Selected Karoo geoheritage sites of palaeontological significance in South Africa and Lesotho Open Access
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Published:July 12, 2024
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Emese M. Bordy, Roger M. H. Smith, Jonah N. Choiniere, Bruce S. Rubidge, 2024. "Selected Karoo geoheritage sites of palaeontological significance in South Africa and Lesotho", Geology's Significant Sites and their Contributions to Geoheritage, R. M. Clary, E. J. Pyle, W. M. Andrews
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Abstract
The main Karoo Basin of South Africa and Lesotho preserves c. 120 myr of Earth's history. The sedimentary rocks of its Karoo Supergroup record massive environmental changes from the glacial Carboniferous to desert dunes and fiery flood basalts in the Early Jurassic. From the early Permian, the Karoo Basin was gradually filled with fluvial and lacustrine deposits, and the alluvial plains were successively colonized by a diverse suite of plants and animals. The fossils of these ancient inhabitants and their behavioural traces form an astounding Gondwanan geoheritage legacy in southern Africa, providing fossil evidence for the moving lithospheric plates and the effects of four mass extinctions and their subsequent biotic recovery. Here, we present six Karoo sites of global geoscientific importance that best display that heritage, with the caveat that these sites only touch upon the Karoo riches that are available for academic research and the emerging palaeotourism industry. It is our hope that these sites will become anchor points for a sustainable geoheritage future in southern Africa.
The story of the Karoo Supergroup (Fig. 1) begins in the late Carboniferous when ice sheets covered most of southern Gondwana, depositing the sediments of the Dwyka Group in a retro-arc foreland basin that was initially filled by the Karoo Sea (Catuneanu et al. 2005). Shark-like cartilaginous fish, such as Dwykaselachus, swam under the floating icebergs in the deep, cool waters. As Gondwana moved northwards, the climate ameliorated, and the Karoo Sea was colonized by vertebrates such as Mesosaurus, an aquatic reptile whose fossils are preserved in the lower Permian Ecca Group. As the basin filled with fluvio-lacustrine sediments, extensive floodplains sustained the diverse pan-Gondwanan Glossopteris floral realm and, with it, early members of tetrapod lineages (Rubidge and Sidor 2001; Rubidge et al. 2016). Well-defined temporal successions of vertebrates in the Permo-Triassic Beaufort Group mark the devastating effects of the end-Guadalupian and end-Permian extinction events – global crises when life on Earth was nearly extinguished forever.
Spatio-temporal distribution of six geoheritage sites in the main Karoo of South Africa and Lesotho. Abbreviations: C, Carboniferous; Gp, Group; Fm, Formation.
Spatio-temporal distribution of six geoheritage sites in the main Karoo of South Africa and Lesotho. Abbreviations: C, Carboniferous; Gp, Group; Fm, Formation.
Ever-increasing aridity ultimately led to the deposition of dryland sediments of the Upper Triassic–Lower Jurassic Stormberg Group, a succession containing some of the earliest body and trace fossils of dinosaurs and true mammals. These upper Karoo strata document another mass extinction at the end of the Triassic, after which Dinosauria rose to become the dominant land vertebrates for the next 140 myr. The wet desert landscape was covered by extensive continental flood basalts in the Karoo's terminal chapter. These Lower Jurassic basaltic lavas, known as the Drakensberg Group, form the tall cliffs in the scenic Maloti-Drakensberg mountains of Lesotho and eastern South Africa, which are now a declared UNESCO World Heritage Site.
The internationally renowned fossil flora and fauna of the Karoo was first brought to the attention of the scientific world by Andrew Geddes Bain (1797–1864) in the 1830s. Bain produced the first geological map of the Karoo, and the tetrapod fossils he discovered were the first records of therapsids, a new group of ‘reptiles’ that were recognized as distant ancestors of mammals. Since then, thousands of Karoo fossils have been discovered and are curated in collections in South Africa and around the world. A series of taxonomical, taphonomical and stratigraphical studies over the past decades (e.g. Rubidge et al. 2013; Bordy et al. 2020; Smith et al. 2020) have advanced understanding of the changes in continental biodiversity from the Permian to Jurassic, including mass extinctions and ensuing ecosystem recovery. New fossils from ongoing excavations and study of museum collections enable continuous refinement of Karoo biostratigraphy and its global correlations. Fossils of the Karoo cemented plate tectonics as the leading paradigm of geosciences and, more recently, via radioisotopic dating, have provided unprecedented insight into the waxing and waning of 120 myr of life in southern Gondwana.
Echoing its tetrapod diversity, the Karoo contains the richest trace fossil record in southern Africa, a region where animal tracking has been actively practised for centuries by the indigenous San people who follow a traditional hunter–gatherer way of life. Using their supreme tracking expertise, the San also documented and interpreted fossil animal spoors, as recorded in pre-1800s cave paintings in Lesotho (Ellenberger et al. 2005, figs 2, 3). Following these early trackers, Karoo vertebrate ichnites were noted in the late nineteenth century (?dicynodont tracks in South Africa by Holub 1881; bird or lizard trackways in Lesotho by Dieterlen 1885; Christol 1897), and have been formally described since the 1960s (e.g. Ellenberger 1970, 1972, 1974 and references in Baucon et al. 2012).
