Hominids and hominid ecology in the fynbos biome
I am responsible for curating the important Langebaanweg fossil collection. This site has provided a unique insight into the terminal Miocene/early Pliocene faunas of the region, which, amongst other species, includes a bear (Agriotherium africanum), an hipparion (Eurygnathohippus cf. baardi), a sivathere (Sivatherium hendeyi), a gomphothere mastodont (cf. Annacus sp.), and a false saber-toothed cat (Dinofelis sp.). Unfortunately primates are rare and currently only includes two fragmentary cercopithecoid teeth.
I am interested in our evolution and the ecological contexts in which we evolved. In the study of human evolution, it is important to realize that our ancestors did not exist in isolation of their environments. Their lives were intricately woven into the fabric of past and changing ecologies. Their interaction with other species and environments were critical factors in shaping their morphology and also in driving further evolutionary change. Thus, in order to gain an understanding of our earliest ancestors, it is important to also study the other species with which they shared the environment. My approach to the study of human evolution is thus holistic and requires expertise in both human and non-human vertebrate palaeontology.
The majority of my projects are situated in South Africa’s Fynbos Biome. Specific foci include:
- Human craniofacial evolution
- Ecomorphological studies of large mammals in the terminal Miocene/early Pliocene Langebaanweg fossil assemblage
- Environmental change in the Fynbos Biome
The fossil record in the Fynbos Biome
The Fynbos Biome contains an abundance of fossil assemblages, many of which include both human and non-human vertebrate fossils. The earliest fossil remains are those from Langebaanweg. The site of Baard’s Quarry, which is situated in close proximity to Langebaanweg, is an equally important, although lesser-known fossil occurrence in the region. In addition to an element of early Pliocene material, it contains a faunal assemblage of presumed late Pliocene/early Pleistocene age. Although the above-mentioned sites have yet to produce hominid remains, evidence from similarly aged East African sites indicates that they fall within the critical period when some of our earliest ancestors made their first appearance. As such, they are important regional resources for studies of African ecologies at the dawn of mankind.
The Fynbos region also contains some of the most important Pleistocene-aged fossil sites. The early to middle Pleistocene site of Elandsfontein has produced thousands of fossils. In addition to its diverse fauna, which includes both archaic and modern components, Elandsfontein is famous for producing a middle Pleistocene (Homo heidelbergensis) human calotte and mandibular fragment.
Human remains have also been found in several terminal middle Pleistocene to late Pleistocene fossil deposits in the region. These include sites such as Hoedjiespunt 1 and Sea Harvest. The middle to late Pleistocene archaeological site of Klasies River has produced some of the earliest and most important modern human material to date.
Terminal Pleistocene to Holocene faunal assemblages are well represented in the region. Most faunal assemblages dating to this time are archaeological. However, they remain an important source of ecological/environmental data for this region. Most importantly, there is also a large, well-dated collection of human osteological remains dating to this period. This material is important to test hypotheses of population continuity in the region during the late Pleistocene to Holocene.
Research past and present
Human craniofacial evolution
I was involved in a description of late middle Pleistocene human teeth from the palaeontological site of Hoedjiespunt 1, along South Africa’s south-west coast.
I described a human incisor and cranial fragment from the Middle Stone Age site of Pinnacle Point, along South Africa’s south coast.
For my PhD thesis I assessed craniometric variation in 153 individually dated human crania from South Africa with the aim of investigating genetic continuity/discontinuity during the Holocene. Evidence from the archaeological and/or skeletal record was used to pinpoint likely episodes of genetic discontinuity. Craniometric data were then used to assess whether genetic change had occurred. Two periods of possible genetic discontinuity were identified: (i) c. 4000 BP, when an increase in overall population size, changes in site organization and diet, and reduced mobility, were accompanied by reductions in stature; (ii) c. 2000 BP, when herding was introduced into the region. Results indicate that there was a noticeable decrease in cranial size and concomitant size-related changes in craniofacial shape between c.4000 BP and 3000 BP. This was followed almost immediately by a recovery in craniofacial size and a return to pre-4000 BP craniofacial shape at c. 3000 BP. This recovery continued gradually, extending into the herder period without any major shifts in morphology at 2000 BP. It is proposed that the fluctuations in craniofacial size/shape were related to changes in environmental factors, possibly nutritional insufficiencies. Results obtained are consistent with long term continuity in South African Later Stone Age populations during the Holocene.
