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THE PLEISTOCENE ERA  

The mammoth 

    After the dinosaurs became extinct approximately 65 million years ago, the birds and especially the mammals fill up the empty spaces and start an impressive march. The ancestors of the mammoths emerged around 40 million years ago in Africa. These are the first proboscideans. The trunk resulted from the growing together of the nose and the upper lip. Elephants grew larger but the neck stayed short, so a trunk was needed to bring food and water to the mouth. The nostril is formed by a big hole at the point of attachment, so that the skull of elephants can easily be recognized.The first elephants evolved into more than 150 different species in the course of time, some of them with very long tusks (these are actually extremely elongated incisive teeth). The bloom of the elephants was in the Miocene. About 20 million years ago the proboscideans could also move into Europe and Asia when the African continental crust came so close to Europe that a land bridge must have been formed. About four or five million years ago in Africa the elephants divided into three lines. From the first one, the Loxodonta, the African elephant emerged. The Indian elephant evolved from the second one, Elephas. The third one, Mammuthus, gave rise to the mammoths. So, as is sometimes thought, the mammoths are not the ancestors of the modern elephants. 

            The proboscideans (mammoths also) are classified into species mainly by characteristics of the teeth (e.g. the number of enamel plates). With most mammals, a new tooth grows vertically. With elephants, however, it grows horizontally. In total elephants will have 24 teeth during their life (six per corner). If the sixth and last tooth is worn away, the animal is condemned to die of starvation. If we assume that mammoths could get as old as modern elephants, their maximum age was about 60 years. 
            The ancestor of all mammoths is the African mammoth (Mammuthus africanavus), which originated in the Middle-Pliocene and died out about about three to four million years ago. About three million years ago the first mammoths appeared in Europe. They belonged to the species Mammuthus meridionalis, also called southern mammoth. M. meridionalis was bigger than the modern elephants – 4 m high, and a weight of 10,000 kg - and without hair (the climate was warm then). But it had curved tusks, which is a characteristic of mammoths. It also spread east to Asia, and crossed the Bering Land Bridge to reach North America about 1.7 million years ago when the climate was cold. When the temperature and thus the sea level rose again, the two continents were separated. In North America, the isolated M. meridionalis evolved into the imperial mammoth (Mammuthus imperator), and it in turn into the Columbian mammoth (Mammuthus columbi). 
            One million years ago the climate changed. The temperature became colder, and this changed the landscape in Europe. Woods changed into open grasslands. M. meridionalis died out, but not before a small population adapted to the changing conditions and evolved into Mammuthus trogontherii (steppe mammoth). Its molars were higher and had more ridges, so that they were more suitable for eating tough grasses. 
            Approximately 300,000 years ago in Europe, the woolly mammoth, Mammuthus primigenius, emerged from M. trogontherii. It was even better adapted to the cold. It was about as big as the Indian elephant - 3.2 m high - with a thick, long-haired woolly skin, a hypodermic fat layer, a short tail and small ears. Its molars were further adapted to eating the tough grasses from the tundra-steppes: they were higher and the number of enamel plates (up to 27) increased. It weighed 4,000 – 6,000 kg. 
M. primigenius is the last species of the Mammuthus family. If people say ‘mammoth’, they usually refer to the woolly mammoth. About 20,000 to 30,000 years ago the woolly mammoth was also able to reach North America through the Bering Land Bridge. But its range was limited to Alaska and Canada, while M. columbi preferred a milder climate and had moved south to the US and Mexico. Besides North America, woolly mammoths also reached Asia
            Woolly mammoths are well-known because of their finds in the Siberian permafrost (constantly frozen soil). The animals are often so well-preserved that even skin, flesh and hair remain. In Europe, fishing boats often find remains in their nets, especially on the North Sea between Holland and England. In the Pleistocene era during the ice ages, the sea level was so low that animals (and humans) could live on the bottom of what is now the sea.
            At the end of the Pleistocene, 10,000 years ago, a lot of big mammals like the cave bear, cave lion, giant deer, steppe wisent, but also the mammoth, died out. On the one hand this was caused by the changing climate (it became warmer, so that the vegetation changed), on the other hand because of the influence of humans, which rose in number and developed more efficient hunting techniques.
            Only a few mammoth populations could survive on a number of islands that were still attached to the main land during the last ice age. When the sea level rose they could not return, and because of the limited food supply on the islands they evolved into dwarf forms. Remains of these so-called pygmy mammoths have been found on Wrangel island, which lies about 200 km north of Siberia. Remains of adult members of the woolly mammoth have been found that are about 12,000 years old, but most remains are from dwarf forms only 1.8 m high and which only died out a few thousand years ago.

Straight-tusked elephant

The straight-tusked elephant (Elephas antiquus) lived in Eurasia during the Pleistocene. During the ice ages he remained in the south, and in warmer periods also moved north. It belongs to the Elephas species, to which the modern Indian elephant also belongs. It was a little bigger than the woolly mammoth, with almost straight tusks. The molars of the straight-tusked elephant had less enamel plates than those of the woolly mammoth, because its food was softer and the molars thus wore less quickly (the woolly mammoth mainly ate tough grasses). It became extinct approximately 100,000 years ago, when another cold period started. Also known as Bush-elephant.

Cave bear

    Cave bears were mainly herbivores. Just like most modern bears, they probably ate dead animals now and then, but only rarely will have killed prey themselves. They hibernated, for which they usually used a cave (hence their name). Some animals died during their winter sleep (because of their old age, or because they had not built enough fat reserves in the autumn), and in some European caves (for example in Austria) the remains of more than a hundred bears have been found. This indicates that such caves have been used by many generations of bears, sometimes over a period of thousands of years. The cave bear (Ursus spelaeus) was about a third bigger than the modern brown bear. It became extinct 50,000 – 60,000 years ago, when the climate was so cold that the forests were replaced by steppes, which did not offer enough plants and fruits.

Woolly rhinoceros

    The ancestors of the woolly rhino (Coelodonta antiquitatis) came from Asia. In the Lower Pleistocene, they moved to Siberia. There they became adapted to a cold climate, after which they moved on to Europe. It had a flat horn that enabled it to push aside snow in order to graze. The horns of a rhino are usually not preserved because they are not made of bone, but consist of thickly compressed hairs that decay after a while. After the last ice age, about 10,000 years ago, they died out, together with a lot of other animals like the woolly mammoth that were adjusted to a cold climate.

Giant deer / Irish elk    

    Officially called Megaloceros giganteus, the giant deer is an extinct deer that lived in Eurasia, from Ireland to China, during the Pliocene and Pleistocene epochs. It is famous for its formidable size (about 2 m at the shoulders), and in particular for having the largest antlers of any known cervid (a maximum of 4 m from tip to tip). Its name is a bit misleading: although large numbers of skeletons have been found in Irish bogs, the animal was not exclusively Irish, and neither was it closely related to either of the living species currently called “elk”. Many of the fossils found in Irish peat bogs are of males suffering from malnutrition after the rutting (mating) season, suggesting that they lived very like modern red deer today where males fight for the right to mate with a group of females every autumn.