The Karoo's wealth of animal, plant and trace fossils represents the most complete Permian–Jurassic continental succession in Gondwana (Rubidge 2005) and has enhanced global understanding of palaeoenvironmental changes in continental palaeo-ecosystems. In addition to being a pivotal area for the study of palaeoecology, biodiversity and evolution, the Karoo offers great potential as a sustainable geotourism destination.
Selected Karoo geoheritage sites in South Africa and Lesotho
We selected six geoheritage sites of palaeontological significance (Fig. 1, Table 1) in the main Karoo Basin to showcase the emerging geoheritage and geotourism markets in South Africa and Lesotho. The sites either already enjoy sustainable visitation with the necessary protective measures in place and/or contain an outstanding assemblage of well-documented vertebrate body and trace fossils. By comparison, plants and insects have received less attention, but there are many fossil sites worth a brief mention here. The rich Permian Glossopteris flora of Gondwana is well preserved and gave rise to the economically important coal fields of southern Africa. The Molteno Formation (Fig. 1) provides an unrivalled window into Late Triassic plant and insect communities (Anderson et al. 1998). A new locality in the SW main Karoo Basin has produced an exceptional fossil assemblage of insects, arachnids and plants in a middle Permian lakeshore ecosystem (Prevec et al. 2022). This vulnerable fossil heritage is protected by legislation in South Africa and Lesotho by the South African Heritage Resources Act No 25 of 1999 and the Historical Monuments, Relics, Fauna and Flora Act, respectively.
Geological and geographical context of selected geoheritage sites in the main Karoo Basin
Site name | Gansfontein palaeosurface | Kitching Fossil Exploration Centre (KFEC) | Fairydale Lystrosaurus graveyard | Lootsberg Pass vertebrate burrow casts | Moyeni footprint terminus | Rooidraai dinosaur eggs and embryos | |
---|---|---|---|---|---|---|---|
Stratigraphy/biostratigraphy | upper Abrahamskraal Formation, lower Beaufort Group/Tapinocephalus AZ | Balfour Formation, lower Beaufort Group/Daptocephalus AZ | lower Katberg Formation, upper Beaufort Group/Lystrosaurus declivis AZ | lower Katberg Formation, upper Beaufort Group/Lystrosaurus declivis AZ | upper Elliot Formation, Stormberg Group/Massospondylus AZ | uppermost Elliot Formation, Stormberg Group/Massospondylus AZ | |
Approximate geological age | middle Permian, Capitanian, c. 262 Ma | late Permian, Wuchiapingian, c. 255 Ma | Early Triassic, Induan, c. 251 Ma | Early Triassic, Olenekian, c. 250 Ma | Early Jurassic, Sinemurian, <190–195 Ma | Early Jurassic, Sinemurian, c. 190 Ma | |
Location | Gansfontein farm, c. 4 km north of Fraserburg on the road to Williston | Gats River bed in Nieu Bethesda alongside the road causeway crossing the river | Farm Donald 207 (Fairydale), between Bethulie and Aliwal North | Roadcuts in the New Lootsberg Pass along the N9, NE of Graaff Reinet | Dinosaur Footprints visitors’ centre next to the A2 national road in Lower Moyeni | Suburban road surface in Mampoboleng, Upper Moyeni | Rooidraai, a roadside exposure along the R712 in the GGHNP |
GPS coordinate | 31° 54′ 05.4″ S, 21° 28′ 54.6″ E | 31° 52′ 01″ S, 24° 33′ 20″ E | — | 32° 6′ 17.54″ S, 25° 47′ 41.30″ E | 30° 23′ 42.78″ S, 27° 41′ 34.94″ E | 30° 24′ 9.74″ S, 27° 42′ 6.41″ E | 28° 30′ 29.10″ S 28° 37′ 22.11″ E |
Site name | Gansfontein palaeosurface | Kitching Fossil Exploration Centre (KFEC) | Fairydale Lystrosaurus graveyard | Lootsberg Pass vertebrate burrow casts | Moyeni footprint terminus | Rooidraai dinosaur eggs and embryos | |
---|---|---|---|---|---|---|---|
Stratigraphy/biostratigraphy | upper Abrahamskraal Formation, lower Beaufort Group/Tapinocephalus AZ | Balfour Formation, lower Beaufort Group/Daptocephalus AZ | lower Katberg Formation, upper Beaufort Group/Lystrosaurus declivis AZ | lower Katberg Formation, upper Beaufort Group/Lystrosaurus declivis AZ | upper Elliot Formation, Stormberg Group/Massospondylus AZ | uppermost Elliot Formation, Stormberg Group/Massospondylus AZ | |
Approximate geological age | middle Permian, Capitanian, c. 262 Ma | late Permian, Wuchiapingian, c. 255 Ma | Early Triassic, Induan, c. 251 Ma | Early Triassic, Olenekian, c. 250 Ma | Early Jurassic, Sinemurian, <190–195 Ma | Early Jurassic, Sinemurian, c. 190 Ma | |
Location | Gansfontein farm, c. 4 km north of Fraserburg on the road to Williston | Gats River bed in Nieu Bethesda alongside the road causeway crossing the river | Farm Donald 207 (Fairydale), between Bethulie and Aliwal North | Roadcuts in the New Lootsberg Pass along the N9, NE of Graaff Reinet | Dinosaur Footprints visitors’ centre next to the A2 national road in Lower Moyeni | Suburban road surface in Mampoboleng, Upper Moyeni | Rooidraai, a roadside exposure along the R712 in the GGHNP |
GPS coordinate | 31° 54′ 05.4″ S, 21° 28′ 54.6″ E | 31° 52′ 01″ S, 24° 33′ 20″ E | — | 32° 6′ 17.54″ S, 25° 47′ 41.30″ E | 30° 23′ 42.78″ S, 27° 41′ 34.94″ E | 30° 24′ 9.74″ S, 27° 42′ 6.41″ E | 28° 30′ 29.10″ S 28° 37′ 22.11″ E |
For spatio-temporal distribution, see Figure 1. For ages, bio- and lithostratigraphy, see Rubidge et al. (2013), Smith et al. (2020), Bordy et al. (2020) and Viglietti et al. (2020). AZ, Assemblage Zone.
