Algae. 2002; 17(3): 135-144.
First Description of Petalonia zosterifolia and Scytosiphon gracilis (Scytosiphonaceae, Phaeophyceae) from Korea with Specieal Reference to nrDNA ITS Sequence Comparisons
Ga Youn Cho, Eun Chan Yang, Sang Hee Lee, Sung Min Boo
Department of Biology, Chungnam National University
Scytosiphonaceae is an ectocarpalean brown algal family, that is a recent focus of systematics and marine biodiversity. We describe Petalonia zosterifolia and Scytosiphon gracilis from Korea for the first time. P. zosterifolia occurred on the East coast, and had flat, linear and solid thalli. S. gracilis was found in Jeju, and had cylindrical to flat and holow thalli. However, these two species are so similar that it is difficult to identify by morhology alone. In order to determine if the nuclear DNA reveals the distinctness of both species and to know their phylogenies, the ITS region sequences were newly determined in 22 samples of P. zosterifolia, Scytosiphon gracilis, and other three members of the genera from Korea. We found 0.12% variation among samples of P. zosterifolia from different locations, and no variation between S. gracilis samples from different years, but extensive interspecific divergences (13.62-22.83%) of each species to other members in Petalonia and Scytosiphon. The ITS sequence data consistently showed a close relationship between P. zosterifolia and S. gracilis. This result is congruent with morphology and with the published data of plastid rbc and partial nrDNA large subunit gene sequences, and suggests that P. zosterifolia and S. gracilis might have diverged from the most recent common ancestor.
ITS region, morphology, Petalonia zosterifolia, Phaeophyceae, phylogeny, Scytosiphon gracilis, Scytosiphonaceae, taxonomy