The History of the World

"The history of the world, my sweet
Is who gets eaten and who gets to eat."
                                    —Stephen Sondheim, Sweeney Todd
Extinct species of the Spec world (not to scale):
Acrotitan: Oligocene (Chattian) Neotropical saltasaurid. Amongst the largest and the last of the South American titanosaurs.
Titanotarsus: Eocene (Lutetian-Priabonian) Australian/Antarctic titanosaur. Amongst the last sauropods found in Australia.
Sauropodimimus: Late Oligocene (Chattian) Asian lambeosaurid that attained enormous sizes. Last of the lambeosaurs, with the extinction of Sauropodimimus and it's kin, Asia was devoid of hadrosaurs until repopulated by stock from North America during the Late Pliocene.
Lycovenator: A plesiomorphic dromaeosaur from the Messel Shales - putative ancestor for the entire Tertiary Holarctic drak radiation
Saltotyrannus: This tiny, metre long tyrannosaur, also from the Messel Shales is considered by many to be the first true errosaurid (or at least a "proerrosaurid"). The superlative preservation of the Messel shows that this animal possessed the full body-covering of feathers present in its modern cousins.
Nanodon: The last of the South American neoabelisaurids from the Pliocene. Became extinct shortly after the invasion of northern predators across the Central American isthmus.
Monoceratops: One of many spectacular large North American protoceratopsians that died out in the Late Pleistocene.
Pikodon: (Miocene) One of the last of the Australian torvodonts and the largest terrestrial predator even discovered.
Massosuchus: (Late Eocene) A European spinosaur with a perculiar arm/leg lenghth ratio that suggests a quadripedal stance.
(Picture by Brett Booth, text by Brian Choo and Daniel Bensen)
     The history of Spec as a timeline distinct from RL begins, as far as paleontologists can determine, 65 million years ago, at the boundary between the Cretaceous and the Tertiary periods.  Spec-world fossils dating before this boundary most often belong to organisms described in Arel, although a few (most notably Mirabilotheridium, a monotreme from Cretaceous South America and Lepelara, an early angiosperm) represent new genera.  Of these novel finds, most have fit comfortably within the accepted theories of Home-Earth's evolutionary history.  No doubt, these pre-Tertiary species simply represent fossils that exist in RL, but have yet to be found.

    In the Tertiary, however, Spec's fossil record begins to diverge from the familiar natural history of our home timeline.

(Text by Daniel Bensen)
A Tectonic Spectacle: The World at the End of the Mesozoic Era

    Across the globe, the Earth has become a grand stage for spectacular tectonic activity. Great mountain ranges are being pushed upwards accompanied by volcanic activity the likes of which have never been seen before in the Mesozoic.  The grandest spectacle takes place on the Gondwanan fragment of India as it dashes itself against the Asian plate.  Erupting in their full glory are the volcanoes that will create the Deccan Traps, leaving an area of 1.5 million square kilometers buried under 2 kilometers of flow basalt.

    This is not the only upheaval facing the world. Across the globe the oceans have been in retreat for the past few million
years, exposing vast tracts of shallow seafloor. Great Britain rises from its watery prison. The two halves of North America are reunited as the Interior Seaway vanishes. The extent of the continental landmasses is dramatically enlarged. Soon it is possible to walk around the entire Northern Hemisphere without getting one's feet wet.

    All this activity has put life on Earth under intense stress. Great clouds of volcanic ash screen the sunlight with dire consequences for many phototrophic organisms. Whole continental shelf communities are left high and dry. Once lush island paradises are suddenly faced with continental climates that bring extremes of temperature and erratic rainfall, now often laced with sulphuric acid.

    In the oceans,  global oceanic cooling and the draining of inland seas leads to a near total annihilation of the world's tropical reef ecosystems.  Many once diverse families are eliminated or reduced to a few cosmopolitan species.  Entire food chains collapse, from tiny plankton to the apex predators.