Footprints in the sands of time: the Gansfontein palaeosurface
The Gansfontein palaeosurface (Figs 1 & 2) is a well-preserved middle Permian crevasse splay where abundant and diverse trace fossils record floodplain colonization between the run-off, standing pools and gradual drying-out phases of successive flooding events. Tetrapod trackways (Fig. 2a–c), fish trails (Fig. 2d) and invertebrate tracks, trails and burrows (Fig. 2e, f) are preserved over the entire 1000 m2 of exposed palaeosurface (Fig. 2″).
The middle Permian Gansfontein palaeosurface. (a) Digitiform trackway, a ?dinocephalian, mapped by Richard Blob and Laura Panko. (a′) Topographic map of the manus–pes pair beneath the tripod (from Blob et al. 2017). (b) Ancient pools on the Permian crevasse splay surface with 3 small tetrapod trackways and a transverse set of large squelch prints. (b′) Five-toed manus–pes tracks, a ?dinocephalian. (b″) Claw drag marks of a ?temnospondyl. (c) Short-toed tracks of a ?pareiasaurian. (d) Natural cast of fish tail grooves. (e) Foraging trail of an ?insect larvae. (f) Natural cast of an arthropod trackway. (g) Reconstruction of the middle Permian Gansfontein palaeosurface. (g′) Falling water-level terracettes, adhesion warts and run-off rills are evidence of the progressive drying-up of the ancient pools. (g″) Sand-filled desiccation cracks cross-cutting dendritic rills. Source: (c) image credit Chris Marais; (g) artwork by Cedric Hunter.
The middle Permian Gansfontein palaeosurface. (a) Digitiform trackway, a ?dinocephalian, mapped by Richard Blob and Laura Panko. (a′) Topographic map of the manus–pes pair beneath the tripod (from Blob et al. 2017). (b) Ancient pools on the Permian crevasse splay surface with 3 small tetrapod trackways and a transverse set of large squelch prints. (b′) Five-toed manus–pes tracks, a ?dinocephalian. (b″) Claw drag marks of a ?temnospondyl. (c) Short-toed tracks of a ?pareiasaurian. (d) Natural cast of fish tail grooves. (e) Foraging trail of an ?insect larvae. (f) Natural cast of an arthropod trackway. (g) Reconstruction of the middle Permian Gansfontein palaeosurface. (g′) Falling water-level terracettes, adhesion warts and run-off rills are evidence of the progressive drying-up of the ancient pools. (g″) Sand-filled desiccation cracks cross-cutting dendritic rills. Source: (c) image credit Chris Marais; (g) artwork by Cedric Hunter.
Large, five-toed footprints and associated squelch prints (Fig. 2a, b) were likely made by dinocephalians and pareiasaurs (Fig. 2c), the most common large quadrupeds living in this part of the main Karoo Basin at the time. Three trackways of a smaller tetrapod were made in wet sand around the edge of one of the ancient pools (Fig. 2b). They show claw drag marks made as the foot was raised from the ground with an outward swing typical of swaggering ‘elbows-out’ gait – possibly made by the temnospondyl Rhinesuchus, an early amphibian resembling a giant salamander (Fig. 2b).
The delicate, interlaced sinuous grooves made by the pectoral and caudal fins of freshwater fishes are best revealed in the low light conditions of sunrise and sunset (Fig. 2d). They were made by individuals trapped in pools as the floodwaters receded, along with the many tiny, rosary-like trails made by foraging insect larvae (Fig. 2e) and tracks of scorpion-like arthropods (Fig. 2f).
Water flowing from the spillway of an earth-filled dam wall exposed the palaeosurface after heavy rains in 1968. Nick van Gass discovered the footprints and alerted Geological Survey geologist Coenie De Beer, who published the first description in 1986. Later, an Iziko South African Museum (ISAM) research team led by RMH Smith uncovered and mapped the individual trackways (Smith 1993). More recently the tetrapod trackways have been laser scanned (Blob et al. 2017), photogrammetrically modelled and assigned to various ichnogenera (Marchetti et al. 2019).
The Gansfontein palaeosurface is of international importance as the best-preserved and most-diverse assemblage of middle Permian therapsid trackways. It provides a wealth of information about the ancient environment in southern Gondwana and minute details of the day-to-day movements of animals over an ancient Karoo floodplain. Each of the ten special interest stops along the palaeosurface affords the rare touristic and educational experience of seeing tracks and trails up close much as they were made c. 260 myr ago.
