Portal:Paleontology/Natural world articles
Articles about paleontology and the natural world
differentiated cells
performing specialised functions.
The earliest see more...
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The Ediacaran biota were ancient lifeforms representing the earliest known complex multicellular organisms. They appeared soon after the Earth thawed from the Cryogenian period's extensive glaciers, and largely disappeared soon before the rapid appearance of biodiversity known as the Cambrian explosion, which saw the first appearance in the fossil record of the basic patterns and body-plans that would go on to form the basis of modern animals. Little of the diversity of the Ediacaran biota would be incorporated in this new scheme, with a distinct Cambrian biota arising and usurping the organisms that dominated the Ediacaran fossil record.
Some Ediacaran organisms might have been closely related to groups that would rise to prominence later, but most non-microscopic fossils are morphologically distinct from later lifeforms, resembling discs, mud-filled bags, or quilted mattresses.Classification is difficult, and the assignment of some species even at the level of kingdom — animal, fungus, protist or otherwise — is uncertain: one paleontologist has even gained support for a separate kingdom Vendobionta. Their strange form and apparent disconnectedness from later organisms have led some to consider them a "failed experiment" in multicellular life, with later multicellular life independently re-evolving from unrelated single-celled organisms. (more...
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extinct species are recognized from fossils found in different regions of China and Mongolia, with possible additional species from Thailand and Russia
.
All species of Psittacosaurus were
bipedal herbivores characterized by a high, powerful beak on the upper jaw. At least one species had long, quill-like structures on its tail and lower back, possibly serving a display function. Psittacosaurs were extremely early ceratopsians and, while they developed many novel adaptations of their own, they also shared many anatomical features with later ceratopsians, such as Protoceratops and the elephant-sized Triceratops
.
Psittacosaurus is not as familiar to the general public as its distant relative Triceratops but it is one of the most completely known dinosaur genera. Fossils of over 150 individuals have been collected so far, including many near-complete skeletons. Most different age classes are represented, from nestling through to adult, which has allowed several detailed studies of Psittacosaurus growth rates and index fossil for Early Cretaceous sediments of central Asia. (see more...
) 
million years ago (mya) in what is now North America. It was one of the last dinosaurs to appear before the great Cretaceous–Paleogene extinction event. Bearing a large bony frill and three horns on its large four-legged body and conjuring similarities with the modern rhinoceros, Triceratops is one of the most recognizable of all dinosaurs. Though it shared the landscape with, and was preyed upon by the fearsome Tyrannosaurus
, it is unclear whether the two battled the way they are commonly depicted in movies and children's dinosaur books.
Although no complete skeleton has been found, Triceratops is well-known from numerous partial specimens collected since the introduction of the genus in 1887. The function of their frills and three distinctive facial horns has long inspired debate. Although traditionally viewed as defensive weapons against predators, the latest theories explain how these features were probably primarily used in display for
rhinoceros beetles
.
Triceratops is the best-known of the ceratopsids, though the genus' exact placement within the group has been a point of contention amongst paleontologists. Two species, T. horridus and T. prorsus, are considered valid, although many other species have been named. (see more...) 
Period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany in the 1850s and the second in France more than a century later. Compsognathus is one of the few dinosaurs for which the diet is known with certainty: the remains of small, agile lizards are preserved in the bellies of both specimens. Teeth discovered in Portugal
may be further fossil remains of the genus.
Although not recognized as such at the time of its discovery, Compsognathus is the first dinosaur known from a reasonably complete skeleton. Today, C. longipes is the only recognized species, although the larger specimen discovered in France in the 1970s was once thought to belong to a separate species, C. corallestris. Until the 1980s and 1990s, Compsognathus was the smallest known dinosaur and the closest supposed relative of the early bird Archaeopteryx. Thus, the genus is one of the few dinosaur genera to be well known outside of paleontological circles. (see more...) 
Period. There is only one currently recognized species, V. mongoliensis, although others have been assigned in the past. Fossils of this species have been found in central Asia, from both Inner and Outer Mongolia
.
Smaller than other dromaeosaurids like , with an upturned snout.
Due in large part to its prominent role in Michael Crichton's novel Jurassic Park and the subsequent motion picture series, Velociraptor (commonly shortened to 'raptor') is one of the dinosaur genera most familiar to the general public. It is also well-known to paleontologists, with over a dozen recovered fossil skeletons — the most of any dromaeosaurid. One particularly famous specimen shows a Velociraptor locked in combat with a Protoceratops. (see more...)
quadruped, Stegosaurus had a distinctive and unusual posture, with a heavily arched back, short forelimbs, head held low to the ground and a stiffened tail held high in the air. Its array of plates and spikes have been the subject of much speculation. The spikes were most likely used for defence, while the plates have also been proposed as a defensive mechanism, as well as having display and thermoregulatory (heat control) functions. Stegosaurus was the largest of all the stegosaurians (bigger than genera such as Kentrosaurus and Huayangosaurus) and, although roughly bus-sized, it nonetheless shared many anatomical features (including the tail spines and plates) with the other stegosaurian genera. (see more...
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chevron bones (Greek
diplos/διπλος meaning 'double' and dokos/δοκος meaning 'wooden beam' or 'bar') located in the underside of the tail. They were initially believed to be unique to Diplodocus; however, they have since then been discovered in other diplodocids.
It lived in what is now western stages. This was an environment and time dominated by gigantic sauropod dinosaurs such as Camarasaurus, Barosaurus, Apatosaurus and Brachiosaurus. Diplodocus is among the most easily identifiable dinosaurs, with its classic dinosaur shape, long neck and tail and four sturdy legs. For many years, it was the longest dinosaur known. Its great size may have been a deterrent to the predators Allosaurus and Ceratosaurus: their remains have been found in the same strata, which suggests they coexisted with Diplodocus. (see more...
) predators
.
Discovered in 1822 and described three years later by
hadrosaurs. The taxonomy
of this genus continues to be a topic of study as new species are named or long-standing ones reassigned to other genera.
Scientific understanding of Iguanodon has evolved over time as new information has been obtained from the fossils. The numerous specimens of this genus, including nearly complete skeletons from two well-known bonebeds, have allowed researchers to make informed hypotheses regarding many aspects of the living animal, including feeding, movement, and social behaviour. As one of the first scientifically well-known dinosaurs, Iguanodon has occupied a small but notable place in the public's perception of dinosaurs, its artistic representation changing significantly in response to new interpretations of its remains. (see more...) 
theropod dinosaur. The species Tyrannosaurus rex, commonly abbreviated to T. rex, is one of the dinosaurs most often featured in popular culture around the world. It hails from what is now western North America
.
Like other tyrannosaurids, Tyrannosaurus was a
tons
in weight.
Period (late Maastrichtian stage, 65 million years ago); it was among the last dinosaurs to exist prior to the Cretaceous–Paleogene extinction event. More than 30 specimens of T. rex have now been identified, some nearly complete, which has allowed significant research into many aspects of its biology, including its life history and biomechanics. The feeding habits and potential speed of T. rex remain controversial. (see more...
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The Origin of Species, set off a firestorm of debate about evolution and the role of transitional fossils
that endures to this day.
The eleven fossils currently classified as Archaeopteryx are the oldest evidence of feathers on the planet and the only ones dated from Jurassic times. Furthermore, their advanced nature and placement suggest their origins must have been even earlier. All remains have been regarded by most as a single species, though this has been debated. (see more...) 
period in North America and was a member of the last dinosaurian fauna before the Cretaceous–Paleogene extinction event around 65.5 million years ago. The preservation and completeness of many of its specimens indicate that it may have preferred to live near stream channels
.
This
hypsilophodont and a herbivore
. Several species have been suggested for this genus, but only one, T. neglectus, is currently recognized; the others have been given their own genera, or are believed to be the same as T. neglectus.
The genus attracted media attention in 2000, when a specimen unearthed in 1993 in South Dakota was interpreted as including a fossilized heart. There was much discussion over whether the remains were actually of a heart. Many scientists now doubt the identification of the object and the implications of such an identification. (see more...) 
stage), about 74 to 72 million years ago. It had four to six long horns extending from its neck frill
, a smaller horn on each of its cheeks and a single horn protruding from its nose, which was around 60 centimeters (2 ft) long and 15 centimeters (6 in) wide. The function or functions of the horns and frills have been the subject of debate for many years.
Styracosaurus was a large dinosaur, reaching lengths of 5.5 meters (18 ft) and weighing nearly 3 herd animal, traveling in large groups, as suggested by bonebeds. Named by Lawrence Lambe in 1913, Styracosaurus is a member of the Centrosaurinae. Three species, S. albertensis, S. ovatus, and S. parksi are currently assigned to Styracosaurus, though the last species may be synonymous with S. albertensis. Other species assigned to the genus have since been reassigned elsewhere. (see more...
