An assessment of Haraldiophyllum (Delesseriaceae, Rhodophyta), including H . crispatum (J.D. Hooker et Harvey) comb. nov. from New Zealand based on rbc L and LSU sequence analysis and morphological evidence

Abstract

Over thirty species from around the world are currently placed in Myriogramme, very few of which have been compared with the type species, M. livida from southern South America and the Falkland Islands. An investigation of two of these, Myriogramme crispata and M. denticulata from New Zealand, demonstrates that they comprise a single morphologically variable species, Haraldiophyllum crispatum (J.D. Hooker et Harvey) comb. nov., that is separable from Myriogramme. A morphological and molecular study of the New Zealand species, together with the type species of Haraldiophyllum, H. bonnemaisonii, from the British Isles, establishes that the genus is correctly placed in the tribe Myriogrammeae. It differs from Myriogramme in having sympodially developed solitary terminal carposporangia, rather than primary carposporangia borne in chains, and sterile-group cells that fuse during carposporophyte development rather than remaining separate. Sequence analyses of the rbcL gene revealed that a range of forms of H. crispatum from the North, South and Stewart Islands, New Zealand were identical and that H. crispatum was sister to H. bonnemaisonii. A sister relationship between Haraldiophyllum and Myriogramme was moderately supported in maximum parsimony analyses of the large subunit rDNA (LSU) and was strongly supported in a Bayesian analysis. Even though rbcL sequence analysis did not support a close relationship between Haraldiophyllum and Myriogramme, alternative topologies enforcing a sister relationship between the respective genera were not rejected by Shimodaira Hasegawa tests. Our studies indicate that many species with similar morphologies placed in Haraldiophyllum, Myriogramme and Nitophyllum require re-investigation.