful tails, and pointed snouts, these insects, amber in fact contains the actual fearsome marine creatures have to swim preserved remains of its hapless victims. In constantly due to their lack of buoyancy, 1992 revolutionary researchers at the although recent studies have revealed their University of California, Berkeley and the sleeping habits on the ocean bottoms where American Museum of Natural History in they have been observed resting absolutely New York successfully recovered and still for hours at a time. Following the cloned DNA from 30-million-year-old extinction of the marine reptiles, sharks insects preserved in amber. Suspended in became (and remain) the dominant predators amber for over 20 million years, these of the seas. Ancestral to the modern great termites and tiny flies are from the Miocene white sharks, the extinct Miocene of Columbia and the Dominican Republic. Carcharodon megalodon ("Great Sharp The spider, perfectly preserved in a bead of Tooth") of 20 million years ago may have colorless amber, is from Mombassa. Private reached lengths of 45 to 50 feet. Equipped collection. with hundreds of sharply serrated and replaceable teeth, its gristly jaws were 112. Order Primates, Superfamily Hominoidea widespread throughout Europe and Asia. Kenyapithecus wickeri While the later Asian group is believed to Early to Middle Miocene, Kenya have given rise to the orangutan, this earlier African genus may well have produced the australopithecine strain that led to humankind. National Museum of Kenya.

113. Order Primates, Family Pongidae Sivapithecus indicus Late Miocene, Pakistan

Discovered by Louis Leakey in 1961, these jaw fragments are the only known remains of what appears to be an early hominoid species that inhabited the early to Middle Miocene forests of Kenya from about 14.4 to 12.5 million years ago. Upon close examination it was determined that there was little, if any, difference between this jaw and that of “Ramapithecus” except that it is a few million years older and was found on a different continent, separated from any known “Ramapithecus” find by a distance of thousands of miles. Formerly known as “Ramapithecus”, Sivapithecus (“Shiva’s Ape”) was long Exhibiting such humanlike features as regarded as the Miocene ancestor of the reduced canines and front teeth along with a Pliocene hominids that gave rise to correspondingly shortened snout, humankind. Owing to the erroneous Kenyapithecus (“Kenya Ape”) is largely reconstruction of its fragmentary dental regarded as the most likely antecedent of the arcade in a humanlike parabolic arc, it was australopithecines. These extremely popularized as the earliest and most specialized teeth imply a small bipedal primitive hominid. Since the subsequent hominoid with advanced manipulative skills. consolidation of “Ramapithecus” with the Erect walking, freeing the hands for the earlier known Sivapithecus, the discovery of preparation of food, reduces the demands on more complete facial skeletons in Turkey the teeth which, in turn, would lead to a and Pakistan ultimately revealed this genus reduction in their size. Perhaps a limited as the ancestor of the Southeast Asian population was restricted to a small area, orangutans. which would account for its scarcity, although “Ramapithecus” finds are DNA sequencing suggests a hominid divergence in Africa from a common younger fragment, discovered at the Tabarin ancestor with the chimpanzee between 6 and site in 1984, is dated 4.15 million years, and 5 million years ago. Despite this evidence, thus was a contemporary of the primitive the fragmentary fossil record of Sivapithecus Australopithecus anamensis (found in 1996 appeared to suggest a contradictory date for near Lake Turkana). Differences in wear the hominid split of between 15 and 9 between the first and second molars suggest million years ago in Asia. Since the DNA that their eruptions were separated by sequence of orangutans suggests a several years. divergence of hominids, chimpanzees, and gorillas from a common ancestor with Discovered at the Lothagam site in 1967 and orangutans between 11 and 12 million years dated at 5.5 million years, the older ago, the fossil record is confirmed by mandible is the earliest known evidence of molecular biology due to the discovery in the hominid line. The wealth of afarensis Africa of Kenyapithecus, an earlier Miocene mandibles from Laetoli and Radar have ancestor of both the Asian ramapithecines provided enough diagnostic information to and the later African hominids. Geological identify the Lothagam remains with the Survey of Pakistan. latter species. The exposed and well- preserved root system exhibits 114. Order Primates, characteristics exclusive to afarensis. The Family Hominidae socket of the missing canine tooth suggest Australopithecus sp. that this most archaic of hominids may have Early Pliocene, Kenya possessed somewhat more prominent canine teeth, its age placing it more or less contemporaneous with the divergence of hominids and chimpanzees from their common ancestor. Kenya National Museum.