Steppe wisent

    The steppe wisent (Bison priscus) was a bison found on steppes in Europe, Central Asia, Beringia and North America during the Quaternary. They probably evolved in South Asia, around the same time as the aurochs, so they probably had the same ancestors. The steppe wisent became extinct in the late Pleistocene. It was replaced in Europe by the wisent and in America by the bison. Steppe wisents were over 2 m high and probably resembled the bison. The tips of the horns were sometimes more than 1 m apart, even the horns themselves measured over 0.5 m long.

Aurochs (Bos primigenius)

    The aurochs evolved in Asia about 2 million years ago and reached Europe, Middle East and Africa approximately 250,000 years ago. It measured about 2 m at the shoulder, weighing 1,000 kg. The tip of the horns could be as much as 150 cm apart. The horn tips themselves are turned forward, as apposed to those of the steppe wisent, which are turned upwards. The last recorded live aurochs, a female, died in 1627 in the Jaktorow Forest in Poland. Part of the aurochs lives on in recent European cattle. Domestication began in the Caucasus and Mesopotamia about 8000 years ago, while genetic evidence suggests that they were independently domesticated in northern Africa and India. Smaller forms of the aurochs were brought to Europe about 6500 years ago.

Cave lion (Panthera leo spelaea) 

The lion evolved in Africa between 1 million and 800,000 years ago. It appeared in Europe 700,000 years ago with the subspecies P. leo fossilis. From this lion evolved the cave lion about 300,000 years ago. During the Upper Pleistocene it also spread to North and South America via the Bering Street and developed there into P. leo atrox, the American lion.
The cave lion is considered to be a subspecies of the extant lion (Panthera leo) and lived from about 300,000 to 10,000 years ago, during the Pleistocene era (although some finds indicate it may have lived until as recently as 2000 years ago in the Balkans). It ranged across Europe and Asia, from England all the way to Siberia.It is known from Paleolithic cave paintings, ivory carvings, and clay busts. These representations indicate that cave lions had protruding ears, tufted tails, and that at least some males had a "ruff" or primitive mane around their neck.
They probably preyed on the large, herbivorous animals of their time. Their extinction may have been related to the Holocene extinction event, which wiped out most of their prey. Cave paintings and remains found in the refuse piles of ancient camp sites indicate that they were hunted by early humans, which may also have contributed to their extinction.
The cave lion is one of the biggest cats that ever lived. It was about 25 % bigger than the modern African lion, and averaged 3.5 m in length, with a typical male weighing between 335 and 400 kg, and a typical female weighing 175 kg. The Siberian tiger and the South American Smilodon (which was the largest of the saber-toothed cats) are both smaller. Only. P. leo fossilis and P. leo atrox were a little bigger than the cave lion.
Until the late Pleistocene the lion was the most widespread large land mammal beside humans. They were found in most of Africa, much of Eurasia from western Europe to India and, in the Americas, from Alaska to Peru. They currently only exist in Africa (south of the Sahara) and northwest India.



Cave hyena (Crocuta crocuta spelaea)

 
Hyenas seem to have originated about 25 million years ago (mya) from an arboreal civet-like ancestor in Eurasia. Fifteen mya, dog-like hyenas flourished, with 30 different species being identified. Unlike some of their modern descendants, these hyenas were not specialized bone-crushers, but were more nimble, wolf-like animals. Five to seven mya, the hyenas were outcompeted by canids travelling from North America to Eurasia via the Bering land bridge. Some hyenas evolved bone-crushing teeth which allowed them to avoid competition with the canids. The peak diversity of the Hyenidae was during the Pleistocene, with 9 species of hyena. The bone-crushing hyenas became the dominant scavengers, taking advantage of the meat left over from the kills of big cats. The cave hyena is a subspecies of the extant spotted hyena (Crocuta crocuta) and lived in Eurasia during the late Pleistocene. Besides fossils it is known from prehistoric cave paintings. They used caves as dens, in which they accumulated the bones and horns of their food.

Hippo (Hippopotamus major)

The hippo is a large, mostly plant-eating African mammal, one of the only two extant species in the family Hippopotamidae (the other being the Pygmy Hippo from central Africa). It is the heaviest extant artiodactyl, inhabiting rivers and lakes in Africa south of the Sahara. They are semi-aquatic, and emerge at dusk to graze on grass.
Despite their resemblance to terrestrial even-toed ungulates, their closest living relatives are cetaceans. The common ancestor of whales and hippos split from other even-toed ungulates around 60 million years ago. The earliest known hippo fossils date to around 16 mya, found in Africa.
 
During the Pleistocene hippos also ranged throughout North Africa and Europe. It can live in cold climates provided the water doesn’t freeze during winter. Hippos are good swimmers which allowed them to reach Crete, Cyprus, Malta and Sicily, where dwarf species developed due to the reduced food supply and the absence of predators.



Epileptobos groeneveldtii , Axis lydekkeri and Rusa sp.

These fossils were found in Java, Indonesia and are about 1.3 million years old. Epileptobos is a large extinct bovid, Axis is an extinct cervid (deer) and Rusa an extant cervid. The fossils were excavated in Trinil and Kedung Brubus. 
Trinil is very well known due to the excavations of the famous Dutch geologist and anatomist Eugene Dubois (1858 – 1940). Trinil is the first hominid site that was described outside Europe. A skull cap and femur have been found by Dubois between 1891 and 1894. He attributed them to the species Pithecanthropus erectus (“upright walking ape-man”). This name was changed later on to Homo erectus. Other Pleistocene mammals from this site include a species of the proboscidean Stegodon, the Java rhino, two monkey species, a large tiger species and a small leopard cat. The presence of these animals indicates an environment with both grassy plains and forests. 
The Kedung Brubus fauna includes a huge extinct pangolin, the proboscideans Stegodon and the fossil elephant Elephas hysudrindicus, the large tiger species that is also known from Trinil, a hyena, otter, tapir, the Javan and Indian rhino and a hippo species. This implies an open landscape with rivers.

Egg from an elephant bird (Aepyornis titan), Upper Pleistocene, Madagascar 

The Ratites, long-legged walking birds that can’t fly, appeared in the Upper Cre-taceous / Lower Tertiary. On the different continents, different species evolved. Nowadays they are represented by the emu and cassowary in Australia and New Guinea, the kiwi of New Zealand, the nandoe in South America and the ostrich in Africa. Two spectacular groups became extinct only fairly recently – the elephant birds of Madagascar and the moas of New Zealand.
            The elephant bird (Aepyornis titan) was the largest of the Aepyornis family. It could become three to four m high and weigh 400 kg, the heaviest bird that ever lived (the giant moa of New Zealand, Dinornis maximus was a little taller, but weighed less). The elephant bird laid huge eggs with a volume of seven litres and a weight of ten kg.
The name ‘elephant bird’ comes from an old Arab legend, which tells of a large bird, the ‘Rukh’, that grabbed elephants and lifted them in the air. The giant bird in the legendary book ‘Thousand and One Nights’ with Sinbad the Sailor was probably also an elephant bird. It became extinct in the 17th century.

