by Tim Flannery
These changes in vegetation—from tropical evergreen to deciduous and dryland types indicate some of the complexity of the floristic shifts that occurred in Europe during the 18 million years of the Miocene. The story is continued in the exceptionally rich fossil floras from south-western Romania. Dating to about 13 million years ago, they reveal a vegetation broadly reminiscent of, but much richer than, that found in contemporary Europe. Mixed forests of oaks and pines grew along the shores of an ancient lake, interspersed with beeches, elms, maples, hornbeam and some members of the laurel family. On boggy ground the swamp cypress flourished, alongside willows and poplars. Overall, this mixed vegetation of pines, evergreen and deciduous species resembles the forests still growing in east Asia and eastern North America, but also includes many genera that continue to dominate Romanian forests. This type of fossil flora, which occurs in many late Miocene and Pliocene deposits in Europe, is known as the Arcto-Tertiary Geoflora.
One strange feature of the European forests at the time the German and Romanian fossils were being deposited is the sudden appearance of the ginkgo. Although known from the age of dinosaurs, it seems to have become extinct in Europe sometime around or soon after the asteroid impact, so its reappearance some 40 million years later is surprising. But conditions in Miocene Europe clearly suited it and, for a time, ginkgoes flourished there.7 The European ginkgo was not precisely the same as the today’s ginkgo, which occurs naturally only in a tiny area in the mountains of China, but it was very close. Europe’s ginkgoes appear to have become extinct sometime before the onset of the ice ages some 2.6 million years ago, with some of the last records coming from Romania. Their recent return to Europe, as street and garden trees should be welcomed as the return of a native.
By the end of the Miocene about five million years ago, mountain-building, dramatic drops in temperature, and lowering sea levels had created a Europe that was topographically broadly similar to the Europe of today. The cooling had also caused the extinction of cold-sensitive species in the European flora, and it is likely that grasslands, arid shrublands and alpine floras had become well-established. Of particular importance for the history of our own species, a mixed woodland-savanna occurred extensively in southeastern Europe—in what is today Greece and Turkey.
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* No single, global climatic event defines the beginning or end of the Miocene; its onset being defined by the extinction of a species of plankton, and its termination by an abrupt shift in Earth’s magnetic poles.
* The height of the Alps can vary by up to 27 centimetres, depending upon the pull of the moon, a fact that only became widely known when the particle accelerator at CERN, near Geneva, was built, and which works with such precision that the lunar pull had to be factored into its workings.
CHAPTER 16
A Miocene Bestiary
At times during the Miocene, the European fauna was almost as rich and diverse as that found in East Africa today. Those creatures have left an abundant fossil record that is at times bewilderingly varied, as well as fast changing. Rhinos had arrived in Europe during the Eocene but were only moderately diverse until the early Miocene. Then, between 23 and 20 million years ago a mosaic of habitats emerged that supported up to six coexisting species—including the small (a mere half-tonne) Pleuroceros, which had two horns side by side at the end of its snout. This, however, was only the beginning of Europe’s rhino proliferation: by 16 million years ago the number of European rhino species had increased to 15, partly through local evolution and partly through the arrival of immigrants from Asia. However, as in earlier times, no more than five or six species co-occurred.1
The chalicotheres were among the strangest mammals that ever lived. They were perissodactyls—relatives of horses, rhinos and tapirs—and if all you had seen of one was its head, you might have mistaken it for a very strange horse. But its body was gorilla-like, and its limbs bore huge, sharp claws. The mix of features is so bizarre that for decades palaeontologists failed to recognise that fossils of the different parts came from the one type of animal.
The chalicotheres arose in Asia about 46 million years ago and spread rapidly to North America, and then to Europe, their migration taking the long way around, via the Bering land bridge and De Geer Corridor.2 During the Miocene, a veritable evolutionary explosion of chalicotheres occurred in Europe, with no less than five genera existing at one time. The oddest of all was Anisodon. A denizen of Europe’s late Miocene, it stood about 1.5 metres high at the shoulder and weighed about 600 kilograms. Its horse-like head was perched atop a long, almost okapi-like neck, which craned out from a body carried on long, stout forelimbs and short hindlimbs, giving it a steeply sloping back like a gorilla. And like a gorilla, Anisodon walked on its knuckles, folding its digits inwards to protect its sharp claws. It fed on foliage and seeds, nuts and hard fruits, whose shells were so tough they wore down its teeth to an extraordinary degree.3 It was, in an ecological sense, Europe’s answer to the ground sloths of South America and the gorillas of Africa.
