The ancient Being, Tapejara (1989)
Phylum : ChordataClass : ReptiliaOrder : PterosauriaFamily : TapejaridaeSubfamily : TapejarinaeGenus : TapejaraSpecies : T. wellnhoferi
Early Cretaceous (108 Ma)
3,5 m wingspan (size)
Santana formation, Brazil (map)
It’s not only modern South America that breeds brilliantly colored varieties of flying creatures. Over 100 million years ago, during the middle Cretaceous period, Tapejara graced the seashores of South America with its huge (up to three feet tall) head crest, which was probably brightly colored to attract mates. In common with the more evolved pterosaurs of this period, Tapejara had a relatively short tail, and it likely used its downward-curving beak to pluck fish from the sea. This pterosaur was closely related to the similarly colorful (and similarly named) Tupuxuara, which also flew the skies of South America.

The ancient Being, Tapejara (1989)

Phylum : Chordata
Class : Reptilia
Order : Pterosauria
Family : Tapejaridae
Subfamily : Tapejarinae
Genus : Tapejara
Species : T. wellnhoferi

  • Early Cretaceous (108 Ma)
  • 3,5 m wingspan (size)
  • Santana formation, Brazil (map)

It’s not only modern South America that breeds brilliantly colored varieties of flying creatures. Over 100 million years ago, during the middle Cretaceous period, Tapejara graced the seashores of South America with its huge (up to three feet tall) head crest, which was probably brightly colored to attract mates. In common with the more evolved pterosaurs of this period, Tapejara had a relatively short tail, and it likely used its downward-curving beak to pluck fish from the sea. This pterosaur was closely related to the similarly colorful (and similarly named) Tupuxuara, which also flew the skies of South America.

The giant tube Worm, Riftia pachyptila (1981)
Phylum : AnnelidaClass : PolychaetaOrder : CanalipalpataFamily : SiboglinidaeGenus : RiftiaSpecies : R. pachyptila
Least concern
2,4 m long (size)
Eastern Pacific ocean (map)
Giant tube worms, are marine invertebrates in the phylum Annelida  related to tube worms commonly found in the intertidal and pelagic zones. Riftia pachyptila lives over a mile deep, and up to several miles deep, on the floor of the Pacific Ocean near black smokers, and it can tolerate extremely high hydrogen sulfide levels. These worms can reach a length of 2.4 m and their tubular bodies have a diameter of 4 cm. Ambient temperature in their environment ranges from 2 to 30 C.
With sunlight not available directly as a form of energy, the tubeworms rely on bacteria in their habitat to oxidize hydrogen sulfide, using dissolved oxygen in the water for respiration. This reaction provides the energy needed for chemosynthesis. For this reason, tube worms are partially dependent on sunlight as an energy source, since they use free oxygen, which has been liberated by photosynthesis in water layers far above, to obtain nutrients. In this way tubeworms are similar to many forms of life which live in the ocean below depths that sunlight can penetrate. However, tubeworms are unique in being able to use bacteria to indirectly obtain all materials they need for growth from molecules dissolved in water. Tube worm growth resembles that of hydroponically grown fungi more than it does that of typical animals which need to “eat”.

The giant tube Worm, Riftia pachyptila (1981)

Phylum : Annelida
Class : Polychaeta
Order : Canalipalpata
Family : Siboglinidae
Genus : Riftia
Species : R. pachyptila

  • Least concern
  • 2,4 m long (size)
  • Eastern Pacific ocean (map)

Giant tube worms, are marine invertebrates in the phylum Annelida  related to tube worms commonly found in the intertidal and pelagic zones. Riftia pachyptila lives over a mile deep, and up to several miles deep, on the floor of the Pacific Ocean near black smokers, and it can tolerate extremely high hydrogen sulfide levels. These worms can reach a length of 2.4 m and their tubular bodies have a diameter of 4 cm. Ambient temperature in their environment ranges from 2 to 30 C.

With sunlight not available directly as a form of energy, the tubeworms rely on bacteria in their habitat to oxidize hydrogen sulfide, using dissolved oxygen in the water for respiration. This reaction provides the energy needed for chemosynthesis. For this reason, tube worms are partially dependent on sunlight as an energy source, since they use free oxygen, which has been liberated by photosynthesis in water layers far above, to obtain nutrients. In this way tubeworms are similar to many forms of life which live in the ocean below depths that sunlight can penetrate. However, tubeworms are unique in being able to use bacteria to indirectly obtain all materials they need for growth from molecules dissolved in water. Tube worm growth resembles that of hydroponically grown fungi more than it does that of typical animals which need to “eat”.

The Elomeryx (1894)
Phylum : ChordataClass : MammaliaOrder : ArtiodactylaFamily : AnthracotheriidaeSubfamily : BothriodontinaeGenus : ElomeryxSpecies : E. armatus, E. brobonicus, E. cluai, E. crispus, E. garbanii
Middle Eocene/Early Oligocene (42 - 33 Ma)
1,5 m long (size)
Eurasia and North America (map)
Elomeryx is an extinct genus of artiodactyl ungulate, and is among the earliest known anthracotheres. The genus was extremely widespread, first being found in Asia in the middle Eocene, in Europe during the latest Eocene, and having spread to North America by the early Oligocene.

Elomeryx was about 1.5 in body length, and had a long, vaguely horse-like head. It had small tusks which it used to uproot plants, and spoon-shaped incisors ideal for pulling and cropping water plants. Elomeryx had five-toed hind legs and four-toed front legs, resulting in wide feet which made it easier to walk on soft mud. It probably had similar habits to the modern hippopotamus, to which it may have been related.

