A lost savanna sea
The Alakol Basin, today a landscape of vast steppe and saline lakes, looked very different during the Neogene Period. Between 9.5 and 5.5 million years ago, in the Late Miocene epoch, this area was a subtropical woodland and open grassland, part of a widespread ecosystem known as the Pikermian biome. Fossil pollen and sedimentary evidence show a mosaic of wooded areas, glades, and river margins, all supporting a diversity of life. This environment, warmer and wetter than today, was sustained by a different configuration of seas and mountains. The basin itself was part of a larger trough that once held ancient seas and, during the Miocene, developed into a system of large, shallow lakes that created ideal conditions for preserving the bones of animals that died near their shores.
The fossil beds here, part of a geological layer known as the Chul'adyr Formation, contain a menagerie of extinct creatures. These fossil assemblages correspond to the Turolian age of the Late Miocene, a period between roughly 9 and 5.3 million years ago, when this particular fauna thrived across Eurasia. The concentration of bones suggests that herds of large mammals congregated in the basin, drawn to the water and abundant vegetation.
The Turolian menagerie
The most striking residents of this lost world were the giraffids. Unlike modern giraffes, Samotherium had a much shorter neck, an intermediate form between a modern giraffe and an okapi. Standing about 3 meters tall at the shoulder with a body mass estimated between 500 and 1300 kg, these were large herbivores. They were not alone. Herds of three-toed horses called Hipparion were common inhabitants of the grasslands. These equines were roughly the size of a small modern horse but possessed two vestigial side toes on each foot, a remnant of their evolutionary past.
The basin also supported a variety of other large mammals. The hornless rhinoceros Chilotherium, a hefty grazer, roamed the area. The diverse herbivore population provided ample food for formidable predators. The saber-toothed cat Amphimachairodus was a likely predator of animals like Samotherium. Another powerful carnivore present was the "bear-dog" Amphicyon, a large predator combining features of both bears and dogs. The fossil record paints a picture of a complex food web in a seasonal woodland environment, different from the arid steppe that defines the region today.