   The mosasaurs and ammonoids somehow manage to pull through. The graceful elasmosaurs and pliosaurs are not so
fortunate. On the seafloor, once vast beds of giant inoceramid clams dwindle then vanish whilst their cousins, the rudists, are reduced to a handful of coolwater species. Although the rudists as a group will survive up until the present day, their time as the dominant reef-builders is over.

   Gone forever are the great shadows cast by pterosaurs soaring high overhead. The pioneers of vertebrate aviation have
surrendered the skies to the birds and recently evolved mammalian bats.  Alas, neither of these groups will ever produce a
flier that comes even close to rivalling the sheer majesty of the largest pterosaurs.

   Life on land is also under siege. Death in different parts of the world might come from earthquakes, volcanoes, chemical contamination, fluctuating temperatures or increasing aridity. Forests wither. Embryoes die within the egg. And if that wasnít enough, the falling sea-levels unite previously isolated landmasses,  allowing populations of dinosaurs to travel unhindered between the continents. Soon their wanderings bring the added burdens of introduced diseases and new competitors. Most non-avian dinosaur lineages suffer a marked drop in diversity. Across the globe, the number of dinosaur species in any given area can usually be counted on one hand.

   In all, an estimated 15-20% of the earth's biodiversity is lost during this time.

   As their struggle for survival becomes an ever-increasing nightmare, few of the animals notice the new star that has
appeared in the heavens. As the weeks progress it gradually grows in size, trailing its gossamer train in its wake.  Bigger and brighter it becomes until it becomes clearly visible in the daylight where the volcanic clouds do not mask the view.  Then on one night the wanderer seems to lose it's resolve and grows almost imperceptibly dimmer. As the nights pass it's waning continues,  smaller and smaller, until it is lost amongst the myriad of stars. The world has arrived at a crossroads and taken one path at the expense of another. For the dinosaurs, the grim struggle to live continues, oblivious to the even grimmer fate that has just been averted.

Picking up Pieces in the Paleocene
 LATE PALEOCENE (c.63 - 57,000,000 bp)

   Depleted ecosystems around the world are regaining their lost biodiversity as conditions improve. Surviving pockets of forest spread outwards across the land, their growth facilitated by the dearth of herbivores. The seas once again teem with plankton allowing marine food chains to reestablish themselves. Insects fill the skies, quickly followed by the birds and early bats. Mammals and lizards scurry in the undergrowth.

   Maybe fewer than 100 non-avian dinosaur species worldwide made it through the K-T boundary in sufficient numbers to keep their kind in existence.  A roll call of the Northern Hemisphere finds many faces missing, Gone are the speedy
ornithomimosaurs , the bizarre alvarezsaurs (which still survive in the south) and all but a handful of the horned ceratopsians. All the northern sauropod species are extinct.  Strangely, the bone-headed pachycephalosaurs seem to survive the K-T intact only to vanish before the end of the Paleocene.

   Biodiversity remains globally poor, most species are generalists with very large distributions. The runaway volcanism and the horrid black clouds of ash and acid have subsided. However, low sea-levels maintain extensive land-bridges between most continents, keeping regional endemism to a minimum (Europe and North American share more than two thirds of their tetrapod genera at this time) but also giving life the chance to repopulate the most remote of depleted areas.

   At this time Africa plus most of the Northern Hemisphere landmasses seem to form one broad biogeographical region. The dominant large plant eaters are hadrosauroid ornithopods, although only three genera are commonly represented---a
hadrosaurine, a lambeosaurine and, restricted to Africa and Europe, a small basal hadrosaur (Anserodromeus). Both the
giant ceratopsids and sauropods are represented by one genus each, the former found throughout the region, the latter largely restricted to Africa and Europe.  Large theropods include at least one tyrannosaur and a moderate-sized abelisaurid. The status of the smaller dinosaurs at this time is unclear - but the presence of hypsilophodonts, protoceratopsians, small ankylosaurs and maniraptorans is inferred.

