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26 April 2018 Photo Supplied
Pretzel-formed fossil of great evolutionary interest
Slab with holotype of Parapsammichnites pretzelifornic from the Urusis Formation, Namibia. Scale bar is 1cm.Picture was taken from Buatois et al., 2018.

The acclaimed scientific journal, Nature, recently published an article about a trace fossil in approximately 543-million-year-old rocks, which elucidates the evolution of the first animals that appeared on Earth and lived in the sea.  

Affiliated Professor in the Department of Geology at the University of the Free State (UFS) Prof Gerard Germs formed part of a team that conducted research with the aim of understanding how the evolution of the first multicellular animals came about and how the Cambrian explosion took place. Prof Germs is of great value to the team for his extended field geological knowledge.

An article which he co-authored was published in the Nature Scientific Reports. The title of the article is: “Sediment disturbance by Ediacaran bulldozers and the roots of the Cambrian explosion”. The international group of writers included authors from Canada, Spain and South Africa. 

Occurrence of the Cambrian explosion
Prof Germs explains the Cambrian explosion: “During the long (4.5-billion-year) history of the Earth, the first life originated and subsequently evolution of plants and animals took place from one-cellular organisms to multicellular vertebrate animals and seed plants. Approximately 573 million years ago the first multicellular animals appeared on the scene. Sometime afterwards, approximately 540 million years ago, a kind of explosion in the origin of many new animal species occurred. This explosion is known as the Cambrian explosion.”

The team studied Earth sediments which are somewhat older than the Cambrian explosion. Such sediments are approximately 573 to 541 million years old and form part of the Ediacaran (late Neoproterozoic) period.

“My discoveries of the past, of among others, the oldest animal with a carbonate skeleton (Cloudina) and of complex horizontal Cambrian-type “worm” tracks (treptichnids) in Ediacaran sediments of Namibia have demonstrated that the Cambrian explosion occurred more gradually than previously thought. This has recently been confirmed in the article that was published in the Nature Scientific Reports.”

Pretzeliformis bulldoze to search for food
According to the article there is evidence that   during the Ediacaran period   worm-like animals such as the Parasammichnites pretzeliformis were already so far developed that they, due to coelom development and size increase, for the first time in the history of the Earth, were able to disturb and bulldoze sediments.  In this way they were able to find a new food source in sea sediments. Bulldozing animals were previously thought to have originated only during and after the Cambrian explosion and not during the older Ediacaran.

“Another major aim of my cooperative research is to improve our knowledge of the geology of the Ediacaran to early Cambrian of South Africa and Namibia. We also intend to establish how the assembly of the supercontinent Gondwana took place. This improved knowledge can be of great future economic interest since large oil, gas and limestone sources occur in Ediacaran-age sediments outside South Africa”.

News Archive

Studies to reveal correlation between terrain, energy use, and giraffe locomotion
2016-11-18



More than half of giraffes in captivity in Europe are afflicted by lameness. This high prevalence represents an important welfare issue, similar to other large zoo animals.

According to Dr Chris Basu, a veterinarian at the Royal Veterinary College in the UK, giraffes in captivity are often afflicted by overgrown hooves, laminitis and joint problems. Diagnosis and treatment is limited by our understanding of anatomy and function, more specifically the locomotion of these animals. Although the giraffe is such a well-known and iconic animal, relatively little has been studied about their locomotor behaviour.

Dr Basu recently visited South Africa to do fieldwork on the locomotion of giraffes as part of his PhD studies under the mentorship of world-renowned Professor of Evolutionary Biomechanics, Prof John Hutchinson. This project is a joint venture between Dr Basu and Dr Francois Deacon, researcher in the Department of Animal, Wildlife, and Grassland Sciences at the UFS. Dr Deacon is a specialist in giraffe habitat-related research. 

Together Prof Hutchinson and Drs Deacon and Basu form a research group, working on studies about giraffe locomotion.

Wild giraffe population decrease by 40% in past decade

“Locomotion is one of the most common animal behaviours and comes with a significant daily energetic cost. Studying locomotion of wild animals aids us in making estimates of this energetic cost. Such estimates are useful in understanding how giraffes fit into ecosystems. Future conservation efforts will be influenced by knowledge of the energy demands in giraffes.

“Understanding aspects of giraffe locomotion also helps us to understand the relationships between anatomy, function and evolution. This is relevant to our basic understanding of the natural world, as well as to conservation and veterinary issues,” said Dr Deacon.

Locomotion study brings strategy for specialist foot care

On face value it seems as if foot disease pathologies are more common in zoo giraffes than in wild giraffes. “However, we need a good sample of data from both populations to prove this assumption,” said Dr Basu. 

This phenomenon is not well understood at the moment, but it’s thought that diet, substrate (e.g. concrete, straw, sand and grass) and genetics play a part in foot disease in giraffes. “Understanding how the feet are mechanically loaded during common activities (standing, walking, running) gives our research group ideas of where the highest strains occur, and later how these can be reduced through corrective foot trimming,” said Dr Basu.

Through the studies on giraffe locomotion, the research group plans to devise strategies for corrective foot trimming. At the moment, foot trimming is done with the best evidence available, which is extrapolation from closely related animals such as cattle. “But we know that giraffes’ specialist anatomy will likely demand specialist foot care,” Dr Basu said.

Studying giraffes in smaller versus larger spaces

The research group has begun to study the biomechanics of giraffe walking by looking at the kinematics (the movement) and the kinetics (the forces involved in movement) during walking strides. For this he studied adult giraffes at three zoological parks in the UK. 

However, due to the close proximity of fencing and buildings, it is not practical to study fast speeds in a zoo setting. 

A setting such as the Willem Pretorius Nature Reserve, near Ventersburg in the Free State, Kwaggafontein Nature Reserve, near Colesberg in the Karoo, and the Woodland Hills Wildlife Estate in Bloemfontein are all ideal for studying crucial aspects such as “faster than walking” speeds and gaits to measure key parameters (such as stride length, step frequency and stride duration). These studies are important to understand how giraffe form and function are adapted to their full range of locomotor behaviours. It also helps to comprehend the limits on athletic capacity in giraffes and how these compare to other animals. 

Drones open up unique opportunities for studying giraffes

The increasing availability of unmanned aerial vehicles (UAVs)/drones opens up unique opportunities for studying locomotion in animals like giraffes. Cameras mounted onto remotely controlled UAVs are a straightforward way to obtain high-quality video footage of giraffes while they run at different speeds.

“Using two UAVs, we have collected high definition slow motion video footage of galloping giraffes from three locations in the Free State. We have also collected detailed information about the terrain that the giraffes walked and ran across. From this we have created 3D maps of the ground. These maps will be used to examine the preferred terrain types for giraffes, and to see how different terrains affect their locomotion and energy use,” said Dr Deacon.

“The raw data (videos) will be digitised to obtain the stride parameters and limb angles of the animals. Later this will be combined with anatomical data and an estimation of limb forces to estimate the power output of the limbs and how that changes between different terrains,” said Dr Basu.


Related articles:

23 August 2016: Research on locomotion of giraffes valuable for conservation of this species
9 March 2016:Giraffe research broadcast on National Geographic channel
18 Sept 2015 Researchers reach out across continents in giraffe research
29 May 2015: Researchers international leaders in satellite tracking in the wildlife environment

 

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