Of all the transitional series amongst the major groups of vertebrates, one of the most extraordinary and best documented is the transition from primitive amniotes to mammals. Amniotes are vertebrates whose embryos are totally enclosed in a fluid-filled sac, called the amnion and include living reptiles, birds and mammals. About 350 million years ago, the amniotes gave rise to two different lineages, namely the reptiles and the mammals. The group of animals that include mammals and all their ancestors is called the Synapsida. The early synapsids that lived between 260 and 180 million years ago are known as the therapsids, a particularly significant group in the study of mammalian evolution as they are the direct ancestors of living mammals.
The South African Karoo Basin contains the best therapsid fossil record in the whole world giving us the exciting opportunity of being able to study the intricate details of the transition into mammals. These animals, that span a period of more than 80 million years from the Middle Permian to the Middle Jurassic, show the gradual acquisition of mammal-like characteristics until it is almost impossible to distinguish the latest most mammal-like therapsids from the earliest true mammals.
The research conducted in the Karoo Palaeontology Department focuses on the biology, ecology and biostratigraphy of these very important animals. Regular field excursions to the Karoo have allowed us to expand our current vertebrate collection and thus conserve these fossils, which form an important part of South Africa’s natural heritage.