Systematic revision of the Family Gelidiaceae (Gelidiales, Rhodophyta) from Taiwan

• Main Authors: Hsi-Ju Hsueh, 薛希如
• Other Authors: Showe-Mei Lin
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/80073533992177387433

碩士 === 國立臺灣海洋大學 === 海洋生物研究所 === 97 === Abstract The Order Gelidiales, consisting of a single family Gelidiaceae, comprises a dominant component of the marine flora in northern Taiwan. No taxonomic studies had been focusing on the Gelidiaceae from Taiwan, and the records of the Gelidiaceae were only seen in the previous marine floristic surveys of Taiwan. Therefore, a monograph of species diversity and systematic studies on Taiwan's Gelidiales based on morphological and molecular datasets is carried out herein. Molecular analyses showed that the newly collected species from around the coastlines of Taiwan felled into five clades (= five genera: Aphanta, Capreolia, Gelidium, Gelidiella and Pterocladiella) and eleven subclades (= eleven species). The number of the species of the Gelidiales found in this study is much fewer than the species recorded in the past and many synonyms and misapplied names might be the causes. Among the five clades/genera based on the molecular analyses and mophological investigations, Clade I Aphanta containing an undescribed species (Aphanta sp.), Clde II Capreolia containing an undescribed species (Capreolia sp.); Clade III Gelidium containing three species (Gelidium elegans, Gelidium japonicum and Gelidium isabelae); Clade IV Gelidiella containing two species (Gelidiella acerosa and Gelidiella fanii), and Clade V Pterocladiella containing four species (Pterocladiella capillacea, Pterocladiella caeurlescens, two undescribed species: Pterocladiella sp. 1 and Pterocladiella sp. 2). Our taxonomic studies on the genera Gelidium and Pterocladiella from Taiwan indicated that many records based on Japanese or European species were misidentification, i.e. G. "amansii", G. "crinale", G. "pusillium", P. "tenuis", P. "nana" etc. The results also showed that eleven species are actually belonging in Gelidiella, Gelidium and Pterocladiella among the eighteen previous records. In particular, the small species with decumbent thalli, recognized as "Gelidium divaricatum" or G. "crinale/pusillum" in the past, are actually containing several new records to Taiwan marine flora or "new" species in various genera of the family. Based on the rbcL sequence analysis, the so-called “Gelidium divaricatum” recorded from Taiwan is genetically different from Gelidium divaricatum from its type locality (Hong Kong Island) and contains four species within three genera (Gelidium isabelae, Pterocladiella caeurlescens, Capreolia sp. and Pterocladiella sp. 2). Among them, G. isabelae, P. caeurlescens are new records for Taiwan. Collections of “Gelidium crinale” from northern and southern and Orchid Island are different from G. crinale from its type locality (England) and are positioned in the genera Aphanta and Pterocladiella as undescribed species. Molecular analysis also indicated that the previous records of Gelidium “amansii” and Gelidium “pacificum” should be placed in Gelidium elegans, which morphologies are very variable in different seasons and habitats. Similarly, Pterocladiella “nana” and Pterocladiella “tenuis” recorded from northern Taiwan are ecotypes of Pterocladiella capillacea.