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Period. Fossils of the only named species (D. torosus) were found in Alberta, although other possible species from Alberta, Montana and New Mexico
await description. Including these undescribed species, Daspletosaurus is the most species-rich genus of tyrannosaur.
Daspletosaurus is closely related to the much larger and more recent Tyrannosaurus. Like most known tyrannosaurids, it was a multi-ton
teeth. Daspletosaurus had the small forelimbs typical of tyrannosaurids, although they were proportionately longer than in other genera. It was probably similar in weight to a modern white rhinoceros or a small elephant
.
As an niche differentiation between the two. While Daspletosaurus fossils are rarer than other tyrannosaurids, the available specimens allow some analysis of the biology of these animals, including social behavior, diet and life history. (see more...
) 
million years ago). Fossils of the only named species (D. antirrhopus) have been recovered from Montana, Wyoming and Oklahoma, though teeth that may belong to Deinonychus have been found much farther east in Maryland
.
Its name refers to the unusually large, sickle-shaped talon on the second toe of each hind foot, which was probably held retracted while the dinosaur walked on the third and fourth toes. It was commonly thought that Deinonychus would kick with the sickle claw to slash at its prey but recent tests on reconstructions of similar Velociraptor talons suggest that the claw was used to stab, not slash. As in other dromaeosaurids, the tail was stiffened by a series of elongated bones and bone processes. This might have given Deinonychus greater balance and turning ability. In both the Cloverly and Antlers Formation, Deinonychus remains have been found closely associated with those of the ornithopod Tenontosaurus. Teeth discovered associated with Tenontosaurus specimens imply it was hunted or at least scavenged upon by Deinonychus.
Paleontologist John Ostrom's study of Deinonychus in the late 1960s revolutionized the way scientists thought about dinosaurs, igniting the debate on whether or not dinosaurs were warm-blooded. Before this, the popular conception of dinosaurs had been one of plodding, reptilian giants. Ostrom noted lightweight bones and stiffened tendons which revealed an active, agile predator. (see more...)
junior synonym
of Majungasaurus.
Like other abelisaurids, Majungasaurus was a
teeth
in both upper and lower jaws than most abelisaurids.
Known from several well-preserved skulls and abundant skeletal material, Majungasaurus has recently become one of the best-studied theropod dinosaurs from the cannibalism is known. (see more...
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quadruped. Three species are recognized: P. walkeri (the type species), P. tubicen, and the short-crested P. cyrtocristatus. Remains are known from Alberta (Canada), and New Mexico and Utah (United States). It was first described in 1922 by William Parks
from a skull and partial skeleton in Alberta.
Parasaurolophus is a China, which may have been its closest relative. The crest has been much discussed by scientists; the consensus is that major functions included visual recognition of both species and gender, acoustic resonance, and thermoregulation. It is one of the rarer duckbills, known from only a handful of good specimens. (see more...
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Period, and Pg is the abbreviation for the Paleogene Period. The event marks the end of the Mesozoic Era, and the beginning of the Cenozoic
Era.
Non-
clades passed through the boundary with few extinctions, and radiation
from those Maastrichtian clades occurred well past the boundary. Rates of extinction and radiation varied across different clades of organisms.
Many scientists theorize that the Cretaceous–Paleogene extinctions were caused by one or more catastrophic geological events such as massive see more...
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ornithischians
. The other species were more modestly sized.
Lambeosaurus was belatedly described in 1923 by William Parks, over twenty years after the first material was studied by Lawrence Lambe. The genus has had a complicated taxonomic history, in part because small-bodied crested hadrosaurids now recognized as juveniles were once thought to belong to their own genera and species. Currently, the various skulls assigned to the type species L. lambei are interpreted as showing age differences and sexual dimorphism. Lambeosaurus was closely related to the better known Corythosaurus, which is found in slightly older rocks, as well as the less well-known genera Hypacrosaurus and Olorotitan. All had unusual crests, which are now generally assumed to have served social functions like noisemaking and recognition. (see more...) 
Period, approximately 125 to 100 million years ago. Like most dinosaur genera, Acrocanthosaurus contains only a single species, A. atokensis. Its fossil remains are found mainly in the U.S. states of Oklahoma and Texas, although teeth attributed to Acrocanthosaurus have been found as far east as Maryland
.
Acrocanthosaurus was a
short tons
). Large theropod footprints discovered in Texas may have been made by Acrocanthosaurus, although there is no direct association with skeletal remains.
Recent discoveries have elucidated many details of its anatomy, allowing for specialized studies focusing on its ornithopods. (see more...
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onychophorans and tardigrades may also be members.(see more...
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hadrosaurids
, measuring up to 13 meters (43 ft) long and weighing around 4.0 metric tons (4.4 short tons). It is known from several well-preserved specimens that include not only bones, but in some cases extensive skin impressions and possible gut contents.
Edmontosaurus has a lengthy and complicated taxonomic history dating to the late 19th century. The type species, E. regalis, was named by Lawrence Lambe in 1917, although several other species that are now classified in Edmontosaurus were named earlier. The best known of these is E. annectens, originally named by Othniel Charles Marsh in 1892.
Edmontosaurus was widely distributed across western North America. The distribution of Edmontosaurus fossils suggests that it preferred coasts and
herbivore that could move on both two legs and four. Because it is known from several bone beds
, Edmontosaurus is thought to have lived in groups, and may have been migratory as well.
(see more...) 
range to the modern-day Canadian province of Alberta, after which the genus is named. Scientists disagree on the number of species
represented in the genus, recognizing either one or two species.
As a tyrannosaurid, Albertosaurus was a predator with a massive head, jaws lined with dozens of large teeth and tiny, two-fingered 'hands' and it may have been at the top of the food chain in its local ecosystem. Although relatively large for a theropod, Albertosaurus was much smaller than its more famous relative Tyrannosaurus, probably weighing only as much as a modern black rhinoceros. Fossils of more than twenty individuals have been recovered, providing scientists with a more detailed knowledge of Albertosaurus anatomy than is available for other tyrannosaurids. The discovery of ten individuals at one site provides evidence of pack behavior and allows studies of developmental biology which are impossible with lesser-known animals. (see more...
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Yucatán, Mexico. The crater is over 180 kilometers (110 mi) in diameter, making the feature one of the largest confirmed impact structures in the world; the asteroid or comet whose impact formed the crater was at least 10 km (6 mi) in diameter. The crater was named for the nearby town, as well as for the literal Maya translation of the name: "tail of the devil
."
The crater was discovered by Glen Penfield, a geophysicist who had been working in the Yucatán while looking for see more...
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period. The first remains that can definitely be ascribed to this genus were described in 1877 by Othniel Charles Marsh. As one of the first well-known theropod dinosaurs, it has long attracted attention outside of paleontological circles, and has been a lead dinosaur in several films and documentaries
.
Allosaurus was a large
Cleveland-Lloyd Dinosaur Quarry
brought the name Allosaurus back to prominence, and established it as one of the best-known dinosaurs.
As the prominent large predator in the sauropods. While it is often thought of as preying on sauropod dinosaurs in groups, there is little evidence for cooperative social behavior in this genus, and individuals may have been aggressive toward each other instead. It may have attacked large prey by ambush, using its upper jaws like a hatchet. (see more...
) 
million years ago). It was described by Sir Richard Owen in 1854 from remains found in South Africa, and is thus one of the first dinosaurs to have been named. Fossils have since been found in Lesotho, Zimbabwe, and other parts of South Africa. Further material from Arizona's Kayenta Formation, India, and Argentina
has been assigned to this genus, but may not belong to Massospondylus.
The type, and only universally recognized species, is M. carinatus, although six other species have been named during the past 150 years. Prosauropod systematics have undergone numerous revisions during the last several years, and many scientists disagree where exactly Massospondylus lies on the dinosaur evolutionary tree. The family name Massospondylidae was once coined for the genus, but because knowledge of prosauropod relationships is in a state of flux, it is unclear which other dinosaurs—if any—belong in a natural grouping of massospondylids; several 2007 papers support the family's validity.
Although Massospondylus was long depicted asherbivore, although it is speculated that the prosauropods may have been omnivorous. This animal, 4–6 meters (13–20 ft) long, had a long neck and tail, with a small head and slender body. On each of its forefeet, it bore a sharp thumb claw that was used in defense or feeding. Recent studies indicate Massospondylus grew steadily throughout its lifespan, possessed air sacs similar to those of birds, and may have cared for its young. (see more...
