A morphological and phylogenetic study of Glaphyrosiphon gen. nov. (Halymeniaceae, Rhodophyta) based on Gvateloupia intestinalis with descriptions of two new species: Glaphyvosiphon lindauevi from New Zealand and Glaphyvosiphon chilensis from Chile

摘要

A new genus, Glaphyrosiphon Hommersand & Leister gen. nov., is proposed to contain the generitype Glaphyrosiphon intestinalis (Harvey) Leister & W.A. Nelson comb. nov., a species known in New Zealand under the name Grateloupia intestinalis (Hooker. f. & Harvey) Setchell ex P.G. Parkinson, and two additional species: Glaphyrosiphon lindaueri W.A. Nelson & P.W. Gabrielson sp. nov. from the northern part of New Zealand and Glaphyrosiphon chilensis M.E. Ramírez, Leister, and P.W. Gabrielson sp. nov. in the southern part of Chile from Valdivia (Región de Los Ríos), to Punta Arenas in the Strait of Magellan (Región de Magallanes). Thalli are borne singly or in clusters from a small discoid holdfast and consist of simple or one- to three-times-branched slippery tubes that are copiously filled with mucilage. The medulla consists of a one- to several-layered network inside the cortex composed of stellate cells that interconnect by short to long extensions linked by pit connections. Primary rhizoidal filaments are absent. Spermatangia are superficial on terminal cortical cells. Carpogonial and auxiliary-cell ampullae are formed separately and link by unsegmented tubular connecting filaments, as in other Halymeniaceae. The auxiliary-cell ampulla consists of a basal cell and four unilaterally branched filaments in which the auxiliary cell is the basal cell of one of the four filaments. The auxiliary cell and inner ampullar filaments unite forming a fusion cell. Ampullar filaments connect terminally to inner cortical cells and laterally with one another by short filaments and pit connections that form an involucral network surrounding the gonimolobes. Tetrasporangia are cruciately divided and borne laterally on filaments produced secondarily from surface cortical cells. Sequence analyses of the rbcL gene place Glaphyrosiphon sister to Polyopes in the Halymeniaceae. The two New Zealand species consist of southern and northern clades separated by 1.2% to 1.7% base-pair distances in rbcL analyses and a Chilean species that forms a single clade separated from the New Zealand clades by 3.9% to 4.4% base-pair distances. Records of Grateloupia intestinalis from Tasmania have not been studied.