The chalicotheres became extinct in Europe several million years ago, but one lineage survived in the forests of south Asia until about 780,000 years ago, so it would have been familiar to Homo erectus. If I possessed the godlike powers to resurrect just one creature from nature’s graveyard, it would be Anisodon, an animal so unfathomable to me that it seems to belong in a fairytale.
Giraffes are often thought of as African, but in fact their origins lie in Asia, from where they migrated into Europe and Africa.4 One extinct group known as the sivatheres grew very large and had antler-like growths on their heads. They probably looked like giant, horned okapis. The sivatheres became extinct about two million years ago, but other giraffes, including the ancestors of the living giraffe species and the okapi, thrived. The most abundant European Miocene giraffes belonged to the genus Palaeotragus, which was thought to have become extinct about five million years ago. Until 2010 Palaeotragus was of little interest to anyone but fossil giraffe specialists, but in that year two palaeontologists, Graham Mitchell and John Skinner, announced that Palaeotragus was not extinct at all. Instead, they opined, it still survived in the mountain forests of central Africa—in the form of the okapi.5
This is rejected by many scientists; but the claim that a supposedly extinct European creature might survive in the jungles of central Africa is astonishing. The okapi, with its purplish, velour-like coat and white rump stripes, has to be Earth’s most beautiful mammal. If it is indeed an ancient European, or even an ecological replacement for one, rewilding enthusiasts in a distant future Europe warmed by anthropogenic greenhouse gases may seek to introduce it there.
Mitchell and Skinner, incidentally, also had surprising news about the origin of the modern, long-necked giraffes. This group, they claimed, probably evolved in Europe about eight million years ago, before spreading to Asia (where they became extinct) and Africa. As original Europeans, perhaps the long-necked giraffes also will one day be considered as candidates for reintroduction around the Mediterranean rim.
Bovids include an enormous variety of ruminants (cud-chewing, cloven-hoofed mammals) from antelopes to sheep and cattle, and are one of the most diverse and successful groups of large mammals ever to exist. Their origins lie in the early Miocene, when they diverged from the ancestors of the deer and giraffes. The oldest known bovid, Eotragus, was a dog-sized forest dweller that evolved in Eurasia, its short, straight horn cores and other bones being found in 18-million-year-old sediments from China to France.6 Shortly thereafter the bovines (which include the cattle and their relatives) originated somewhere in Eurasia.
The antelopes originated in Europe about 17–18 million years ago—the oldest fossils (Pseudoeotragus) coming from Austria and Spain. Their spread—around 14 million years ago—to Africa and Asia, marks a great European success story. The caprines (a group that includes the goats, sheep and ibex) originated about 11 million years ago in either Africa or Europe, the earliest fossils comin
g from Africa and Greece. With the spread of grasslands around 10 million years ago all these bovids—which are superbly adapted to extracting nutrients from this fibrous resource—diversified rapidly.
Elephants originated in Africa and arrived in Europe 17.5 million years ago, probably via Asia.7 The first to reach Europe belonged to a now-extinct family known as gomphotheres—primitive, four-tusked creatures. They became extinct in most places about 2.7 million years ago, when other kinds of elephants emerged from Africa and became widespread. But some survived in South America until humans arrived about 13,000 years ago: In geological terms, we missed out on seeing gomphotheres by a whisker.