) .jpg)
Period. Fossils have been recovered in Mongolia with more fragmentary remains found further afield in parts of China. Although many species have been named, modern paleontologists recognize only one, T bataar, as valid. Some experts contend that this species is actually an Asian representative of the North American genus Tyrannosaurus; if true, this would invalidate the genus Tarbosaurus altogether.
Tarbosaurus and Tyrannosaurus are considered closely related genera, even if they are not
and equipped with dozens of large, sharp teeth. It had a unique locking mechanism in its lower jaw and the smallest forelimbs relative to body size of all tyrannosaurids, renowned for their disproportionately tiny, two-fingered forelimbs. Tarbosaurus lived in a humidphylogeny, skull mechanics, and brain structure. (see more...
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, G. libratus, although other species have been erroneously referred to the genus.
Like most known tyrannosaurids, Gorgosaurus was a
junior synonym
of that genus.
Gorgosaurus lived in a lush niche differentiation between the two. Gorgosaurus is the best-represented tyrannosaurid in the fossil record, known from dozens of specimens. These plentiful remains have allowed scientists to investigate its ontogeny, life history and other aspects of its biology. (see more...
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permineralised life forms, generally having a round shape. Coal balls were formed roughly 300 million years ago, during the Carboniferous Period. They are exceptional at preserving organic matter, which makes them useful to scientists, who cut and peel the coal balls to research the geological past of the Earth.
In 1855, two English scientists, Joseph Dalton Hooker and Edward William Binney, discovered coal balls in England, and the initial research on coal balls was carried out in Europe. It was not until 1922 that coal balls were discovered and identified in North America. Since then, coal balls have been discovered in other countries and they have led to the discovery of over 300 species and 130 genera.
Coal balls can be found incoal seams across North America and Eurasia. North American coal balls are relatively widespread, both stratigraphically and geologically, as compared to coal balls from Europe. The oldest known coal balls were found in Germany and the former Czechoslovakia
. 
period. They are very diverse, and there is no formal definition of "small shelly fauna" or "small shelly fossils". Almost all are from earlier rocks than more familiar fossils such as trilobites. Since most SSFs were preserved by being covered quickly with phosphate
and this method of preservation is mainly limited to the Late Ediacaran and Early Cambrian periods, the animals that made them may actually have arisen earlier and persisted after this time span.
The bulk of the fossils are fragments or disarticulated remains of larger organisms, including brachiopods, echinoderms, and onychophoran-like organisms that may have been close to the ancestors of arthropods. Although the small size and often fragmentary nature of SSFs makes it difficult to identify and classify them, they provide very important evidence for how the main groups of marine invertebrates evolved, and particularly for the pace and pattern of evolution in the Cambrian explosion. Besides including the earliest known representatives of some modern phyla, they have the great advantage of presenting a nearly continuous record of Early Cambrian organisms whose bodies include hard parts. (see more...
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Middle Cambrian Burgess Shale Lagerstätte of Canada. It grew to a length of about8 cm (3 in) and resembled modern shrimp in both morphology and habit. It had a large bivalved carapace
and a segmented body terminating into a pair of tail flaps. It was an active swimmer, feeding on organic particles it gathers from the seafloor substrate.
Based on the number of individuals, Waptia fieldensis is the third most abundant arthropod from the Burgess Shale Formation, with thousands of specimens collected. It was among the first
Charles D. Walcott in 1909. He described it in 1912 and named it after two mountains near the discovery site – Wapta Mountain and Mount Field
.
Waptia fieldensis is the only species classified under the ) 
biostratigraphic
markers.
Their bizarre form has made
eggs
or juvenile stage of a marine animal.
The ecology of chitinozoa is also open to speculation; some may have floated in the water column, where others may have attached themselves to other organisms. Most species were particular about their living conditions, and tend to be most common in specific paleoenvironments. Their abundance also varied with the seasons.(see more...) 
form genus
, which is used to categorise any small, branched filaments with external ornamentation. It has been applied to microfossils of Devonian age with possible fungal affinities; two "species" have been described, and further Silurian fossils closely resemble it. These Silurian specimens hint that the organisms may have been fungal, placing them among the oldest representatives of this kingdom.
(see more...) 
great appendages that resembled headless shrimp. These appendages are thought to have passed food to the animal's mouth, which resembled a ring of pineapple.(see more...
) 
monospecific genus of extinct sarcopterygian (lobe-finned fish) from the late Devonian period, about 375 Ma (million years) ago, having many features akin to those of tetrapods
(four-legged animals).
Tiktaalik has a possibility of being a representative of the evolutionary transition from fish to amphibians. It is an example from several lines of ancient
sarcopterygian fish
developing adaptations to the oxygen-poor shallow-water habitats of its time, environmental conditions which led to the evolution of tetrapods.
It and similar animals may possibly be the common ancestors of the broad swath of all terrestrial fauna: amphibians, reptiles, birds, and mammals. The first well-preserved Tiktaalik fossils were found in 2004 on Ellesmere Island in Nunavut, Canada. (see more...) 
lepospondyls, or even as descendants of both groups (with caecilians evolving from lepospondyls and frogs and salamanders evolving from temnospondyls). Recent studies place a family of temnosondyls called the amphibamids as the closest relatives of modern amphibians. Similarities in teeth, skulls, and hearing structures link the two groups. (see more...
) 
Early Permian, around 299–270 million years ago (Ma). It is a member of the family Sphenacodontidae. The most prominent feature of Dimetrodon is the large sail on its back formed by elongated spines extending from the vertebrae. It walked on four legs and had a tall, curved skull with large teeth of different sizes set along the jaws. Generally reptile-like in appearance and physiology, Dimetrodon is nevertheless more closely related to mammals than it is to any living reptilian group, though it is not a direct ancestor of any mammals. Most fossils have been found in the southwestern United States, the majority coming from a geological deposit called the Red Beds in Texas and Oklahoma. More recently, fossils have been found in Germany. Over a dozen species have been named since the genus was firstdescribed
in 1878.
Dimetrodon was probably one of the top predators in Early Permian ecosystems, feeding on fish and tetrapods, including reptiles as well as amphibians. Smaller Dimetrodon species may have had different ecological roles. The sail of Dimetrodon may have been used to stabilize its spine or to heat and cool its body as a form of sexual display. (see more...
) Burgess shale type preservation
, which preserves fairly tough tissues such as cuticle as thin films and soft tissues as solid shapes.
In the 1970s and early 1980s the Burgess fossils were largely regarded as evidence that the familiar Hallucinogenia, were evolutionary relatives of modern animal groups rather than a rapid proliferation of separate phyla, some of which were short-lived. Nevertheless, there is still debate, sometimes vigorous, about the relationships between some groups of animals. (see more...
) 
nomina dubia. (see more...
) 
sauropods, while other studies find it preyed mainly on relatively small animals. Carnotaurus was well adapted for running and was possibly one of the fastest large theropods. (see more...
) 
million years ago) in northwestern Argentina. The type species, Herrerasaurus ischigualastensis, was described by Osvaldo Reig in 1963 and is the only species assigned to the genus. Ischisaurus and Frenguellisaurus are synonyms
.
For many years, the classification of Herrerasaurus was unclear because it was known from very fragmentary remains. It was hypothesized to be a basal theropod, a basal sauropodomorph, a basal saurischian, or not a dinosaur at all but another type of archosaur. However, with the discovery of an almost complete skeleton and skull in 1988, Herrerasaurus has been classified as either an early theropod or an early saurischian in at least five recent reviews of theropod evolution, with many researchers treating it at least tentatively as the most primitive member of Theropoda.
It is a member of thedinosaurian evolutionary radiation. (see more...
) 
theropod
dinosaurs and, consequently, they are considered a subgroup of dinosaurs by many paleontologists. Some birds survived the extinction event and their descendants continue the dinosaur lineage to the present day.
Using fossil evidence, sauropod dinosaurs may have achieved lengths of 58 meters (190 feet). Many dinosaurs were quite small: Xixianykus, for example, was only about 50 cm (20 in) long. (see more...
) 
Coprolites
containing fish remains found in the Jydegaard Formation may belong to this animal.
Dromaeosauroides was discovered in the titanosaur tooth. Remains and tracks of other dinosaurs have been found in several formations on Bornholm. (see more...
) 
Republic of Niger
. Fossils of this dinosaur were first described in 1976, but it was only named in 1999 after further and more complete remains were found and described. The genus contains a single species, Nigersaurus taqueti.
