Colloquium - Nigel Hughes

Bio:

In the 1940’s George Gaylord Simpson opined that the principal contribution of paleontology to evolutionary biology lies in the assessment of evolutionary tempo and mode. Since that time the importance of understanding the accumulation history of the stratigraphic record in making such assessments has received wide recognition. Dikelocephalid trilobites from late Cambrian shelfal facies are a “good” group of fossils with a “good” record of their occurrence, meaning that membership of the group can be defined with reasonable confidence, and that it is moderately well represented in terms of sample sizes, at least for rocks of Cambrian age. Given this situation, what can be said about the tempo and mode of their evolution over timescales beyond the scope of studies of living organisms, and may we dissect patterns that speak of biological processes from those that were geologically driven? Our group’s work on this group of fossils, on-going for almost 40 years, suggests examples of patterns of morphological variation driven by stratigraphic controls, but also reveals patterns consistent with both Darwin’s expectations of evolution within/among populous species, and with rapid turnover and accelerated rates of morphological change, with a possible example of evolution in punctuated mode. Uncertainties of various kinds remain. 

Nigel Hughes received his PhD from the University of Bristol, UK, in 1990 and has enjoyed positions in museums and universities in Ireland, Australia and the USA. His research has focused mainly on the precollisional geology of the northern Indian margin and its implications of models of Himalayan uplift and erosion, and on the evolution of developmental regulation in trilobites.