Evolution of colour and vision in marine invertebrates
The evolutionary history of colour and vision has been closely intertwined over the last 500 million years, leading to a dazzling diversity of colours and visual systems in marine invertebrates.
Colour and marine invertebrates
The fabulous and diverse colours and patterns of molluscan shells and brightly coloured echinoderms are widely recognised, however their function for the animal is sometimes less clear and has been the focus of many ecological and evolutionary studies. Despite these studies, almost nothing is known about the evolution of colour in these groups.
My lab is working with international collaborators to identify shell pigments in a range of molluscan species using methods such as high-performance liquid chromatography and resonance Raman spectroscopy.
We are building on that information to identify the molecular pathways responsible for the biosynthesis of pigments in molluscs and echinoderms using transcriptomics and differential gene expression.
Our ultimate aim is to determine the effect of colour on adaptation, ecology, geographical range and speciation.
Publications – evolution of colour
Wade, J., Pugh, H., Nightingale, J., Kim, J. S. and S. T. Williams. (2019). Colour in bivalve shells: Using resonance Raman spectroscopy to compare pigments at different phylogenetic levels. Journal of Raman Spectroscopy 50: 1527–1536.
Grant, E. H. & S. T. Williams. (2018). Phylogenetic distribution of shell colour in Bivalvia (Mollusca). Biological Journal of the Linnean Society 125: 377–391. doi.org/10.1093/biolinnean/bly122
Williams, S. T., Lockyer, A. E., Dyal, P., Nakano, N., Churchill, C. K. C. and D. I. Speiser. (2017). Colourful seashells: Identification of haem pathway genes associated with the synthesis of porphyrin shell colour in marine snails. Ecology and Evolution 7: 10379-10397.
Williams, S. T. (2017). Molluscan shell colour. Biological Reviews 92: 1039-1058.
Williams, S. T., Ito, S., Wakamatsu, K., Goral, T., Edwards, N. P., Wogelius, R. A., Henkel, T., de Oliveira, L. F. C., Maia, L. F., Strekopytov, S., Jeffries, T., Speiser, D. I. and J. T. Marsden. (2016). Identification of shell colour pigments in marine snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda). PLoS One 11(7): e0156664
Williams S.T., J.A.H. Benzie. (1998). Evidence of a biogeographic break between populations of a high dispersal starfish, congruent regions within the Indo-West Pacific defined by colour morphs, mtDNA and allozyme data. Evolution 52: 87-99
PhD student at the Natural History Museum and University College London
Previous lab members
Nathan Kenny (postdoc)
Emily Noone (NHM/IC MSc student)
Eleonora Rossi (Torno Subito Fellowship)
Sophie Sykes (NHM/UCL MRes student)
Hazel Pugh (NHM/IC MRes student)
Heather Grant (NHM/IC MRes student)
Nearly all molluscs are thought to be colour blind and most have poor visual acuity, yet they showcase the greatest diversity of eye types in the animal kingdom.
My lab is working to investigate the loss of eyes in dark environments, in particular the deep-sea family Solariellidae (with Dr Lauren Sumner-Rooney).
While it may come as no surprise to find that some solariellids living in the deep sea have lost their eyes, it is surprising that vision has been lost at least seven times in this family of detritovores.
Even more surprisingly, their pigment-cup eyes have degenerated via more than one evolutionary pathway (loss of pigment, degeneration of vitreous body obstruction of aperture), making solariellids an ideal system to look at repeated evolution of vision loss.
My lab has also started looking at the evolution and diversification of eyes in the iconic gastropod superfamily Stromboidea.
Publications – molluscan vision
Sumner-Rooney, L., Kenny, N. J., Ahmed, F. and S. T. Williams. (2019). The utility of micro-computed tomography for the non-destructive study of eye microstructure in snails. Scientific Reports 9: 15411.
Sumner-Rooney, L. H., Sigwart, J. D., Smith, L. and S. T. Williams. (2016). Repeated eye reduction events reveal multiple pathways to degeneration in a family of marine snails. Evolution 70(10): 2268-2295.
PhD student Natural History Museum/ University of Bristol