About 16.5 million years ago two other kinds of elephants—deinotheres and mastodons—arrived on Europe’s shores. Prodeinotherium (a deinothere) was about the size of today’s Asian elephant, but its trunk was similar in size and function to that of a tapir. It lacked upper tusks, instead having a pair of downwards-pointing tusks in the lower jaws which may have been used to strip bark from trees. Over the Miocene the European deinotheres became enormous, some reaching weights of 15 tonnes—making them among the largest land mammals ever to have existed. Mastodons looked like living elephants, but the cusps of their molars resembled breasts (the name means breast-tooth), at least in the imaginations of some nineteenth century savants. They became extinct in Eurasia about 2.7 million years ago, but survived until 13,000 years ago in North America.
The advanced deer—the species with multi-pronged antlers that are shed annually—were present in Eurasia by around 14 million years ago. One, known as Dicrocerus, would give rise to the two great lineages of antlered deer, the Capreolinae and the Cervinae. Among the capreolines can be counted the roe deer, the moose, the reindeer and most American deer species (with the notable exception of the elk). The Cervinae include the muntjacs, the red deer and American elk, the fallow deer and the extinct Irish elk, as well as many Asian species including Pere David’s deer and the chital.
The cervines are arguably Europe’s greatest mammalian success story: the earliest type, Cervavitus, first appeared about 10 million years ago—in Europe. By around three million years later it had spread to east Asia and the cervines were well on the way to becoming the most abundant large herbivores in much of Eurasia.8 When it was realised that cervines were European in origin, researchers were astonished, one writing: ‘Europe should be considered more as a Dead End [in terms of migration] than an area with a normal evolutionary diversification.’9
Horses of the genus Hipparion (three-toed horses) migrated from North America into Europe 11.1 million years ago—one of the few successful migrant species at this time. Their arrival marks the start of Europe’s Vallesian age—a subdivision of the Miocene.10 Their fossils are extremely abundant, providing an easy way to date fossil deposits. Broadly similar in appearance to modern horses, they were about half the weight and had two small, hoofed side toes on each foot. Horses had been confined to North America for tens of millions of years, but were now able to migrate because a cold spell led to an expansion of the Antarctic ice cap, and with so much water frozen at the poles, sea levels dropped by 140 metres, opening a grassy land bridge across the Bering Strait.11 Nothing like horses had existed in Eurasia, and they quickly filled the vacant ecological niche.
The strange dog-bears and bear-dogs of the Oligocene lingered into the Miocene in Europe, as did those primitive sabre-toothed predators the nimravids. The lynx-sized Felis attica, the ancestor of all living cats, was stalking the forests of ancient Greece and other parts of Eurasia by 12 million years ago, and the sabre-toothed cats were on the rise.12 Fossil deposits, exposed by mining at Cerro de los Batallones near Madrid, reveal details of their evolution.13 The deposits date from between 11.6 million and nine million years ago and are in filled-in gullies or caves. Most of the bones are from carnivores, indicating that the cavities functioned as natural traps, which were baited with the smell of rotting carcasses. An unusual find from the site is the bones of an extinct kind of red panda.
Complete skulls of several early kinds of sabre-toothed cats were recovered from Batallones, including an early member of the Smilodon lineage and a primitive kind of scimitar-toothed cat. The Smilodon ancestor was only the size of a leopard, while the scimitar-toothed cat was already as big as a lion.14 The Smilodon ancestor was short-legged and almost bulldog-like in shape. Males and females were similar in size, suggesting that they were solitary ambush predators. Scimitar cats had a sloping back like a spotted hyena and were probably excellent runners. Males were much larger than females and may have had territories that overlapped with those of several females, like today’s tiger.
The largest sabre-tooths, which survived until 13,000 years ago in North America, could kill young elephants. It’s not known exactly how the sabre-like upper canines were used; but they were often broken, suggesting violent struggles by the prey. Some researchers believe they were used to sever the arteries in the neck; others think the sabre-toothed cats disembowelled their victims. Their sabres must have made it difficult to fit large hunks of flesh into their mouths, and their large, pointed incisors may have been used to pluck lumps of meat from the carcass. They may also have had rasp-like tongues covered in spines, like those of lions, to lick muscles from bones.