115-116. Order Primates, Family Hominidae Australopithecus afarensis Middle Pliocene, Ethiopia

Among the oldest recognized hominid remains are two mandible fragments found in the North Kenya Rift Valley at the Lothagam and Tabarin sites. Falling within the recorded range of dimensions and contours of Australopithecus afarensis, they are generally attributed to that species. The

arboreal, chimp-like ancestors than her The genealogy of humankind emerges with distant Homo descendants. With slimmer the line of australopithecine hominids, hips and narrower birth canals, females which appears to have begun between 4 and apparently gave birth to infants with far 5 million years ago with the appearance of smaller heads and brains. Possessing Australopithecus anamensis (“Southern Ape smaller canines than their quadrupedal of the Lake”) and its earliest descendants, ancestors, they presumably foraged in the well-documented Australopithecus family groups for fruits and seeds along the afarensis (“Southern Ape of Afar”). vanished lakes and streams of Ethiopia and Presumably descended from a divergent Tanzania, possibly sleeping in high tree group of Miocene apes such as branches to avoid predators. Disappearing Kenyapithecus, these early species of gracile by 2.5 million years ago, this hominid australopiths are the most primitive known. species gave rise to all of the subsequently Among the oldest and most complete varied tribes of Australopithecus and Homo. remains of an erect-walking ancestral Courtesy of the Institute of Human Origins. hominid ever found, this amazing afarensis National Museum of Ethiopia. skeleton is dated at about 3.2 million years. Known throughout the world as “Lucy” 117-118. Order Primates, (from a Beatles song), it was discovered in Family Hominidae Radar, Ethiopia in 1974 by Donald Johanson Australopithecus afarensis and Tom Gray. Lucy was 3-and-a-half feet Middle Pliocene, Ethiopia tall and about 25 years old when she died. Though her scarcely worn wisdom teeth had only recently erupted, she was already showing signs of bone disease on her spine. Whether she accidentally drowned or quietly laid down in the sand and died, her remains were deposited in the shore of an ancient lake and covered over by sediment until eventually exposed by rain.

In 1975 the bones of at least 13 individual hominids were discovered strewn down a slope at Radar, Ethiopia, now known as the famous 333 site. Apparently exposed and washed down from the top of the slope by recent rains, the inference was that they had originally been deposited together. Unmarked by signs of aggression or

scavenging, the group seemingly perished Lucy herself had an apelike face with a low together about 3.5 million years ago, forehead, resembling far more her recent possibly in a flash flood. Popularly known as the “First Family,” this extraordinary find From 3 million to 1 million years ago, is evidence that even the earliest hominids several species of bi-pedal ape-men lived in bands (or tribes). coexisted throughout Kenya, Ethiopia, Tanzania, and South Africa. Descended from afarensis and thoroughly established by 3 million years ago, the gracile africanus species is believed by many to be intermediate between afarensis and Homo habilis, although its direct relation to humankind is still the subject of debate due to the robust size of its molars, a characteristic of subsequent species of australopiths not shared by the genus Homo.

A controversy arose over the naming of the species because the closer in time the separate species of hominids are to their original common ancestor, the more they look alike, making it difficult to distinguish between them. Close to the ancestor of the gorilla and even closer to that of the chimpanzee, afarensis was among the earliest of the divergent line that led to Homo; in fact the origin of the human race can be traced directly back to this ancient Using their hands for gathering and tribe of gracile australopiths. Ranging from carrying, Australopithecus africanus walked 3 to 5 feet in height and weighing from 60 to erect, presumably foraging for roots and 90 pounds, afarensis had long arms with seeds and perhaps even scavenging remains slightly curved finger and toe bones, from carnivore kills in small groups suggesting at least a partially arboreal life. throughout the tropical savannas of eastern These composites of a male skull and hand and southern Africa. Formerly recognized are reconstructed from the incomplete as “Plesianthropus (“Near Human”), this remains of several individuals from the 333 skull was discovered by Robert Broom in site. Collected by Donald Johanson in 1947 in the Sterkfontein quarry and became Radar, Ethiopia. Courtesy of the Institute of popularly known as “Mrs. Ples”, although it Human Origins. National Museum of is now recognized as Australopithecus. Ethiopia. From 3 to 4 feet tall and weighing 45 to 90 pounds, these small apelike creatures ranged 119. Order Primates, throughout the grasslands of Kenya, Family Hominidae Ethiopia, Tanzania, and South Africa, living Australopithecus africanus alongside their evolutionary descendants for Late Pliocene, South Africa over a million years. They became extinct about 1 million years ago, survived, Remarkably preserved with its furrows and according to some paleoanthropologists, by convolutions intact, the fossilized cast of the their Homo descendants. Transvaal Taung Child’s brain indicates that these Museum. ancestral hominids possessed small brains, midway in size between those of apes and humans. Transvaal Museum. 120. Order Primates, 121. Order Primates, Family Hominidae Family Hominidae Australopithecus africanus transvaalensis Australopithecus aethiopicus Late Pliocene, South Africa Late Pliocene, Kenya

