About the Project
This project will be supervised by Dr Julia Sigwart of Queen’s University School of Biological Sciences, Dr Alex Brasier of the University of Aberdeen’s School of Geosciences, and Mr Shaun Graham of Carl Zeiss Microscopy. The start date will be 1 October 2019.
Animals with hard parts often incorporate penetration of nerves through the skeleton as part of their sensory systems. This is true in a very broad range of animal groups: vertebrates have nerves that penetrate bones, whereas polyplacophoran molluscs or chitons have “aesthetes”, special nerve channels in their shells, and some even have “shell eyes”. Chitons are marine animals with a slug like soft foot, which they use to crawl on the ocean floor. They are completely protected on their top surface by a hard shell armour constructed of the calcium carbonate mineral aragonite. This is the same mineral used by modern corals to build their skeletons, so like the corals the chitons are at increasing risk of dissolution as ocean pH falls due to rising input of anthropogenic CO2. Helping survival of these organisms in the Anthropocene gives one good reason for us to study the skeletons of chitons.
But there is another excellent reason to study the aragonite shells of chitons, as these animals achieve an incredible feat of engineering. Although they have a hard shell for strength and rigidity they have soft nerve tissues penetrating through their armour that are needed for the animal to perceive the outside world. Revealing the hidden secrets of these incredible constructions presents a technical challenge for microscopy: how to visualise, characterise and describe the soft tissues that are hidden within the solid shells. This is a challenge the student will take on, in collaboration with CASE partner CarlZeiss Microscopy.
Chitons have a distinctive armature of eight overlapping but separate aragonite shells that cover the dorsal body surface and protect the soft ventral foot underneath. The articulation of the shell series has been studied as optimizing strength in a flexible arrangement to accommodate locomotion. However, in all living species of chitons, these valves are not solid. The shells or valves are penetrated by a dense array of sensory pores. The aesthetes are a feature of fossil as well as living chiton species, and may represent a deep homology shared with other lophotrochozoans with shell pores.
This PhD project will use advanced microscopy techniques, to visualise and to describe both (1) the aesthete sensory networks and the distribution of empty space within chiton valves and (2) the neural structures inside these pores, to understand the cell types involved and their likely function. The student will gain skills in a broad range of microscopy and anatomy techniques including X-Ray Microscopy (XRM), analysis of image data include 3D tomographic models, data management, statistical analysis and data visualisation, descriptive neuroanatomy, and phylogenetic analyses. Training will also be supported by the student undertaking an internship with CASE partner CarlZeiss. This research has important implications for sensory neurobiology (understanding how organisms sense and gain information about their environment), materials science (inspiring biomimetic innovation), and evolutionary biology.
Funding Notes
This studentship is available to UK and other EU nationals and provides funding for tuition fees and stipend, subject to eligibility.
Candidates should have (or expect to achieve) a minimum of a 2.1 Honours degree in a relevant subject.
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