Description on Marsupials
Kangaroos  

A kangaroo is a herbivorous marsupial from the family Macropodidae (macropods, meaning ‘large foot’). Besides the well-known larger species such as the red and grey kangaroo, the family also includes many smaller species which include the wallabies, tree kangaroos, wallaroos, pademelons and the quokka, more than 60 living species in all. The bigger species are endemic to Australia, while some smaller species can also be found in New Guinea. Like all marsupials, female kangaroos have a pouch in which the young (the ‘joeys’) complete postnatal development.  
Kangaroos arose in the early Miocene, but, being grazers, they prospered in the Pliocene and Pleistocene, after Australia’s tropical rainforests were replaced by grasslands in the late Miocene. Dozens of extinct species are known, two genera (Ekaltadeta and Propleopus) were even carnivorous or at least omnivorous.  

Baringa nelsonensis  
This is a very rare extinct species of wallaby known only from the Nelson Bay site in western Victoria. It lived in the early Pleistocene. ‘Baring’ is a Victorian Aboriginal word meaning ‘to cut’, an allusion to the unusual truncation by wear of the lower incisors. The species name reflects the type locality. Baringa was named on the basis of several fragmentary dentaries, maxillae and isolated teeth.  

Macropus 
The genus Macropus includes the (eastern and western) grey kangaroo, the red kangaroo, wallaroos and some wallabies. 
M. giganteus (the grey kangaroo) is an extant species. However, the grey kangaroos in the Pleistocene were much larger than their modern descendants. 
M. titan is an extinct giant form of the grey kangaroo. It was flat-faced and about twice as big as the modern grey kangaroo. Some scientists regard it as a pre-dwarfing version of M. giganteus (as a sub-species, M. giganteus titan
M. siva is a rare Macropus species from eastern Australia. Some scientists consider it a sub-species of the extant agile wallaby (M. agilis).  

Protemnodon 
Protemnodon is a genus of macropods that existed in Australia and New Guinea in the Pleistocene. Based on fossil evidence it is thought that the known species were physically similar to wallabies bur far larger. They are commonly called “giant wallabies”. 
P. anak was one of the biggest Protemnodons, with a weight of at least 90 kilos, while P. roechus was one of the smallest. 

Sthenurus 
Sthenurus is an extinct genus of the so-called short-faced kangaroo. The sthenurines became numerous about 2 million years ago. Fourteen species are now extinct, with a single related species (the banded hare-wallaby) surviving on two islands off the coast of Western Australia. The extinct sthenurines varied in size from quite small animals the size of a wallaby to giants which stood 2.5 metres high and weighed up to 200 kilograms. All had a single long toe with a hoof-like claw on their hind foot, a short, thick tail and long arms. Most characteristic of all, the sthenurines had short, broad faces with an expanded nasal area that may have been used for amplifying sound. 
S. occidentalis was a leaf-eating kangaroo, about the size of a modern grey kangaroo. In order to grind tough leaves and shrubs it had powerful jaws and striations (sharp vertical ridges) on its teeth. The name ‘Sthenurus’ (Latin for strong-tailed) was derived from the first description of this group by Sir Richard Owen in the 19th century. He noted that the bones were undoubtedly kangaroo-like and suggestive of powerful hind limbs and strong tails.  
S. gilli was a rather small sthenurine, with a body weight of about 20 kg. 

Troposodon minor  
This genus lived in the Pliocene and Pleistocene. They were browsers (while most other kangaroos are grazers), some could reach a body weight of 100 kg. T. minor was its smallest member with a body weight of approximately 40 kg. 

Diprotodontids 

Diprotodontids were adapted for life in a land of forests. They were browsers with simple premolars and ate soft vegetation. There were several species of diprotodons, which all lived in Australia. They evolved in the mid-Miocene. The smallest were about the size of a small sheep, the biggest (D. optatum) was the size of a rhino. Diprotodons, along with a wide range of other Australian megafauna, became extinct a few thousand years after humans arrived in Australia. This mass extinction was probably a result of climate change (in the late Pleistocene, the forests were replaced by deserts and grasslands), human hunting and/or human land management. 

Kolopsis torus lived in the late Miocene and was about 1.5 m long with a shoulder height of 80 cm. It was one of the first diprotodontids and relatively small. Later species were much larger.  

Palorchestes parvus was characterized by retracted nasal bones, a narrow elongated rostrum and enlarged infra-orbital foramina capable of carrying large bundles of nerves and blood vessels probably supplying a trunk. It was about the size of a bull. 

Zygomaturus trilobus got its name from its wide flaring zygomatic arches. The Zygomaturus species were somewhat smaller than Diprotodon, and probably favoured the forested areas of south-eastern and south-western Australia, while Diprotodon was more suited to the open grasslands of the interior. The adult Zygomaturus was about 2.5 metres long and about 1 metre high at the shoulder, with a weight of 300-500 kilograms. 

Diprotodon optatum was the largest marsupial that ever lived. It was 3 m long and 2 m tall at the shoulder, weighing about two tonnes. It existed from 1.6 million years ago until about 40,000 years ago, through most of the Pleistocene era. It inhabited open forests, wood- and grasslands, eating leaves, shrubs and grasses. D. optatum was first described in the 1830s by the famous British anatomist Sir Richard Owen. 

Thylacoleo carnifex 

T. carnifex is a member of the extinct thylacoleonid family, whose members evolved in the Oligocene and are informerly known as ‘marsupial lions’. T. carnifex was a leopard-sized marsupial very distantly related to wombats. It was first described by the distinguished British palaeontologist Sir Richard Owen in 1858. It weighed about 120 kg and was the largest mammalian predator in Australia. A study of carnivorous mammals of the world concluded that T. carnifex was the most specialised mammalian carnivore that has ever evolved, mainly because of its incredibly huge, sectorial meat-cutting premolar. It also had long sharp claws on its thumbs to grasp or slash prey. The limb proportions of Thylacoleo indicate that it could not run fast. This is probably related to the inability to run fast while carrying young in a pouch. Thylacoleo is thought to have been primarily an arboreal (tree dwelling) animal. 

Sarcophilus 

Sarcophilus is a genus of carnivorous marsupial best known for its only living member, the Tasmanian Devil (S. harrisii). Three species are known, S. laniarius and S. moornaensis are only known from Pleistocene fossils. D. harrisii can now only be found on Tasmania, on the Australian mainland it became extinct about 600 years ago (due to predation by human-introduced dingoes and hunting by indigenous Australians). The Tasmanian Devil is now the largest carnivorous marsupial in the world (after the recent extinction of the Thylacine (‘Tasmanian Tiger’) in 1936. It is known to hunt both prey and scavenge carrion. It is a nocturnal animal. The fur is usually black, although irregular white patches on the chest and rump are common. Males are somewhat larger than females, with a head and body length of about 65 cm, a tail of 25 cm and an average weight of 8 kg. An analysis of mammalian bite force relative to the body size shows that the Tasmanian Devil has the strongest bite of any living mammal.  

