Two new species of Currant Bush <i>Coprosma</i> (Rubiaceae) from an endemic radiation on Lord Howe Island

Abstract Molecular and morphological evidence provide support for the description of two new species of Coprosma (Rubiaceae) from Lord Howe Island, a remote oceanic island in the Tasman Sea. The first species, C. savolainenii sp. nov., was discovered during a plant survey, whereas the second species, C. ptotopetra sp. nov., was identified using DNA fingerprinting. Confirmation of both is currently being obtained through high-throughput sequencing. We provide detailed descriptions of each new species, alongside an updated description of C. putida, a species with similar morphology to C. ptotopetra sp. nov.. We also provide phenological, distribution, and conservation data for each species. This description goes beyond a traditional species account, as it represents a unique endemic radiation occurring in sympatry on an isolated island of global conservation significance. It may also represent a rare botanical example of the syngameon hypothesis, where hybrid speciation accelerates evolutionary radiation.