Nigersaurus was 9 m (30 ft) long, which is small for a
keratinous sheath. Unlike other tetrapods
, the tooth-bearing bones of its jaws were rotated transversely relative to the rest of the skull, so that all of its teeth were located far to the front.
Nigersaurus was probably a crocodylomorphs. (see more...
) 
"prosauropod". As of 2011, two species are recognized: the type species
P. engelhardti and the slightly earlier P. gracilis.
Discovered in 1834 by Johann Friedrich Engelhardt and described three years later by Hermann von Meyer, Plateosaurus was the fifth named dinosaur genus that is still considered valid. It is now among the dinosaurs best known to science: over 100 skeletons have been found, some of them nearly complete.
Plateosaurus was a bipedal herbivore with a small skull on a long, mobile neck, sharp but plump plant-crushing teeth, powerful hind limbs, short but muscular arms and grasping hands with large claws on three fingers, possibly used for defence and feeding. Unusually for a dinosaur, Plateosaurus showed strong developmental plasticity: instead of having a fairly uniform adult size, fully grown individuals were between 4.8 and 10 metres (16 and 33 ft) long and weighed between 600 and 4,000 kilograms (1,300 and 8,800 lb). Commonly, the animals lived for at least 12 to 20 years, but the maximum life span is not known. (see more...)
Majungasaurus crenatissimus) survived until the end of the Mesozoic
era 66 million years ago.
Like most theropods, abelisaurids were tyrannosaurids. (see more...
) 
Tarbosaurus bataar
.
Alioramus were Tyrannosaurus rex, but their adult size is difficult to estimate since both species are known only from juvenile or sub-adult remains. The genus Alioramus is characterized by a row of five bony crests along the top of the snout, a greater number of teeth than any other genus of tyrannosaurid, and a lower skull than other tyrannosaurids. (see more...
) 
Period of what is now Europe
. Its type species is A. atacis, named by Le Loeuff in 1995. A possible unnamed species has given Ampelosaurus an age reaching to the latest Cretaceous, from about 70 to 66 million years ago.
Like most sauropods, it would have had a long neck and tail but it also carried
osteoderms. The blade of the scapula, contrary to most titanosaurs, is triangular. The blade narrows at one end instead of showing an expansion like most other genera. Titanosaurians were a flourishing group of sauropod dinosaurs during Cretaceous
times. The Spanish locality from the latest Cretaceous of “Lo Hueco” yielded a relatively well preserved, titanosaurian braincase, which shares a number of unique features with A. atacis from France. However, it appeared to differ from A. atacis in some traits also. The specimen has been provisionally identified as Ampelosaurus sp..
Ampelosaurus lived alongside many other animals. Over 8500 specimens have been found alongside it, including gastropods, bivalves, crocodiles, other sauropods, plants and invertebrates in the Gres de Labarre formations. Recent attention has made Ampelosaurus one of the most well-known dinosaurs known from France. (see more...
) 
sauropod dinosaur that includes what may be the largest dinosaur ever discovered, A. fragillimus. Based on surviving descriptions of a single fossil bone, A. fragillimus may have been the longest known vertebrate at 40 to 60 metres (130 to 200 ft) in length, and may have had a mass of up to 122 tonnes (135 short tons). However, because the only fossil remains were lost at some point after being studied and described in the 1870s, evidence survives only in drawings and field notes. The fossil was found in the Morrison Formation. (see more...
) 
Period (between about 66.5–66 Ma ago) in western North America
.
Although a complete skeleton has not been discovered and several other dinosaurs are represented by more extensive fossil material, Ankylosaurus is often considered the archetypal armored dinosaur. Other ankylosaurids shared its well-known features—the heavily armored body and massive bony tail club—but Ankylosaurus was the largest known member of the family. (see more...) 
type specimen
.
Seventy million years ago, world sea levels were higher, and the location where its fossils are found was a part of the sauropod, its strange features have been argued to show the effects of its island habitat on its evolution. (see more...
) 
Yinlong downsi, lived between 161.2 and 155.7 million years ago. The last ceratopsian species became extinct in the Cretaceous–Paleogene extinction event, 66
million years ago.
Early members of the ceratopsian group, such as quadrupeds and developed elaborate facial horns and frills extending over the neck. While these frills might have served to protect the vulnerable neck from predators, they may also have been used for display, thermoregulation, the attachment of large neck and chewing muscles or some combination of the above. Ceratopsians ranged in size from 1 meter (3 ft) and 23 kilograms (50 lb) to over 9 meters (30 ft) and 5,400 kg (12,000 lb).
Period) of England (about 165 to 161 million years ago [mya]). Cetiosauriscus was a quadrupedal, herbivorous, saurischian. It was named by Friedrich von Huene in 1927, the species name being C. leedsi. Later it was shown that C. leedsi was not a Cetiosauriscus species, so, in 1993, Alan J. Charig sent a petition to the ICZN to designate C. stewarti as the type species. The remains include a series of vertebra, a hind leg, a possible whiplash tail, a partial sacrum, and a front leg. Cetiosauriscus has, over time, been classified in Cardiodontinae within Cetiosauridae, Diplodocidae, and Mamenchisauridae. It lived alongside Eustreptospondylus, Sarcolestes, Callovosaurus, Lexovisaurus, and possibly Megalosaurus, and Cetiosaurus. (see more...
) 
genera or abandoned. Only one species is currently recognized as valid: the type species, C. fragilis, described by Othniel Charles Marsh in 1879. It is known from one partial skeleton found in the Morrison Formation of Wyoming, United States. It was a small bipedal carnivore with elongate legs. (see more...
) 
Cryolophosaurus is known from a skull, a femur and other material, the skull. C. ellioti possessed a distinctive crest on its head that spanned the head from side to side. Based on evidence from related species and studies of bone texture, it is thought that this bizarre crest was used for intra-species recognition. Since its original description, the consensus is that Cryolophosaurus is either a primitive member of the Tetanurae or a close relative of that group.
Cryolophosaurus was first excavated from Antarctica's Early Jurassic,Period. (see more...
) 
Period. The name Dromaeosauridae means 'running lizards', from Greek dromeus (δρομευς) meaning 'runner' and sauros (σαυρος) meaning 'lizard'. In informal usage they are often called raptors (after Velociraptor), a term popularized by the film Jurassic Park
; a few types include the term "raptor" directly in their name and have come to emphasize their supposed bird-like habits.
Dromaeosaurid fossils have been found in North America, Europe, Africa, Japan, China, Mongolia, Madagascar, Argentina, and Antarctica. They first appeared in the mid-Jurassic Period (late Bathonian stage, about 164 million years ago) and survived until the end of the Cretaceous (Maastrichtian stage, 66 ma), existing for over 100 million years, up until the Cretaceous–Paleogene extinction event. The presence of dromaeosaurs as early as the Middle Jurassic has been confirmed by the discovery of isolated fossil teeth, though no dromaeosaurid body fossils have been found from this period. (see more...) 
stages) of North America. Named species of Gryposaurus are known from the Dinosaur Park Formation in Alberta, Canada and the Lower Two Medicine Formation in Montana and the Kaiparowits Formation of Utah
in the United States.
Gryposaurus is similar to quadrupedal herbivore around 9 meters long (30 ft), it may have preferred river settings. (see more...
) 
Period, and a few late-surviving species persisted into the Early Cretaceous
.
Heterodontosaurids were ) 
eggs, and hatchlings belonging to H. stebingeri in the 1990s. (see more...
) hadrosaur, or "duck-billed" dinosaur, whose snouts bear likeness to ducks' bills. Some of the species' bones found at the Chronister Dinosaur Site are housed in Washington, D.C.'s Smithsonian Institution. (see more...
) 
Roman nose" (in the original specimen, the nasal region was fragmented and disarticulated, and was originally restored flat). Despite the dearth of material, this herbivore appeared frequently in dinosaur books until the 1990s, although what was usually represented was the much more completely known Gryposaurus, then thought to be a synonym. (see more...
) 
period (Bathonian stage, 166 million years ago) of Southern England. Although fossils from other areas have been assigned to the genus, the only certain remains of Megalosaurus come from the late Middle Jurassic of the Oxfordshire
.
Megalosaurus was, in 1824, the first genus of dinosaur to be validly named, apart from birds. The
Dinosauria. On Owen's directions a model was made as one of the Crystal Palace Dinosaurs
, which greatly increased the public interest for prehistoric reptiles. Subsequently, over fifty other species would be classified under the genus, originally because dinosaurs were not well known, but even during the 20th century after many dinosaurs had been discovered. Today it is understood these additional species were not directly related to M. bucklandii, which is the only true Megalosaurus species.