Darkly stained by manganese, the enigmatic “Black Skull” was discovered in 1985 by Discovered by Raymond Dart in 1924 in a Alan Walker on the west shore of Lake limestone cave in Taung, South Africa, this Turkana in northern Kenya. Dated at 2.6 extraordinary specimen of a 3-year-old million years, this vegetarian hominid gracile australopith is the first ancestral exhibits primitive skull traits of the earlier hominid fossil ever to be found. Once afarensis species from which it was derived, known as “The Missing Link”, it is now along with advanced facial characteristics of formally recognized as Australopithecus both the later robustus and boisei species. africanus, popularly known as the Taung Child. The opening for the spinal nerves, Prior to the Black Skull’s discovery, the located at the bottom of the skull rather than direct ancestor of the robust hominids was near the back, indicates this young hominid firmly believed to be Australopithecus stood erect and walked on 2 feet, a fact africanus. The age of aethiopicus, however, reinforced by the subsequent discovery of with its massive teeth and sagittal crest, humanlike africanus pelvic bones. implies that it, and not the gracile africanus, is the intermediate stage between afarensis Judging by other fossilized bones of known and the robust australopiths, thus giving extinct mammals found in the cave, the credence to the standing of africanus as the geological age of the Taung Child has been transitional species between afarensis and estimated at about 2 million years. Homo, a more plausible scheme according to many paleoanthropologists. Possessing argued by some that robustus and africanus the smallest brain of any known hominid, are simply males and females of the same this profoundly controversial fossil species, undisputed robustus finds appear to provoked a complete redrawing of be exclusive to South Africa. Appearing humankind’s family tree. From Lake about 2.5 million years ago, robustus died Turkana. Kenya National Museum. out after about a million years, though not 122. Order Primates, before giving rise to boisei. Ascribed Family Hominidae female from the Sterkfontein Valley. Australopithecus robustus Transvaal Museum. Late Pliocene, South Africa 123. Order Primates, Family Hominidae Australopithecus boisei Late Pliocene, Tanzania

Although the early gracile australopiths were scarcely larger than a chimpanzee, the later robust species were a little over 5 feet in height. Walking upright throughout the savannas of eastern and southern Africa, these larger hominids were gatherers who fed on leaves, seeds, berries, and perhaps From a specimen discovered by Mary insects, possessing little, if any, knowledge Leakey in the Olduvai Gorge in Tanzania of toolmaking. Presumably descended from and named Zinjanthropus (“East African the gracile afarensis, the robust australopiths Human”) by Louis Leakey, this early were a branch that did not survive. hominid was subsequently renamed to include it in the closely related groups of Largely regarded as a female (due to its australopiths. 1.8 million years old, it was size), this individual was discovered in 1950 the first fossil of an australopith to be at the Swartkrans cave in Transvaal, where successfully dated. Ranging in height from its carcass had apparently been dragged by a 5 to nearly 6 feet, they were about the size leopard. An advanced primate closely of modern humans. related to humankind, Australopithecus robustus was not on the evolutionary path Australopithecus boisei (“Boise’s Southern that led to Homo. Though it has been Ape”) was named for one of the Leakey’s benefactors, Charles Boise. Despite their habilis (“Handy Man”) derives his name. significantly smaller brains and apelike An early form of habilis, this 2-million- skulls (with a pronounced sagittal crest for year-old individual is separately classified anchoring powerful jaw muscles), in many by some as Homo rudolfensis. Ranging ways “Zinj” resembled humans. Apparently from 4 to 5 feet in height and living perhaps the largest of the 5-million-year-old line of 30 years, they were sexually mature and australopiths, “Zinj” was also the last. reproducing by their early teens, with all of Possibly killed off by the more advanced their adult molars by age 3. Homo habilis, whose chipped tools are sometimes found with the remains of these Their elongated, apelike arms were hominids, the species became extinct about extremely adapted for climbing, but with 1 million years ago. Unassociated jaw from their facile hands, long freed by walking the Koobi Fora Formation of East Turkana. upright, they were prolific makers of stone Kenya National Museum. Skull from the tools for breaking open bones and scraping National Museum of Tanzania. meat, as well as the first known to favor one hand over the other. The long-held belief 124. Order Primates, that Homo habilis was the first hominid to Family Hominidae make stone tools may have been dispelled Homo habilis by the discovery of the Ethiopian Late Pliocene, Kenya Australopithecus garhi (“Surprise Southern Ape”) fossils, found in the vicinity of fossil animal bones that had been scraped with stone implements 2.6 million years ago. The famous 1470 skull was collected at Koobi Fora by Bernard Ngeneo and Richard Leakey. Kenya National Museum.