   The situation in Greater Gondwana (South America, Antarctica and Australia) is patchily understood. The sauropods
apparently fared much better in this part of the world with at least 3 genera surviving. Large ornithopods are rare but at least two smaller-bodied families, ancestors of the modern Neodryosauria and Antarctornithopoda, are widespread. The
alvarezsaurids are also alive while the ankylosaurs are very rare and scattered.  The top predators appear to be giant
maniraptoran protobirds although the more primitive abelisaurids are also in force.

    As the Paleocene draws to a close, the dinosaurs which made it through the K-T extinction event are well on the road to recovery and diversification. Varying conditions across the globe prod widely distributed species to form clines, then distinct races before ultimately speciating into completely new forms. Their empire may have recently been through hard times but the great beasts have survived and continue to rule the Earth. The Age of the Dinosaurs goes on...

A Brief Golden Age
EARLY TO LATE EOCENE  (c.57 - 40,000,000 bp)
    It is a time of plenty. The continents are altering their outlines and positions as the seafloors spread rapidly. The seas have advanced since the Paleocene, severing land-bridges and facilitating isolation and regional endemism. Global temperatures are warm, nurturing lush tropical floras as far north as Britain. In the seas, warm climate and the return of shallow inland seas put evolution into overdrive.  Most modern fish families are now present while the mosasaurs undergo a major diversification event, the archetypal serpentine body shifting into everything from small eel-like river-dwellers to delphinoid pelagic forms.

    On land, one could be forgiven for thinking that they were back in the Cretaceous. The dinosaurs are everywhere in huge numbers and at levels of diversity not seen since the Campanian over 20 million years earlier.

    In North America, the hadrosaurine  duckbills have branched into a number of endemic lineages. But these animals live in the shadow of the immense Brontoceratops, the largest ceratopsian to have ever existed.  Stalking the herds are tyrannosaurs, which have obviously hit upon a winning formula and are practically unchanged since the Cretaceous. Notable in their absence are the club-tailed ankylosaurids, although their spiny nodosaurid  cousins are present.



    Africa, now sliced in half by inland seas, is once again isolated and its dinosaurs are now heading off in their own evolutionary direction. Once again, the land is dominated by herds of giant duckbills, mostly the descendents of
Paleocene-Asian immigrants but members of a more primitive local clade are also on the march.  Sauropods also flourish as do a host of smaller, poorly understood herbivores.  Africa has acquired some Asian tyrannosaurs but they face competition from a much older theropod clan, the neoceratosaurian abelisaurs.

    On the other side of the world, this was the final hour for the united Greater Gondwanan dinosaur-fauna, just before the
terminal breakup. The last land-connection to South American has only just been severed to Antarctica, while Australia is
hanging on by a thread.  The sauropods reign supreme; herds of giant long-necked earthshakers are everywhere. Aside from a few duckbills, descendents of a Paleocene interchange with North America, the ornithischians are less conspicuous, but they are still diverse and abundant in the smaller herbivore guilds. Two endemic ornithopod radiations are now recognizable, the medium-sized browsing neodryosaurs and the diminutive omnivorous antarctornithopods . As in Africa, the abelisaurids are on the prowl, but here they play second fiddle to the notoraptors, a group of enigmatic giant sickle-clawed maniraptorans.

   The status of the dinosaur fauna of India at this time and during the folling period of extinction is presently unknown.

A New Crisis
   During the closing phase of the Eocene Epoch (the Priabonian) and the opening phase of the Oligocene (the Rupelian),
dinosaur communities worldwide were once again plunged into crisis. Across the globe, countless species were facing
extinction, both on the land and in the oceans. The direction of evolution on the Specworld was to be forever altered.

