Molecular phylogeny of the widespreadMartensia fragiliscomplex (Delesseriaceae, Rhodophyta) from the Indo-Pacific region reveals three new species ofMartensiafrom Taiwan

Abstract

The genus Martensia is characterized primarily by its unique thallus morphology, wherein a proximal membranous blade is interrupted distally by one to several bands of net-like tissue (networks). Among the known species, M. fragilis is characterized by fan-shaped, membranous blades with multiple bands of networks. The species has been frequently reported from warm temperate and tropical regions. Collections from various localities in the Indo-Pacific region included many specimens fitting this broad concept of M. fragilis, but differed in several aspects and were difficult to assign to any named species with confidence. In order to delineate the species boundaries within this suite of M. fragilis-like specimens and to clarify the phylogenetic significance of the morphological features used for separating species of Martensia, we used analyses of rbcL sequence to infer phylogenetic relationships among the available species with multiple bands of networks. Molecular analyses revealed that M. fragilis was restricted to its type locality Sri Lanka and that collections of M. 'fragilis' from other regions were split into six clades. Martensia 'fragilis' collections from Taiwan contained three cryptic species, which were described as new species (M. leeii W.

Reappraisal of nine species of Martensia (Delesseriaceae, Rhodophyta) reported from Korea based on morphology and molecular analyses

“…53, Figures 1-4) with our Martensia specimens and discovered that Okamura's four morph types of Martensia resemble Lee's species concepts (2006Lee's species concepts ( , 2008 of M. australis (Figures 3 and 12), M. jejuensis (Figures 9 and 16), M. bibarii (Figures 4 and 13), and M. fragilis (Figures 7 and 15 Lin et al (2013: 187) that M. denticulata from Japan should be recognized as M. jejuensis. Lin et al (2013) mentioned that the changed environmental conditions, especially the enriched seawater from seashell farms, might have considerable effects on the growth and thallus morphology of Martensia populations around Jeju Island. It is noticeable that individuals having fragmented networks and linear membranous segments, such as M. jejuensis type and M. bibarii type, were collected mostly from somewhat sheltered and shallow places of Jeju Island.…”

“…Mature tetrasporangia are borne on both sides of fertile blades, globose, 70-100 μm in diameter, and tetrahedrally divided ( Figure 59). Lin et al (2013) recently showed that the widespread Martensia fragilis in the northwestern Pacific Ocean (e.g., Taiwan, Korea, and Japan) contained several cryptic species, which share some morphological similarity. They also concluded that some morphological features used for separating species (e.g., size of network structure, blade shape, branching pattern) are not reliable, and they merged Martensia bibarii from Korea into Martensia jejuensis based on molecular and morphological evidence.…”

“…Southern coast of the Korean Peninsula and Jeju Island (Lee and Kang 2001, this study); Japan (Lin et al 2013).…”

“…Because information was missing for the 5′ ends of many sequences, the first 190 sites were excluded from the analyses, the final data matrix being restricted to 1254 base pairs, 438 of which were informative characters (30.3%). In the phylogenetic tree ( Figure (Figures 11,18,19), were all identical to those of M. jejuensis generated by Lin et al (2013) available from GenBank (JX982269, JX982281, and JX982283). Six specimens identified as Martensia albida (Figures 2,40,41) and two specimens as M. elegans sensu Lee (thallus blades with entire margins: Figures 6, 42) formed a clade with 0% sequence divergence and were separated from M. elegans from Natal, South Africa (type locality), with a 3.0% divergence.…”

“…The diagnostic features reported for Korean species of Martensia are branch patterns, thallus shapes, blade thickness, network structures, presence or absence of dentation along thallus margins, and positions of reproductive organs by following various taxonomic studies, e.g., Svedelius (1908), Millar (1990), Yoshida and Mikami (1996), and Lin et al (2001bLin et al ( , 2004. Lin et al (2013) demonstrated that the widespread species known as Martensia fragilis Harvey in the Pacific Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 6/19/15 7:20 PM Ocean, including Hawaii, Japan, Korea, Philippines, and Taiwan, is a species-complex composed of at least six different species based on rbcL sequence analyses. In addition, they showed that the M. bibarii and M. fragilis from Korea (Lee 2004) and M. denticulata from Japan are conspecific with M. jejuensis.…”