The Elomeryx (1894)

Phylum : Chordata
Class : Mammalia
Order : Artiodactyla
Family : Anthracotheriidae
Subfamily : Bothriodontinae
Genus : Elomeryx
Species : E. armatus, E. brobonicus, E. cluai, E. crispus, E. garbanii

  • Middle Eocene/Early Oligocene (42 - 33 Ma)
  • 1,5 m long (size)
  • Eurasia and North America (map)

Elomeryx is an extinct genus of artiodactyl ungulate, and is among the earliest known anthracotheres. The genus was extremely widespread, first being found in Asia in the middle Eocene, in Europe during the latest Eocene, and having spread to North America by the early Oligocene.

Elomeryx was about 1.5 in body length, and had a long, vaguely horse-like head. It had small tusks which it used to uproot plants, and spoon-shaped incisors ideal for pulling and cropping water plants. Elomeryx had five-toed hind legs and four-toed front legs, resulting in wide feet which made it easier to walk on soft mud. It probably had similar habits to the modern hippopotamus, to which it may have been related.

The swift Seizer, Velociraptor (1924)
Phylum : ChordataClass : ReptiliaOrder : SaurischiaFamily : DromaeosauridaeSubfamily : VelociraptorinaeGenus : VelociraptorSpecies : V. mongoliensis, V. osmolskae
Late Cretaceous (85,2 - 76,4 Ma)
2 m long and 15 kg (size)
Ömnögovi, Mongolia (map)

If all you know about Velociraptor comes from the movie Jurassic Park, put those images out of your head right away: the villains in that blockbuster weren’t really Velociraptors, but the larger (and more threatening-looking) Deinonychus. Velociraptors were vicious, all right, but they were also very small—and it’s unlikely a 35-pound feathered raptor reminiscent of a giant chicken would have elicited all those “ooh“‘s and “aah“‘s at the local cineplex. (See 10 Facts About Velociraptor.)
Jurassic Park aside, much of what makes Velociraptor so popular is the romantic story behind its discovery. The bones of this dinosaur were discovered in the remote Gobi Desert (on the outskirts of Mongolia) in 1922, in an adventure-filled expedition sponsored by the American Museum of Natural History in New York. Museum president Henry F. Osborn gave this raptor its name, Greek for “swift thief;” as a historical curiosity, he came within a Jurassic inch of choosing “Ovoraptor” (a couple of years later, he did bestow the similarly spelled Oviraptor on yet another feathered Mongolian dinosaur).
Velociraptor is one of the few theropods whose prey has been conclusively identified: paleontologists have found the fossilized remains of a Velociraptor locked in combat with a comparably sized Protoceratops, a pig-sized ceratopsian of late Cretaceous central Asia. 
Today, the main controversy about Velociraptor concerns what, exactly, this raptor looked like. This small theropod used to be depicted with boring, green reptilian skin, but lately the fashion has been to portray it with a coat of primitive, downy, brightly colored feathers, which has given artists plenty of leeway in their various depictions. Unfortunately, pending a spectacularly well-preserved fossil find, artists’ conceptions will have to remain just that—conceptions.

The swift Seizer, Velociraptor (1924)

Phylum : Chordata
Class : Reptilia
Order : Saurischia
Family : Dromaeosauridae
Subfamily : Velociraptorinae
Genus : Velociraptor
Species : V. mongoliensis, V. osmolskae

  • Late Cretaceous (85,2 - 76,4 Ma)
  • 2 m long and 15 kg (size)
  • Ömnögovi, Mongolia (map)

If all you know about Velociraptor comes from the movie Jurassic Park, put those images out of your head right away: the villains in that blockbuster weren’t really Velociraptors, but the larger (and more threatening-looking) Deinonychus. Velociraptors were vicious, all right, but they were also very small—and it’s unlikely a 35-pound feathered raptor reminiscent of a giant chicken would have elicited all those “ooh“‘s and “aah“‘s at the local cineplex. (See 10 Facts About Velociraptor.)

Jurassic Park aside, much of what makes Velociraptor so popular is the romantic story behind its discovery. The bones of this dinosaur were discovered in the remote Gobi Desert (on the outskirts of Mongolia) in 1922, in an adventure-filled expedition sponsored by the American Museum of Natural History in New York. Museum president Henry F. Osborn gave this raptor its name, Greek for “swift thief;” as a historical curiosity, he came within a Jurassic inch of choosing “Ovoraptor” (a couple of years later, he did bestow the similarly spelled Oviraptor on yet another feathered Mongolian dinosaur).

Velociraptor is one of the few theropods whose prey has been conclusively identified: paleontologists have found the fossilized remains of a Velociraptor locked in combat with a comparably sized Protoceratops, a pig-sized ceratopsian of late Cretaceous central Asia.

Today, the main controversy about Velociraptor concerns what, exactly, this raptor looked like. This small theropod used to be depicted with boring, green reptilian skin, but lately the fashion has been to portray it with a coat of primitive, downy, brightly colored feathers, which has given artists plenty of leeway in their various depictions. Unfortunately, pending a spectacularly well-preserved fossil find, artists’ conceptions will have to remain just that—conceptions.

The North american Beaver, Castor canadensis (1820)
Phylum : ChordataClass : MammaliaOrder : RodentiaFamily : CastoridaeGenus : CastorSpecies : C. canadensisSubspecies : C.c. acadicus, C.c. baileyi, C.c. belugae, C.c. caecator, C.c. canadensis, C.c. concisor, C.c. carolinensis, C.c. duchesnei, C.c. frondator, C.c. idoneus, C.c. labradorensis, C.c. leucodonta, C.c. mexicanus, C.c. michiganensis, C.c. missouriensis, C.c. pacificus, C.c. pallidus, C.c. phaeus, C.c. rostralis, C.c. repentinus, C.c. sagittatus, C.c. shastensis, C.c. subauratus, C.c. taylori, C.c. texensis
Least concern
90 cm long and 30 kg (size)
North America (map)
Beavers are mainly active at night. They are excellent swimmers and may remain submerged for up to 15 minutes. More vulnerable on land, they tend to remain in the water as much as possible. They use their flat, scaly tail both to signal danger by slapping the surface of the water and as a location for fat storage.