Hyenas evolved in Eurasia during the Miocene from ferret-like ancestors. They diverged into two types—the heavy-bone crushers, and fast running, dog-like types. These dog-like hyenas were extremely abundant in Miocene Europe, their fossils outnumbering those of all other carnivores in some 15 million-year-old deposits. But by five to seven million years ago, a changing climate, and possibly competition from the first dogs to reach Europe, caused them to decline. Today the only dog-like hyena is Africa’s termite-eating aardwolf. The bone-crushing hyenas became the main scavengers of Eurasia—a role that they continue to play in Africa and Asia today. Part of their success seems to have lain in a partnership with the sabre-toothed cats, for the two carnivore types flourished together. Sabre-tooth cats had no ability to break up bones, so presumably the hyenas fed on the skeletons after the sabre-tooths had their fill.
But where were the dogs? They were still a continent away—in North America, awaiting a suitable land bridge to cross into Eurasia. Seven to five million years ago, at the very end of the Miocene Eucyon, a jackal-sized member of the dog family, made that crossing and spread quickly.15. But shortly thereafter they became extinct, and it would take another immigration from North America, about four million years ago, to bring new and larger canid species to Eurasia: these dogs would endure.
Ostriches strode the plains of Eastern Europe from the Miocene to the early Pleistocene. They all, with the exception of a diminutive species from Moldova, belonged to a single type, Struthio asiaticus, which was very similar to the living ostrich, but heavier. It is a scientific conundrum that while the fossil bones look alike, three distinctive kinds of fossil ostrich eggs have been found. Cariamas—metre-high, ground-dwelling predators that today are restricted to grasslands in South America—strode the Miocene plains of France, and parrots found a home in Miocene Germany. Many of the other birds inhabiting Miocene Europe were much like those you might see in Europe today.
We think of giant tortoises as denizens of islands, but in the past enormous chelonians could be found on every continent, and they thrived in Miocene Europe. Miocene python bones have been found in Greece and Bavaria, while a quarry at Wallenreid in Switzerland provided the world’s oldest venomous snake fang.16 Studies of a slightly more recent fang found in southern Germany indicate that these teeth were used to inject venom the same way that venomous snakes use their fangs today.17
The choristerans were crocodile-like reptiles with long, narrow jaws used for catching fish. In appearance and behaviour, they probably resembled India’s gharial, yet they were entirely unrelated to crocodiles. Despite scads of research, the choristerans’ placement on the tree of life remains unclear. But they seem to have originated before the dino
saurs evolved. By the Miocene, they were living fossils, unique to Europe. When scientists found the bones of a primitive choristeran in 20-million-year-old deposits in France and the Czech Republic they were surprised, describing the creature as having a ‘ghostly lineage’ of 11 million years—for no choristeran fossils are known from between 31 and 20 million years ago. They named the fossil Lazarussuchus, because it appears to have risen from the dead.18 We do not know how long Lazarus lived after his resurrection, but Lazarussuchus’ time in the sun appears to have been brief, for it is the last we hear of this venerable reptilian lineage.
CHAPTER 17
Europe’s Extraordinary Apes
Apes seem alien to Europe today, but for about 12 million years, during the Miocene, the continent played a crucial role in their evolution. The ape family (Homindae), includes the human lineage, orangs, gorillas, chimpanzees. Very recent discoveries have revealed that the first hominids, the first bipedal apes, and possibly the first gorillas, all evolved in Europe. This would not have surprised Charles Darwin, who more than 100 years ago speculated that apes ‘nearly as large as a man…existed in Europe during the Upper Miocene; and since so remote a period the earth has certainly undergone many great revolutions, and there has been ample time for migration on the largest scale’.1
The last common ancestors of the Old World monkeys and apes were monkey-like creatures called pliopithecoids. They probably originated in Asia, but soon spread to Europe and Africa.2 Pliopithecoids persisted in Europe, Asia and Africa long after the first true apes and Old World monkeys appeared, and the fossil of one was the specimen Darwin was referred to. It was discovered in the 1820s by workers at a mine in Eppelsheim, near Mainz in Germany. The thigh bone was found in deposits containing the remains of many long-extinct creatures, and was long and straight, with a small hip joint. Overall it was so human-like that some nineteenth century savants posited that it must have belonged to a little girl.
