The typification and status ofPhymatolithon(Corallinaceae, Rhodophyta)

Abstract

The taxonomy and nomenclature of Phymatolithon Foslie, 1898 (Corallinaceae, Rhodophyta) have been reassessed on the basis of studies of the designated generitype and other critical specimens. Phymatolithon was based on P. polymorphum (L.) Foslie whose basionym, Millepora polymorpha Linnaeus, is one of several superfluous substitute names for Millepora calcarea Pallas. A neotype for M. calcarea is designated and described and the concept of Phymatolithon is reviewed and amended in the light of information from the neotype. The generic name Phymatolithon is proposed for conservation against Apora Gunnerus 1768 and Nullipora Lamarck 1801, both of which are also based on Millepora polymorpha and hence on M. calcarea. The name Phymatolithon polymorphum has been misapplied for many years to a quite different species of Phymatolithon, the correct name for which is P. purpureum (P. & H. Crouan) comb. nov. (Basionym: Lithothamnion purpureum P. & H. Crouan). The taxonomic status of Phymatolithon is discussed briefly, particularly in relation to Lithothamnion, Kvaleya and Leptophytum.