Perameles 

Perameles is a genus also called long-nosed bandicoots. A bandicoot is any of about 20 living species of small to medium-sized, rat-like terrestrial marsupial omnivores of the family Peramelidae. They feed on insects and plants and have a long, tapering snout and elongated hind legs. 

Lasiorhinus 

Wombats are Australian herbivorous marsupials. They are short-legged, muscular quadrupeds, about one meter in length with a very short tail. They dig extensive burrow systems with rodent-like front teeth and powerful claws. They are mainly nocturnal animals. Their fur color can vary from a sandy color to brown, or from grey to black. There are three species, each around a meter in length and weighing between 20 and 35 kg: the Common Wombat (Vombatus ursinus), the Southern Hairy-nosed Wombat (Lasiorhinus latifrons) and the Northern Hairy-nosed Wombat (Lasiorhinus krefftii). 

Bettongia leseur 

Bettongia leseur, also known as the Boodie or Burrowing Bettong, is a small extant marsupial related to the kangaroo. It belongs to the family Potoroidae, which includes the rat-kangaroos, potoroos and other bettongs. Fossils of this family appear in the Mid-Miocene. B. leseur is a small, rat-like marsupial with short, rounded ears and a lightly-haired, thick tail. It has a pointed rostrum and beady black eyes, hind limbs longer than the forelimbs and large hind feet. It is about the size of a wild rabbit, weighing about 1.5 kg. 

Potorus 

Potorus is a small extant marsupial also known as a Potoroo. Potoroos are the same size as rabbits. They have long feet and toes to hop and have grey fur. They come out at night to feed on seeds, fungi and insects. The potoroos weight is 1.5-2.5 kg. 

Megalania prisca 

Megalania was a giant varanid lizard also known as the Giant Goanna, that lived in the Pliocene and Pleistocene. It grew to lengths of at least 5 metres, perhaps 7. At about 600 kg, it was several times as heavy as the largest living goanna, the Komodo Dragon of Indonesia (Varanus komodensis). It was probably an ambush killer and scavenger. Megalania is known only from fragmentary material. It is the largest known land-dwelling lizard and belonged to the family that includes the goannas or monitor lizards. It appears to have become extinct around 40,000 years ago (although numerous people claim to have seen very large lizards in Australia and New Guinea in the last 100 years, suggesting Megalania is still alive). It was the largest predator in Australia during the last 2 million years. Megalania is now often put in the genus Varanus, which includes all monitor lizards.

Tiliqua scincoides  

Members of the genus Tiliqua are also called blue-tongued skinks. It contains some of the largest members of the skink family. They are commonly called blue-tongued lizards in Australia, where true lizards do not naturally occur. T. scincoides is an extant species with a pale brown head with alternating streaks or blotches of dark brown and cream on its back. Its English name comes from its distinctive blue tongue. When disturbed it gapes its mouth open, sticks out its blue tongue and puffs up its body, hissing loudly. This is an effective defence mechanism, deterring many intruders.  

Emydura  

Emydura is a genus of extant turtles, also called Australian short-necked turtles. The six species of the genus Emydura are webbed-footed and semi-aquatic river turtles. They are characterized by unusually short necks. 

Pallimnarchus pollens 

Pallimnarchus is an extinct genus of crocodile from the Pliocene and Pleistocene of Australia. The genus consists of only one species, P. pollens. It was about as big as a modern saltwater crocodile. It had conical ziphodont (serrated and curved posteriorally) teeth and probably specialized in ambushing prey like kangaroos and diprotodons in shallow water.

THE TERTIARY ERA (Pliocene, Miocene, Oligocene, Eocene and Paleocene)  © Henskens Fossils & John v. Straaten

Carcharocles megalodon

    Carcharodon was a white shark species that lived in the Miocene and Pliocene. It must have grown to about 15-18 m in length. However, this is difficult to tell exactly, since a shark skeleton consists of cartilage that hardly fossilizes since it is very soft. What we do find a lot from sharks are their teeth. Not only because they are hard and have a big chance to be preserved, also because a shark constantly replaces them. A shark has several rows of teeth, and can produce up to 15,000 teeth during its life. Carcharodon teeth can be 20 cm long. The height of its wide open jaws must have been about 1.5 m. Its main food source were probably whales.

Cainotherium

    The Cainotheriidae are small artiodactyls (even-toed hoofed plant-eating mammals) that suddenly appeared in the Lower Oligocene of western Europe. Cainotherium looked like a hare. This is probably because it lived the same life style, a good example of convergent evolution. It is not related to hares, but has evolved similar adaptations as it occupied similar niches. Cainotherium became extinct in the Upper Miocene and left no descendants.

Messelornis cristata

    Messelornis cristata is a fossil rail-like bird from the famous Messel Pit fossil site in Germany, near Darmstadt. This pit has yielded lots of superb Eocene fossils of animals that lived in or close to a fresh-water lake. A lot of fossils even show the outlines of hairs and feathers. The Messel site was actively mined for its oil shales from 1859 to 1971 but now falls under the Heritage Protection Act. 
    Collecting fossils from the Messel site requires a special technique. Once is fossil is discovered (by splitting the thin shale slabs) it needs to be kept wet. If the shale is allowed to dry out, then the fossil disintegrates. Then, still keeping the fossil damp, the shale is carefully removed from around the bones. Then the bones are coated with resin to hold them in place. Now, the whole slab is turned over and the other side of the fossil exposed in the same way. Eventually, the fossil is completely free from the rock and encased in resin. 

    M. cristata  was about the size of a moorhen and earlier they were also classified in this group, the rails. It now appears, however, that the Messelornithidae are more related to the present crane family (Gruiformes). They had short wings, long legs and short toes. The tail feathers were long. On the head they had a helmet-shaped crest. The full skeleton is 25 to 30 cm in size.

The fishes Atractosteus starusi, Amphiperca multiformis, Thaumaturus intermedius and Palaeoperca proxima from the Fish page also come from this site.

Palaeobatrachus

    The Palaeobatrachidae is an extinct group of frogs. They lived mainly from the Eocene through Pliocene in Europe, but some fossils are known from the Cretaceous. They were purely aquatic amphibians, even their tadpoles have been found as fossils. Some palaeobatrachids reached a size of 12 cm snout-vent length.

Phareodus testis, Diplomystus dentatus, Knigthia eocaenea and Priscacara serata

    All these fishes come from the world-famous fossil locality of the Green River Formation in Wyoming, US (named for the present-day Green River, a tributary of the Colorado River). It covers about 25,000 square miles of Wyoming, Colorado and Utah and is one of the largest lacustrine sedimentary formations in the world. The deposits are from 40 - 50 million years ago. The region at that time was sub-tropical to temperate. Some 60 vertebrate taxa have been described, inlcuding crocodiles and birds. The excellent preservation of the Green River fossils is probably caused by the great depth of the lakes and the resulting anoxic conditions that would have kept scavengers away from the dead animals and plants. The limestone matrix is so fine-grained that fossils often show spectacular details, like the veins in insect wings and leaves.