They construct their homes, or “lodges,” out of sticks, twigs, rocks and mud in lakes, streams, and tidal river deltas. These lodges may be surrounded by water, or touching land, including burrows dug into river banks. They are well known for building dams across streams and constructing their lodge in the artificial pond which forms. When building in a pond, the beavers first make a pile of sticks and then eat out one or more underwater entrances and two platforms above the water surface inside the pile. The first is used for drying off. Towards winter, the lodge is often plastered with mud which when it freezes has the consistency of concrete. A small air hole is left in the top of the lodge.

The dam is constructed using logs from trees the beavers cut down, as well as rocks, grass and mud. The inner bark, twigs, shoots and leaves of such trees are also an important part of the beaver’s diet. The trees are cut down using their strong incisor teeth. Their front paws are used for digging and carrying and placing materials. Some researchers have shown that the sound of running water dictates when and where a beaver builds its dam. Besides providing a safe home for the beaver, beaver ponds also provide habitat for waterfowl, fish, and other aquatic animals. Their dams help reduce soil erosion and can help reduce flooding. However, beaver dams are not permanent and depend on the beavers’ continued presence for their maintenance. Beavers generally concentrate on building and repairing dams in the fall in preparation for the coming winter. In northern areas they often don’t repair breaches in the dam made by otters, and sometimes breach the dam themselves and lower the water level in the pond in order to create more breathing space under the ice or get easier access to trees below the dam. In a 1988 study in Alberta, Canada, no beavers repaired “sites of water loss” during the winter. Of 178 sites of water loss, beavers repaired 78 when water was opened, and did not repair 68. The rest were partially repaired.

Beavers are best known for their dam-building. They maintain their pond-habitat by reacting quickly to the sound of running water, and damming it up with tree branches and mud. Early ecologists believed that this dam-building was an amazing feat of architectural planning, indicative of the beaver’s high intellect. This theory was questioned when a recording of running water was played in a field near a beaver pond. Despite the fact that it was on dry land, the beaver covered the tape player with branches and mud. The largest beaver dam is 850 m in length—more than half a mile long—and was discovered via satellite imagery in 2007. It is located on the southern edge of Wood Buffalo National Park in northern Alberta and is twice the width of the Hoover Dam which spans 379 m.


Normally, the purpose of the dam is to provide water around their lodges that is deep enough that it does not freeze solid in winter. The dams also flood areas of surrounding forest, giving the beaver safe access to an important food supply, which is the leaves, buds, and inner bark of growing trees. They prefer aspen and poplar, but will also take birch, maple, willow, alder, black cherry, red oak, beech, ash, hornbeam and occasionally pine and spruce. They will also eat cattails, water lilies and other aquatic vegetation, especially in the early spring (and contrary to widespread belief, they do not eat fish). In areas where their pond freezes over, beavers collect food in late fall in the form of tree branches, storing them underwater (usually by sticking the sharp chewed base of the branches into the mud on the pond bottom), where they can be accessed through the winter. Often the pile of food branches projects above the pond and collects snow. This insulates the water below it and keeps the pond open at that location.

Beavers usually mate for life. The young beaver “kits” typically remain with their parents for up to two years.

The North american Beaver, Castor canadensis (1820)

Phylum : Chordata
Class : Mammalia
Order : Rodentia
Family : Castoridae
Genus : Castor
Species : C. canadensis
Subspecies : C.c. acadicus, C.c. baileyi, C.c. belugae, C.c. caecator, C.c. canadensis, C.c. concisor, C.c. carolinensis, C.c. duchesnei, C.c. frondator, C.c. idoneus, C.c. labradorensis, C.c. leucodonta, C.c. mexicanus, C.c. michiganensis, C.c. missouriensis, C.c. pacificus, C.c. pallidus, C.c. phaeus, C.c. rostralis, C.c. repentinus, C.c. sagittatus, C.c. shastensis, C.c. subauratus, C.c. taylori, C.c. texensis

  • Least concern
  • 90 cm long and 30 kg (size)
  • North America (map)

Beavers are mainly active at night. They are excellent swimmers and may remain submerged for up to 15 minutes. More vulnerable on land, they tend to remain in the water as much as possible. They use their flat, scaly tail both to signal danger by slapping the surface of the water and as a location for fat storage.

They construct their homes, or “lodges,” out of sticks, twigs, rocks and mud in lakes, streams, and tidal river deltas. These lodges may be surrounded by water, or touching land, including burrows dug into river banks. They are well known for building dams across streams and constructing their lodge in the artificial pond which forms. When building in a pond, the beavers first make a pile of sticks and then eat out one or more underwater entrances and two platforms above the water surface inside the pile. The first is used for drying off. Towards winter, the lodge is often plastered with mud which when it freezes has the consistency of concrete. A small air hole is left in the top of the lodge.

The dam is constructed using logs from trees the beavers cut down, as well as rocks, grass and mud. The inner bark, twigs, shoots and leaves of such trees are also an important part of the beaver’s diet. The trees are cut down using their strong incisor teeth. Their front paws are used for digging and carrying and placing materials. Some researchers have shown that the sound of running water dictates when and where a beaver builds its dam. Besides providing a safe home for the beaver, beaver ponds also provide habitat for waterfowl, fish, and other aquatic animals. Their dams help reduce soil erosion and can help reduce flooding. However, beaver dams are not permanent and depend on the beavers’ continued presence for their maintenance. Beavers generally concentrate on building and repairing dams in the fall in preparation for the coming winter. In northern areas they often don’t repair breaches in the dam made by otters, and sometimes breach the dam themselves and lower the water level in the pond in order to create more breathing space under the ice or get easier access to trees below the dam. In a 1988 study in Alberta, Canada, no beavers repaired “sites of water loss” during the winter. Of 178 sites of water loss, beavers repaired 78 when water was opened, and did not repair 68. The rest were partially repaired.

