Imagine the deserts of the Quaternary period. The boundless continental deserts, such as the Gobi and the Kyzylkum in Asia, which are so distant from the sea that little moisture reaches them. The rainshadow deserts, such as Death Valley in North America, which are tucked in behind coastal mountain ranges that form a rocky barrier to the moist oceanic air. The so-called trade wind deserts, such as the Sahara of Africa, where clouds are chased away by hot winds, leaving the sun to scorch the sand. And the coastal deserts, such as the Namib in Africa, where cold ocean currents cool the air and desiccate the land. 200 million AD, these deserts have run into one another. Separated only by jagged mountain peaks, they cover the largest continent that has ever existed on the planet.
The Central Desert is a wilderness of drifting sand seas, sun-cracked stones and shattered gravel. Unbearable extremes of heat and dryness combine to produce the most hostile living conditions. There are no clouds and the summer sun sears the bare rocks and sand so that temperatures reach a withering 120 degrees Fahrenheit (50 degrees Celsius) in the daytime. At night, the accumulated heat is radiated away to the frosty sky and temperatures dive to a bitter -20 degrees Fahrenheit (-30 degrees Celsius). In winter, parts of the northern interior are colder than Earth's surface has ever been.
Such are the conditions for life (or survival) at the heart of Novopangaea. The most remote areas of the Central Desert have not seen rain for hundreds of years. So where is the water that is essential for life? This region was once covered by warm, shallow seas, formed when sea levels were high and the climate was temperate. Gradually, as the continents piled into on another, the land was uplifted and the shallow seas drained off into deep ocean basins. Rain filtered into the limestone and created a sprawling labyrinth of limestone caves deep below the Central Desert.
At the edge of Novopangaea, constant rain drenches the seaward mountain slopes and soaks into the strata, eventually seeping into the porous limestone of the mainland. Over time, this water fills the subterranean reservoirs that lie below the Central Desert, giving life to the barren wastes above. The animals and plants that exists in this arid land are true specialists. Experts in enduring extremes of temperature, they survive through the single-minded pursuit of water.
The most successful living creatures in the Central Desert are insects. For 600 million years, their remarkable adaptability has enable them to survive the most extreme conditions and weather out all the great mass extinctions the planet has suffered. More than any other living animal, insects are able to diversify into and exploit any number of ecological niches.
In the hostile environment of the Central Desert, insects have found a way to create their own living conditions.
The sunburnt surface of the Central Desert belies the labyrinth of limestone caves and water-filled fissures beneath. They stay the same temperature all year, and stretch for thousands of kilometers beneath the desert. To explore this hidden world, it is necessary to look in more detail at its formation. The limestone deposits are a relic of the reefs and muds of the shallow seas that once existed here. As the continents collided, the land rose up, displacing the shallow seas and compressing the muds reefs into solid stone. Limestone is made up of the shelly debris of marine life and is easily eroded and dissolved by acids in the groundwater. The action of these acids initially creates small pores but, over time, larger caves can result. Despite the acidity of the water and the total lack of sunlight, one group of animal has flourished: polychaetes, a class of segmented annelid worms also known as bristle worms.
Normally all life derives indirectly from sunlight: plants convert carbon dioxide and water into food using the energy of the sun; plant-eating animals eat this food and are in turn eaten by carnivorous predators. In the darkness of the caverns, this does not apply. Instead, the initial energy is derived from chemicals. Bioluminescent bacteria break down sulfur compounds in the rocks and grow on the energy released, forming an encrustation on the cave walls.