Paleoanthropology and Comparative Anatomy

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The Palaeoanthropology and Comparative Anatomy (PACA) lab is co-directed by Matt Skinner and Christophe Soligo. A high-end environment for research is created by a combination of recent refurbishments with high-end computers, availability of 3D-data capture equipment, including microscribes, surface laser-scanners and analysis software, access to a growing database of CT-scan and 3D-morphometric data, and an expanding fossil cast and comparative osteological collection. Our research covers a diverse range of topics, but is directed by a common aim of understanding the relationship between biological form and function using a comparative approach and with the ultimate goal of expanding our knowledge of human biology and of the processes that lead to the evolution of modern humans.

Research Projects

Evolution of the skull in primates. The skull is the most complex hard-tissue element of the body. It contains all the major sensory organs (vision, hearing, smell and taste) as well as the brain, and performs key elements of the feeding process including the capture, initial processing (chewing) and ingurgitation (swallowing) of food. The skull's complexity means that it is the most likely part of the skeleton to reflect measurable degrees of evolutionary and environmental influences. In addition, elements of the skull are the most frequently recovered body parts in the fossil record, making them the focus of the vast majority of research on the evolution of extinct species. Our current research is concerned with identifying and quantifying phylogenetic and environmental signals as well as their respective rates of evolution in different elements of the primate skull and is supported, in part, by a NERC Standard Research Grant and a NERC/ESRC studentship.

Evolution of the brain in primates and other mammals. Humans stand out amongst primates and other mammals for having a particularly large brain to body size ratio. While a large brain may bring computational advantages, brains are also an energetic liability. As a result, brain size has long been a major focus of comparative anatomical research in human evolution. Recent work has taken advantage of new phylogenetic comparative methods to increase substantially the resolution with which evolutionary processes underlying brain to body size ratios can be inferred, and was published in PNAS (Smaers et al. 2012). New results are also beginning to highlight the importance of organisational variability, as opposed to differences in relative brain size, between species and evolving lineages (Smaers & Soligo, 2013).

Teeth, taxonomy and human evolution. Teeth and jaws are the most commonly found human fossils because they are highly mineralized and preserve very well in the fossil record. Teeth in particular are the source of a staggering amount of information about a fossil species that allow us to reconstruct dietary habits, patterns of growth and development and evolutionary relationships between different fossil species. Our research employs cutting edge imaging techniques (microtomography) and analytical tools that breathes new life into old fossils and allows to address new questions. UCL Anthropology has excellent computing and imaging facilities that create a dynamic environment in which we regularly explore never before seen aspects of important human fossils. We also collaborate closely with researchers working with living apes to understand links between diet, climate, and developmental stress that are recorded in skeletal tissues, such as teeth.

Evolution of post-cranial adaptations in primates. Locomotor and postural adaptation is a key element of any animal's biology. It is of particular interest in primates, which show a diversity of locomotor and postural adaptations that exceeds that seen in most other orders of mammals. Recent projects, partly funded by a Portuguese Foundation for Science and Technology studentship, use 3-D imaging technology to quantify post-cranial characteristics to test hypotheses of form-function relationships and to infer biological characteristics of fossil primate taxa including hominines.

Evolution of the human hand: grasping trees and tools. The unique manipulative abilities of the human hand, which are unrivalled in the animal kingdom, have fascinated scientists since the time of Darwin. However, we know remarkably little about how this capacity evolved because we have lacked the necessary fossil human (hominin) evidence as well as the appropriate methods to investigate if, when and how our early ancestors used their hands for locomotion (climbing) and manipulation (tool-use). We participate in a collaborative research network that uses novel morphological, experimental and biomechanical methods to directly investigate different locomotor and manipulative behaviours in living humans and other apes and use this knowledge to reconstruct hand use in hominin fossils.

Timing divergence events using the fossil record. Accurate chronological contextualisation of evolutionary events is crucial to understand the driving forces behind primate diversity. A collaborative project with colleagues in England and the United States addresses the time of origins of primates and resulted in a publication in Nature (Tavaré et al. 2002). An improved, Bayesian approach allows for the simultaneous estimation of more than one divergence time and was published in Systematic Biology (Wilkinson et al. 2011). There we used posterior probabilities derived from the fossil record as prior probabilities for estimations of divergence times from molecular data. Future developments aim to improve the modelling power through the inclusion of more detailed data from the fossil record.

Taphonomy and palaeoenvironmental reconstruction of Palaeogene and Neogene fauna. Interpretation of evolutionary processes requires knowledge of the environmental conditions under which they operated. This research is therefore concerned with developing methods to assess and control for taphonomic bias prior to palaeoenvironmental reconstruction. The approach concentrates on the interpretation of entire assemblages of fossil mammals through multivariate analyses and using an extensive comparative database of modern faunas. At present, this work is focussed on the earliest appearance of primates in the fossil record at the base of the Eocene and the time of the main diversification of the hominine lineage in the Pliocene and early Pleistocene.

Selected Publications

  • Smaers JB, Soligo C. 2013. Brain reorganization, not relative brain size, primarily characterizes anthropoid brain evolution.  Proceedings of the Royal Society B: Biological Sciences 280 (1759): 20130269; doi:10.1098/rspb.2013.0269
  • Ortiz, A, Skinner, MM, Bailey, SE, Hublin, J-J. 2012. Carabelli’s trait revisted: an examination of mesiolingual features at the enamel-dentine junction and enamel surface of Pan and Homo sapiens upper molars. Journal of Human Evolution 63: 586–596
  • Skinner, MF, Skinner, MM, Boesch, C. 2012. Developmental defects of the dental crown in chimpanzees from the Taï National Park, Côte D‘Ivoire: coronal waisting. American Journal of Physical Anthropology 149: 272–282
  • Smaers JB, Dechmann DKN, Goswami A, Soligo C, Safi K. 2012. Comparative analyses of evolutionary rates reveal different pathways to encephalization in bats, carnivorans, and primates Proceedings of the National Academy of Sciences of the United States of America; DOI 10.1073/pnas.1212181109
  • Wilkinson RD, Steiper ME, Soligo C, Martin RD, Yang Z, Tavaré S. 2011. Dating primate divergences through an integrated analysis of palaeontological and molecular data. Systematic Biology 60: 16–31
  • Kivell, TL, Skinner, MM, Lazenby, R, Hublin, J-J. 2011. Methodological considerations for analyzing trabecular architecture: an example from the primate hand. Journal of Anatomy 218: 209–225
  • Skinner, MM, Gunz, P, Wood, BA, Hublin, J-J. 2008. Enamel-dentine junction (EDJ) morphology distinguishes the lower molars of Australopithecus africanus and Paranthropus robustus. Journal of Human Evolution 55: 979–988
  • Soligo C, Martin RD. 2006. Adaptive origins of primates revisited. Journal of Human Evolution 50: 414–430
  • Soligo C. 2005. Anatomy of the arm and hand in Daubentonia madagascariensis: a functional and phylogenetic outlook. Folia Primatologica 76: 262–300
  • Soligo C, Andrews PJ. 2005. Taphonomic bias, taxonomic bias and historical non-equivalence of faunal structure in early hominin localities. Journal of Human Evolution 49: 206–229

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