Travelling through time: The roadmap for Namibia is in the rocks

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Patricia Vickers-Rich , Peter Trusler, Steve Morton, Peter Swinkels, Thomas H Rich, Mike Hall and Steve Pritchard (Australia)

The “road map” allowing (time) travellers to move across more than 1,000 million years in Namibia is recorded in the rocks of this land. And, it is on display in several museums in Namibia – in Swakopmund, Windhoek, Rosh Pinah and Farm Aar.

The old part of the road

In drafting the early section of this map, Southern Namibia has been a key region for understanding some of the sights our time traveller will come into contact with, some being the weird organisms called Ediacarans. Since the early days of the twentieth century, when geologists, such as Paul Range, and German soldiers occupying isolated outposts in the Aus region of Southern Namibia, some of these strange fossils were reported.

These were the first ‘large’ multicellular organisms that prospered on planet Earth before the development of true animals, and amongst them were the tiny cloudinids. Their fossils are preserved in the thick rock sequences that can be seen along the “time road” in Southern Namibia. These showcase a time in the history of life when there were fundamental and pivotal changes in life occurring, with life transitioning from an enigmatic biota to what we consider normal today.

And, at a number of museums in Namibia, including the Swakopmund Museum and the Namibian Geological Survey in Windhoek, several of these intriguing organisms are on show – such as the soft-bodied Ernietta, Pteridinium and Rangea,and the tiny hard shelled cloudinids.

Fig. 1. The Nama Group of Southern Namibia hosts a rich collection of Ediacaran organisms, a group that prospered more than 538.8 million years ago, just around the time of the first appearance of true animals on planet Earth. (Photo by P Vickers-Rich.)
Fig. 2. The Nama Group, just south of Aus at Pockenbank, where long sequences of rocks reflect changing sea levels, from near shore to deep water up section, and with volcanic layers, which allow the determining of the timing when these events took place more than 538.8 million years ago and what organisms were in the shallow seas at that time. (Photo by Peter Swinkels.)
Fig. 3. One of the cases in the Swakopmund Museum with the late Precambrian fossils from the Nama Group – Ernietta and Pteridinium – some of the early large, multicellular organisms known on planet Earth. (Photo by P Vickers-Rich.)
Fig. 4. One of the information panels that grace the wall on Farm Aar near Aus, which hosts a small local museum for visitors.
Fig. 5. First three dimension Rangea specimen discovered near Farm Aar by Patricia Vickers Rich and the basis for the reconstruction of this genus made by Peter Trusler.
Fig. 6. Reconstruction of one of the three-dimensional specimens of Rangea graced the cover of one of the respected research journals when found in the early 2000s and provided insights into the lifestyle and detailed structure of this weird organism. (Photos by S Morton.)
Fig. 7. Interpretation of life position and how preservation of Rangea took place in the shallow, near shore marine setting of the ancient Nama sea, some 540 million years ago. (Art by Peter Trusler.)
Fig. 8a. Images of Ernietta. The two above are nearly complete specimens recovered by participants in UNESCO International Geoscience Programs 493, 587 and 673. The spectacular one on the right was found by Andrey Ivantsov. It is the first truly complete individual and was found in situ. (Photos by S Morton and P Vickers-Rich.)
Fig. 8b. Images of Ernietta. These engravings were made by San artists, long ago, and seem to depict the first discovery of these ancient organisms by humans. (Photo by P Vickers-Rich.)
Fig. 8c. Images of Ernietta. Painting by Peter Trusler of Pteridinium fossils on Farm Aar, in a setting where they were found.
Fig. 9. Cloudina, highly magnified on left. Carbonate rock specimen on right from southern Namibia filled with cloudinids. (Photo on right by P Vickers Rich and left unknown.)

The “time road” travelled showcases the fossil record that helps humans understand the progress of life on Earth. This allows for the examination of rocks that host an abundance of the world’s first skeletal fossils, preserved in a number of carbonate rocks exposed throughout the Nama Group in southern Namibia.

Some of these early, hard-skeletoned forms played a major role in building some of the world’s first reefs (Germs, 1972; Grotzinger et al., 2000, 2005; Wood et al., 2002; Wood, 2015; Penny et al., 2014). Cloudina Germs, 1972, the first pre-Cambrian shelly fossil named anywhere in the world, consists of millimetre-scale diameter calcified tubes, with a distinctive pattern of stacked, funnel-shaped transverse partitions inside the tube. Most researchers consider it likely that Cloudina was a true animal.

