MORPHOLOGY, LIFE HISTORY, AND MOLECULAR PHYLOGENY OF CHORDA RIGIDA, SP. NOV. (LAMINARIALES, PHAEOPHYCEAE) FROM THE SEA OF JAPAN AND THE GENETIC DIVERSITY OF CHORDA FILUM
Article first published online: 21 DEC 2001
Journal of Phycology
Volume 37, Issue 1, pages 130–142, February 2001
How to Cite
Kawai, H., Sasaki, H., Maeda, Y. and Arai, S. (2001), MORPHOLOGY, LIFE HISTORY, AND MOLECULAR PHYLOGENY OF CHORDA RIGIDA, SP. NOV. (LAMINARIALES, PHAEOPHYCEAE) FROM THE SEA OF JAPAN AND THE GENETIC DIVERSITY OF CHORDA FILUM . Journal of Phycology, 37: 130–142. doi: 10.1046/j.1529-8817.1999.014012130.x
- Issue published online: 21 DEC 2001
- Article first published online: 21 DEC 2001
- 1Received 27 December 1999. Accepted 10 October 2000.
- 5.8S rDNA;
- Chorda filum;
- Chorda rigida sp. nov;
- molecular phylogeny;
- Rubisco spacer
Chorda rigida Kawai et Arai, sp. nov. (Chordaceae, Laminariales) is described from the Sea of Japan, NW Pacific. This species resembles Chorda filum (Linnaeus) Stackhouse but is distinguished by the following characteristics: 1) the sporophytes grow on more or less exposed rocks at 2–7 m depth and do not form dense tufts; 2) compared with C. filum, sporophytes of C. rigida are much more rigid and are composed of denser cortical layers (6–18 cells thick); 3) C. filum becomes fertile and disappears in late spring to summer, whereas C. rigida appears in early summer, oversummers, and becomes fertile only in late autumn at the same localities; 4) in culture, C. rigida sporophytes tolerate higher temperature conditions (20 and 25° C) than C. filum; and 5) C. rigida has considerably longer sequences of the rDNA ITS region than does C. filum. The independence of the species is further supported by molecular phylogenetic analyses using sequence of the ITS + 5.8S ribosomal DNA. Interestingly, C. filum is shown to be genetically diverse and possibly paraphyletic, and it may require subdivision into several species or subspecies. The rbcL and associated spacer sequence data established monophyly of the genus Chorda among Laminariales, but the resolution was limited for discussing the phylogenetic relationships within the genus.