125. Order Primates, Family Hominidae Homo erectus Late Pliocene, Kenya

Contemporary with “Zinj” and descended from a common ancestral australopith, these ancient, more advanced hunter-scavengers are the earliest to be classed in our genus, Homo (Man), due to the abundant evidence of their tools found in the Olduvai Gorge. It is from these primitive tools that Homo Museum.

126. Order Primates, Family Homindae Homo sapiens neanderthalensis Middle Pleistocene, Israel

First discovered in the Neander Valley, West Germany, this short rugged subspecies, with its thick skull and heavy brow ridges, had a larger brain than modern humans and probably spoke a primitive language. Despite their big bones and heavy build, Neanderthals grew to a height of 5 feet, 7 inches. Appearing about 200,000 years ago, their advanced intelligence and adaptability enabled them to survive in the harsh arctic climate of the last Ice Age. Clothed in animal skins cut with stone tools, they hunted in groups, apparently sharing Although possessing the thickest skull of the kill. Remains of crippled individuals any hominid, the superior intelligence of hint at the compassionate nature of their Homo erectus (“Upright Man”) enabled this society. Showing remarkable self- Early Stone Age hunter to venture from the awareness, their ritual burials with floral ancient habitats of its African ancestors to offerings are the oldest known. Bear skulls thinly populate such diverse regions as found enshrined in their caves suggest the Europe and Southern Asia, perhaps emergence of primitive mystical expression. following the migrating herds of large mammals as they hunted.

Descended from Homo habilis by 1.7 million years ago and credited with the discovery of fire, their improved hunting methods appear to have included the use of brush fires to drive herds of big game into ravines. Homo erectus sites yield abundant evidence of tent dwellings, hearths, and sophisticated stone tools. Possibly growing to heights of 6 feet, their brains were substantially larger than those of their more primitive predecessors. One of the earliest known erectus skulls, separately identified by some as Homo ergaster, dated at 1.7 million years. No. KNM-ER 3733, collected at Koobi Fora by Bernard Ngeneo and Richard Leakey. Kenya National From 70,000 to 40,000 years ago these hominids inhabited large caves of Mediterranean Europe, the Middle East, 128. Order Carnivora, northern Africa, and Russia, some sheltering Family felidae up to 40 individuals at a time. Probably as a Smilodon fatalis result of interbreeding with our own Late Pleistocene, California subspecies, this once flourishing culture became extinct about 30,000 years ago. From Mt. Carmel, Israel. Harvard University.

127. Order Proboscidea, Family Elephantidae Mammuthus jeffersoni exilis Pleistocene, California

Evolved from Eocene African elephants, the giant dome-headed, spiral-tusked mammoths migrated into North America over the land bridge from Asia 1.5 million years ago.

With their thick coats of shaggy, reddish fur insulating them against the harsh climates of This large, ferocious saber-toothed cat the tundra regions during the Ice Age, they evolved in North America and spread widely used their great tusks to sweep aside snow throughout the world, living all through the and permafrost while foraging for plants. Pleistocene (from 2 million to 11,000 years ago) when much of Europe and North America was covered with ice. Stalking their prey silently in the open countryside until close enough to pounce, then stabbing their great dagger-like canine teeth into the ambushed victim’s neck or belly, they are believed by some to have been specially adapted for preying on mammoths. The largest and perhaps most successful of the saber-tooths, Smilodon (“Knife Tooth”) was As these creatures spread to warmer regions, also the last. It possessed a lower jaw that some of them, such as this Pleistocene dwarf could open as wide as 90 degrees. They mammoth (named for Thomas Jefferson), became extinct about 11,000 years ago, became adapted to insular isolation. When many of them lured to their deaths while sea levels rose during the interglacials, scavenging the remains of other unfortunate forming new islands as the coastal plains creatures trapped in the deadly tar pits of were flooded, large mammals, suddenly Southern California. This skull is from the isolated from predators and competing for famous Rancho La Brea deposits. Page limited food supplies, died out while the Museum. smaller ones requiring less food survived. This fossil jawbone was found on Santa 129. Order Coleoptera, Rosa Island. Private collection. Family Dytiscidae Dytiscus Engraved reindeer antler Pleistocene California Carved reindeer antler Mammoth carved in bone Bulls carved in bone Wild horse of Vogelherd Small Venus Late Pleistocene, Western Europe

