Pleistocene Hamerkop Scopus umbretta (Scopidae) tracks and other new avian ichnosites on South Africa’s Cape south coast

Although tortoises (Testudinidae) are a familiar clade of reptiles, with a body fossil record extending to at least the Eocene, hitherto no tortoise ichnosites have been described. Here, a number of sites attributed to tortoise trackmakers are identified within Pleistocene aeolianites on South Africa's Cape south coast. These date from late Marine Isotope Stage 6 to Marine Isotope Stage 4. The findings indicate large trackmakers, with evidence of a trackmaker length of more than a meter—substantially longer than the largest extant tortoises in southern Africa. This suggests either the presence of an extinct very large tortoise species, or that Pleistocene leopard tortoises in the region were larger than their descendants. Variations in substrate properties are responsible for a variety of track and trace forms. A mismatch exists between the reported ichnological evidence for large tortoises, and the regional archaeological and body fossil records, which almost exclusively comprise smaller tortoises. The findings illustrate the potential of ichnology to complement and augment the paleontological and archaeological records.

Aeolianites and cemented foreshore deposits on South Africa's Cape south coast have the capacity to record and preserve events that transpired on them when they were composed of unconsolidated sand. Thirty-five Pleistocene elephant tracksites have been identified along this coastline. This abundance of sites along what was the margin of the vast Palaeo-Agulhas Plain allows for an appreciation of the forms that elephant tracks and traces can take in the context of the global proboscidean track record. They point to a significant regional elephant presence from Marine Isotope Stage (MIS) 11 (~400 ka) through MIS 5 (~130–80 ka) to MIS 3 (~35 ka) and also indicate repeated use of certain dune areas. They buttress Holocene and historical evidence that elephants made use of open areas in the region, and that the remaining “Knysna elephants” retreated into dense afrotemperate forest for protection in recent centuries. Analogies can be drawn between Pleistocene elephant tracks and Mesozoic dinosaur tracks, and some of the Cape south coast elephant tracks are among the largest Cenozoic (and hence, Quaternary) tracks ever to be described. A newly identified tracksite in this area may provide the first reported evidence of elephant trunk-drag impressions.

Palaeoenvironments and plant availability during MIS 6 to MIS 3 on the edge of the Palaeo-Agulhas Plain (south coast, South Africa) as indicated by phytolith analysis at Pinnacle Point

A fossil trackway, attributed to a probable pangolin trackmaker, has been identified on a Pleistocene aeolianite surface of the Waenhuiskrans Formation in the Bosbokfontein Private Nature Reserve on South Africa’s Cape south coast. The trackway consists of eight tracks and two probable tail traces. This appears to be the first description of a pangolin trackway in the global fossil record. The trackway was probably registered during Marine Isotope Stage 6 or 5. Trackway assessment and interpretation involved the integration of indigenous African and Western-based ichnological approaches, leading to a reasonably confident conclusion on the probable trackmaker’s identity. Alternative trackmakers (felids, viverrids and canids) were considered, but excluded or regarded as less likely candidates. There are three Cenozoic body fossil records of pangolins from the southwestern Cape, which have been assigned to the giant pangolin (Smutsia gigantea). Only Temminck’s pangolin (Smutsia temminckii) currently occurs in southern Africa. All eight extant pangolin species are considered to be threatened with extinction according to the IUCN Red List of Threatened Species.

East of Still Bay on the Cape south coast of South Africa lies a rugged, remote stretch of sea cliffs that expose Late Pleistocene aeolianites. A zone of dense concentration of fossil tracks occurs within this area. Two large rocks, which we call Roberts Rock and Megafauna Rock, were identified ~400 metres apart. These rocks contained a variety of trackways, individual tracks, burrow traces and invertebrate trace fossils on multiple bedding planes. Both rocks were found ex situ, but their context could be determined. Roberts Rock has subsequently slid into the ocean, and Megafauna Rock lies at the base of a coastal cliff. Probable trackmakers include elephant, long-horned buffalo, giant Cape horse, rhinoceros, medium and small artiodactyls, golden mole, birds and invertebrates. Dating studies at an adjacent site, which is comparable to the stratigraphy described here, indicate that both rocks were most likely deposited in Marine Isotope Stage 5e (~128–116 ka). Analysis and description of these tracksites confirms the potential of ichnology to complement the skeletal fossil record and to enhance the understanding of Pleistocene life in southern Africa. The ephemeral nature of such tracksites makes repeated visits to this coastline desirable, both to monitor the fate of known sites and to search for newly exposed trace fossil surfaces.
 Significance:
 