Beavers are best known for their dam-building. They maintain their pond-habitat by reacting quickly to the sound of running water, and damming it up with tree branches and mud. Early ecologists believed that this dam-building was an amazing feat of architectural planning, indicative of the beaver’s high intellect. This theory was questioned when a recording of running water was played in a field near a beaver pond. Despite the fact that it was on dry land, the beaver covered the tape player with branches and mud. The largest beaver dam is 850 m in length—more than half a mile long—and was discovered via satellite imagery in 2007. It is located on the southern edge of Wood Buffalo National Park in northern Alberta and is twice the width of the Hoover Dam which spans 379 m.

Normally, the purpose of the dam is to provide water around their lodges that is deep enough that it does not freeze solid in winter. The dams also flood areas of surrounding forest, giving the beaver safe access to an important food supply, which is the leaves, buds, and inner bark of growing trees. They prefer aspen and poplar, but will also take birch, maple, willow, alder, black cherry, red oak, beech, ash, hornbeam and occasionally pine and spruce. They will also eat cattails, water lilies and other aquatic vegetation, especially in the early spring (and contrary to widespread belief, they do not eat fish). In areas where their pond freezes over, beavers collect food in late fall in the form of tree branches, storing them underwater (usually by sticking the sharp chewed base of the branches into the mud on the pond bottom), where they can be accessed through the winter. Often the pile of food branches projects above the pond and collects snow. This insulates the water below it and keeps the pond open at that location.

Beavers usually mate for life. The young beaver “kits” typically remain with their parents for up to two years.

The Nichollsemys (2006)
Phylum : ChordataClass : ReptiliaOrder : TestudinesFamily : ToxocheliidaeGenus : NichollsmysSpecies : N. baieri
Late Cretaceous
60 cm long (size)
North America (map)

The Nichollsemys (2006)

Phylum : Chordata
Class : Reptilia
Order : Testudines
Family : Toxocheliidae
Genus : Nichollsmys
Species : N. baieri

  • Late Cretaceous
  • 60 cm long (size)
  • North America (map)
The double snout, Dipnorhynchus (1927)
Phylum : ChordataClass : SarcopterygiiSubclass : DipnoiOrder : DipteriformesFamily : DipnorhynchidaeGenus : DipnorhynchusSpecies : D. sussmilchi
Devonian (410 - 360 Ma)
90 cm long (size)
Australia (map)
Dipnorhynchus was a primitive lungfish, but still it had features that set it apart from other sarcopterygians. Its skull lacked the joint that divided the skull in two in rhipidists and coelacanths. Instead, it was a solid bony structure similar to that of the first tetrapods. Instead of cheek teeth, Dipnorhynchus had tooth-like plates on the palate and lower jaw. Also like land vertebrates, the palate was fused with the brain case. It was relatively large for a lungfish, measuring 90 centimetres in length.

The double snout, Dipnorhynchus (1927)

Phylum : Chordata
Class : Sarcopterygii
Subclass : Dipnoi
Order : Dipteriformes
Family : Dipnorhynchidae
Genus : Dipnorhynchus
Species : D. sussmilchi

  • Devonian (410 - 360 Ma)
  • 90 cm long (size)
  • Australia (map)

Dipnorhynchus was a primitive lungfish, but still it had features that set it apart from other sarcopterygians. Its skull lacked the joint that divided the skull in two in rhipidists and coelacanths. Instead, it was a solid bony structure similar to that of the first tetrapods. Instead of cheek teeth, Dipnorhynchus had tooth-like plates on the palate and lower jaw. Also like land vertebrates, the palate was fused with the brain case. It was relatively large for a lungfish, measuring 90 centimetres in length.

The Verreaux’s Sifaka, Propithecus verreauxi (1867)
Phylum : ChordataClass : MammaliaOrder : PrimatesFamily : IndriidaeGenus : PropithecuesSpecies : P. verreauxi
Vulnerable
1 m long and 3,5 kg (size)
Southern Madagascar (map)
Verreaux’s sifaka are diurnal and arboreal, and engage in sunbathing with outstretched arms and legs. Verreaux’s sifaka move through the trees by clinging and leaping between vertical supports. They are capable of making remarkable leaps through the trees - distances of 9-10m are not uncommon. On the ground, they hop bipedally. They live in family groups, or troops, of 2-12, which may consist of one male and female, or many males and females together. Group and population sex ratio can be more or less skewed toward males. Many groups seem to be effectively harem groups with a single dominant male unrelated with resident female(s). They have a home range of 2.8.5ha, and although they are territorial, it is the food source they will defend rather than the territory’s boundaries, as often boundaries overlap. Females are dominant over males, forming a matriarchal society.

Females use anogenital secretion mainly for territory demarcation whereas males seem to use specialized secretions (via anogenital and throat glands) more for sexual “advertisement” than for territorial purposes. Males show bimorphism, by showing either a clean or stained chest, derived from throat gland secretions and smeared on surfaces by rubbing the upper part of the chest. Stain-chested males engage in the most active marking, and chest staining seems to be related to testosterone levels.
Males and females were found to engage in a biological market, exchanging grooming for grooming during the non-mating period, and grooming (“offered” by males) for reproductive opportunities (sexual access “offered” by females) during the mating period. A study found that females copulate more with stained-chested than with clean-chested males. On the other hand, clean-chested males, with a lower scent-releasing potential, usually offer more grooming to females. This “grooming for sex” tactic allows males with a clean chest to get to copulate with females, even if at low rate. It has also been discovered that sifaka dyads often engage in post-conflict reunions after aggressive episodes: reconciliation occurs more frequently when food is not involved and for low intensity aggressions. In this species play behavior persists into adulthood where it is used, especially by stranger males during the mating period, as an ice-breaking mechanism to reduce xenophobia

The Verreaux’s Sifaka, Propithecus verreauxi (1867)

