Until now Eocene chimeroid holocephalians of Antarctica have been known from only a few specimens attributed to two species from the Eocene of Seymour Island. New material collected by Polish and English field parties includes numerous tooth plates and fin spine fragments from the Eocene La Meseta Formation. We describe a new species, Callorhinchus stahli, based on two mandibular and a single fragmentary palatine tooth plate. In addition, the stratigraphic distribution and diversity of Eocene Antarctic chimeroids is discussed. The chimeroid Ischyodus shows the greatest stratigraphic distribution with its greatest abundance in the middle parts of the La Meseta Formation while Chimaera and Callorhinchus are restricted to the lower ones. Changes in the environment and habitat availability most probably triggered the distributional pattern and the disappearance of chimeroids.