pocket-like skin flap which extends along the midline of the back from the tail, which distinguishes the springbok from true gazelles. Taxonomy and evolution The springbok, in the family Bovidae, was first described by the German zoologist Eberhard August Wilhelm von Zimmermann in 1780, who assigned the genus Antilope (blackbuck) to the springbok. In 1845, Swedish zoologist Carl Jakob Sundevall placed the springbok as the sole living member of the genus Antidorcas. Subspecies Three subspecies of Antidorcas marsupialis are recognised: A. m. angolensis (Blaine, 1922) – Occurs in Benguela and Moçâmedes (southwestern Angola). A. m. hofmeyri (Thomas, 1926) – Occurs in Berseba and Great Namaqualand (southwestern Africa). Its range lies north of the Orange River, stretching from Upington and Sandfontein through Botswana to Namibia. A. m. marsupialis (Zimmermann, 1780) – Its range lies south of the Orange River, extending from the northeastern Cape of Good Hope to the Free State and Kimberley. Evolution Fossil springbok are known from the Pliocene; the antelope appears to have evolved about three million years ago from a gazelle-like ancestor. Three fossil species of Antidorcas have been identified, in addition to the extant form, and appear to have been widespread across Africa. Two of these, A. bondi and A. australis, became extinct around 7,000 years ago (early Holocene). The third species, A. recki, probably gave rise to the extant form A. marsupialis during the Pleistocene, about 100,000 years ago. Fossils have been reported from Pliocene, Pleistocene, and Holocene sites in northern, southern, and eastern Africa. Fossils dating back to 80 and 100 thousand years ago have been excavated at Herolds Bay Cave (Western Cape Province, South Africa) and Florisbad (Free State), respectively. Description The springbok is a slender antelope with long legs and neck. Both sexes reach at the shoulder with a head-and-body length typically between . The weights for both sexes range between . The tail, long, ends in a short, black tuft. Major differences in the size and weight of the subspecies are seen. A study tabulated average body measurements for the three subspecies. A. m. angolensis males stand tall at the shoulder, while females are tall. The males weigh around , while the females weigh . A. m. hofmeyri is the largest subspecies; males are nearly tall, and the notably shorter females are tall. The males, weighing , are heavier than females, that weigh . However, A. m. marsupialis is the smallest