where its closest relatives are the hartebeest (Alcelaphus spp.), the hirola (Beatragus hunteri), and species in the genus Damaliscus, such as the topi, the tsessebe, the blesbok and the bontebok. The name Connochaetes was given by German zoologist Hinrich Lichtenstein in 1812. Dutch settlers first discovered wildebeest in about 1700, on their way to the interior of South Africa. Due to their resemblance to wild cattle, these people called them "wild ox" or "wildebeest". The blue wildebeest was first known to westerners in the northern part of South Africa a century later, in the 1800s. In the early 20th century, one species of the wildebeest, C. albojubatus, was identified in eastern Africa. In 1914, two separate races of the wildebeest were introduced, namely Gorgon a. albojubatus ("Athi white-bearded wildebeest") and G. a. mearnsi ("Loita white-bearded wildebeest"). However, in 1939, the two were once again merged into a single race, Connochaetes taurinus albojubatus. In the mid-20th century, two separate forms were recognised, Gorgon taurinus hecki and G. t. albojubatus. Finally, two distinct types of wildebeest – the blue and black wildebeest – were identified. The blue wildebeest was at first placed under a separate genus, Gorgon, while the black wildebeest belonged to the genus Connochaetes. Today, they are united in the single genus Connochaetes, with the black wildebeest being named (C. gnou) and the blue wildebeest (C. taurinus). According to a mitochondrial DNA analysis, the black wildebeest are estimated to have diverged from the main lineage during the Middle Pleistocene and became a distinct species around a million years ago. A divergence rate around 2% has been calculated. The split does not seem to have been driven by competition for resources, but instead because each species adopted a different ecological niche and occupied a different trophic level. Blue wildebeest fossils dating back some 2.5 million years ago are common and widespread. They have been found in the fossil-bearing caves at the Cradle of Humankind north of Johannesburg. Elsewhere in South Africa, they are plentiful at such sites as Elandsfontein, Cornelia, and Florisbad. The earliest fossils of the black wildebeest were found in sedimentary rock in Cornelia in the Free State and dated back about 800,000 years. Today, five subspecies of the blue wildebeest are recognised, while the black wildebeest has no named subspecies. Genetics and hybrids The diploid number of chromosomes in the wildebeest is 58. Chromosomes were studied in a