Fig. 10. Display in the museum at the headquarters of the Namibian Geological Survey in Windhoek, showcasing the Nama Fauna, with a reconstruction of these once living organisms by Christine Marias in the background. (Photo be P Vickers-Rich.)

The road takes a turn (the Early Palaeozoic) and “crosses the line” of the biodiversity landscape – 538.8 million years ago

At the end of the Precambrian (the Neoproterozoic) over a few million years, life took a path that changed the landscape forever. Some organisms began to lay down hard parts – skeletons  like the cloudinids. And, at around the same time, true predators first appeared, so there was a push to develop some sort of protection – thus skeletons appeared and digging into the sediments to escape developed.

This changed the landscape – there were burrows dug and skeletons became a common part of the fossil landscape. And for our traveller, this helps in understanding these changes, because the skeletons are better preserved than just soft parts. As a result, a range of new life forms start to appear on the horizon – snails (gastropods), a variety of arthropods (trilobites), nautiloids and ammonites (relatives of the squid and octopus – but with shells), corals, starfish and their relatives (crinoids, or sea lilies, for example) and then, a bit later, animals with backbones, first in the water and then on land.

Fig. 11. Left. The transition from the Precambrian to the Phanerozoic (first the Palaeozoic). Right. Early Palaeozoic time. (Art by Peter Trusler.)
Fig. 12. Early Palaeozoic life. (Art courtesy of the Paleontological Institute, Russian Academy of Science, Moscow.)

The road comes out of the water and onto land (the Late Palaeozoic and Mesozoic) – 270-66 million years ago

Fig. 13. Case at the Swakopmund Museum with fossils from the Dwyka and Ecca rocks of Late Palaeozoic age, including the water-dwelling temnspondyl amphibian and the land-loving Lystrosaurus, a mammal-like reptile. (Photo by P Vickers-Rich.)
Fig. 14a. Animals with backbones that would have been in the ponds and on land during the late Palaeozoic and early Mesozoic in Namibia. Above is a Koolasuchus, which is a temnospondyl amphibian. (Art by Peter Trusler.)
Fig. 14b. Animals with backbones that would have been in the ponds and on land during the late Palaeozoic and early Mesozoic in Namibia. Above are a couple of Lystrosaurus staring at the body of one of the temnospondyl amphibians, which is being guarded by another mammal-like reptile. (Art by Peter Trusler.)

Driving might have become very difficult, and dangerous, as one neared the road section for the Late Palaeozoic – during times called the Carboniferous and Permian. And the driver would have to transition from a boat to a terrestrial vehicle most of the time.

Not only had the fauna and flora changed, for example, there were great coal swamps in the Carboniferous that were “treed” by non-flowering plants (unlike the sorts that make up so much of our modern forests), but that was followed by a time of huge glaciations in turn followed by mass extinctions on an horrific scale at the end of the Palaeozoic – at the end of the Permian around 251 million years ago.

Thus, at the end of the Palaeozoic, the landscape changed. If you could have a break from your “driving down the time road” and stopped for a little fishing in one of the freshwater ponds, you could well have landed one of the many primitive palaeoniscoid fish, as well as a little carnivorous Mesosaurus freshwater reptile that also lived there, fossils of which have been found in abundance near Keetmanshoop in the Permian rocks there. This little reptile was very closely related to another that lived in the freshwaters of South America, when it lay close to Africa and was not separated by an ocean differing from the geography of today.

Fig. 15. Most of the body of a Mesosaurus skeleton, which are abundant in the Permian rocks of Southern Namibia. These little reptiles were about a metre long as adults and their genus is found in both Namibia and Brazil. (Photo by P Vickers-Rich.)

And now into dinosaur territory – middle of the road trip (the Mesozoic)

As the traveller moves across the time boundary into the Mesozoic, around 240 million years ago, and into the Triassic and down the road to the Jurassic and Cretaceous, he or she will find the rocks of the Erni Formation (Triassic). The Etjo Formation (late Triassic or Early Jurassic) and finally into Twyfelfontein (of Cretaceous age) dinosaurs make their appearance in the Namibian landscape – so watch out!

Most of the remains are those of plant-eaters, such as the little, bipedal ornithopods, so far only known from fragmentary remains, and perhaps even the Massospondylus, which left only footprints. Along with these water-dwelling and terrestrial fauna, there are also actinopterygian fish fossils, trace fossils of such forms as Planolites (whatever those might represent), ammonites and a variety of fossil plants, including conifers, horsetails and an expanding number of flowering plants (angiosperms).

