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The rocks of the Beaufort Group contain fossils that illustrate several important threads of the evolutionary tapestry of life on earth. One of the most important is the one which traces the evolution of the mammals from their early reptilian ancestors. Some of the most primitive known Therapsida (or mammal-like reptiles ) are found in the basal rocks of the Beaufort Group in South Africa, and the BPI has an active ongoing research program studying these very early ancestors of mammals. Close relatives of these primitive South African therapsids are known elsewhere only from Russia and China in rocks of similar age. |
All known major vertebrate groups from the Beaufort Group are represented in the Karoo Vertebrate Collection, with good collections of Dicynodontia, Gorgonopsia, Therocephalia and Cynodontia. These fossils are available for study by accredited and approved researchers. Any researcher who qualifies and who wishes to study specimens in the BPI Collections may apply to do so by completing and submitting the electronic application form.
The Karoo Verteberate Collection also contains a good sample of dinosaurs and other archosauriforms from the later rocks of the Stormberg Group, which followed the deposition of the Beaufort Group. The rocks of the Stormberg Group cover a period of earth history from the Mid Triassic (about 210 myr ago) to the Mid- or Late Jurassic (about 150 myr ago). In these beds are found advanced protomammals ( mammal-like reptiles ), the earliest mammals, primitive saurischian and ornithischian dinosaurs, and a variety of minor faunal elements including crocodilians and tortoises (turtles), most of which are well represented in the Karoo Vertebrate Collection.
The extensive outpourings of basaltic lava (Drakensberg Group) during the early and middle portions of the Jurassic Period marked the close of the deposition of the Karoo Supergroup, and heralded the breakup of the great supercontinent of Gondwana.
2a. Fossil Plants
There are over 30 000 catalogued specimens of fossil plants and insects in the Institute s Fossil Herbarium, mostly from southern Africa. They include Devonian fossils from the Bokkeveld and Witteberg groups (Cape Supergroup: Devonian to mid-Permian in age) up to Lower and Middle Cretaceous cycadophytes, ferns, conifers and angiosperms. Most of the plants come from the Permian and Triassic deposits of South Africa, with a wide variety of Glossopteris leaves and fruiting structures, ferns, sphenophytes, gingkophytes and the Dicroidium flora.
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Leaf of the Permian seed-fern, Glossopteris
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Frond of the Triassic seed-fern, Dicroidium
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The collectors of these plants over the years have included such people as Thomas Leslie, Edna Plumstead, George Stumke, Stephanus Le Roux, James Kitching and Heidi and John Anderson.
2b. Fossil Wood
This fairly new collection has over 700 specimens of fossil wood from southern Africa, ranging in age from Lower Permian to Pleistocene. Most of the specimens have been sectioned to make petrographic slides and research is still in progress, identifying and describing the material. One aim of our current research is to establish a database of the Karoo woods.
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Microscopic section of Miocene fossil wood, Legumenoxylon
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3. Plio-Pleistocene Vertebrates
This huge collection has resulted mainly from work on the excavated fossil-bearing cavern infills of the Makapansgat Limeworks in the Potgietersrus District of the Northern Province (in what used to be called the Northern Transv l ). These deposits represent sediments that progressively fill caverns which develop in dolomitic or calcareous rocks as a result of the action of ground water. The water dissolves limestone and dolomite below the water table to leave a patchwork of voids in the country rock. Once these voids acquire openings to the surface through erosion, they become caves available for use by living organisms as refuges or lairs, or they become traps into which living animals fall, some dying there because they cannot escape. Whichever way they get into the caves, their carcasses become excellent candidates for fossilisation.
In this way vast quantities of bone have been preserved in the honeycombed network of caves in the Makapansgat region over a period of several million years during the Pliocene and Pleistocene, and the process continues to this day.
Included in the fossil fauna recovered from Makapansgat are the remains of the early human ape-like ancestor, Australopithecus, and an enormous variety of broken bones and bone flakes, many of which the late Professor Raymond Dart believed showed evidence of deliberate and controlled damage, and also signs of intelligent use. He proposed that the accumulations of bone in the Makapansgat caves could be attributed to the actions of the australopithecines, and that they practised a primitive culture based on the use of the bones, teeth and horns of animals, which he termed the Osteodontokeratic Culture of the australopithecines .
More recent work has largely refuted this theory, and it now seems clear that the main agents of accumulation of the vast quantities of bone were hyaenas and to a lesser extent other carnivores and porcupines.
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Hyaena skull from Makapansgat (Plio-Pleistocene)
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The collection consists mostly of the remains of many different kinds of medium-sized to small mammals dominated by antelopes, but including also equids (mainly zebras), pigs, elephants, rhinos, hippos, a variety of carnivores including at least two species of sabre-toothed cats, hyaenas, lions, leopards, cheetahs, small cats, jackals, etc. In addition there is a large collection of microfauna - dominantly rodents - accumulated by owls which used the twilight-zone of the ancient caves as roosting places, as their descendants do today. Their pellets of regurgitated food remains were cast below their roosting sites, to be buried in the cave sediments and preserved as fossils.
Unusual elements in this collection include the fossilised remains of blowfly pupae, dung-balls rolled by dung-beetles (scarabeids), and other clear signs of the action of invertebrates like hide beetles (dermestids) and horn moths.
4. Trace Fossils
The various strata of the Karoo preserve an impressive variety of trace fossils - traces of the actions of living animals going about their normal activities of life. These traces include feeding trails left in muddy bottom sediments by aquatic invertebrates, swimming traces drawn by the fin spines of fish swimming close to the bottom in quiet waters, and trackways of bottom-dwelling crustaceans and insects as they scuttled over the surface muds.
This is not a large collection, and at present is somewhat static as no new research in this direction is currently being carried out in the Institute.
5. Bone Histological Slide Collection
This small but growing collection contains microscopic thin-sections of the bones of a variety of vertebrates mainly from the Karoo, including therapsids and dinosaurs. Most of the slides result from specific individual research projects, so the collection is not yet comprehensive or fully representative of the entire fauna of the Karoo.
6. Palynological Slides Collection
As each palynological project is completed, the microscope slides which were prepared for that particular study are catalogued and filed. The microscopic size of pollen (average around 25 microns) means that each slide holds many pollen grains. Individual pollen grains, if significant, are grid-referenced in the report which completes each study, so that they can be easily relocated as and when required.
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Striatobietites, a fossil pollen grain from a gymnosperm, (Late Permian)
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Fossil fern spore, Dictyophyllidites, Early Tertiary
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7. Replicas of Fossils for Sale
The Institute has a large number of fossil casts for sale at very reasonable prices. These include therapsid ( mammal-like reptile ) skulls and postcranials, dinosaur skulls and postcranials, and a variety of fossils from the Makapansgat Plio-Pleistocene deposits, amongst others. Please enquire about prices and other details by emailing Sonia.sequeira@wits.ac.za at the BPI.
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