Titanothere sp.

Titanotheriidae, also called Brontotheriidae, is a family of extinct mammals from the order Perrisodactyla, that includes horses, rhinos, and tapirs. They looked like rhinos but are probably related to horses. They lived in the Eocene and Oligocene. The term “Brontothere” means “thunder beast” in Sioux Indian language. Brontotheres have four toes on their front feet and three on their hind feet. Their teeth are adapted to cutting leaves. The history of this group is well known due to an excellent fossil record in the U.S. The earliest brontotheres were rather small, no more than a meter in height, and were hornless. Later brontotheres evolved massive body sizes, up to 2.5 m in height and had evolved bizarre hornlike appendages. The sexually dimorphic forked horns suggest that brontotheres were highly social and males probably competed for mates by clashing their heads. However, unlike rhinos, the horns were composed of bone, and were placed side-to-side instead of front-to-back. Brontotheres probably became extinct when the great forests were replaced by grasslands where horses, rhinos and other mammals became more abundant.

THE CRETACEOUS ERA  © Henskens Fossils & John v. Straaten

Aegyptosaurus

    As its name suggests, Aegyptosaurus was discovered in Egypt. It lived in northern Africa during the mid and late Cretaceous. It was a herbivore which was about 15 m long, with a long neck and tail. A lot of its fossils were found by German scientists in the 1930s. The fossils were stored in a Munich museum but were destroyed during a bomb raid in 1944. Aegyptosaurus was a close relative of Argentinosaurus, a larger dinosaur found in South America. It may have evolved from Argentinosaurus after it crossed the ancient land bridge between South America and Africa.

Crocodilus spenceri and Phosphatosaurus gavialoides

    Alligators, caimans, gavials, and crocodiles belong to the family Crocodylidae. Although this family has existed since the upper Triassic, over 200 million years ago, reptiles which can definitely be classed as modern Crocodylidae only appear in the fossil record about 80 million years ago. The group Crocodylia consists of modern crocodiles, alligators, and gavials. Crocodilians have a long head with nostrils at the tip of the snout, four legs projecting sideways, heavy scales, a muscular tail, and partially webbed hind feet. Crocodilians are semi-aquatic; they spend much of their time in water, but must lay their eggs on land. Their extinct relatives share many skeletal features with modern crocodilians, but were quite different. Some were small (less than 50 cm), lightly built, and probably preyed on insects and very small reptiles. Others even walked on two legs, or had hind limbs longer than their forelimbs, betraying their bipedal ancestry. The biggest croc that ever lived was Sarcosuchus imperator. It lived about 110 million years ago in what is now northern Africa. Based on measurements of the skulls and bones, and comparison to recent crocs, Sarcosuchus grew to lengths of 11-12 m.

Elasmosaurus

    Elasmosaurus was a plesiosaur with an extremely long neck that lived in the world sees in the late Cretaceous. Its name means “thin-plated lizard”. This is because it had platelike bones in its pelvic girdle. It is the longest plesiosaur that ever lived (about 14 m in length). More than half of its length was neck, which had more than 70 vertebrae, more than any other animal. It had a large body and four flippers for limbs, a small head with sharp teeth, and probably ate fish, belemnites and ammonites. It was described in 1868 by Edward Drinker Cope from fossils found in Kansas, US. He accidentally placed the head at the tail end. Othniel Charles Marsh made him aware of the error, and this event is cited as the cause of their long-lasting rivaly knows as the Bone Wars.

Mosasaurs

Mosasaurs were carnivorous marine reptiles with flippers that likely descended from varanid lizards. They are named after the Dutch river Meuse where the fossils were first discovered. This river runs next to the city of Maastricht, after which the period they lived in (Upper Cretaceous) was named (Maastrichtian). These fossils were from the species Mosasaurus hoffmanni. Mosasaurs dominated the shallow seas worldwide during the late Cretaceous. They were top predators that ate almost anything, even ammonites. Some fossil ammonites cary the bite marks of mosasaurs.
Mosasaurus was the largest of all mosasaur types known. It could reach a length of 18 m, with a skull of almost 2 m. The lower jaw is loosely hinged to the skull with a moveable joint on each side just behind the teeth. This loose joint must have permitted the animal to swallow large prey, much as some living snakes do. Finds of mosasaur embryos inside the skeleton of adult specimens indicate that mosasaurs, just like ichthyosaurs, were viviparous and gave birth to live young.

Tharrhias araripis

    These fishes come from the Santana Formation, in northeast Brazil, one of the richest fossil deposits in the world. About 110 million years ago this was a shallow inland sea. At that time Africa and South America had only just drifted apart, and were still located close to each other. The geological formation, named after the village of Santana do Cariri, lies at the base of the Araripe Plateau. The strata were laid down during the early Cretaceous, 114 to 90 million years ago, in a shallow inland sea. At that time, the South Atlantic was opening up in a long narrow shallow sea. The Santana Formation is well-known for the well-preserved fossil fishes. Even the contents of their stomachs are preserved, permitting paleontologists to establish predator-prey relationships in this ecosystem. There are also fine examples of pterosaur reptiles and amphibians, invertebrates (particularly insects), plants and even dinosaurs. The fossils are often found as accretions that formed nodules around dead organisms, preserving even soft parts of their anatomy.

Coelacanths

Coelacanths evolved approximately 380 million years ago. Since no fossils of these fishes have been found in rocks from the Tertiary or younger, palaeontologists assumed they had died out at the end of the Cretaceous, 65 million years ago, together with the dinosaurs and other big reptiles. Until a Coelacanth was caught at a depth of 200 m off the coast of Madagascar in 1938. Closer investigation showed a population that consisted of several hundred specimens. In 1998, another Coelacanth population was found near Sulawesi, Indonesia. These modern Coelacanths grow to about 1.8 m in length. They are the last of the lobe-finned fishes. This class had four more subclasses in the Devonian, which are now all extinct. The bones of the pectoral and pelvic fins in lobe-finned fishes already clearly show a humerus, radius and ulna. Scientists used to think that the lung fishes were the direct ancestors of the amphibians, nowadays most palaeontologists think these were the lobe-finned fishes. In a group of lobe-finned fishes living in the Devonian, the swim-bladder evolved into lungs, when, for unknown reasons, they left the sea water.



Confuciusornis sanctus

    Just like Archaeopteryx, Confuciusornis is proof that birds evolved from reptiles. Confuciusornis is about 25 million years younger than Archaeopteryx and is the oldest known bird to have a toothless beak. However, the wings still have three claws. It must have been a better flyer than Archaeopteryx because it had lighter bones (in modern birds the bones are completely hollow to save weight). The males were a little larger than the females and had two very long, narrow tail feathers. Confuciusornis is found in deposits from the Lower Cretaceous of the Liaoning province in China. The first specimen was found in 1994. The fossils have almost all been found in a relatively small area, indicating they lived in large colonies close to water (the fossils are deposited in what was once the bottom of a large freshwater lake).