Fig. 16. Case at the Swakopmund Museum, with the remains of dinosaurs known from Namibia, including the bones of one of the prosauropod dinosaurs and a reconstruction of one of the little ornithopods. (Photo by P Vickers-Rich.)
Fig. 17. Little, metre-high ornithopods like these are known from the Cretaceous rocks of Namibia. (Art by Peter Trusler.)
Fig. 18. A prosauropod in a typical Mesozoic forest of conifers and ferns, with flowering plants clearly not abundant at this time. (Art by Peter Trusler.)

And the road wanders into the present (the Cenozoic) – 66 million years to now

The remainder of the museum exhibitions deal with a fauna and flora that moves into the modern – during the last 66 million years. Specimens include the teeth of a variety of fossil sharks that inhabited a growing ocean between Africa and South America, along with the bones and teeth of the land fauna of Namibia – fossils such as ostrich eggs and bones of both mammals and birds that are clearly related to the fauna that graces Namibian lands today.

Undoubtedly as exploration continues, there will be new discoveries that will appear in these cases in the Namibian museums, so stay tuned and keep exploring.

Fig. 19. Swartpunt in the distance – the “avenue” where the last vestiges of the SuperEon biota, the Ediacarans, are replaced by the Modern World of the Cambrian (the Phanerozoic) – where the Line is Crossed – in Southern Namibia at 538.8 million years ago. (Photo by P Vickers-Rich.)

About the authors

Patricia Vickers-Rich and Peter Trusler are based at Monash and Swinburne Universities; Steve Morton and Peter Swinkels at Monash University, and Tom Rich at Museum Victoria, all in Melbourne.

Useful references

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Grant, S. W. F., 1990. Shell, structure and distribution of Cloudina, a potential index fossil for the terminal Proterozoic. American Journal of Science, 290-A: 261-294.

Grotzinger, J. P., Adams, E. W., Schröder, S., 2005. Microbial–metazoan reefs of the terminal Proterozoic N Nama Group (c. 550–543 Ma) Namibia. Geological Magazine 142: 499–517.

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Ivantsov, A. Yu., Narbonne, G. M., Trusler, P. W., Greentree, C. and Vickers- Rich, P., 2015. Elucidating Ernietta: new insights from exception specimens in the Ediacaran of Namibia. Lethaia, DOI:10.1111/let.12164: 1-15.

Linnemann U, Ovtcharova M, Schaltegger U, Gärtner, A., Hautmann, M. Geyer, G., Vickers-Rich, P., Rich, T., Plessen, B., Hofmann, M., Zieger, J., Krause, R., Kiesfeld, L., Smith, J., 2019. New high‐resolution age data from the Ediacaran–Cambrian boundary indicate rapid, ecologically driven onset of the Cambrian explosion. Terra Nova, 1–10.; 31: 49-58.

Linnemann, U., Vickers-Rich, P., Ovcharova, M., Gartner, A., Hofmann, M. & Zieger, J., 2019. Field Workshop. Precambrian-Cambrian Boundary, Ediacara Biota, Snowball Earth deposits, and the Geology of the Nama Basin around Aus (Southern Namibia). March 4, 2019 to March, 12, 2019. 18pp + Appendix of 11 Research Publications.

Penny, A. M., Wood, R., Curtis, A., Bowyer, F., Tostevin, R. And K.-H. Hoffman, 2014. Ediacaran metazoan reefs from the Nama Group, Namibia. Science, 344 (6191): 1504-1506.

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Vickers-Rich, P., Mhopjeni, K. and Schneider, G., et al., 2020. Crossing the Line. The Ediacaran-Cambrian Transition in Southern Namibia-How the world began to change @ 538 million years ago. Berichte (Reports) Scientific Society Swakopmund Namibia, 52: 2-25.

Vickers-Rich, P., Ivantsov, A. Yu., Trusler, P. W., Narbonne, G., Hall, M., Wilson, S. A., Greentree, C. Fedonkin, M. A., Elliott, D. A., Hoffmann, K. H. and Schneider, G. I. C., 2013. Reconstructing Rangea: New discoveries from the Ediacaran of Southern Namibia. Journal of Paleontology, 87 (1): 1-15.

 Vickers-Rich, P., Narbonne, G., Laflamme, M., Darroch, S., Kaufman, A. J. and Kriesfeld, L. et al., 2016. The Nama Group of Southern Namibia. Field Guide for Workshop of the 35th International Geological Congress, 21-25 August 2016. New Artworx in cooperation with the 35th International Geological Congress Committee, Melbourne: 77 pp.

Vickers-Rich, P. and P. Komarower, eds., 2007. The Rise and Fall of the Ediacaran biota. Geological Society of London Special Publication, 286: 456 pp.

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