 Roberts Rock and Megafauna Rock are two remarkable fossil tracksites on the Cape south coast, which contain tracks of four members of the Late Pleistocene megafauna. They provide a glimpse of Pleistocene dune life and suggest an area teeming with large mammals.
 These tracks were made on dune surfaces near an interface between the grassland of the Palaeo-Agulhas Plain and the inland Fynbos–Strandveld–Renosterveld. Faunal assemblages from both vegetation zones might therefore be recorded.
 The trace fossil record and body fossil record both have inherent biases, but have the potential to independently provide complementary information on palaeofaunal composition.
 The two rocks have provided the first South African records of fossil elephant tracks (as first described by Dave Roberts and colleagues in 2008), the first rhinoceros track and the first extinct giant Cape horse track, and track evidence of the extinct long-horned buffalo.
 Roberts Rock has slumped into the ocean, and it provides an example of the fate of many exposed tracksites. Conversely, new sites frequently become exposed. This scenario stresses the need for regular ichnological surveys along this track-rich coastline to monitor existing sites and to search for new sites.

Helm, C.W.; Carr, A.S.; Cawthra, H.C.; De Vynck, J.C.; Dixon, M.; Stear, W.; Stuart, C.; Stuart, M., and Venter, J.A., 2022. Possible Pleistocene pinniped ichnofossils on South Africa's Cape south coast. Journal of Coastal Research, 38(4), 735–749. Coconut Creek (Florida), ISSN 0749-0208. Exposed surfaces of cemented foreshore deposits and aeolianites on the Cape south coast of South Africa have been demonstrated to contain numerous Pleistocene vertebrate tracksites. Two ichnosites have recently been identified that appear to demonstrate traces made by seals. These would be the first seal trace fossils thus far described in the global fossil record. The sites are situated 560 m apart in the Goukamma Nature Reserve. One site exhibits apparent flipper traces and a furrow, and the other site exhibits impressions consistent with moulds of juvenile seals. In conjunction with new luminescence dating of the associated sediments, these findings suggest a seal presence on Cape south coast beaches ∼75,000 years ago in the mild glacial period of Marine Isotope Stage 5a.

Seven hominin ichnosites in aeolianites on the Cape south coast of South Africa have been dated using Optically Stimulated Luminescence, yielding age estimates from Marine Isotope 6 through Marine Isotope Stage 4. All rock outcrops containing these sites are situated on the modern coastline. The new ages are consistent with geomorphological expectations, and with other numerical dating results from the wider southern Cape coastline. Seen in a global ichnological context, the cluster of South African sites (including two previously dated sites) contains nine of the twenty-three sites older than 70 ka from which hominin tracks have been reported. With a single exception they are also the only sites older than 40 ka that have been attributed to Homo sapiens, and include the oldest tracks (153 ± 10 ka) thus far attributed to our species. The South African coastline contains an archaeological and palaeoanthropological record of global significance, to which the hominin ichnological record, preserved on aeolianite palaeosurfaces and now chronologically constrained, can make a substantial contribution.

Twelve new avian ichnosites have been identified on South Africa’s Cape south coast, adding to the 29 sites previously identified. More than half of these 41 avian ichnosites are found along a 9-km stretch of coastline east of Still Bay. The new sites provide the first southern African trace fossil records of the dove, stork and heron families, as well as a possible ostrich trackway and evidence of probable ostrich eggshell fragments. They buttress the previous inference of large avian chronospecies during the Pleistocene. The preponderance of large- and mediumsized tracks can be attributed to a bias whereby fossil tracks of larger, heavier birds are easier to recognise and interpret. Four of the longest fossil avian trackways ever to be identified occur within a 350-m stretch of coastline in the Driefontein area, east of Still Bay. The new findings provide an enhanced picture of the Pleistocene avifauna of the region. Many of the new sites are fragile and have limited prospects to endure, emphasising the need to document them through photogrammetry, and to regularly explore the coastline in high-yield areas in search of further sites.