Allopleuron

    Turtles are an ancient group of reptiles. The earliest turtles were enormous, tortoise-like animals. Millions of years of evolution resulted in some species adapting to life in the oceans. The earliest known marine turtle fossils are about 110-150 million years old. Allopleuron is known from Upper Cretaceous deposits of North America, northern Africa and Europe. Once the oceans of the world had an abundance of turtle species, but the last hundred years have seen a steady decline of the turtle population. Marine turtles are now an endangered species. There are just seven extant species today.

THE JURASSIC ERA © Henskens Fossils & John v. Straaten

Rhamphorhynchus

    Pterosaurs (‘flying reptiles’) evolved approximately 230 million years ago. They developed in the same period as the dinosaurs, at the end of the Triassic, and also had the same ancestors (the archosaurs, from which the crocodiles also evolved). The wing is formed by a greatly elongated fourth finger. From the top of this finger, a leathery skin stretched towards the thigh bone of the hind legs. The other three fingers formed a claw halfway the wing. The fifth finger was still present in early species (although already greatly reduced), but was gone in later forms. The wings could be folded backwards, so that pterosaurs were able to walk on their hind legs on the ground, supported by their wing claw.

More than 120 different species are known. The smallest had the size of a sparrow, the largest (Quetzalcoatlus) had a wing span of about 12 m. Just as in birds, pterosaur bones were hollow to save weight. It were the first vertebrates that were able to fly. Most species lived from insects and fishes, which they caught from the surface waters of the seas. Pterosaurs were probably active, warm-blooded animals. The ones with a large wing span must have been able to glide for a long time by using the thermal currents (upward movement of heated air). Just like many other reptile families, they became extinct at the end of the Cretaceous.

Pterosaurs are not the ancestors of birds. Birds developed in the Jurassic from small, carnivorous reptiles (probably dinosaurs), and pterosaurs and birds still shared the skies for almost 100 million years.

    Rhamphorhynchus had a long tail. Its name means “beak snout”. It had a wingspan of 1 m and a long tail stiffenened with ligaments which ended in a vane. It probably ate fish and it is believed that one of the ways it hunted was by dragging its beak in the water, catching fish, and tossing them into its throat pouch, a structure similar to that of pelicans, which has been preserved in some specimens. Although fossils have been found in England, the best preserved come from the Solnhofen quarry in Germany. Many of these fossils preserve not only the bones but skin impressions too. It lived in the Upper Jurassic.

    Scaphognathus had a skull length close to 12 cm and a wingspan of about 90 cm. It had a characteristically broad jaw, relatively short tail and short wings in comparison to other rhamphorhynchoids and a broad sternum. Compared to Rhamphorhynchus, the teeth pointed downward instead of forward.

Arocles altivelis, Allothrissops salmoneus, Allothrissops mesogaster, Tharsis dubius, Ascalabos voithii, Pachytrhissops, and Leptolepides sprattiformis

    All these fishes come from the world-famous fossil Lagerstätte of Solnhofen near Munich in southern Germany. In the Upper Jurassic, approximately 150 million years ago, a lagoon with a direct connection to the open sea covered this area. The deposits have formed light-coloured rock layers that can easily be broken into plates. Already in the Middle Ages these were used as roof and floor covering, but especially in the 19th century they were used a lot in the lithographic industry. During this period, a lot of fossils were found. Due to the fine-grained structure of the rocks, they show even the smallest details. Also, almost all of the fossils are still intact, not being touched by scavengers. This probably means that life was not possible in the lagoon’s lower water levels. It must have been very salty at the bottom, without any oxygen. More than 400 different fossil animal species from the Solnhofen area have been determined. Not only from marine animals such as fishes, crustaceans, star fishes etc., but also from animals that lived on land. These have been carried to the lagoon by rivers and mudflows (reptiles, insects, and even one dinosaur species, Compsognathus), or flew above the lagoon and fell down in the water (maybe during a storm) and drowned (pterosaurs, and the most famous of all Solnhofen fossils, the prehistoric bird Archaeopteryx).

Mesolimulus walchi

    Horsehoe crabs are distant relatives of spiders and probably descended from the ancient eurypterids (sea scorpions). They evolved in the Cambrian with other primitive arthropods like the trilobites. Horseshoe crabs are one of the oldest classes of marine arthropods, and are often referred to as "living fossils", as they have not changed much in the last 350 to 400 million years. Limulus polyphemusis one of the few surviving species of Limulus, and it closely resembles Mesolimulus walchi. They are found in the Gulf of Mexico and along the northern Atlantic coast of North America.

Hyphalosaurus lingyuanensis

    Hyphalosaurus is an extinct genus from the order Choristodera, (semi-)aquatic diapsid reptiles which ranged from the Jurassic, or possibly late Triassic, to at least the early Miocene. They are found in the early Cretaceous Jehol group from the Yixian Formation in China. The slab and counterslab of the holotype were given to different groups of researchers, each giving it a diffent name, Sinohydrosaurus and Hyphalosaurus. It was quickly recognized that they represented the same animal, and since the name Hyphalosaurus appeared in a publication first, this is its official name. It achieved an adult body size of about 80 cm. It was aquatic, a lifestyle reflected by its elongate neck and tail and reduced limbs. In 2007 a specimen was found with two heads, marking the oldest case of polycephaly.


Pseudorhina minor

Pseudorhina is related to the recent squatinids, the so-called angel sharks, bottom-dwelling sharks with a ray-like shape. They are an ancient lineage, first appearing in the fossil record about 150 million years ago during the late Jurassic period. The remains of articulated angel sharks are known from the marine deposits of Solnhofen, southern Germany. Specimens of more than one meter in length have been recorded. The oral aperture is located underneath and at the forward end of the head. Pectoral and ventral fins are close to one another. 
The genus Pseudorhina is extinct but it has close relationships with the genus Squatina which has 15 extant members.

Ichthyosaurs

Ichthyosaurs were reptiles of which the ancestors lived on land, but later decided to go back to sea (possibly under pressure of the dinosaurs, which dominated on land). Their body shape looks a lot like that of a dolphin (but with a vertical instead of a horizontal tail, and four instead of two flippers). Just like dolphins (mammals which later also returned to sea), ichthyosaurs had lungs and had to come to the surface now and then to breathe. More than 80 species are known, of which the biggest one (Shonisaurus) could reach 15 m in length. Skeletons of ichthyosaurs have been found containing the remains of unborn young. This proves they had an internal egg development and that the young were delivered alive. They evolved in the Triassic (about 245 million years ago) and became extinct in the Cretaceous (some 90 million years ago, long before the dinosaurs and many other reptiles died out).