Phylum : Chordata
Class : Mammalia
Order : Primates
Family : Indriidae
Genus : Propithecues
Species : P. verreauxi

  • Vulnerable
  • 1 m long and 3,5 kg (size)
  • Southern Madagascar (map)

Verreaux’s sifaka are diurnal and arboreal, and engage in sunbathing with outstretched arms and legs. Verreaux’s sifaka move through the trees by clinging and leaping between vertical supports. They are capable of making remarkable leaps through the trees - distances of 9-10m are not uncommon. On the ground, they hop bipedally. They live in family groups, or troops, of 2-12, which may consist of one male and female, or many males and females together. Group and population sex ratio can be more or less skewed toward males. Many groups seem to be effectively harem groups with a single dominant male unrelated with resident female(s). They have a home range of 2.8.5ha, and although they are territorial, it is the food source they will defend rather than the territory’s boundaries, as often boundaries overlap. Females are dominant over males, forming a matriarchal society.

Females use anogenital secretion mainly for territory demarcation whereas males seem to use specialized secretions (via anogenital and throat glands) more for sexual “advertisement” than for territorial purposes. Males show bimorphism, by showing either a clean or stained chest, derived from throat gland secretions and smeared on surfaces by rubbing the upper part of the chest. Stain-chested males engage in the most active marking, and chest staining seems to be related to testosterone levels.

Males and females were found to engage in a biological market, exchanging grooming for grooming during the non-mating period, and grooming (“offered” by males) for reproductive opportunities (sexual access “offered” by females) during the mating period. A study found that females copulate more with stained-chested than with clean-chested males. On the other hand, clean-chested males, with a lower scent-releasing potential, usually offer more grooming to females. This “grooming for sex” tactic allows males with a clean chest to get to copulate with females, even if at low rate.
It has also been discovered that sifaka dyads often engage in post-conflict reunions after aggressive episodes: reconciliation occurs more frequently when food is not involved and for low intensity aggressions. In this species play behavior persists into adulthood where it is used, especially by stranger males during the mating period, as an ice-breaking mechanism to reduce xenophobia

The Pantylus (1881)
Phylum : ChordataClass : AmphibiaSubclass : LepospondyliOrder : MicrosauriaFamily : PantylidaeGenus : PantylusSpecies : P. cordatus
Early Permian (300 Ma)
25 cm long (size)
North America (map)
Pantylus was probably a largely terrestrial animal, judging from its well-built legs. It was about 25 centimetres long, and resembled a lizard with a large skull and short limbs. It had numerous blunt teeth, and probably chased after invertebrate prey.

The Pantylus (1881)

Phylum : Chordata
Class : Amphibia
Subclass : Lepospondyli
Order : Microsauria
Family : Pantylidae
Genus : Pantylus
Species : P. cordatus

  • Early Permian (300 Ma)
  • 25 cm long (size)
  • North America (map)

Pantylus was probably a largely terrestrial animal, judging from its well-built legs. It was about 25 centimetres long, and resembled a lizard with a large skull and short limbs. It had numerous blunt teeth, and probably chased after invertebrate prey.

The Earth lizard, Mapusaurus (2006)
Phylum : ChordataClass : ReptiliaOrder : SaurischiaSuborder : TheropodaFamily : CarcharodontosauridaeGenus : MapusaurusSpecies : M. roseae
Late Cretaceous (100,5 - 93,9 Ma)
12 m long and 3 000 kg (size)
Neuquén province, Argentina (map)

The large theropod dinosaur Mapusaurus was discovered all at once, and in a big heap—an excavation in South America in 1995 that yielded hundreds of jumbled bones, which required years of work by paleontologists to sort out and analyze. It wasn’t until 2006 that researchers announced the “diagnosis” of Mapusaurus, a three-ton theropod that was closely related to the even bigger Giganotosaurus and must have been one of the most feared predators of its day.
Interestingly, the fact that so many Mapusaurus bones were found jumbled together can be taken as evidence of herd, or pack, behavior—raising the possibility that this meat-eater hunted cooperatively in order to take down the huge titanosaurs populating middle Cretaceous South America. On the other hand, a flash flood could also have resulted in the accumulation of unrelated Mapusaurus bones, so the pack-hunting hypothesis should be taken with a big grain of prehistoric salt.

The Earth lizard, Mapusaurus (2006)

Phylum : Chordata
Class : Reptilia
Order : Saurischia
Suborder : Theropoda
Family : Carcharodontosauridae
Genus : Mapusaurus
Species : M. roseae

  • Late Cretaceous (100,5 - 93,9 Ma)
  • 12 m long and 3 000 kg (size)
  • Neuquén province, Argentina (map)

The large theropod dinosaur Mapusaurus was discovered all at once, and in a big heap—an excavation in South America in 1995 that yielded hundreds of jumbled bones, which required years of work by paleontologists to sort out and analyze. It wasn’t until 2006 that researchers announced the “diagnosis” of Mapusaurus, a three-ton theropod that was closely related to the even bigger Giganotosaurus and must have been one of the most feared predators of its day.

Interestingly, the fact that so many Mapusaurus bones were found jumbled together can be taken as evidence of herd, or pack, behavior—raising the possibility that this meat-eater hunted cooperatively in order to take down the huge titanosaurs populating middle Cretaceous South America. On the other hand, a flash flood could also have resulted in the accumulation of unrelated Mapusaurus bones, so the pack-hunting hypothesis should be taken with a big grain of prehistoric salt.

The tsetse Fly, Glossina (1830)
Phylum : ArthropodaClass : InsectaOrder : DipteraSuperfamily : HippoboscoideaFamily : GlossinidaeGenus : GlossinaSpecies : G. morsitans, G. fusca, G. palpalis
Least concern
1 cm long (size)
Africa (map)
Like all other insects, Tsetse flies have an adult body comprising three visibly distinct parts: the head, the thorax and the abdomen.

