A new combination for Caloplaca macquariensis C.W. Dodge is made in Sirenophila Søchting, Arup & Frödén, S. macquariensis (C.W. Dodge) Søchting & de Lange. In the process we reduce the Aotearoa / New Zealand Caloplaca maculata D.J. Galloway into synonymy within the new combination, noting the lack of morphological distinctions between that species and S. macquariensis. Very little is known about S. macquariensis which is known only from the type collected from Macquarie Island, however, we offer an update on the species ecology based on collections and observations of the species on the Chatham Islands – the eastern most extension of the Aotearoa / New Zealand archipelago. Keywords: Teloschistaceae, Sirenophila, Caloplaca, C. macquariensis, C. maculata, new combination.