   The extinctions of Eocene-Oligocene transition did not take place as a single discrete event, but rather as a series of
extinction pulses. The first took place close to the start of the Priabonian about 40 million years ago with three or four
additional pulses taking place throughout the Eocene-Oligocene transition, the last one occurring 31 million years ago
towards the end of the Rupelian. A similar phenomenon occurs in Arel's fossil record and the progression of events in both timelines show strong similarities with regards to the marine fossil record.  In the oceans during the extinction pulses, those groups most seriously affected were generally tropical and inshore forms. Many foraminiferans disappear, and those that survive show a heightened amount of oxygen 18 in their tests (a phenomenon associated with a lowering in temperature). Tropical calcareous nanoplankton are decimated whilst high-latitude floras of these organisms appear at the equator.

   The evidence points to both a cooling of the world's oceans as well as a severe drop in global sea-levels during the final
pulse of extinctions in the Oligocene.  Such conditions at sea would in turn have a direct consequence for life on land.
Although there is some evidence of extraterrestrial impacts during this time, it seems likely that this climatic deterioration and fluctuation was tied in with final breakup of the ancient Gondwana.

   Towards the end of the Eocene, Australia rifted away from its last connections with Antarctica. Cold water flowed into the widening gap, deflecting the warm currents that had previously kept the south polar climates mild. For the first time since the Paleozoic, a permanent ice cap began to form at the South Pole. With the formation of the psychrosphere,  a great chilling engine was created in the southern oceans. Warm water was trapped in the south where it was cooled and forced to descend into the ocean depths before spreading back towards the equator.  Each time the cool temperatures were sent towards the lower latitudes via wind, oceanic currents or upwellings, it triggered off a wave of extinctions. In the longer term, this marked the start of a profound shift in the Earth's climatic history would ultimately lead to the ice ages of the Pleistocene.

Winners and Losers
LATEST EOCENE  TO  LATE OLIGOCENE (40,000,000 - 24,000,000 bp)
     The exact timing of many of the terrestrial extinctions is unclear. Most dinosaurs seemed relatively unaffected by the first extinction pulse at the start of the Priabonian, but took losses close to the Eocene-Oligocene boundary. The final pulse, accompanied by the dramatic dip in sea-levels, seems to have been the final nail in the coffin for many already struggling taxa.

     Overall, the climate on land seems to have gotten colder and drier during the pulses. As seas retreated, once coastal regions were left far inland and faced increasingly dry conditions.  Areas once blanketed by humid forest gave way to semiarid scrub and, for the first time, grasslands.

     In a repeat of K-T, sauropods vanish across the Northern Hemisphere while they only just manage to scrape through in Africa. The Asian ankylosaurs have had their diversity halved and will remain a minor component of the fauna up until their extinction at the end of the Miocene. In North America and Asia, Brontoceratops and the other horned giants face their final curtain call. The great evolutionary dynasty of the Ceratopsidae has come to an end. However their more primitive protoceratopsian cousins are thriving and soon grow to enormous sizes, filling niches vacated by the recently departed sauropods.


         Expansion and Isolation in the Miocene
         THE MIOCENE EPOCH (c.24,000,000 - 5,000,000 bp)

         The longest epoch of the Cenozoic, while less tumultuous than its predecessors, still bears witness to great changes in the geography and biota of the planet. The wandering landmass of India finally collides with the Asian mainland, an event which spawns the highest mountains on the planet. The Americas head westwards against the Pacific Plate, pushing up the Rockies and the Andes. As Africa draws ever closer to Europe, it sounds the death knell for the ancient Tethys Sea. Cut off from neighbouring oceans, it quickly evaporates into a vast dry salt-encrusted basin. While the Atlantic will ultimately break through the straights of Gibraltar towards the end of the epoch and thus give rise to the Mediterranean, the terrestrial link between Africa and Eurasia will remain unbroken.

    Life in the seas is rich and varied. Calcareous plankton is abundant while, at the other end of the food chain, giant predatory saurocetes and sharks prowl the tropics. Taking advantage of the rich polar waters, large swimming birds have successfully radiated at the higher latitudes. At several times during the Miocene, the seas experience sharp drops in temperature accompanied by an expansion of the Antarctic ice sheet. However these episodes are not severe enough to trigger off anything more that mild, localised extinctions at sea or on land.

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