Kitching Fossil Exploration Centre (KFEC)
The quaint village of Nieu Bethesda (Figs 1 & 3a) is a popular tourist destination nestled on the banks of the Gats River along the foothills of the majestic Compassberg. Tetrapod fossils have been collected from its vicinity since the early 1900s and are curated at various museums in South Africa. Most early discoveries were made by Croonie Kitching, a road builder stationed in the village. He trained his eight children in the art of fossil hunting, and three of his sons James, Ben and Scheepers later were employed as field officers to collect specimens for the Bernard Price Institute (BPI) for Palaeontological Research at the University of the Witwatersrand. James (1922–2003) went on to become a legendary fossil hunter, complete a PhD in palaeontology, and to serve as Professor and Director of the BPI. Kitching discovered many fossils of the land-dwelling therapsids Lystrosaurus and Thrinaxodon and, in 1970, he also discovered these species in Antarctica, providing irrefutable palaeontological evidence that Antarctica and Africa were united during the Early Triassic, c. 250 myr ago.
Late Permian tetrapod fossils near Nieu Bethesda. (a) View over Nieu Bethesda village with Compassberg, the highest peak in the Sneeuberg mountain range, in the background. (b) In situ skull of the dicynodont Oudenodon in the Gats River (left) alongside the cast of an excavated specimen (skull length 29 cm) (c) Palaeo-art mural of a late Permian scene near Nieu Bethesda. Source: artwork by Gerhard Marx, reproduced with permission from Albany Museum, Makhanda and displayed in the KFEC orientation centre.
Late Permian tetrapod fossils near Nieu Bethesda. (a) View over Nieu Bethesda village with Compassberg, the highest peak in the Sneeuberg mountain range, in the background. (b) In situ skull of the dicynodont Oudenodon in the Gats River (left) alongside the cast of an excavated specimen (skull length 29 cm) (c) Palaeo-art mural of a late Permian scene near Nieu Bethesda. Source: artwork by Gerhard Marx, reproduced with permission from Albany Museum, Makhanda and displayed in the KFEC orientation centre.
The terraced hillsides around Nieu Bethesda are dominated by thick successions of blue-grey mudstones that were deposited on the floodplains of large, sandy, meandering river channels some 253 myr ago. Fossils of late Permian-aged tetrapods and plants are preserved in the bed of the Gats River that flows through the village. In 2005, the University of the Witwatersrand teamed up with the Department of Science and Technology and the Albany Museum to establish the Kitching Fossil Exploration Centre (KFEC) with financial assistance of philanthropist Ross Foxton. Visitors to the KFEC experience the thrill of finding in situ Karoo fossils with the assistance of trained palaeo- and geotourism guides, who are community members running the local Karoo Fossil Tours.
The KFEC tells the story of life in the Daptocephalus Assemblage Zone towards the end of the Permian, just before the Permo-Triassic extinction event, when the chief predators were gorgonopsian and therocephalian therapsids (Fig. 3b, c). Rubidgea, the largest gorgonopsian to roam the floodplains of this area, was a formidable tiger-sized carnivore with gigantic sabre-like canines. These carnivores preyed on dicynodonts – smaller, herbivorous therapsids with tortoise-like horny beaks, and only a pair of tusks in their jaws. A skull of the more superficially mammal-like therocephalian Theriognathus is preserved in situ for visitors to see, and the basal cynodont Procynosuchus has also been found. Apart from therapsids, the Permian fauna of the KFEC includes the lizard-sized early reptile Youngina and equally small parareptiles Owenetta and Milleretta (Kitching 1977). Fossils of ferns, horsetails and the ubiquitous Permian Glossopteris flora are also preserved in the riverbed. Explanatory exhibits in the KFEC depict the lush floodplains of the huge meandering rivers that traversed the area (Fig. 3c) and display life-sized models of the therapsids that once roamed the Karoo.
Lystrosaurus graveyard on Fairydale
In the central main Karoo Basin, relatively flat exposures of the top surface of a multi-storey channel sandstone contain abundant tetrapod fossils that evidence extreme climatic fluctuations in the southern Gondwana in the aftermath of the end-Permian mass extinction (Smith and Botha-Brink 2014). These outcrops contain the partially articulated skeletons of the wide-ranging dicynodont Lystrosaurus, with its distinctive spade-shaped beak (Figs 4a, a′). At the Fairydale site (Figs 1 & 4) several hundred skeletons have been logged and left in situ for ongoing taphonomic research (Fig. 4a). Evidence for drought-induced mass death in the turbulent post-extinction climate comes from unusual clusters of spreadeagled Lystrosaurus carcasses (some perhaps with mummified skin; Smith et al. 2022), and in a bonebed containing a mass of disarticulated bones from at least nine juvenile Lystrosaurus (Viglietti et al. 2013). Intertwined articulated skeletons of two different taxa (i.e. Galesaurus planiceps and Saurodektes kitchingorum) in behaviourally-arranged poses are interpreted as evidence of shelter-sharing (Abdala et al. 2006) and several sandstone-filled casts of tetrapod burrows (Fig. 4a″) displaying scratch marks are attributed to the digging activity of cynodonts (e.g. Thrinaxodon) and L. murrayi. Other research-worthy fossils from this site include a fully articulated Galesaurus (Fig. 4b) with distinctive rib morphology indicative of the possible presence of a diaphragm and a close association of adult and infant Thrinaxodon (Fig. 4b′), suggesting that these pre-mammalian ancestors may have practised parental care (Jasinoski and Abdala 2017).