I am currently involved in several projects aimed at determining the phenotypic origins of southern Africa’s Khoesan people.
After the completion of my thesis I was involved in post-doctoral research on craniofacial variation in Nubian populations (pre-Meroitic to medieval Christian periods) at the Univerisity of Paul Sabatier (Toulouse 3) in Toulouse, France. This post-doctoral research was funded by the European Virtual Anthropology Network (EVAN) which focuses on using new morphological analysis methods to elucidate human origins.
I am in the process of setting up a research project focusing on ecomorphological investigations of several large mammal species from Langebaanweg. The ecomorphology of a fossil species is exemplified by its overall body shape and size, skeletal and dental anatomy, dental wear patterns and stable isotopic signals. This type of information is used to deduce diet, locomotion, positional and social behaviour, foraging strategies and preferred habitat. Ecomorphological data gathered from individual fossil species may be combined to recreate aspects of past ecologies. These are essential to our understanding of the ecological contexts in which our earliest ancestors evolved and provide biological information on the animals that existed at the time.
This project follows on from and expands on previous ecomorphological studies by employing a battery of methods (e.g. a study of morphology, isotopes, microwear and mesowear) to all studied species. It is hoped that this approach will provide precise ecological data on each of the studied species. The study will not only be limited to ungulates, as in many previous studies, but will also include other groups such as carnivores. The eventual aim of this study is to combine the data from individual species to reconstruct aspects of the Langebaanweg large mammal paleoecology as accurately as possible e.g. the niche separation between the Langebaanweg hyaenid species.
Ungulate diets and environmental change
The Fynbos biome gets its name from the indigenous sclerophyllous shrublands or “fynbos”, which occur throughout. Fynbos species are characteristically hard, woody, tough shrubs, often with narrow, leathery leaves. Although indigenous grasses are scarce, those species that do occur are overwhelmingly of the cool growth season C3 type. Fynbos did not always dominate the biome though. Fossil evidence indicates that prior to the Holocene, grazing animals far outnumbered browsers. This is specifically the case at sites such as Elandsfontein and Duinefontein. The predominance of grazers suggests that extensive grasslands dominated the region at the time. Although Fynbos (as we know it) was probably present in the region since the early Pliocene, it apparently only became dominant during the Holocene, as suggested by the predominance of browsers over grazers during this period.
The dietary determinations of Fynbos ungulate species have primarily been based on taxonomic uniformitarianism, a method grounded in the assumption that fossil taxa exhibited the same ecological preferences as their nearest living relatives. This method has several problems though. Firstly, it assumes that taxonomic groups remained ecologically constant through time. This is not always the case, as indicated by ecologically related temporal shifts in the diets of some bovid taxa. Secondly, fossil occurrences from the Miocene to Pliocene and Pliocene to Pleistocene are dominated by extinct taxons, some of which do not have any historic descendents on which to base dietary reconstructions. In order to generate taxon-independent dietary evidence, I am in the process of setting up several projects which employ more empirical methods of dietary determination (isotopes, mesowear, microwear). This information will be used to test previous palaeoenvironmental reconstructions.
A new excavation at Langebaanweg is being planned in conjunction with colleagues from the National Museum Bloemfontein for the 2008 field season. This excavation will focus on exposing an area which previously produced remains of the famous Agriotherium africanum skeleton.
Dr Deano Stynder
Curator: Cenozoic Palaeontology Collections
Natural History Department
Iziko South African Museum
Box 61, Cape Town 8000
Phone: +27 (0)21 481 3894
Fax: +27 (0)21 481 3993