Megalosaurus was about seven metres long, weighing roughly 1.5 tonnes. It was bipedal, walking on stout hindlimbs, its horizontal torso balanced by a horizontal tail. Its forelimbs were short, though very robust. Megalosaurus had a rather large head, equipped with long curved teeth. It was generally a robust and heavily muscled animal. (see more...) 
see more...
) 
synonymized
with Pachycephalosaurus.
Like other pachycephalosaurids, Pachycephalosaurus was a
roof. It possessed long hindlimbs and small forelimbs. Pachycephalosaurus is the largest known pachycephalosaur. The thick skull domes of Pachycephalosaurus and related genera gave rise to the hypothesis that pachycephalosaurs used their skulls in intraspecific combat. This hypothesis has been disputed in recent years. (see more...)
Upper Cretaceous Dinosaur Park Formation in Alberta, and the roughly contemporaneous Two Medicine Formation in Montana, dating to around 76-75 million years ago. Its most recognizable feature is a small solid crest formed by the nasal bones
, sticking up in front of the eyes.
The type species is P. maximus, described by American paleontologist Barnum Brown of the American Museum of Natural History in 1916. A second species, P. blackfeetensis, was described by Jack Horner of the Museum of the Rockies in 1992. The two species are differentiated mainly by crest size and skull proportions. (see more...) 
theropod dinosaur with an unusual head crest. Between 1982 and 1984, its fossilized bones were discovered by Suresh Srivastava of the Geological Survey of India (GSI). Excavated from the Narmada River valley in Rahioli in the Kheda district of Gujarat, India, the find was announced as a new genus of dinosaur by American and Indian scientists on August 13, 2003
.
, and Srivastava worked together as an Indo–American group to study the Narmada River fossils. The fossils represented the partial skeleton of the new species Rajasaurus narmadensis, which means "princely lizard from the Narmada Valley."
The fossilized bones of Rajasaurus have also been found in the upriver region of the Narmada, at Jabalpur, in the state of Madhya Pradesh.(see more...) 
quadrupedally
.
The type species, S. osborni, was described by Barnum Brown in 1912 from Canadian fossils. A second valid species, S. angustirostris, is represented by numerous specimens from Mongolia, and was described by Anatoly Konstantinovich Rozhdestvensky. A third species, S. morrisi from California, was described in 2013, and a fourth species, S. kryschtofovici from China, is considered dubious. (see more...) 
kilograms (3,300 lb). The extra weight was largely due to its extensive bony body armor, including the characteristically large spines projecting from its neck. (see more...
) 
million years ago. This genus and related genera at the time lived on the supercontinent Laurasia. Its fossils have been found near Charmouth in Dorset, England, and are known for their excellent preservation. Scelidosaurus has been called the earliest complete dinosaur. It is the most completely known dinosaur of the British Isles
.
Scelidosaurus was about 4 metres (13 ft) long. It was a largely
quadrupedal
animal, feeding on low scrubby plants, the parts of which were bitten off by the small, elongated, head to be processed in the large gut. Scelidosaurus was lightly armoured, protected by long horizontal rows of keeled oval scutes, that stretched along the neck, back and tail.
One of the oldest known and most "primitive" of the thyreophorans, the exact placement of Scelidosaurus within this group has been the subject of debate for nearly 150 years. This was not helped by the limited additional knowledge about the early evolution of armoured dinosaurs. Today most evidence indicates that Scelidosaurus is a basal member of the Thyreophora, lower placed in the evolutionary tree of life than the Ankylosauridae or the Stegosauridae. (see more...) 
Sinoceratops was a medium-sized, averagely-built, ground-dwelling,
chasmosaurines, are known from fossils discovered in North America, except for possibly Turanoceratops. Sinoceratops is also significant because it is one of the largest known centrosaurines, and is much larger than any other known basal
members of this group.
Sinoceratops existed in the Huaxiaosaurus, and Zhuchengtyrannus. (see more...
) 
compsognathid dinosaur. Described in 1996, it was the first dinosaur taxon outside of Avialae (birds and their immediate relatives) to be found with evidence of feathers
. It was covered with a coat of very simple filament-like feathers. Structures that indicate colouration have also been preserved for some of the feathers, which makes Sinosauropteryx the first non-avialian dinosaurs where colouration has been determined. Colouration includes a reddish and light banded tail.
Sinosauropteryx was a small theropod with an unusually long tail and short arms. The longest known specimen reaches up to 1.07 m (3.5 ft) in length, with an estimated weight of 0.55 kg (1.2 lb). It was a close relative of the similar but older genus Compsognathus, both genera belonging to the family Compsognathidae. Only one species of Sinosauropteryx has been named: S. prima, meaning "first" in reference to its status as the first feathered non-avialian dinosaur species discovered.
Sinosauropteryx lived in what is now northeasternLiaoning Province, and was a member of Jehol Biota. Well-preserved fossils of this species illustrate many aspects of their biology, such as their diet and reproduction. (see more...
) 
million years ago. This genus was first known from Egyptian remains discovered in 1912 and described by German paleontologist Ernst Stromer in 1915. The best known species is S. aegyptiacus from Egypt, although a potential second species S. maroccanus has been recovered from Morocco
.
Spinosaurus may be the largest of all known spines of Spinosaurus, which were long extensions of the vertebrae, grew to at least 1.65 meters (5.4 ft) long and were likely to have had skin connecting them, forming a sail-like structure. Multiple functions have been put forward for this structure, including thermoregulation and display. (see more...
) 
It was originally mentioned by
Acanthopholinae. The family has gone through many taxonomic revisions since it was defined by Nopcsa in 1902. It is now recognized as a junior synonym of the family Nodosauridae. The subfamily now includes the genera Anoplosaurus, Europelta, Hungarosaurus, and Struthiosaurus, designated as the type genus. Because of the instability of Acanthopholis, the generic namesake of Acanthopholinae, and its current identification as a nomen dubium
, Struthiosaurinae, the next named group, was decidedly used over the older one.
Struthiosaurinae appeared at about exactly the same time as the North American subfamily see more...
) 
Although descended from smaller ancestors, tyrannosaurids were almost always the largest predators in their respective ecosystems, putting them at the apex of the food chain. The largest species was Tyrannosaurus rex, one of the largest known land predators, which measured up to 12.3 metres (40 ft) in length and up to 6,500 kilograms (7.2 short tons) in weight. Tyrannosaurids were bipedal carnivores with massive skulls filled with large teeth. Despite their large size, their legs were long and proportioned for fast movement. In contrast, their arms were very small, bearing only two functional digits.
Unlike most other groups of dinosaurs, very complete remains have been discovered for most known tyrannosaurids. This has allowed a variety of research into their biology. Scientific studies have focused on their ontogeny, biomechanics and ecology, among other subjects. Soft tissue, both fossilized and intact, has been reported from one specimen of Tyrannosaurus rex. (see more...)
Cretaceous Period, tyrannosauroids were the dominant large predators in the Northern Hemisphere, culminating in the gigantic Tyrannosaurus itself. Fossils of tyrannosauroids have been recovered on what are now the continents of North America, Europe, Asia, possibly South America and Australia
.
Tyrannosauroids were skeletal features, especially of the skull and pelvis. Early in their existence, tyrannosauroids were small predators with long, three-fingered forelimbs. Late Cretaceous genera became much larger, including some of the largest land-based predators ever to exist, but most of these later genera had proportionately small forelimbs with only two digits. Primitive feathers have been identified in fossils of two species, and may have been present in other tyrannosauroids as well. Prominent bony crests in a variety of shapes and sizes on the skulls of many tyrannosauroids may have served display functions. (see more...
) 
placental
mammals. It is the oldest known mammal with putatively tribosphenic teeth; at the time of its discovery it antedated the second oldest example by about 25 million years.
Upon its description in 1999, Ambondro was interpreted as a primitive relative of Tribosphenida (marsupials, placentals, and their extinct tribosphenic-toothed relatives). In 2001, however, an alternative suggestion was published that united it with the Cretaceous Australian Ausktribosphenos and the monotremes (the echidnas, the platypus, and their extinct relatives) into the clade Australosphenida, which would have acquired tribosphenic molars independently from marsupials and placentals. The Jurassic Argentinean Asfaltomylos and Henosferus and the Cretaceous Australian Bishops were later added to Australosphenida, and new work on wear in australosphenidan teeth has called into question whether these animals, including Ambondro, did in fact have tribosphenic teeth. Other paleontologists have challenged this concept of Australosphenida, and instead proposed that Ambondro is not closely related to Ausktribosphenos plus monotremes, or that monotremes are not australosphenidans and that the remaining australosphenidans are related to placentals. (see more...) brachydont
) teeth and possibly a fragment of a lower jaw. Ferugliotherium is estimated to have weighed 70 g (2.5 oz).