            They lived on fish, ammonites and belemnites. Ichthyosaurs have, in comparison to the rest of their body, the biggest eyes of all animals. Species of the genus Temnodontosaurus even had the biggest eyes ever, with a diameter of 26 cm (even bigger than those of a blue whale). Even the eyes are adapted to the streamlined ichthyosaur body. Like most birds and other reptiles, ichthyosaurs have a bony eye ring, the so-called sclerotic ring. This ring, which encircles the lens, is flattened in ichthyosaurs, and the outer edge is bent inwards, so that also the eye ball is flattened, and the extraordinary big eyes hardly stick out. 

Stenopterygius sp., Lower Jurassic, Holzmaden, Germany

 Stenopterygius is known from Europe (England, France, Germany, Luxembourg and Switzerland). Its maximum length was 4 m. Stenopterygius was physically similar to the better known Ichthyosaurus, but had a smaller skull and narrower flippers. Stenopterygius was a very fast swimmer, with a cruising speed similar to that of tuna, which is among the fastest of all living fishes.

Since the skeleton is as good as complete, this ichthyosaur must have drifted at the surface only for a short while after its death, before it started to sink. The deeper it sank, the more the chest and lungs were compressed. The body’s centre of gravity moved into the direction of the head. As a consequence, such ichthyosaurs often sank towards the sea bottom head first, with a speed of ± 1.5 m/s. When it collided with the sea floor, the snout broke into several pieces, and also the skull was damaged. Approximately 30 cm behind the skull, the spinal column is broken, and some vertebrae are dislocated. Several parts of the snout and left front flipper entered the left eye ball and are now lying on top of the sclerotic ring. The flipper at the left front became detached from the shoulder joint and moved towards the skull. The fossilized stomach contents can still be seen in the form of a brown spot.

This ichthyosaur is mentioned in a German scientific article about ichthyosaurs which sank to the sea bottom head first (Der Ichthyosaur vom Hauensteiner Nebelmeer, H. Hänggi, 2007, Naturforschende Gesellschaft des Kantons Solothurn).

THE TRIASSIC ERA © Henskens Fossils & John v. Straaten

Keichousaurus hui

    Keichousaurus is a marine reptile from the Triassic. The name derives from Kweichow (now Guizhou province) in China where the first fossil specimen was found in 1958. Keichousaurus was highly adapted to the aquatic environment. They grew to about 30 cm in length, and had both long necks and tails, with elongated, five-toed feet. The pointed head and sharp teeth indicate they ate fish. They belonged to the sauropterygians (“lizard flippers”), a group of very successful aquatic reptiles that are united by a radical adaptation of their shoulder, designed to support powerful flipper strokes.

Nothosaurus

    Nothosaurs were Triassic marine sauropterygian reptiles that had the same life style as seals today, catching food in the sea water but coming ashore on rocks and beaches. They averaged about 3 m in length, with a long body and tail. The feet had become paddle-like, and were most certainly webbed in life, to help power the animal when swimming. The neck was quite long, and the head was elongate and flattened, and relatively small in relation to the body. The margins of the long jaws were equipped with numerous sharp outward-pointing teeth, indicating it ate fish. Nothosaurs evolved from pachypleurosaurs and were the ancestors of the more completely marine plesiosaurs, which replaced them at the end of the Triassic. They lived in Europe, North Africa and Asia.

THE PERMIAN ERA © Henskens Fossils & John v. Straaten

Archegosaurus

    Archegosaurus belongs to the Labyrinthodontia, a group of extinct amphibians. They were the first vertebrates to conquer land in the Devonian. The Labyrinthodontia  evolved from the Crossopterygii, a class of lobe-finned fishes, consisting of lungfish and coelacanths. In a group of lobe-finned fishes living in the Devonian, the swim-bladder evolved into lungs, when, for unknown reasons, they left the sea water. Archegosaurus could reach a length of 1 m. Together with Sclerocephalus and Actinodon it belonged to the biggest amphibians of Europe during the Permian.

Discosauriscus

    Discosauriscus was an amphibium that lived in the early Permian. Lots of its fossils have been found in deposits of fresh water lakes in central and western Europe, especially in the Czech Republic. Until now only fossils from juvenile specimens have been found, not from adults. This is probably because adults used these lakes as spawning grounds and that animals, as soon as they reached maturity, moved to another habitat. Two species are known: D. austriacus and D. pulcherrimus. The first one is much more common.

Sclerocephalus  

    Sclerocephalus was a salamander that lived about 280 million years ago (in the Lower-Permian) of what is now south-western Germany. It lived in freshwater lakes and with its maximum length of 2 m it was one of Europe’s biggest amphibians ever. It fed on fish and other amphibians. Like all amphibians, the larvae had gills with which they retrieved oxygen from the water. The adult animals had lungs and so were able to also temporarily live on land.

Micromelerpeton credneri

Micromelerpeton was an amphibian that lived in the Permian in what is now southwestern Germany. They belong to the branchiosaurs: mature amphibians that show larval characters such as external gills and unossified elements in the wrist and ankle. Micromelerpeton could reach a length of 20 cm. It lived 290 – 260 mya. During that time, Germany lay far more to the south and the regional temperature was tropical and humid, ideal for amphibians. The main enemies of Micromelerpeton in the Permian lakes must have been the much larger amphibian Sclerocephalus (see above article) and freshwater sharks like Orthacanthus.

Orthacanthus senckenbergianus

Orthacanthus is a fresh water shark that lived in the Upper Carboniferous and Lower Permian of Europe and North America. With its long body and long dorsal fin it looked a bit like a moray. It had a spine just behind its head and could reach a length of 3 m. It was first described in 1889. The white color of the fossil is a result of heating-up of the sedimentary rock by rising lava. It belonged to the Xenacanths, the first sharks to enter fresh water. They lost their primitive shark shape and evolved toward an eel-like form, with a long, slender body, tapered tail, and elongate dorsal fin.
Fossils of complete sharks are rare as their skeleton is from cartilage which is much softer than bone.

THE CARBONIFEROUS ERA © Henskens Fossils & John v. Straaten

Ferns 

Ferns are vascular plants that differ from the more primitive lycophytes in having true leaves, and from the more advanced seed plants in lacking seeds. Unlike the other vascular plants, the flowering plants and conifers, where the adult plant grows immediately from the seed, ferns reproduce from spores. Ferns are (relatively) delicate plants that only grow in areas with moist conditions. They favour sheltered areas under the forest canopy, along creeks and streams and other sources of permanent moisture. 
Ferns first appear in the fossil record in the Lower Carboniferous, meaning they were already around for two hundred million years before the flowering plants evolved. By the Triassic, the first evidence of ferns related to several moden families appeared. The first modern families evolved in the Upper Cretaceous.