The head has large eyes, distinctly separated on each side, and a distinct, forward-pointing proboscis attached underneath by a large bulb. The thorax is large, made of three fused segments. Three pairs of legs are attached to the thorax, as are two wings and two halteres. The abdomen is short but wide and changes dramatically in volume during feeding.

The internal anatomy of tsetse is fairly typical of the insects. The crop is large enough to accommodate a huge increase in size during the bloodmeal since tsetse can take a bloodmeal weighing as much as themselves. The reproductive tract of adult females includes a uterus which can become large enough to hold the third instar larva at the end of each pregnancy.
Most tsetse flies are physically very tough. Houseflies are easily killed with a fly-swatter but it takes a great deal of effort to crush a tsetse fly.

Tsetse are biological vectors of trypanosomes meaning that tsetse, in the process of feeding, acquire and then transmit small, single-celled organisms called trypanosomes from infected vertebrate hosts to uninfected animals. Some tsetse transmitted trypanosome species cause trypanosomiasis, an infectious disease. In humans, tsetse transmitted trypanosomiasis is called sleeping sickness. In animals, tsetse vectored trypanosomiases include nagana, souma, and surra according to the animal infected and the trypanosome species involved, although the usage is not strict and nagana is occasionally used for any form of animal trypanosomiasis.
Trypanosomes are animal parasites, specifically protozoa of the genus Trypanosoma. These organisms are approximately the size of red blood cells. Different species of trypanosomes infect different hosts as can be seen in the table attached to this section. Trypanosomes range widely in their effects on the vertebrate hosts. Some species, such as Trypanosoma theileri, do not seem to cause any health problems except perhaps in animals that are already sick.
Some strains are much more virulent. Tsetse seem to be unaffected by the infection of trypanosomes but it is entirely possible that the parasites alter tsetse behavior or have other effects that improve the chances of transmission and survival. These trypanosomes are highly evolved and have developed a life cycle that requires periods in both the vertebrate and tsetse hosts.

The tsetse Fly, Glossina (1830)

Phylum : Arthropoda
Class : Insecta
Order : Diptera
Superfamily : Hippoboscoidea
Family : Glossinidae
Genus : Glossina
Species : G. morsitans, G. fusca, G. palpalis

  • Least concern
  • 1 cm long (size)
  • Africa (map)

Like all other insects, Tsetse flies have an adult body comprising three visibly distinct parts: the head, the thorax and the abdomen.

The head has large eyes, distinctly separated on each side, and a distinct, forward-pointing proboscis attached underneath by a large bulb. The thorax is large, made of three fused segments. Three pairs of legs are attached to the thorax, as are two wings and two halteres. The abdomen is short but wide and changes dramatically in volume during feeding.

The internal anatomy of tsetse is fairly typical of the insects. The crop is large enough to accommodate a huge increase in size during the bloodmeal since tsetse can take a bloodmeal weighing as much as themselves. The reproductive tract of adult females includes a uterus which can become large enough to hold the third instar larva at the end of each pregnancy.

Most tsetse flies are physically very tough. Houseflies are easily killed with a fly-swatter but it takes a great deal of effort to crush a tsetse fly.

Tsetse are biological vectors of trypanosomes meaning that tsetse, in the process of feeding, acquire and then transmit small, single-celled organisms called trypanosomes from infected vertebrate hosts to uninfected animals. Some tsetse transmitted trypanosome species cause trypanosomiasis, an infectious disease. In humans, tsetse transmitted trypanosomiasis is called sleeping sickness. In animals, tsetse vectored trypanosomiases include nagana, souma, and surra according to the animal infected and the trypanosome species involved, although the usage is not strict and nagana is occasionally used for any form of animal trypanosomiasis.

Trypanosomes are animal parasites, specifically protozoa of the genus Trypanosoma. These organisms are approximately the size of red blood cells. Different species of trypanosomes infect different hosts as can be seen in the table attached to this section. Trypanosomes range widely in their effects on the vertebrate hosts. Some species, such as Trypanosoma theileri, do not seem to cause any health problems except perhaps in animals that are already sick.

Some strains are much more virulent. Tsetse seem to be unaffected by the infection of trypanosomes but it is entirely possible that the parasites alter tsetse behavior or have other effects that improve the chances of transmission and survival. These trypanosomes are highly evolved and have developed a life cycle that requires periods in both the vertebrate and tsetse hosts.

Near the horn beast, Paraceratherium (1911)or Indricotherium (Indric beast)/Baluchitherium (beast of Baluchistan)
Phylum : ChordataClass : MammaliaOrder : PerissodactylaFamily : HyracodontidaeSubfamily : IndricotherinaeGenus : ParaceratheriumSpecies : P. bugtiense, P. transouralicum, P. prohorovi, P. orgosensis, P. zhajremensis
Oligocene (38 - 20,4 Ma)
9,5 m long and 15 000 kg (size)
Pakistan, Mongolia and western China (map)

Ever since its scattered, oversized remains were discovered in the early 20th century, Indricotherium has occasioned controversy among paleontologists, who have named this giant mammal not once, but three times—Indricotherium, Paraceratherium and Baluchitherium have all been in common usage, with the first two currently battling it out for supremacy. (For the record, Paraceratherium seems to have won the race among paleontologists, but Indricotherium is still preferred by the general public—and may yet wind up being assigned to a separate, but similar, genus.)
Whatever you choose to call it, Indricotherium was, hands-down, the largest terrestrial mammal that ever lived, approaching the size of the giant sauropod dinosaurs that preceded it by over a hundred million years. An ancestor of the modern rhinoceros, the 15-to-20-ton Indricotherium had a relatively long neck (though nothing approaching what you’d see on a Diplodocus or Brachiosaurus) and surprisingly thin legs with three-toed feet, which years ago used to be portrayed as elephant-like stumps. The fossil evidence is lacking, but this huge herbivore probably possessed a prehensile upper lip—not quite a trunk, but an appendage flexible enough to allow it to grab and tear the tall leaves of trees.
To date, fossils of Indricotherium have only been found in the central and eastern parts of Eurasia, but it’s possible that this gigantic mammal also stomped across the plains of western Europe and (conceivably) other continents as well during the Oligocene epoch. Classified as a “hyrocodont” mammal, one of its closest relatives was the much smaller (only about 500 pound) Hyracodon, a distant North American anecstor of the modern rhinoceros.

