Life History Types of the Florideophyceae (Rhodophyta) and their Evolution

Abstract

Life histories in the Florideophyceae, Rhodophyta, are classified into eleven types: I (the ancestral type), II (the isomorphic type), III (the heteromorphic type), IV (the Lemanea mamillosa type), V (the Mastocarpus papillatus type), VI (the Liagora tetrasporifera type), VII (the Rhodophysema elegans type), VIII (The Audouinella purpurea type), IX (the Palmaria palmata type), X (the Hildenbrandia proto(ypus type), and XI (the Audouinella pectinata type). The evolutionary paths from the ancestral type (type I) to type V through type II, type III and type IV (A course), to type VII through type III and type VI (B course), to type X through type III, type VI, type VIII and type IX (C course), and to type XI through type II (D course) in the existing algae are discussed. No close relationship in the life history has been found between phylogenetic orders in the class. The order Nemaliales, the most primitive order, has eight types of life history, being very variable in the evolution of life history, while the orders Rhodymeniales and Ceramiales, which have each two types, are in an evolutionally stable position. Some species in the class have two types oflife history: in addition to primitive types (type II and type III) apomictic type (V), non-carposporophyte type (IX) and sporophytic type (type X) are known.