Half of the known species of insects are beetles, whose vast varieties outnumber those of any other animal order. Their hard By 19,000 to 15,000 years ago, lifelike front wings, when folded, serve to protect representations of game painted on cave their delicate, membranous hind wings. walls began to appear, such as “The Hall of Apparently evolved from early relatives of Bulls” at Lascaux cave in France. Reindeer the cockroaches, they first appeared in the carved on a spear-thrower made of antler, as Permian and have survived relatively well as horses engraved on a perforated unchanged, rarely developing any extreme antler (presumably used for straightening specializations either structurally or in their wooden spears) may have been thought to habits. A predaceous water beetle, Dytiscus invoke the seasonal return of migratory fed by diving for its prey. prey, while carved figurines with exaggerated female features, known as Although in some groups of beetles the male Venuses, suggest the development of lives with the female and assists in caring symbolic expressions of fertility. Nearly for their young from the larval stage to 40,000 years old, this small and elegant pupation, the vigorous behavior of the carving of a wild horse was discovered in carnivorous groups precludes the gentle the cave of Vogelherd in Wurttemberg, social behavior in caring for young, whose Germany. nearly legless larvae suggest the ancestral form of these ancient creatures. Trapped in the asphalt of the Pleistocene tar pits of Southern California, these perfectly preserved Dytiscus specimens were recovered from the famous Rancho La Brea deposits. Private collection.

130. Cro-Magnon artifacts Spear point Ornamental bear claws Fishhooks

The harpoons, spear-throwers, needles pierced with an “eye”, fishhooks, and handles invented by Cro-Magnons led the way not only to mankind’s taming of the First appearing in Africa, this subspecies of environment, but also to the artful recording wandering hunter-gatherers eventually of his abstract perception of it. American colonized every continent except Antarctica. Museum of Natural History. Interbreeding with archaic local populations throughout the world may have produced the 131. Order Primates variety of races known today. Collectively Family Hominidae known as Cro-Magnon Man (named for Homo sapiens sapiens fossil remains found at Cro-Magnon in Middle Pleistocene, France southern France), this race of early Homo sapiens sapiens of 40,000 to 10,000 years ago were fully modern members of our own subspecies. Surviving the harsh climates of the Ice Age, these Late Stone Age hunters were the ancestors of present-day European Caucasoids (whites).

With sophisticated and often elaborately decorated implements fashioned from stone and bone, Cro-Magnon culture appears to stress hunting, as evidenced by their artful paintings, engravings and sculptures of such big game animals as reindeer, oxen, and horses. Advanced weapons and hunting methods enabled these people to double the hurling range of their spears in hunting big game and to introduce freshwater fish to their diets. Nourished by the availability of 133. Moon Rocks vast herds of wild game, the explosive Apollo Lunar Landing Missions growth of their population succeeded even Lunar crust Apollo 15 in the severe arctic climate. Dated at 30,000 years and known as Cro-Magnon I, this classic skull of an elderly individual was recovered from Les Eyzies. Musee de l’Homme.

132. Venus of Willendorf Late Pleistocene, Austria

Known as the “Genesis Rock”, this white feldspar was the first sample of lunar crust used for determining the age of the Moon. Evidence that the Moon, like the Earth, emerged from a swirling cloud of condensing gases during the formation of the Solar System some 4.6 billion years ago, its composition differs (chiefly calcium aluminum silicate, a form of reflective feldspar that doesn’t occur on Earth),

suggesting that the Moon was captured by Found in 1908 in the Danube Valley, the Earth’s gravity after its formation. The Austria, and dated at about 40,000 years, “Genesis Rock” was found lying on a this ancient and meticulously detailed mountainside, undisturbed for eons, where limestone carving was probably used as a its glittering crystals attracted the astronauts fertility fetish by Cro-Magnons. The careful to it. styling of its hair attests to the age of this ancient practice. The tapering of the legs, with their missing feet, implies that it once Lunar basalt Apollo 17 stood in a specially carved out base, presumably a primitive altar. Vienna This black basaltic rock, similar to those Natural History Museum. found on Earth, is pitted with glassy holes left by the heat of escaping gases in the Moon’s vacuous atmospheric pressure. Pitted on both sides with tiny Mainly composed of iron and pyroxene micrometeorite craters and composed (magnesium iron silicate) with occasional primarily of iron and magnesium, this small traces of calcium, this rock is evidence that gray basaltic rock was evidently shifted the Moon’s iron core was formerly molten from its original position on the lunar like the Earth’s. surface at some point in its history. NASA specimens courtesy of W. R. Muehlberger, Lunar basalt Apollo 12 University of Texas, Austin.

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