Near the horn beast, Paraceratherium (1911)
or Indricotherium (Indric beast)/Baluchitherium (beast of Baluchistan)

Phylum : Chordata
Class : Mammalia
Order : Perissodactyla
Family : Hyracodontidae
Subfamily : Indricotherinae
Genus : Paraceratherium
Species : P. bugtiense, P. transouralicum, P. prohorovi, P. orgosensis, P. zhajremensis

  • Oligocene (38 - 20,4 Ma)
  • 9,5 m long and 15 000 kg (size)
  • Pakistan, Mongolia and western China (map)

Ever since its scattered, oversized remains were discovered in the early 20th century, Indricotherium has occasioned controversy among paleontologists, who have named this giant mammal not once, but three times—Indricotherium, Paraceratherium and Baluchitherium have all been in common usage, with the first two currently battling it out for supremacy. (For the record, Paraceratherium seems to have won the race among paleontologists, but Indricotherium is still preferred by the general public—and may yet wind up being assigned to a separate, but similar, genus.)

Whatever you choose to call it, Indricotherium was, hands-down, the largest terrestrial mammal that ever lived, approaching the size of the giant sauropod dinosaurs that preceded it by over a hundred million years. An ancestor of the modern rhinoceros, the 15-to-20-ton Indricotherium had a relatively long neck (though nothing approaching what you’d see on a Diplodocus or Brachiosaurus) and surprisingly thin legs with three-toed feet, which years ago used to be portrayed as elephant-like stumps. The fossil evidence is lacking, but this huge herbivore probably possessed a prehensile upper lip—not quite a trunk, but an appendage flexible enough to allow it to grab and tear the tall leaves of trees.

To date, fossils of Indricotherium have only been found in the central and eastern parts of Eurasia, but it’s possible that this gigantic mammal also stomped across the plains of western Europe and (conceivably) other continents as well during the Oligocene epoch. Classified as a “hyrocodont” mammal, one of its closest relatives was the much smaller (only about 500 pound) Hyracodon, a distant North American anecstor of the modern rhinoceros.

The limb lizard, Scelidosaurus (1861)
Phylum : ChordataClass : ReptiliaOrder : OrnithischiaFamily : ScelidosauridaeGenus : ScelidosaurusSpecies : S. harrisonii
Early Jurassic (199,3 - 190,8 Ma)
4 m long and 270 kg (size)
England (map)

As dinosaurs go, Scelidosaurus has a fairly deep provenance, popping up at the start of the Jurassic period 208 million years ago and persisting for the next 10 or 15 million years. In fact, this plant-eater is so ancient that paleontologists speculate it may have given rise to the line, the thyreophorans, that included both the ankylosaurs (Ankylosaurus) and stegosaurs (Stegosaurus) that lived a hundred million years later.
Whatever its place on the thyreophoran family tree, Scelidosaurus was clearly one of the first ornithischian (“bird-hipped”) dinosaurs, a family that embraced all of the highly specialized, herbivorous dinosaurs of the Jurassic and Cretaceous periods. Some ornithischians were bipedal, some were quadrupedal, and some were capable of walking on both two and four legs; although its hind limbs were longer than its forelimbs, paleontologists speculate that Scelidosaurus was a devoted quadruped.

The limb lizard, Scelidosaurus (1861)

Phylum : Chordata
Class : Reptilia
Order : Ornithischia
Family : Scelidosauridae
Genus : Scelidosaurus
Species : S. harrisonii

  • Early Jurassic (199,3 - 190,8 Ma)
  • 4 m long and 270 kg (size)
  • England (map)

As dinosaurs go, Scelidosaurus has a fairly deep provenance, popping up at the start of the Jurassic period 208 million years ago and persisting for the next 10 or 15 million years. In fact, this plant-eater is so ancient that paleontologists speculate it may have given rise to the line, the thyreophorans, that included both the ankylosaurs (Ankylosaurus) and stegosaurs (Stegosaurus) that lived a hundred million years later.

Whatever its place on the thyreophoran family tree, Scelidosaurus was clearly one of the first ornithischian (“bird-hipped”) dinosaurs, a family that embraced all of the highly specialized, herbivorous dinosaurs of the Jurassic and Cretaceous periods. Some ornithischians were bipedal, some were quadrupedal, and some were capable of walking on both two and four legs; although its hind limbs were longer than its forelimbs, paleontologists speculate that Scelidosaurus was a devoted quadruped.

The Hallucigenia (1977)
Phylum : LobopodiaOrder : ScleronychophoraFamily : HallucigeniidaeGenus : HallucigeniaSpecies : H. sparsa, H. fortis, H. hongmeia
Late Cambrian (505 Ma)
3,5 cm long (size)
Canada (map)
Hallucigenia is a 0.5—3.5 cm long tubular organism with seven or eight pairs of slender legs, each terminating with a pair of claws. Above each leg is a rigid conical spine. The ‘head’ and ‘tail’ end of the organism are difficult to identify; one end extends some distance beyond the legs and often droops down as if to reach the floor. Although some specimens display traces of a gut, the internal anatomy has not been formally described.

Hallucigenia’s spines are made up of one to four nested elements. Their surface is covered in an ornament of minute triangular ‘scales’.

