Abstract
Crinoids are an emblematic group of marine invertebrates, represented by sea lilies and featherstars, with records dating from the Ordovician Period to the present. Promachocrinus Carpenter, 1879 is a genus of the family Antedonidae, endemic to Antarctic and sub-Antarctic islands, representing the most abundant crinoid in the Antarctic Ocean. Until 2023, Promachocrinus was considered a mo…