Earliest Triassic Lystrosaurus graveyard on Fairydale. (a) View of the fossil-rich outcrops with a fully articulated skeleton of Lystrosaurus lying prone and spreadeagled in foreground. (a′) Skull of Lystrosaurus declivis lying left side up and showing its characteristic angular downturned snout. (a″) Oblique view of a tetrapod burrow cast that was dug with an inclination of 35° into the Permian floodplain sediments. (b) Fully articulated skeleton of Galesaurus planiceps, now on display in ISAM. (b′) Side view of a juvenile Thrinaxodon skull.
Earliest Triassic Lystrosaurus graveyard on Fairydale. (a) View of the fossil-rich outcrops with a fully articulated skeleton of Lystrosaurus lying prone and spreadeagled in foreground. (a′) Skull of Lystrosaurus declivis lying left side up and showing its characteristic angular downturned snout. (a″) Oblique view of a tetrapod burrow cast that was dug with an inclination of 35° into the Permian floodplain sediments. (b) Fully articulated skeleton of Galesaurus planiceps, now on display in ISAM. (b′) Side view of a juvenile Thrinaxodon skull.
The exceptional abundance of Lystrosaurus fossils at Fairydale was first documented by James Kitching in 1977. Following a field visit with Kitching in 1990, RMH Smith and an ISAM team began a series of research projects focused on the sedimentology and geochronology of the preserved Permo-Triassic boundary (PTB) succession incorporating tetrapod biostratigraphy of the end-Permian mass extinction. This research continues today.
The continuous exposures, stratigraphical completeness and tetrapod fossil abundance of ‘Bethel Canyon’ are unparalleled among the world's continental PTB successions, showcased in Smith's (1995) initial study and subsequent detailed research (e.g. Ward et al. 2005). Fossil data from this site have been used to test hypotheses for the timing, tempo and kill mechanisms of the end-Permian mass extinction and for understanding tetrapod survival strategies in its wake. Currently, the site has no public access, although the site might be visited in a high-clearance, four-wheel drive vehicle and with the farm owner's prior permission.
Vertebrate burrow casts from the Lower Triassic
Karoo vertebrate burrow casts associated with scratch marks and/or fossil bones are abundant in the Permo-Triassic Beaufort Group, and also occur in the Triassic–Jurassic Stormberg Group (Fig. 1; e.g. Smith 1987; Groenewald et al. 2001; Damiani et al. 2003; Abdala et al. 2006; Bordy et al. 2011, 2017, 2019; Fernandez et al. 2013; Bordy and Krummeck 2016; Krummeck and Bordy 2018; Abrahams et al. 2020). Vertebrate burrow casts are particularly common in the earliest Triassic Lystrosaurus declivis Assemblage Zone, and herein we present some burrow casts from the easily accessible new Lootsberg Pass (Fig. 1). Confined to the lower Katberg Formation, the burrow casts are located a few hundred metres above the Permo-Triassic boundary (Bordy et al. 2011). They were discovered during sedimentological work in these roadcuts by E. M. Bordy and Orsolya Sztanó in 2007.
The burrow casts are contained in both multi-storey channel sandstones and floodplain mudstones that are associated with laterally persistent thinner sandstones (Fig. 5a, b). Mudstones both within and between the multi-storey sandstones often contain desiccation cracks of up to 0.5 m in depth (Fig. 5c). The burrow casts are very large (c. 30–35 cm), semi-horizontal, cylindrical tunnels of uniform diameter, connecting a single opening at the top to a rounded bottom (Fig. 5d–f). The structures are up to 3 m long and devoid of chambers, branching, cross-cutting, coiling or spiraling. The burrows descend at angles of c. 30°, but level out before their lower limit. Many of these burrow casts are associated with scratch marks (Fig. 5g), and were likely dug by therapsids (e.g. Lystrosaurus) in dryland fluvial environments of the earliest Triassic.
Sedimentological and ichnological characteristics at the new Lootsberg Pass in the Lower Triassic Katberg Formation. (a, b) Panoramic and close-up views showing the multi-storey sandstone and mudstone units. (c) Mudstone beds with desiccation cracks of up to 0.5 m in depth. Person for scale in a–c. (d–f) Outcrop view of large-diameter, therapsid burrow cast that can attain a length of 3 m. Arrows point to the burrow cast. (g) Triangular-shaped scratch marks on burrow cast surfaces.
Sedimentological and ichnological characteristics at the new Lootsberg Pass in the Lower Triassic Katberg Formation. (a, b) Panoramic and close-up views showing the multi-storey sandstone and mudstone units. (c) Mudstone beds with desiccation cracks of up to 0.5 m in depth. Person for scale in a–c. (d–f) Outcrop view of large-diameter, therapsid burrow cast that can attain a length of 3 m. Arrows point to the burrow cast. (g) Triangular-shaped scratch marks on burrow cast surfaces.
The Karoo vertebrate burrow casts are significant because they show that floodplain-dwelling tetrapods engaged in fossorial behaviours both before and after the end-Permian and end-Triassic mass extinctions. The apparent stratigraphical variation in the morphology of the Karoo burrow casts (Fig. 6) is yet to be explained. To date, it is unclear whether this ichnological diversity reflects ethological responses (i.e. species dependency) to changing environmental conditions through geological time or facies-controlled changes within the individual fluvio-lacustrine systems (e.g. temperature, moisture, substrate conditions).