Hallucigenia was originally described by Walcott as a species of the polychaete worm Canadia. In his 1977 redescription of the organism, Simon Conway Morris recognized the animal as something quite distinct, establishing the new genus. No specimen was available that showed both rows of legs, and as such Conway Morris reconstructed the animal walking on its spines, with its single row of legs interpreted as tentacles on the animal’s back. A dark stain at one end of the animal was interpreted as a featureless head. Only the forward tentacles could easily reach to the ‘head’, meaning that a mouth on the head would have to be fed by passing food along the line of tentacles. Conway Morris suggested that a hollow tube within each of the tentacles might be a mouth. This raised questions such as how it would walk on the stiff legs, but it was accepted as the best available interpretation. A picture of the animal as reconstructed by Morris can be found here.

An alternative interpretation considered Hallucigenia to be an appendage of a larger, unknown animal. There had been precedent for this, as the species Anomalocaris had been originally identified as three separate creatures before being identified as a single huge (for its time) 0.91 m creature. Given the uncertainty of its taxonomy, Hallucigenia was tentatively placed within the phylum Lobopodia, a catch-all clade containing numerous odd “worms with legs.”

In 1991, Lars Ramskold and Hou Xianguang, working with additional specimens of a “hallucigenid,” Microdictyon, from the lower Cambrian Maotianshan shales of China, reinterpreted Hallucigenia as an Onychophoran (velvet worm). They inverted it, interpreting the tentacles, which they believe to be paired, as walking structures and the spines as protective. Further preparation of fossil specimens showed that the ‘second legs’ were buried at an angle to the plane along which the rock had split, and could be revealed by removing the overlying sediment. Ramskold and Hou also believe that the blob-like ‘head’ is actually a stain that appears in many specimens, not a preserved portion of the anatomy.

The Hallucigenia (1977)

Phylum : Lobopodia
Order : Scleronychophora
Family : Hallucigeniidae
Genus : Hallucigenia
Species : H. sparsa, H. fortis, H. hongmeia

  • Late Cambrian (505 Ma)
  • 3,5 cm long (size)
  • Canada (map)

Hallucigenia is a 0.5—3.5 cm long tubular organism with seven or eight pairs of slender legs, each terminating with a pair of claws. Above each leg is a rigid conical spine. The ‘head’ and ‘tail’ end of the organism are difficult to identify; one end extends some distance beyond the legs and often droops down as if to reach the floor. Although some specimens display traces of a gut, the internal anatomy has not been formally described.

Hallucigenia’s spines are made up of one to four nested elements. Their surface is covered in an ornament of minute triangular ‘scales’.

Hallucigenia was originally described by Walcott as a species of the polychaete worm Canadia. In his 1977 redescription of the organism, Simon Conway Morris recognized the animal as something quite distinct, establishing the new genus. No specimen was available that showed both rows of legs, and as such Conway Morris reconstructed the animal walking on its spines, with its single row of legs interpreted as tentacles on the animal’s back. A dark stain at one end of the animal was interpreted as a featureless head. Only the forward tentacles could easily reach to the ‘head’, meaning that a mouth on the head would have to be fed by passing food along the line of tentacles. Conway Morris suggested that a hollow tube within each of the tentacles might be a mouth. This raised questions such as how it would walk on the stiff legs, but it was accepted as the best available interpretation. A picture of the animal as reconstructed by Morris can be found here.

An alternative interpretation considered Hallucigenia to be an appendage of a larger, unknown animal. There had been precedent for this, as the species Anomalocaris had been originally identified as three separate creatures before being identified as a single huge (for its time) 0.91 m creature. Given the uncertainty of its taxonomy, Hallucigenia was tentatively placed within the phylum Lobopodia, a catch-all clade containing numerous odd “worms with legs.”

In 1991, Lars Ramskold and Hou Xianguang, working with additional specimens of a “hallucigenid,” Microdictyon, from the lower Cambrian Maotianshan shales of China, reinterpreted Hallucigenia as an Onychophoran (velvet worm). They inverted it, interpreting the tentacles, which they believe to be paired, as walking structures and the spines as protective. Further preparation of fossil specimens showed that the ‘second legs’ were buried at an angle to the plane along which the rock had split, and could be revealed by removing the overlying sediment. Ramskold and Hou also believe that the blob-like ‘head’ is actually a stain that appears in many specimens, not a preserved portion of the anatomy.

The knife tooth, Machairodus (1832)
Phylum : ChordataClass : MammaliaOrder : CarnivoraFamily : FelidaeGenus : MachairodusSpecies : M. aphanistus
Late Miocene (15 - 2 Ma)
2 m long and 120 kg (size)
North America, Africa and Eurasia (map)
You can tell a lot about a prehistoric cat by the shape of its limbs. Clearly, the squat, muscular fore and hind legs of Machairodus weren’t suited for high-speed chases, leading paleontologists to infer that this saber-toothed cat leaped on its prey suddenly from high trees, wrestled it to the ground, punctured its jugular with its large, sharp canines, then withdrew to a safe distance while its unfortunate victim bled to death. Machairodus is represented in the fossil record by numerous individual species, which varied widely in size and probably fur pattern (stripes, spots, etc.).

The knife tooth, Machairodus (1832)

Phylum : Chordata
Class : Mammalia
Order : Carnivora
Family : Felidae
Genus : Machairodus
Species : M. aphanistus

  • Late Miocene (15 - 2 Ma)
  • 2 m long and 120 kg (size)
  • North America, Africa and Eurasia (map)

You can tell a lot about a prehistoric cat by the shape of its limbs. Clearly, the squat, muscular fore and hind legs of Machairodus weren’t suited for high-speed chases, leading paleontologists to infer that this saber-toothed cat leaped on its prey suddenly from high trees, wrestled it to the ground, punctured its jugular with its large, sharp canines, then withdrew to a safe distance while its unfortunate victim bled to death. Machairodus is represented in the fossil record by numerous individual species, which varied widely in size and probably fur pattern (stripes, spots, etc.).