New Book by UKZN Honorary Professor Interrogates Theory of Bird Evolution

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Professor Theagarten Lingham-Soliar, an Honorary Professor in the School of Life Sciences at UKZN, recently published a book The Vertebrate Integument Volume 1, which examines afresh the theory that birds evolved from dinosaurs and challenges some of the science behind the accepted theory through his research on the integument, which is the outer covering of an animal, including the skin, scales, hair and feathers.

Professor John Ruben at Oregon State University considered the book ‘Fantastic, ground-breaking and a huge contribution’, while on his website Professor Prosanth Chakrabarty of Louisiana State University declared Lingham-Soliar’s book ‘the best review of ostracoderm jawless fishes’ he had ever seen.

Lingham-Soliar’s research in The Vertebrate Integument Volume I is centred around the origin and development of the integument and the biomechanical nature of the dermis, a topic which has been the focus of his work for almost 15 years, beginning with fossils and progressing to the study of extant vertebrates. His most recent research deals with the biomechanical microstructure of the feather because so little is in fact known about it and how it forms the basis of feather strength. His interest in the evolutionary history of the integument was inspired by his undergraduate Lecturer, Professor Beverly Halstead, one of the world’s experts on the early evolution of vertebrates over 450 million years ago.

The dearth of sound knowledge about the feather and the evolution of the integument led Lingham-Soliar to dedicate considerable time to examining the structure of the feather, even waiting 18 months for fungi which feed on keratin to break down the feather structure to allow it to be examined on a microscopic level. This allowed him to see how filaments in the feathers are organised and revealed that they contain keratin fibres considerably thicker than those envisaged before in any form of keratin.

Lingham-Soliar’s publication deals predominantly with the development of the integument in a variety of creatures, from fish to dinosaurs, reptiles and mammals. However, it is the exciting and controversial discussions of the integumental structures, in particular feather-like structures, found on the famous Liaoning fossils in China, which has drawn his attention. His assertion that these alleged “protofeathers” found on many small dinosaurs are in all probability the degraded remains collagen fibres has received global attention, leading to Lingham-Soliar being one of the most cited persons on the National Geographic website.

This element of Lingham-Soliar’s publication, which questions a particular theory of evolution dealing with feather origins, has drawn strong opposition and, conversely, strong support from various corridors of the global scientific community. The controversies have become heated enough for Lingham-Soliar to devote a section of Volume II, to be published towards the end of 2014 or early 2015, to these controversies. Volume II will also deal with the biomechanics of the integument in more detail.

Lingham-Soliar says he does not necessarily oppose theories on the evolution of modern birds from dinosaurs, but is instead critical of the bad science which frequently accompanies these assertions. His aim is to stimulate conversation and research around the evolution of skin and feather structures through the production of good, clear science and logic.

‘I hope the book shows that any organ (in this case the skin – the biggest organ in the human body) that has evolved over 450 million years is inevitably complex,’ explained Lingham-Soliar, ‘and not given the simplistic treatment that many workers adopt in the field.’

‘In my research and that of colleagues, which involves its biomechanical function in vertebrates, we are showing how vital an understanding of the integuments of animals is, not just in biology but for providing solutions to engineering problems (Biomimetics). The hope is that the present book will make this understanding more widely known among scientists across different disciplines.’

Renowned Ornithologist, Palaeontologist and Emeritus Professor at the University of North Carolina, Alan Feduccia, said: ‘Lingham-Soliar’s The Vertebrate Integument is a splendid exposition on a difficult and broad biological topic, the vertebrate integument, an organism’s barrier between itself and the environment.  Lingham-Soliar is an internationally renowned, world-class expert in this field. Beginning with the first vertebrates, the jawless ostracoderms, through the transition to land, and finally the rise of land vertebrates, he brings together provocative new evidence from disparate fields in a beautifully integrative fashion with clear and engaging scientific prose.

‘There are few people with such diverse knowledge of biology, physiology, biomechanics and paleontology who could have assembled such a marvellous and beautifully written essay on this expansive field,’ added Feduccia. ‘Solly [the name by which he is most commonly known] is truly a renaissance paleontologist, led only by evidence, not by hopes and fears. He only takes a position when evidence leads him in that direction, and shows that while some speculation is necessary to advance the field (otherwise one’s reach cannot exceed one’s grasp), it must be done only with substantial convincing evidence, otherwise a field will drift into an abyss. There is little question that this book represents a landmark publication, and will be the gold standard on the integument for years to come.’

The scholarly journey which led to the publication of The Vertebrate Integument began when Lingham-Soliar saw that palaeontology needed to use highly rigorous research methods regardless of the difficulties of working just with fossilised bones and occasionally decayed soft tissue. For instance, when notable British Mathematician Sir James Lighthill extrapolated a relationship of high-speed swimming in the extinct ichthyosaurs to some of the fastest modern swimmers like tuna and dolphins based on body shape alone, Lingham-Soliar knew more evidence was needed.

‘Fast swimming in the latter two animal groups was also aided by a crossfibre collagen network in the skin, so I decided to look for it in ichthyosaurs – quite a task because it meant finding preserved skin in a 200 million-year-old fossil,’ said Lingham-Soliar. ‘The study was successful and published by the Royal Society of London in 1999 and it has led to studies in many animals since, including the great white shark.’

Lingham-Soliar acknowledges the influence of many mentors and colleagues in the development of his career, most notably his mother who, he says, ‘filled [his life] with culture, kindness and hope’, giving his family ‘dignity amidst the undignified world of pre-1994 South Africa’, and his brother who stimulated his love of knowledge.

Lingham-Soliar also credited the leadership and encouragement of Les Leedham, who encouraged his first career as a Research Chemist and subsequently in biology. He thanked Professors Beverly Halstead (Reading University) and Richard Estes (San Diego State University), his PhD supervisors, for his success during his years in exile in the UK when South Africa was still in the grip of apartheid. His acknowledgements go on to thank supervisors and collaborators from Oxford University, the Smithsonian, Tubingen University, the Paleontological Institute of the Russian Academy of Sciences and the University of North Carolina, to name a few, and evidence of the breadth of his work. In Life Sciences at UKZN he thanks Professor Sam Mukaritirwa (Head of the School of Life Sciences) who, Lingham-Soliar says, he respects as a person who would find solutions rather than obstacles.

Lingham-Soliar expressed the hope that future studies in biomechanics will form a core structure of research in universities in South Africa, as they already do in leading universities overseas. He remains grateful for the opportunities presented to him at UKZN, including its facilitation of his seminal research on the great white shark that ultimately led to research in diverse animals including feather microstructure in birds: “a chain reaction,” said Lingham-Soliar. He has a particularly soft spot for the support staff at UKZN, who he said have always bent over backwards to aid his research.

Lingham-Soliar plans to continue to work on the microstructure of keratin using a method he developed at UKZN which involves using microbes to expose hidden microstructural features that are otherwise tightly locked in, and thereby understand reasons for their biomechanical strength. He also plans to develop a new enzymatic hydrolytic method to investigate structural proteins – bringing together his two careers in Chemistry and Biology.

Christine Cuénod