Permo-Triassic Karoo burrow cast morphologies (in side-view and cross-section) show that burrowing was likely a common behaviour among tetrapods in the semi-arid fluvio-lacustrine sediments of southern Gondwana. Source: burrow outlines are modified from: 1, Odendaal (2021); 2, Smith (1987); 3, Damiani et al. (2003), Abdala et al. (2006), Fernandez et al. (2013); 4, Bordy et al. (2011); 5, Krummeck and Bordy (2018); 6, Bordy and Krummeck (2016); 7, Groenewald et al. (2001); 8, Bordy et al. (2019).
Permo-Triassic Karoo burrow cast morphologies (in side-view and cross-section) show that burrowing was likely a common behaviour among tetrapods in the semi-arid fluvio-lacustrine sediments of southern Gondwana. Source: burrow outlines are modified from: 1, Odendaal (2021); 2, Smith (1987); 3, Damiani et al. (2003), Abdala et al. (2006), Fernandez et al. (2013); 4, Bordy et al. (2011); 5, Krummeck and Bordy (2018); 6, Bordy and Krummeck (2016); 7, Groenewald et al. (2001); 8, Bordy et al. (2019).
Jurassic footprint terminus at Moyeni (Quthing, Lesotho)
The bustling town of Moyeni in southwestern Lesotho is the ultimate destination for Early Jurassic animal tracking in southern Africa. Moyeni boasts two well-documented vertebrate tracking surfaces preserved in the upper Elliot Formation, a highly fossiliferous Hettangian–Sinemurian red bed succession in the upper Karoo's Stormberg Group (Fig. 1; Bordy et al. 2020). The Lower Moyeni tracksite is the most accessible trace fossil location in southern Africa, and preserves c. 200 individual tracks under the protective shelter of the Dinosaur Footprints visitors’ centre (Fig. 7a, b). The discovery of the site is attributed to Paul Ellenberger, the most eminent ichnologist of southern Africa to date. He gave highly detailed ichnological accounts of the site (Ellenberger et al. 1963; Ellenberger 1970, 1974), which were recently updated with modern ichnological techniques (Smith et al. 2009; Wilson et al. 2009; Marsicano et al. 2014).
Jurassic animal tracks at Lower Moyeni (Lesotho). (a, b) Outside and inside views of the Dinosaur Footprints visitors’ centre at lower Moyeni. (c) The Lower Moyeni tracksite as originally illustrated by P. Ellenberger et al. in 1963. (d) Dinosaur tracks in intersecting trackways. Area is enlarged from under the footbridge in the middle of (c). (e) Reconstruction of the trackway-maker amphibian and details of impressions of a left manus–pes pair with digit drag marks. Roman numerals denote digit impressions; dm, drag mark; dd, digit drag; mt, metatarsal; mm, microbial-matted surfaces. Source: images (c–d) modified from Ellenberger (1974), Wilson et al. (2009) and Marsicano et al. (2014), respectively.
Jurassic animal tracks at Lower Moyeni (Lesotho). (a, b) Outside and inside views of the Dinosaur Footprints visitors’ centre at lower Moyeni. (c) The Lower Moyeni tracksite as originally illustrated by P. Ellenberger et al. in 1963. (d) Dinosaur tracks in intersecting trackways. Area is enlarged from under the footbridge in the middle of (c). (e) Reconstruction of the trackway-maker amphibian and details of impressions of a left manus–pes pair with digit drag marks. Roman numerals denote digit impressions; dm, drag mark; dd, digit drag; mt, metatarsal; mm, microbial-matted surfaces. Source: images (c–d) modified from Ellenberger (1974), Wilson et al. (2009) and Marsicano et al. (2014), respectively.
The Lower Moyeni tracksite formed along an ancient riverbank some 195 Ma ago and is significant for its unparalleled diversity of footprints that are attributed to carnivorous and herbivorous dinosaurs, early crocodilians and temnospondyl amphibians. Close inspection also shows trace fossils of nematodes and arthropods amid exquisitely preserved ripple marks and microbially induced sedimentary structures (i.e. fossil microbial mats and biofilms; Fig. 7c–e). Importantly, this site preserves tail impressions, resting traces and digit drag marks, allowing rare behavioural insights into an ancient animal community (Fig. 7c). For example, the slippery surface forced one ornithischian to hobble on all fours and then alternate its movement to a bipedal walk (Fig. 7c, d), whereas one short-legged, salamander-like amphibian (Fig. 7c, e) instead dragged itself across the rippled sandbar leaving behind toe-prods and scrapes with a distinctive belly drag (see Wilson et al. 2009; Marsicano et al. 2014).
The Upper Moyeni tracksite (Fig. 8) is located c. 65 m above the Lower Moyeni tracksite, in the uppermost part of the upper Elliot Formation, only c. 35 m below the conformably overlying Clarens Formation (Abrahams et al. 2020). Exposed on a busy suburban road, informally referred to as ‘Eubrontes Avenue’, the tracks were first identified as ancient animal footprints by local resident Mrs Mampoboleng several decades ago (Fig. 8a), and were reported to E. M. Bordy by the local community in 2016. While these younger footprints at Upper Moyeni are morphologically less diverse, the size distribution of the c. 50 three-toed tracks is remarkable as footprint lengths range from 15 to 51 cm (Fig. 8b). The largest tracks were likely made by a bipedal theropod dinosaur with a body length of up to 7–8 m, ranking it among the top Karoo sites where the largest Jurassic carnivores stalked their prey in southern Gondwana (Sciscio et al. 2017; Abrahams et al. 2020). The discovery of the very large tracks at Upper Moyeni reinforces the tendency towards increasing diversity in size of three-toed dinosaur tracks and, by extension, trackmaker body size, in the Sinemurian–Pliensbachian of southern Africa (Abrahams et al. 2022).