Most ferugliotheriids come from the Late Cretaceous epoch (dryolestoids and a variety of other animals, including dinosaurs. Ferugliotheriids may have been herbivores or omnivores. (see more...
) phylogenetic relationships, and within Gondwanatheria as a member of the family Sudamericidae. Lavanify is most closely related to the Indian Bharattherium; the South American Sudamerica and Gondwanatherium
are more distantly related. Gondwanatheres probably ate hard plant material.
Lavanify had high-perikymata—wave-like ridges and grooves in the enamel surface. (see more...
) 
genera
of aetosaurs have been described.
Aetosaur fossil remains are known from
index fossils
. Many aetosaurs had wide geographic ranges, but their stratigraphic ranges were relatively short. Therefore, the presence of particular aetosaurs can accurately date a site that they are found in.
Aetosaur remains have been found since the early 19th century, although the very first remains that were described were mistaken for fish scales. Aetosaurs were later recognized as crocodile relatives, with early paleontologists considering them to be semiaquatic scavengers. They are now considered to have been entirely terrestrial animals. Some forms have characteristics that may have been adaptations to digging for food. There is also evidence that some if not all aetosaurs made nests. (see more...
) 
The species was originally described as a
palynomorphs of uncertain nepenthacean affinity).Archaeamphora is also one of the three oldest known genera of angiosperms (flowering plants). Li (2005) wrote that "the existence of a so highly derived Angiosperm in the Early Cretaceous suggests that Angiosperms should have originated much earlier, maybe back to 280 mya as the molecular clock
studies suggested".
Subsequent authors have questioned the identification of Archaeamphora as a pitcher plant. (see more...) 
saprobic on plant litter or other forest debris
.
The genus is solely known from the Upper Cretaceous. Archaeomarasmius is one of only five known agaric fungus species known in the fossil record, and the only one to be described from New Jersey amber. (see more...
) 
palaeontologist David J. Gower
22 years after its discovery.
The locality where Batrachotomus lived was a swampy region and the name comes from the dinosaurs. (see more...
) multituberculate mammal from Gondwana and another (UA 8699) has been interpreted as either a marsupial or a placental. (see more...
) 
Period (228 to 66 million years ago). Pterosaurs are the earliest vertebrates known to have evolved powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the ankles to a dramatically lengthened fourth finger. Early species had long, fully toothed jaws and long tails, while later forms had a highly reduced tail, and some lacked teeth. Many sported furry coats made up of hair-like filaments known as pycnofibres, which covered their bodies and parts of their wings. Pterosaurs spanned a wide range of adult sizes, from the very small Nemicolopterus to the largest known flying creatures of all time, including Quetzalcoatlus and Hatzegopteryx
.
Pterosaurs are often referred to in the popular media and by the general public as flying see more...
) zhelestid placentals and favored a close relationship between UA 8699 and the Spanish zhelestid Lainodon. Krause used the tooth as evidence that marsupials were present on the southern continents (Gondwana) as early as the late Cretaceous and Averianov and colleagues proposed that the tooth represented another example of faunal exchange between Africa and Europe at the time. (see more...
) 
ornithomimosaur (ostrich dinosaur) that lived during the Late Cretaceous around 70 million years ago. In 1965, a pair of large arms, shoulder girdles, and a few other bones of a new dinosaur were first discovered in the Nemegt Formation of Mongolia. In 1970, this specimen became the holotype
of the only species within the genus, Deinocheirus mirificus. No further remains were discovered for almost fifty years, and its nature remained a mystery. Two more complete specimens were described in 2014, which shed light on many aspects of the animal.
Deinocheirus was largest ornithomimosaur at 11 m (36 ft) long, and weighing 6.36 t (14,000 lb). The arms were among the largest of any bipedal dinosaurs at 2.4 m (7.9 ft) long, with large, blunt claws on its three-fingered hands. The legs were relatively short, and bore blunt claws. Its vertebrae had tall neural spines that formed a "sail" along its back. The tail ended in omnivorous; its skull shape indicate a diet of plants, whereas fish scales were found in association with a specimen. (see more...
) 
Ma), during the late Cretaceous period. The name translates as "terrible crocodile" and is derived from the Greek. Although Deinosuchus was far larger than any modern crocodile or alligator, with the largest adults measuring 10.6 m (35 ft) in total length, its overall appearance was fairly similar to its smaller relatives. It had large, robust teeth built for crushing, and its back was covered with thick hemispherical osteoderms
. One study indicated Deinosuchus may have lived for up to 50 years, growing at a rate similar to that of modern crocodilians, but maintaining this growth over a much longer time.
Deinosuchus fossils have been found in 10 US states, including Texas, Montana, and many along the East Coast. Fossils have also been found in northern Mexico. It lived on both sides of the Western Interior Seaway, and was an opportunistic apex predator in the coastal regions of eastern North America. Deinosuchus reached its largest size in its western habitat, but the eastern populations were far more abundant. Deinosuchus was probably capable of killing and eating large dinosaurs. It may have also fed upon sea turtles, fish, and other aquatic and terrestrial prey. (see more...) 
stem group known as eosimiiforms
.
Afrasia is known from four isolated molar teeth found in the Pondaung Formation of Myanmar. These teeth are similar to those of Afrotarsius and Eosimiidae, and differ only in details of the chewing surface. For example, the back part of the third lower molar is relatively well-developed. In the Pondaung Formation, Afrasia was part of a diverse primate community that also includes the eosimiid Bahinia and members of the families Amphipithecidae and Sivaladapidae. (see more...) 
monotypic genus of gilled fungus in the Mycenaceae family, of order Agaricales. At present it contains the single species Protomycena electra, known from a single specimen collected in an amber mine in the Cordillera Septentrional area of the Dominican Republic. The fruit body of the fungus has a convex cap that is 5 mm (0.2 in) in diameter, with distantly spaced gills on the underside. The curved stipe is smooth and cylindrical, measuring 0.75 mm (0.030 in) thick by 10 mm (0.39 in) long, and lacks a ring. It resembles extant (currently living) species of the genus Mycena. Protomycena is one of only five known agaric fungus species known in the fossil record and the second to be described from Dominican amber. (see more...
) 
The taxonomic assignment of C. megalodon has been debated for nearly a century, and is still under dispute. The two major interpretations are Carcharodon megalodon (under family Lamnidae) or Carcharocles megalodon (under the family Otodontidae). Consequently, the scientific name of this species is commonly abbreviated C. megalodon in the literature.
C. megalodon is regarded as one of the largest and most powerful predators in vertebrate history, and likely had a profound impact on the structure of marine communities. Fossil remains suggest that this giant shark reached a maximum length of 18 metres (59 ft), and also affirm that it had a cosmopolitan distribution. Scientists suggest that C. megalodon looked like a stockier version of the great white shark, Carcharodon carcharias. (see more...)
humans first arrived on Madagascar, and it would have been vulnerable to hunting and habitat loss. (see more...
) 
strepsirrhine primate, from Madagascar that contains a single species, Babakotia radofilai. Together with Palaeopropithecus, Archaeoindris, and Mesopropithecus, it forms the family Palaeopropithecidae, commonly known as the sloth lemurs. Due to its mix of morphological traits that show intermediate stages between the slow-moving smaller sloth lemurs and the suspensory large sloth lemurs, it has helped determine the relationship between both groups and the closely related and extinct monkey lemurs
.
Babakotia radofilai and all other sloth lemurs share many traits with living see more...
) 
subfossil bones found in a variety of caves in northern, western, southern, and central Madagascar. In some sites, it occurs with remains of C. ferox, but there is no evidence that the two lived at the same time. Living species of comparably sized, related carnivores in other regions manage to coexist, suggesting that the same may have happened with both C. spelea and C. ferox. C. spelea would have been able to prey on larger animals than its smaller relative could have, including the recently extinct giant lemurs. (see more...
) 
postcranial skeleton shows Mesopropithecus had longer forelimbs than hindlimbs—a distinctive trait shared by sloth lemurs but not by indriids. However, as it had the shortest forelimbs of all sloth lemurs, it is thought that Mesopropithecus was more quadrupedal and did not use suspension
as much as the other sloth lemurs.
