A tourist to the south eastern tip of what was to become the continent of Africa 350 million years ago would have had to watch where they were treading as scorpions were lurking amongst the primitive plants. We know this because Dr. Robert Gess from the Evolutionary Studies Institute at the University of Witswatersrand (Johannesburg), has discovered the fossilised exoskeleton of one such creature. This unique specimen, a new species named Gondwanascorpio emzantsiensis represents the oldest known terrestrial animal from the super-continent of Gondwana discovered to date. Fossils of terrestrial animals are known from the super-continent of Laurasia, but this is a first for the ancient landmass that dominated the southern hemisphere during the Late Devonian and into the Carboniferous.
A Photograph showing the Scorpion’s Pincers (Gondwanascorpio emzantsiensis)
Picture Credit: University of Witwatersrand
Commenting on his fossil find, Dr. Gess stated that early life arose in the sea and that colonisation of the land took place much later on in the history of life on Earth. This process is believed to have begun back in the Silurian geological period, approximately 420 million years ago, although some palaeobotanists have suggested that microscopic spores preserved in Ordovician strata indicate that plant life was established on land even earlier. Once plants had become established on land in significant numbers, then detritus and plant eating invertebrates followed, animals such as primitive arthropods. By the Late Silurian, around 415 million years ago, terrestrial food chains were much more complex with apex predators such as mites, scorpions and early spiders feeding on the herbivorous invertebrates. By the Late Devonian, some 365 million years ago, the first vertebrates (Tetrapods) had ventured out onto land.
Some palaeontologists believe that the first vertebrates were established on land some 390 million years ago, click the link below to read an article published by Everything Dinosaur in 2010, that provides details of a remarkable fossilised trackway studied by Polish scientists: Tetrapods Venture onto Land Thirty-Five Million Years Earlier
Fossils found in Palaeozoic strata that represent the land mass of Laurasia, a super-continent the straddled much of the northern hemisphere in the Devonian, suggest that this landmass was inhabited by a diverse and abundant group of invertebrates. Laurasia and Gondwana were separated by an ocean over a thousand miles across at its widest extent. Evidence of the earliest colonisation of land animals has until now come only from the northern hemisphere continent of Laurasia (land that was to form North America, parts of Europe and Asia), and there has been no evidence that Gondwana was inhabited by land living invertebrate animals at that time, however, the discovery of this southern hemisphere scorpion suggests that Gondwana too, had its fair share of creepy crawlies.
The discovery of an invertebrate predator leads to the assumption that there were other invertebrates present that this creature would have fed upon. This new species has been named Gondwanascorpio emzantsiensis.
Dr. Gess stated:
“For the first time we know for certain that not just scorpions, but whatever they were preying on were already present in the Devonian. We now know that by the end the Devonian period Gondwana also, like Laurasia, had a complex terrestrial ecosystem, comprising invertebrates and plants which had all the elements to sustain terrestrial vertebrate life that emerged around this time or slightly later.”
The fossil fragments were found in black carbonaceous shale which represents a marine lagoon and an estuarine environment. The fossiliferous material is from the Witpoort Formation (Witteberg Group) at a location known as Waterloo Farm, near Grahamstown, South Africa. Other organic material identified includes traces of algae, terrestrial plants, small fish, a sea scorpion (Eurypterid) and a number of molluscs. All the fossil material ascribed to G. emzantsiensis consists of two-dimensional compressions in which all the original organic material has been replaced by secondary metamorphic mica. The mica has largely been altered to chlorite during the uplifting of the strata. The Witpoort Formation strata at the Waterloo Farm location were laid down towards the end of the Devonian (Famennian faunal stage), approximately 360 million years ago.
A Close up of the Preserved Pincers