Elphidium williamsoni Haynes, 1973 is a foraminiferal species that has been used extensively in relative sea level and climate change studies, as it is characteristic of intertidal zones. Identifying this and other species of Elphidium has proven difficult because key morphological characteristics show a wide range of variation causing widespread confusion in determinations.
A study led by University of St Andrews PhD student Angela Roberts and recently published in the Journal PloSOne, has gone a long way to clearly define this important foraminiferal species. The study is based on measurements from Museum type specimens as well as genetic studies on contemporary material collected from the same location as the type specimens.