THE DEVONIAN ERA © Henskens Fossils & John v. Straaten

Rhinopteraspis dunensis        Coccosteus cuspidatus

Pterichthyodes milleri

Armored fishes

The first armored fishes developed in the Lower Ordovician. They belong to the class Agnathans, the first vertebrates, which were still jawless. Most species lacked paired fins, and only possessed a tail fin. Many species also did not have a dorsal fin. For compensation, they had protrusions on the head shield that served as a stabilizer. They swam using only their tail. The Agnathans also included non-armored fishes. This class became extinct at the end of the Devonian. A second class which includes armored fishes are the Placoderms. As opposed to the Agnathans, they had jaws and paired fins. They already die out in the Lower Carboniferous.All armored fishes had an amazing exoskeleton, consisting of a head shield, and, for the Placoderms, hard, bony plates halfway the body. Their length varied from a few centimeters to 6 m (Dunkleosteus). Besides protection against predators, the armor also served to support the body.
            Rhinopteraspis is an Agnathan.
Although lacking paired fins, the pteraspids were probably powerful swimmers.  Stability was provided by the wing-like outgrowths from the back of the head shield.  A large spine over the back acted as a kind of dorsal fin while two rigid 'wings' or keels functioned as pectoral hydrofoils.   The long, flexible tail was also hydrodynamic, with the lower lobe elongated to provide lift at the front of the body during swimming. Additional lift was provided by the elongated snout, which was drawn out into a bladelike 'rostrum', below which the mouth opened. The rostrum may have served a dual purpose, both hydrodynamic and used to probe the mud and sediment for small organisms.
            Coccosteus is a genus of arthrodire placoderm (“arthrodire” means “jointed neck”, with well developed neck joints between head shield and trunk shield). Its fossils have been found throughout Europe and North America in freshwater sediments, although such a large range suggests it may have been able to enter saltwater. Its average length was 20 – 25 cm, the largest specimens were about 40 cm.
           
Pterichthyodes is a genus of placoderm fish from the Devonian period. It had heavily armored heads and front bodies, while their tail ends were uncovered. As placoderms, they were members of one of the first group of animals to possess jaws, though they had grinding plates rather than teeth. They are distinguished easily from other placoderms by their odd wing-like appendage where fins would be found on a modern fish ("pterichthys" is ancient Greek for “wing-fish”). Pterichthyodes was first described by the famous Scottish geologist Hugh Miller (1802 – 1856) and bearing his name in recognition. At the time, these fossils were among the oldest vertebrates ever discovered.

Cheirolepis trailli 
Cheirolepis (“hand-fin”) is an extinct genus of ray-finned fish (Actinopterygians) that lived in the Devonian period of Europe and North America. It was a predatory freshwater fish of about 30 cm long, with a streamlined body with small, triangular ganoid scales. It had well-developed fins to give it speed and stability, and was probably and active predator. Based on the size of its eyes, it hunted by sight. Its jaws, lined with sharp teeth, could be opened very wide, allowing it to swallow prey two-thirds of its own size. Cheirolepis was first named and described by Agassiz in his famous work “Les poissons fossiles”.

Gyroptychius agassiz
Gyroptychius is an extinct genus of coelacanthiform lobe-finned fish from the Devonian period. It was a fast riverine predator with an elongated body about 30 cm long. As it eyes were relatively small, it is presumed to have hunted by smell rather than by sight. It had short jaws which gave it a powerful bite. All its fins except the pectorals were moved to the back of the body, increasing the power of the tail while swimming.

Eurypterus

    The eurypterids were the largest known arthropods that ever lived. They are members of the extinct class Eurypterida. The largest, such as Pterygotus, reached 2 m or more in length, but most species were less than 20 cm. They were formidable predators that lived in warm shallow water in the Cambrian to Permian from 510 to 250 million years ago. Eurypterids were the most fearsome swimming predators of the Paleozoic. Although called "sea scorpions", only the earliest ones were marine (most became brackish or freshwater animals), and they were not true scorpions. The typical eurypterid had a large, flat, semicircular carapace, followed by a jointed section, and finally a tapering, flexible tail, with a long spine at the end. Some eurypterids have paddles, which were used to propel themselves through water. They had four pairs of jointed legs for walking, and two small claws at the front. Some species may have been amphibious, emerging onto land for at least part of their life cycle. They may have been capable of breathing both in water and in air.

THE SILURIAN ERA © Henskens Fossils & John v. Straaten

Graptolites  

    Graptolites are fossil colonial animals known from the Upper Cambrian through the Lower Carboniferous. Each graptolite consisted of a stick- or twig-like colony of tiny animals that either floated in the sea or was attached to the sea floor like a tiny, up-right shrub. The graptolite colony consisted of branches that were straight, curved or spiral. The individual animals lived in a series of tiny, cup-like structures organised along the length of the graptolite skeleton. They are common fossils and have a worldwide distribution. Graptolites are important index fossils for dating Paleozoic rocks as they evolved rapidly with time and formed many different species. They are often found in rock having formed from sediment deposited in deep water that had poor bottom circulation, lacked oxygen and had no scavengers. Graptolites vary in shape, but are often dendritic or branching, saw-blade like, or tuning-fork shaped

THE ORDIVICIAN ERA © Henskens Fossils & John v. Straaten

Cystoids  

    Cystoids are an extinct group of echinoderms, with a typical 5-way pseudosymmetry and body composed of calcitic plates. They are animals although they resemble plants. The body plates are quite irregular in arrangement, and the arms are irregular and rarely preserved. Attached to the sea bottom by a flexible stem, their limy-plated bodies were a a few millimetes to 5 cm in diameter. Numerous small tentacles extended from their heads to capture microscopic food particles from sea water. The cystoids lived from the early Ordovian till the mid Carboniferous.

THE CAMBRIAN ERA © Henskens Fossils & John v. Straaten

Paradoxides gracilis 

    Paradoxides gracilis (Boeck, 1827) belongs to the order Redlichiida. These are primitive trilobites with numerous thoracic segments with spinose tips. The cephalon is large and semicircular; the glabella long, well-segmented, tapering or expanding forwards; genal spines are strong, usually continued from a narrow, tubular cephalic border; eyes large, crescentic, with large, inflated palpebral lobe ridges running toward front of glabella; eye ridge may be subdivided; hypostome typically conterminant, usually very wide rostral plate present. The thorax has numerous segments (up to 90+), pleurae usually with spinose tips; may be subdivided into prothorax and opisthothorax. The pygidium is typically tiny (micropygous), with one or very few segments. Trilobites from the order Redlichiida lived from Middle to Late Cambrian.

THE PRE-CAMBRIAN ERA © Henskens Fossils & John v. Straaten

Stromatolites

    Stromatolites ((from Greek strōma, mattress, bed, stratum, and lithos, rock) are fossils which show the life processes of cyanobacteria (blue-green algae). The primitive cells (Prokaryotic type, which did not have a nucleus yet), lived in huge masses that could form floating mats or extensive reefs. Masses of cyanobacteria on the sea floor deposited calcium carbonate in layers or domes. These layered deposits are called laminar stromatolites. Stromatolites were abundant in Pre-Cambrian times. The Precambrian atmosphere was rich in carbon dioxide, but prior to 2.4 billion years ago, it lacked the oxygen that sustains the complex multicellular life that has evolved since about 600 million years ago. Stromatolites in the geological record declined sharply in both diversity and number during the latest Precambrian and are present, but uncommon in modern day marine environments.