Highlights of ‘Eubrontes Avenue’ in Upper Moyeni (Lesotho). (a) Dinosaur tracks being inspected by international ichnologists, next to the Kholumolumo spaza shop. Inset shows the front view of the general dealership. (b) Partial overview of the Upper Moyeni dinosaur tracksite and photographs, interpretative outlines and/or false-colour depth maps of representative three-toed tracks (numbered). The 51 cm-long track #26 is the largest footprint at Moyeni. Source: images in (b) modified from Abrahams et al. (2020).
Highlights of ‘Eubrontes Avenue’ in Upper Moyeni (Lesotho). (a) Dinosaur tracks being inspected by international ichnologists, next to the Kholumolumo spaza shop. Inset shows the front view of the general dealership. (b) Partial overview of the Upper Moyeni dinosaur tracksite and photographs, interpretative outlines and/or false-colour depth maps of representative three-toed tracks (numbered). The 51 cm-long track #26 is the largest footprint at Moyeni. Source: images in (b) modified from Abrahams et al. (2020).
Dinosaur embryos in petrified eggs at Rooidraai
The soaring sandstone buttresses of Golden Gate Highlands National Park (GGHNP) mark the northern verge of the majestic Drakensberg Mountains. Here, the Lower Jurassic upper Elliot and Clarens formations crop out among a mixture of rare, high-altitude grasslands, afromontane forests and protea woods (Fig. 9a). These outcrops hold abundant fossils of a dinosaur-dominated ecosystem that characterized southern Gondwana in the Early Jurassic, and echo the legacy of the Basotho and San people, for whom Golden Gate was their ancestral home. For example, the Basotho legend of the people-eating monster ‘Kholumolumo’ is thought to have been inspired by the giant dinosaur footprints in the region. To showcase GGHNP's palaeontological, archaeological and geological heritage, a site museum and research facility – the ‘Kholumolumo Dinosaur Centre’ – was recently built.
Dinosaur nesting grounds at Rooidraai in the GGHNP. (a) A view of Rooidraai looking to the SW across the R712. Arrows point to the loessic mudstone that hosts the Massospondylus nests; star marks the Kholumolumo Dinosaur Centre in the middle right. (b) Clutch of fossilized Massospondylus eggs. (c) James Kitching's original clutch of fossil eggs, with embryo skeletons in the bottom and middle right egg. (d) Digital reconstruction of an embryonic Massospondylus skull from Rooidraai. (e) Digital model of the postcranial skeleton of the most complete embryo from Rooidraai. (f) Reconstruction of the Early Jurassic dinosaur-dominated ecosystem of southern Gondwana. Source: (a) image credit Peter Gordon, SANParks; (c) photo credit Brett Eloff/GENUS; (d) image credit Kimberley Chapelle; (e) image credit Vincent Fernandez; (f) artwork by Maggie Lambert-Newman, reproduced with the permission of the artist.
Dinosaur nesting grounds at Rooidraai in the GGHNP. (a) A view of Rooidraai looking to the SW across the R712. Arrows point to the loessic mudstone that hosts the Massospondylus nests; star marks the Kholumolumo Dinosaur Centre in the middle right. (b) Clutch of fossilized Massospondylus eggs. (c) James Kitching's original clutch of fossil eggs, with embryo skeletons in the bottom and middle right egg. (d) Digital reconstruction of an embryonic Massospondylus skull from Rooidraai. (e) Digital model of the postcranial skeleton of the most complete embryo from Rooidraai. (f) Reconstruction of the Early Jurassic dinosaur-dominated ecosystem of southern Gondwana. Source: (a) image credit Peter Gordon, SANParks; (c) photo credit Brett Eloff/GENUS; (d) image credit Kimberley Chapelle; (e) image credit Vincent Fernandez; (f) artwork by Maggie Lambert-Newman, reproduced with the permission of the artist.
Among the most scenic drives in southern Africa, regional route 712 meanders through the GGHNP, passing a renowned upper Karoo roadside outcrop at Rooidraai (‘Red Bend’; Fig. 9a). Located in the last few metres of the upper Elliot Formation, this succession includes c. 10 m of the reddish-brown siltstones that grade into the c. 150 m-thick cream-coloured, cliff-forming sandstones of the Clarens Formation. These rocks document southern Africa's increasing aridity and climatic fluctuations during the Early Jurassic (Bordy et al. 2020). Two dolerite dykes inclined at c. 45° form a natural shelter over the Rooidraai exposure (Fig. 9a) and extend up-section to their ultimate release point in the Drakensberg continental flood basalts, which mark the protracted end of deposition in the main Karoo Basin.
James Kitching discovered an ex-situ block of siltstone at Rooidraai in 1976, containing six fossilized eggs (Fig. 9c). Kitching's preliminary report (1979) noted that the eggs contained embryonic material with ‘dinosaurian features’. Further preparation in 2005 revealed two near-complete embryonic skeletons (Fig. 9c; Reisz et al. 2005), identified as Massospondylus carinatus, a 450 kg long-necked, bipedal herbivore related to the giant sauropod dinosaurs of the Late Jurassic (Viglietti et al. 2020). More excavations at Rooidraai starting in 2006 discovered a 2 m-thick unit containing more than 10 shallow nests (Fig. 9b), with up to 34 eggs arranged in tightly packed rows (Reisz et al. 2012). High-resolution scans and digital reconstructions of Kitching's original eggs in 2020 showed that the embryos (Fig. 9d) were only 60% of the way to hatching and that the emerging Massospondylus babies would have rapidly stood on their hind legs and left the nest (Chapelle et al. 2020a, b).