Southern Africa features an intensively studied Stone Age sequence, though one with geographical and temporal gaps. The archaeology of Marine Isotope Stage (MIS) 3 remains understudied, particularly between ~ 50 and 25 ka. This period encompasses important ecological, demographic and cultural changes, most notably the transition from Middle Stone Age (MSA) to Later Stone Age (LSA) technologies. In western South Africa, previous research postulated a demographic hiatus during the second half of MIS 3, potentially due to hyperarid climatic conditions. Here, we provide evidence of occupation during this period at Mertenhof Rock Shelter (MRS) in the form of new chronometric and technological data. OSL estimates suggest two pulses of low-intensity occupations at ~ 50 ka and 41–37 ka, allowing for a diachronic assessment of technological changes. These sporadic MSA occupations complement the more widespread occurrence of open-air settlements along the Doring River during ~ 50–35 ka. At MRS, knappers procured local rock types and produced small flakes and some laminar elements via platform, bipolar and Levallois reduction. The retouched elements feature splintered pieces and denticulates but mostly lack points. Differences to contemporaneous sites in eastern southern Africa underscore ongoing technological regionalisation and demographic partitioning during MIS 3. The temporal changes in the sequence show some antecedents of Early LSA technological systems, which appear in the region around 25 ka, but not in a unidirectional manner. Lithic and chronometric evidence from MRS supports scenarios of a long MSA persistence within MIS 3 in southern Africa and a late emergence of the LSA sometime after 35 ka.

The Cape south coast of South Africa contains a wealth of Pleistocene vertebrate trace fossil sites in aeolianites and cemented foreshore deposits. Published studies have described mammal and avian tracksites identified along this coastline. We report here on a number of Pleistocene palaeosurfaces within the Garden Route National Park that exhibit tracks of large reptiles, including probable swim traces. The tracks were probably made by more than one species, and may include a crocodylian. There are no extant reptiles in this coastal region capable of making such tracks and traces, which probably represent an indication of a previously more extensive range for the Nile crocodile and a monitor lizard. These findings demonstrate the potential for ichnology to complement the traditional body fossil record. Two Middle Stone Age stone artifacts were found embedded in one palaeosurface containing multiple reptile trackways. These discoveries have implications for the understanding of Pleistocene palaeoenvironment and palaeoclimate – in an area which is important in the study of modern human origins. Significance: Large reptile Pleistocene fossil tracksites have recently been discovered on the Cape south coast of South Africa where there are no previous such records, and no reptiles of this size are currently found in the region. These sites include the first reported probable reptile swim traces in Africa and one tracksite also contained two Middle Stone Age artifacts. These discoveries have implications for Pleistocene environments and climate on the Cape south coast.

Until now there have been no reliable historical or skeletal fossil records for the giraffe (Giraffa camelopardalis) south of the Orange River or northern Namaqualand. The recent discovery of fossil giraffe tracks in coastal aeolianites east of Still Bay, South Africa, significantly increases the geographical range for this species, and has implications for Late Pleistocene climate and vegetation in the southern Cape. Giraffe populations have specialised needs, and require a savanna ecosystem. Marine geophysical and geological evidence suggests that the broad, currently submerged floodplains of the Gouritz and Breede Rivers likely supported a productive savanna of Vachellia karroo during Pleistocene glacial conditions, which would have provided a suitable habitat for this species. We show evidence for the hypothesis that the opening of the submerged shelf during glacial periods acted as a pathway for mammals to migrate along the southern coastal plain. Significance: The identification of fossil giraffe tracks on the Cape south coast, far from the area in which giraffe have previously been known to occur, is unexpected; conclusions about prehistoric conditions and vegetation can be drawn from this discovery.

To reveal the characteristics and environmental indications for the combination of the grain size and magnetic susceptibility of coastal sediments, we provided a necessary basis for further study on their genetic mechanisms. Based on the data of grain size and magnetic susceptibility of the 36.10 m long core 07SR01 sediments in the Xiyang tidal channel of western South Yellow Sea, we analyzed their variations and correlations and further revealed their environmental indications and corresponding regional sedimentary evolution via the combination of the aforementioned analysis results, the reinterpretation results of the sedimentary sequence and the age of core 07SR01 and shallow seismic profiles, and the findings of climate and glacial–eustatic cycles during Late Quaternary. The three stages of the sedimentary evolution of the Xiyang tidal channel between marine isotope stage (MIS) 7 and MIS 5 were summarized as follows: First is the stage of marginal bank and riverbed developments in the tidal estuary under a relatively high sea level and strong hydrodynamic conditions during MIS 7 (core section: 36.10–26.65 m). The sediments deposited in this stage were mainly affected by the paleo-Changjiang River and characterized by a coarse grain size (mean: 4.02 Φ) and relatively high magnetic susceptibilities (mean: 27.06 × 10−8 m3·kg−1), with small fluctuations which were strongly and positively correlated with the sand component. Second is the stage dominated by fluviolacustrine and littoral environments with the weak hydrodynamics during MIS 6–5, in which the climate changed from cold and dry to warm and humid as the sea level rose after a drop (core section: 26.65–15.77 m). The sediments deposited in this stage were characterized by a fine grain size (mean: 5.27 Φ) and low magnetic susceptibilities with minor variations (mean: 10.83 × 10−8 m3·kg−1) which were weakly and positively correlated with the coarse silt component. Third is the stage of delta front in the tidal estuary with a relatively high sea level and strong hydrodynamics during MIS 5 (core section: 15.77–0 m). The sediments deposited in this stage were strongly influenced by the paleo-Yellow River and characterized by a relatively coarse grain size (mean: 4.86 Φ), and high magnetic susceptibilities (mean: 37.15 × 10−8 m3·kg−1) with large fluctuations which were weakly and positively correlated with the sand and coarse silt components.