All three species ate leaves, fruits, and seeds, but the proportions were different. M. pithecoides was primarily a leaf-eater (folivores), but also ate fruit and occasionally seeds. M. globiceps ate a mix of fruits and leaves, as well as a larger quantity of seeds than M. pithecoides. M. dolichobrachion also consumed a mixed diet of fruits and leaves, but analysis of its teeth suggests that it was more of a seed predator than the other two species. (see more...) subfossil lemur and a species of sloth lemur
.Subfossil lemurs are
subfossil) remains dating from nearly 26,000 years ago (during the late Pleistocene) to approximately 560 years ago. They include both living and extinct
species, although the term more frequently refers to the extinct giant lemurs. The diversity of subfossil lemur communities was greater than that of present-day lemur communities, ranging from as high as 20 or more species per location, compared with 10 to 12 species today. Extinct species are estimated to have ranged in size from slightly over 10 kg (22 lb) to roughly 160 kg (350 lb).
Despite their size, the giant lemurs shared many features with living lemurs, including rapid development, poor day vision, relatively small brains, and lack of male dominance. They also had many distinct traits among lemurs, including a tendency to rely on koala lemurs), and Archaeolemuridae (monkey lemurs). Two other types were more closely related and similar in appearance to living lemurs: the giant aye-aye and Pachylemur, a genus of "giant ruffed lemurs".(see more...
) 
spiny thickets of southwestern Madagascar, they were also likely to have dispersed seeds evolved to attach to fur and be carried away. Unlike ruffed lemurs, the fore- and hindlimbs of Pachylemur were nearly the same length, and therefore it was likely to be a slow, deliberate climber. However, both used hindlimb suspension to reach fruit on small branches below them. (see more...
) subfossils
available for the Saint Croix macaw represent incomplete fragments of the whole bones coloured in red.see more...
) 
cave paintings. The mammoth was identified as an extinct species of elephant by Georges Cuvier
in 1796.
The woolly mammoth was roughly the same size as modern see more...
) 
Middle Pleistocene layer of the Oumm-Qatafa cave in Palestine. The premaxillaries resemble those of the house and Spanish sparrows, but differ in having a deep groove instead of a crest on the lower side. Israeli palaeontologist Eitan Tchernov, who described the species, and others have considered it to be close to the ancestor of the house and Spanish sparrows, but molecular data point to an earlier origin of modern sparrow species. Occurring in a climate Tchernov described as similar to but rainier than that in Palestine today, it was considered by Tchernov as a "wild" ancestor of the modern sparrows which have a commensal association with humans, although its presence in Oumm-Qatafa cave may indicate that it was associated with humans. (see more...
) 
strepsirrhine primate, from Madagascar that includes a single species, Hadropithecus stenognathus. Due to its rarity and lack of sufficient skeletal remains, it is one of the least understood of the extinct lemurs. Both it and Archaeolemur are collectively known as "monkey lemurs" or "baboon lemurs" due to body plans and dentition that suggest a terrestrial lifestyle and a diet similar to that of modern baboons. Hadropithecus had extended molars and a short, powerful jaw, suggesting that it was both a grazer and a seed predator
.
The monkey lemurs are considered to be most closely related to the living subfossil or recent remains and is considered to be a modern form of Malagasy lemur. It died out around 444–772 CE, shortly after the arrival of humans on the island. (see more...
) 
mesoloph. Carletonomys was probably herbivorous and lived in a wet habitat. (see more...
) 
Iberia. Baryonyx was about 7.5 m (25 ft) long and weighed 1.2 t (1.3 short tons). It had a long, low snout and narrow jaws, which have been compared to those of a gharial
. Baryonyx had many finely serrated teeth. It had robust forelimbs, with the eponymous first-finger claw measuring about 31 cm (12 in) long.
Now recognised as a member of the family senior synonym; however, subsequent authors have kept them separate. Baryonyx was the first theropod dinosaur demonstrated to have been piscivorous (fish-eating), as evidenced by fish scales in the stomach region of the holotype specimen. It may also have been an active predator of larger prey and a scavenger, since it also contained bones of a juvenile Iguanodon. The creature would have caught and processed its prey primarily with its forelimbs and large claws. Baryonyx lived near bodies of water. (see more...
) 
period and became extinct at the base of the Cambrian. They formed millimetre-scale conical fossils consisting of calcareous
cones nested within one another; the appearance of the organism itself remains unknown. Current scientific opinion is divided between classifying them as polychaetes and regarding it as unsafe to classify them as members of any broader grouping.
Cloudinids had a wide geographic range, reflected in the present distribution of localities in which their fossils are found, and are an abundant component of some deposits. They never appear in the same layers as soft-bodied Ediacaran biota, but the fact that some sequences contain Cloudinids and Ediacaran biota in alternating layers suggests that these groups had different environmental preferences.
Cloudinids are important in the history of animal evolution for two reasons. They are among the earliest and most abundant of theCloudina specimens from China bear the marks of multiple attacks, which suggests they survived at least a few of them. The evolutionary arms race which this indicates is commonly cited as a cause of the Cambrian explosion of animal diversity and complexity. (see more...
) 
bilaterian known only from rocks of the Ediacaran
period. The slug-like organism fed by scratching the microbial surface on which it dwelt in a manner similar to the molluscs, although its affinity with this group is contentious.
Specimens were first found in Australia's
mollusc. Although some paleontologists dispute its classification as a mollusc, it is generally accepted as being at least a bilaterian
.
The classification of Kimberella is important for scientific understanding of the Cambrian explosion: if it was a mollusc or at least a protostome, the protostome and deuterostome lineages must have diverged significantly before 555 million years ago. Even if it was a bilaterian but not a mollusc, its age would indicate that animals were diversifying well before the start of the Cambrian. (see more...) 
sauropod dinosaur that is known from fossils uncovered in modern-day Portugal. It may represent a species of Supersaurus. The only species is Dinheirosaurus lourinhanensis, first described by José Bonaparte and Octávio Mateus in 1999 for vertebrae and some other material from the Lourinhã Formation. Although the precise age of the formation is not known, it can be dated around the early Tithonian of the Late Jurassic
.
The known material includes two
ornithopods
, as well as at least one other diplodocid.
Dinheirosaurus is a diplodocid, a relative of Apatosaurus, Diplodocus, Barosaurus, Supersaurus, and Tornieria. Among those, the closest relative to Dinheirosaurus is Supersaurus, and together they form a clade of primitive diplodocids. While they were once considered to be diplodocines they are likely more basal than Apatosaurus. (see more...) 
scientific name
Anthropopithecus erectus, then later renamed it Pithecanthropus erectus.
The fossil aroused much controversy. Less than ten years after 1891, almost eighty books or articles had been published on Dubois's finds. Despite Dubois' argument, few accepted that Java Man was a
modern humans
, whereas many scientists considered Java Man as a primitive side branch of evolution not related to modern humans at all.
Eventually, similarities between Pithecanthropus erectus (Java Man) and Sinanthropus pekinensis (hominin fossils ever found. (see more...
) 
mya
–10,000 years ago). The genus was named in 1842, based on fossils from Brazil. Three species are recognized today: S. gracilis, S. fatalis and S. populator.
Overall, Smilodon was more robustly built than any
canines
. Its jaw had a bigger gape than that of modern cats and its upper canines were slender and fragile, being adapted for precision killing. S. gracilis was the smallest species at 55 to 100 kg (120 to 220 lb) in weight. S. populator from South America is perhaps the largest known felid at 220 to 400 kg (490 to 880 lb) in weight and 120 cm (47 in) in height.
Smilodon probably lived in closed habitats such as forests and megafauna disappeared, about 10,000 years ago. Its reliance on large animals has been proposed as the cause of its extinction, along with climate change and competition with other species, but the exact cause is unknown. (see more...
) Titanoceratops ouranos
skeletal restoration.land-vertebrate ages were identified from the Late Cretaceous. as identified by Loris S. Russell in 1975, they include the Paluxian, Aquilan, Judithian, Edmontonian, and the Lancian
. Before the naming of the Kirtlandian, three gaps, between the Paluxian and Aquilan, the Aquilan and the Judithian, and the Judithian and Edmontonian, were identified but not named.
The Fruitland Formation measures 97 to 107 metres (318 to 351 ft) thick, and with the 594 metres (1,949 ft) of the Kirtland Formation, the Kirtlandian consists of 701 metres (2,300 ft) of sediments. The rock types within the formations are primarily see more...
) 
Nothomyrmecia macrops, but has not been conclusively assigned to any tribe, instead generally regarded as incertae sedis within Myrmeciinae. However, the sole specimen lacks definitive traits, and its classification in Myrmeciinae, and even its identity as an ant, has been challenged. (see more...