The geoscientific evidence at Rooidraai suggests that Massospondylus mothers were returning annually to lay eggs in shallow, closely spaced nests (Reisz et al. 2012). These nests were made in pond-margin sediments (Fig. 9f) derived from wind-blown dust as aridity increased in southern Gondwana during the Early Jurassic (ultimately resulting in the aeolian dunes in parts of the Clarens Formation). The Rooidraai site is of similar age to the recently described nesting site in Patagonia (Pol et al. 2021) and, together, they provide the world's oldest evidence for dinosaur embryos, communal nesting and site fidelity that are critical for understanding the biology and behaviour of Dinosauria.
Conclusions
The world-famous rocks in the main Karoo Basin (Fig. 1) preserve evidence for climatic and tectonic changes in southern Gondwana from the late Carboniferous to the Early Jurassic. Preserving a rich assemblage of fossil tetrapods, plants, insects and traces, the Karoo fossil and rock record of 120 myr is widely celebrated for capturing four of the major biodiversity crises that governed the shape and direction of life on Earth, for documenting the world's finest evidence for the early diversification of terrestrial vertebrates and for cementing the paradigm of plate tectonics.
The fossils of the main Karoo Basin are protected by legislation both in South Africa and Lesotho and have great appeal to tourists. To capitalize on this potential, several sites with adequate protection have been opened for tourism and job creation ventures (e.g. Gansfontein, Nieu Bethesda, Lower Moyeni, GGHNP), and more will develop in the future (e.g. Fairydale, Upper Moyeni; Fig. 1). From the lower Karoo, this contribution provides a peek at a remarkable middle Permian trackway site at Gansfontein (Fig. 2), on-site guided tours to late Permian therapsid fossils near Nieu Bethesda (Fig. 3), a fossil graveyard at Fairydale (Fig. 4) that records the devastation of the end-Permian mass extinction, and tetrapod burrow casts from the central Karoo (Figs 5 & 6) showcasing the fossoriality in the biotic recovery period after the end-Permian mass extinction event. At Moyeni (Lesotho; Figs 7 & 8), the upper Karoo preserves an excellent vertebrate trace fossil record and attests to the Early Jurassic palaeodiversity of southern Gondwana. At GGHNP, one of the world's oldest dinosaur nesting grounds (Fig. 9) provides evidence for nesting behaviour and embryonic growth of the dinosaur Massospondylus. A soon-to-open museum near the site will further explain the global significance of this remarkable Early Jurassic ecosystem.
These selected geoheritage sites of palaeontological significance offer a travel though deep time aided by the fossil occurrences in the continental successions of the Karoo, which will no doubt reveal more treasures in the future to showcase the ancient landscapes and lifeforms in southern Gondwana from the Carboniferous to Jurassic.
Acknowledgements
The enormous contribution of the late Ian McKay and Billy de Klerk for establishing the KFEC and popularizing the fossil record of southern Africa is acknowledged with gratitude. EMB thanks the ongoing research support from Mme’ Molibeli (Lesotho Ministry of Tourism, Environment and Culture), Ntate Gill and Mme’ Lesego (Lesotho Morija Museum and Archives); Ntate Oa Qeme (Moyeni Dinosaur Footprints visitors’ centre); Ntate Phakisi (Masitise Cave House) and Prof Ambrose (National University of Lesotho). RMHS is grateful for the field and logistical support from Karoo Palaeontology Laboratory at ISAM, and JNC acknowledges assistance from Peter Gordon (SANParks), Brett Eloff (GENUS) and Kimi Chapelle (ESI WITS). We also thank reviewers, Ragna Redelstorff and Paul Barrett, and volume editor, Renee Clary, for contributing with their insightful comments to the overall quality of this chapter. Opinions expressed are those of the authors and are not necessarily to be attributed to the funders or anybody else.
Competing interests
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Author contributions
EMB: conceptualization (lead), formal analysis (equal), funding acquisition (equal), investigation (equal), project administration (lead), validation (equal), visualization (lead), writing – original draft (equal), writing – review & editing (equal); RMHS: conceptualization (supporting), formal analysis (equal), funding acquisition (equal), investigation (equal), validation (equal), writing – original draft (equal), writing – review & editing (equal); JNC: conceptualization (supporting), formal analysis (equal), funding acquisition (equal), investigation (equal), validation (equal), writing – original draft (equal), writing – review & editing (equal); BSR: conceptualization (lead), formal analysis (equal), funding acquisition (equal), investigation (equal), project administration (supporting), validation (equal), writing – original draft (equal), writing – review & editing (equal).
Funding
The authors acknowledge ongoing financial support of the National Research Foundation (NRF) of South Africa from the Hungarian–South African Intergovernmental S & T Cooperation Programme (GUN 2072841), the Competitive Programme for Rated Researchers (GU 93544, 113394, 98906 – EB), the African Origins Platform (GU 93544, 98825 – EB; 136503 – RHMS; 118794, 136516 – JNC) and GENUS (DSI-NRF Centre of Excellence in Palaeosciences; grants 2015–20).
Data availability
No new data were generated during the current study.