Snakes form a large, familiar, and distinctive component of the world’s reptile fauna, with a rich body fossil record stretching back to the Jurassic. The sparse, minimal, and questionable evidence of snake traces in the ichnological record is therefore surprising. Extant snakes in southern Africa employ three types of locomotion—rectilinear, sidewinding, and undulatory, all of which result in distinctive, recognizable traces. A site exhibiting convincing evidence of rectilinear motion, probably made by a puff adder, has been identified in Pleistocene aeolianites on South Africa’s Cape south coast. A new ichnogenus and ichnospecies, Anguinichnus linearis, have been erected to describe this trace. A new suite of optically stimulated luminescence (OSL) ages from aeolianites from the De Kelders Cave locality, 1.4 km to the south, suggests that the site dates to ∼93–83 ka. Trace fossil evidence of sidewinding and undulatory motion is more equivocal and open to alternative interpretations.

Three new Pleistocene hominin tracksites have been identified on the Cape south coast of South Africa, one in the Garden Route National Park and two in the Goukamma Nature Reserve, probably dating to Marine Isotope Stage 5. As a result, southern Africa now boasts six hominin tracksites, which are collectively the oldest sites in the world that are attributed to Homo sapiens. The tracks were registered on dune surfaces, now preserved in aeolianites. Tracks of varying size were present at two sites, indicating the presence of more than one trackmaker, and raising the possibility of family groups. A total of 18 and 32 tracks were recorded at these two sites, respectively. Ammoglyphs were present at one site. Although track quality was not optimal, and large aeolianite surface exposures are rare in the region, these sites prove the capacity of coastal aeolianites to yield such discoveries, and they contribute to what remains a sparse global hominin track record. It is evident that hominin tracks are more common in southern Africa than was previously supposed. Significance: Three new Pleistocene hominin trackways have been identified on the Cape south coast, bringing thenumber of known fossil hominin tracksites in southern Africa to six. The tracks were all registered on dune surfaces, now preserved as aeolianites. These are the six oldest tracksites in the world that are attributed to Homo sapiens. Hominin tracks are more common in southern Africa than was previously supposed.

Helm, C.W.; Cawthra, H.C.; De Vynck, J.C.; Dixon, M., and Stear, W., 2021. Elephant tracks: A biogenic cause of potholes in Pleistocene South African coastal rocks. Journal of Coastal Research, 37(1), 59–74. Coconut Creek (Florida), ISSN 0749-0208.The Cape south coast of South Africa contains extensive outcrops of Pleistocene aeolianite and cemented foreshore deposits. More than 250 vertebrate tracksites have been identified in these deposits, including 35 elephant tracksites. In places, where large palaeosurfaces are occasionally exposed, numerous potholes are evident on the remains of what is most likely a palaeo-coastline. Features suggestive of elephant tracks are apparent on such surfaces and in overlying layers. In order to develop, potholes require a disturbance or depression in the surface to act as a "pothole-precursor" on which erosive forces can act. While elephant tracks or similar biogenic origins for potholes have not previously been described, such an explanation appears plausible for at least some pothole features in areas known to have harboured elephants or other large vertebrate trackmakers when these surfaces were composed of unconsolidated sand. Four sites on the Cape south coast are examined and described. Evidence for use of beaches as travel corridors for elephants is described, and candidate Pleistocene trackmaker species are considered. The age of these palaeo-surfaces is considered to range from Marine Isotope Stage 11 to Marine Isotope Stage 5. It is concluded that depressions formed by elephant tracks should be considered as a precursor for the formation of potholes on suitable Pleistocene surfaces in littoral zones.