) 
mya) of what is now Argentina. The only known skeleton was discovered in 1984 and described in 1991, forming the holotype specimen of the single species Amargasaurus cazaui. The skeleton is nearly complete, including a fragmentary skull, making Amargasaurus one of the best-known sauropods from the Early Cretaceous. Amargasaurus was small for a sauropod, reaching 9 to 10 meters (30 to 33 feet) in length. It sported two parallel rows of tall spines down its neck and back, taller than in any other known sauropod. It is unclear how these spines appeared in life—they could have supported skin sails or stuck out of the body as solitary structures supporting a keratinous
sheath. They might have been used for display, combat, or defense.
Amargasaurus was discovered in sedimentary rocks of the La Amarga Formation, which dates back to the Barremian and late Aptian of the Early Cretaceous epoch. Amargasaurus probably fed at mid-height, as shown by the orientation of its inner ear and the articulation of its neck vertebrae, which suggest a habitual position of the snout some 80 centimeters (31 inches) above the ground and a maximum height of 2.7 meters (8.9 feet). Within the Sauropoda, Amargasaurus was a member of the family Dicraeosauridae. (see more...) 
period. Othniel Charles Marsh described and named the first-known species, A. ajax in 1877, and a second species, A. louisae, was discovered and named by William H. Holland in 1916. Fossils are known from the Morrison Formation of modern-day Colorado, Oklahoma, and Utah
, in the United States. Apatosaurus had an average length of 22.8 m (75 ft), and an average mass of at least 16.4 metric tons (18.1 short tons).
The cervical vertebrae of Apatosaurus are less elongated and more heavily constructed than those of air sacs that made the bones internally full of holes. Like that of other diplodocids, its tail may have been used as a whip to create loud noises.
junior synonym of Apatosaurus; its only species was reclassified as A. excelsus in 1903. However, the 2015 study concluded that Brontosaurus was a valid genus of sauropod distinct from Apatosaurus. (see more...
) 
sauropod dinosaur of the Late Cretaceous Period discovered in the Gobi Desert of Mongolia. The only species is Opisthocoelicaudia skarzynskii. A well-preserved skeleton lacking only the head and neck was unearthed in 1965 by Polish and Mongolian scientists, making Opisthocoelicaudia one of the best known sauropods from the Late Cretaceous. Tooth marks on this skeleton indicate that large carnivorous dinosaurs had fed on the carcass and possibly had carried away the now-missing parts. A relatively small sauropod, Opisthocoelicaudia measured approximately 11 metres (36 ft) in length. The name Opisthocoelicaudia means "posterior cavity tail", alluding to the unusual, opisthocoel condition of the anterior tail vertebrae that were concave
on their posterior sides. This and other skeletal features lead researchers to propose that Opisthocoelicaudia was able to rear on its hindlegs.
Named and described by Polish paleontologist Titanosauria. Its exact relationships within Titanosauria are contentious, but it may have been close to the North American Alamosaurus. All Opisthocoelicaudia fossils stem from the Nemegt Formation. (see more...
) 
premolars
or true molars).
Bharattherium molariforms are high, curved teeth, with a height of 6 to 8.5 millimetres (0.24 to 0.33 in). In a number of teeth tentatively identified as fourth lower molariforms (mf4), there is a large furrow on one side and a deep cavity (infundibulum) in the middle of the tooth. Another tooth, perhaps a third lower molariform, has two furrows on one side and three infundibula on the other. The tooth enamel has traits that have been interpreted as protecting against cracks in the teeth. The hypsodont (high-crowned) teeth of sudamericids like Bharattherium are reminiscent of later grazing mammals, and the discovery of grass in Indian fossil sites contemporaneous with those yielding Bharattherium suggest that sudamericids were indeed grazers. (see more...) 
extant relative of the Columbian and other mammoths is the Asian elephant
.
Reaching 4 m (13 ft) at the shoulders and 8–10 tonnes (18,000–22,000 lb) in weight, the Columbian mammoth was one of the largest species of mammoth. It most likely used its tusks and trunk like modern elephants—for manipulating objects, fighting, and foraging. The Columbian mammoth preferred open areas, such as
wooly mammoths
.
Before they went extinct, Columbian mammoths coexisted in North America for a few thousand years with Palaeoamericans, who hunted them for food, used their bones for making tools, and depicted them in ancient art. Columbian mammoth remains have been found in association with Clovis culture artefacts; these remains may have stemmed either from hunting or from scavenging. The Columbian mammoth disappeared at the end of the Pleistocene around 11,000 years ago, most likely as a result of habitat loss caused by climate change, hunting by humans, or a combination of both. (see more...
) 
see more...
) 
extinct species of hominin, provisionally assigned to the genus Homo. Discovered in 2013 and described in 2015, fossil skeletons were found in South Africa's Gauteng province, in the Dinaledi Chamber of the Rising Star Cave system, part of the Cradle of Humankind World Heritage Site. As of 10 September 2015[update]
, fossils of at least fifteen individuals, amounting to 1550 specimens, have been excavated from the cave.
The species is characterized by a body mass and stature similar to small-bodied human populations, a smaller
more recent features
associated with later hominins. The fossils have not been dated.
The fossils were discovered by recreational Lee Berger of the University of the Witwatersrand, who proposed the bones represent a new Homo species. Other experts contend more analysis and evidence is needed to support this classification. There are some indications that the individuals may have been deliberately placed in the cave near the time of their death; other experts state more evidence is needed to support this hypothesis. (see more...
) 
thorax) and petiole. (see more...
) multituberculate mammal from the Cretaceous of Argentina. The single species, Argentodites coloniensis, is known from a single blade-like fourth lower premolar (p4) from the La Colonia Formation, which is mostly or entirely Maastrichtian (latest Cretaceous) in age. The p4 is 4.15 mm long and bears eight cusps on its upper margin and long associated ridges on both sides. The enamel consists of prisms that are completely or partly surrounded by a sheath and that are on average 6.57 μm apart. Zofia Kielan-Jaworowska, who described and named the fossil in 2007, regarded it as a multituberculate, perhaps a cimolodontan—and thus, a member of a mostly Laurasian (northern) group and an immigrant to Argentina from North America—on the basis of the shape of the tooth and features of its enamel. In 2009, however, two teams argued that Argentodites may in fact be close to or identical with Ferugliotherium, a member of the small Gondwanan (southern) group Gondwanatheria; although their relationships are disputed, gondwanatheres may themselves be multituberculates. (see more...
) pheromone trails to food sources. Avitomyrmex has not been assigned to any tribe, instead generally being regarded as incertae sedis within Myrmeciinae. However, its identity as an ant has been challenged, although it is undoubtedly a hymenopteran insect. (see more...
) 
Middle Cretaceous of North America. The genus is one of several ants described from Middle Cretaceous Ambers of New Jersey. Brownimecia was initially placed in the subfamily Ponerinae, until it was transferred to its own subfamily in 2003; it can be distinguished from other ants due to its unusual sickle-like mandibles and other morphological features that makes this ant unique among the Formicidae. The ant is also small, measuring 3.43 millimetres (0.135 in), and a stinger is present in almost all of the specimens collected. The morphology of the mandibles suggest a high level of feeding specialization. (see more...
) 
Early Eocene) deposits, all three of the described species and one unplaced fossil are from British Columbia, Canada, while the second unplaced fossil is from Washington State, USA. These ants were large, with the largest specimens collected reaching 3 centimetres (1.2 in). The behaviour of these ants would have been similar to extant Myrmeciinae ants, such as solitary foraging, nesting either in the soil or trees, and leaving no pheromone trail to food sources. Due to the poor preservation of these ants, their phylogenetic position among Myrmeciinae is unclear, and no type species has been designated. These ants are classified as incertae sedis in Myrmeciinae, but some writers have classified it as incertae sedis wihin the insect order Hymenoptera. This reclassification however has not been accepted; instead, Myrmeciites remains in Myrmeciinae. (see more...
) 
Nothomyrmecia macrops and a species he described both belonged to Prionomyrmex, but this proposal has not been widely accepted by the entomological community. Instead, scientists still classify the two genera distinctive from each other, making Nothomyrmecia a valid genus. (see more...
) cusps, one at the inner (lingual) side and the other at the outer (labial) side, which are connected by transverse ridges separated by deep valleys. This pattern is reminiscent of Ferugliotherium, a gondwanathere mammal from similarly aged deposits in Argentina, and Trapalcotherium is therefore recognized as a member of the same family Ferugliotheriidae. Ferugliotheriidae is one of two families of gondwanatheres, an enigmatic group without close relationships to any living mammals. (see more...
) 
ocelli present. (see more...
)