Molecular systematics of the genus Actinotrichia (Galaxauraceae, Rhodophyta) from Taiwan, with a description of Actinotrichia taiwanica sp nov.

摘要

Three species of Actinotrichia from Taiwan (Galaxauraceae, Rhodophyta) are described on the basis of morphological and molecular evidence, including A. fragilis, the generitype, A. robusta, a new record for Taiwan, and A. taiwanica sp. nov. Actinotrichia fragilis can be distinguished from the other two species by having a wider branching angle (usually 40), persistent and distinctly whorled assimilatory filaments and paraphyses issuing from the pericarp, which do not intermix with the gonimoblasts. Actinotrichia robusta can be distinguished from A. taiwanica by its narrower branches, thinner cortex, more obvious whorled assimilatory filaments and smaller fusion cell that is usually indistinguishable in the mature cystocarp. Recognition of these three species was also supported by rbcL sequence analysis. While A. fragilis is distributed in the pantropical regions of the Indian and Pacific oceans, A. robusta and A. taiwanica sp. nov. are only found along the Kuroshio Current in the northwestern Pacific Ocean.