MOLECULAR PHYLOGENETIC RELATIONSHIPS IN THE FRESHWATER FAMILY HYDRODICTYACEAE (SPHAEROPLEALES,CHLOROPHYCEAE), WITH AN EMPHASIS ON PEDIASTRUM DUPLEX1

The freshwater green algal family Hydrodictyaceae (Sphaeropleales, Chlorophyta) has traditionally consisted of four coenobial genera, Pediastrum Meyen 1829, Hydrodictyon Roth 1797, Sorastrum Kützing 1845, and Euastropsis Lagerheim1894. Two recent molecular phylogenetic studies demonstrated the need for reevaluation of the generic and species boundaries in this morphology‐rich family. This study expands the previous work to include phylogenetic analyses of 103 ingroup isolates representing North America, Europe, and Australia, with an emphasis on the common and geographically widespread species Pediastrum duplex. Nucleotide sequence data were collected from the nuclear LSU (26S rDNA) and the chloroplast RUBISCO LSU (rbcL) genes, totaling >3,000 aligned characters. The 26S and rbcL data sets were analyzed using maximum‐likelihood (ML) and Bayesian phylogenetic methods. In addition, SEM was used to examine the wall morphology of a majority of the isolates. The results supported previous indications that the P. duplex Meyen 1829 morphotype is nonmonophyletic and resolved some previously ambiguous relationships recovered in earlier phylogenetic estimations using fewer isolates. These new data allowed testing of the recent taxonomic revisions of the family that split Pediastrum into five genera. Some of the previous revisions by Buchheim et al. (2005) were well supported (erection of Stauridium and Monactinus), while others were not (Pediastrum, Pseudopediastrum, Parapediastrum).     

PHYLOGENY OF LOBOCHARACIUM (CHLOROPHYCEAE) AND ALLIES: A STUDY OF 18S AND 26S rDNA DATA1

The phylogenetic affinities of Lobocharacium coloradoense were investigated by analysis of combined 18S and 26S rDNA data. Results from both parsimony and likelihood methods supported a close alliance among Lobocharacium, Characiosiphon, and Characiochloris. These three taxa formed a clade near the base of the “Dunaliella” group within the chlamydomonad lineage. Protosiphon, which exhibits a siphonous habit similar to Characiosiphon and Lobocharacium, was not resolved as a close ally of the latter two taxa. The Lobocharacium alliance was characterized by the presence of an attachment pad associated with the nonmotile vegetative stage and pyrenoids that possess cytoplasmic invaginations. The pyrenoid feature is an ultrastructural trait that has now been observed in five different chlorophycean lineages. The Lobocharacium–Characiosiphon–Characiochloris clade is not predicted by any classifications of green algae. Additional taxon and data sampling need to be completed to resolve inconsistencies between the molecular phylogenetic evidence and at least some of the current family‐level taxa.     

MORPHOLOGY AND MOLECULAR PHYLOGENY OF AUREOPHYCUS ALEUTICUS GEN. ET SP. NOV. (LAMINARIALES,PHAEOPHYCEAE) FROM THE ALEUTIAN ISLANDS1

A previously unknown species of kelp was collected on Kagamil Island, Aleutian Islands. The species can be easily distinguished from any known laminarialean alga: the erect sporophytic thallus is composed of a thin lanceolate blade attaining ～2 m in height and ～0.50 m in width, without midrib, and the edge of the blade at the transition zone is thickened to form a V‐shape; the stipe is solid and flattened, slightly translucent, attaining ～1 m in length; the holdfast is semidiscoidal and up to 0.15 m in diameter. Anatomically, the blade has the typical trumpet‐shaped hyphae characteristic of the Chordaceae and derived foliose laminarialean species (i.e., Alariaceae/Laminariaceae/Lessoniaceae). No hair pits or mucilaginous structures were observed on the blade or stipe. No fertile sporophytes were collected, but abundant juvenile sporophytes were observed in the field. In the molecular phylogenetic analyses using chloroplast rbcL gene, nuclear ITS1‐5.8S‐ITS2 rDNA, and mitochondria nad6 DNA sequences, the new species (Aureophycus aleuticus gen. et sp. nov.) showed a closer relationship with Alariaceae of conventional taxonomy, or the “Group 1” clade of Lane et al. (2006) including Alaria and related taxa than with other groups, although the species was not clearly included in the group. Aureophycus may be a key species in elucidating the evolution of the Alariaceae within the Laminariales. Because of the lack of information on reproductive organs and insufficient resolution of the molecular analyses, we refrain from assigning the new species to a family, but we place the new species in a new genus in the Laminariales.     

PHYLOGENY OF THE SUBFAMILY SCOTIELLOCYSTOIDEAE (CHLOROPHYCEAE, CHLOROPHYTA) AND RELATED TAXA INFERRED FROM 18S RIBOSOMAL RNA GENE SEQUENCE DATA

Nuclear-encoded small subunit ribosomal RNA gene (18SrDNA) sequences were determined for Coelastrella multistriata (Trenkwalder) Kalina et Punčochářová, two species of Scotiellopsis ( S. oocystiformis (Lund) Kalina et Punčochářová and S. terrestris (Reisigl) Kalina et Punčochářová) and two species of Muriella ( M. aurantiaca Vischer and M. terrestris Boye- Petersen). Coelastrella and Scotiellopsis are members of the subfamily Scotiellocystoideae, and Muriella is a member of the subfamily Chlorelloideae in the family Chlorellaceae. Phylogenetic trees were constructed based on these sequence data and on previously known 18SrDNA sequences of 25 taxa. Coelastrella and Scotiellopsis were closely related to each other and formed a cluster with Scenedesmus vacuolatus (Shihira et Krauss) Kessler et al. This cluster shared a monophyletic ancestry with other Scenedesmus species. Muriella aurantiaca formed a sister relationship with the monophyletic lineage of Scenedesmus. However, another species, M. terrestris, was placed in the Trebouxiophyceae and was strongly related to Chlorella. The genus Mychonastes belonging to the Scotiellocystoideae was also not monophyletic. This study suggests that the subfamily Scotiellocystoideae should be removed from the Chlorellaceae.     

PRESCOTTIELLA,A NEW GENUS OF ASYMMETRICAL DESMIDS (CHLOROPHYCEAE)1

Bipolar asymmetry has been considered a morphological characteristic sufficient for differentiation of genera among the Desmidiaceae. Therefore, Micrasterias sudanensis Grönbl., Prowse & Scott, the only species of Micrasterias showing such asymmetry, is made the type of a new genus, Prescottiella, gen. nov.     

PHYLOGENY OF CARTERIA (CHLOROPHYCEAE) INFERRED FROM MOLECULAR AND ORGANISMAL DATA1

Comparative ultrastructural data have shown that at least two distinct groups exist within Carteria. Similarly, interpretations of variation in gross morphological features have led to the discovery of morphologically distinct groups within the genus. Partial sequences from the nuclear-encoded small- and large-subunit ribosomal RNA molecules of selected Carteria taxa were studied as a means of 1) testing hypotheses that distinct groups of species exist within the genus and 2) assessing monophyly of the genus. Parsimony analysis of the sequence data suggests that three Carteria species, C. lunzensis, C. crucifera, and C. olivieri, form a monophyletic group that is the basal sister group to all other ingroup flagellate taxa (including species of Chlamydomonas, Haematococcus, Stephanosphaera, Volvox, and Eudorina). Two other Carteria taxa, C. radiosa and Carteria sp. (UTEX isolate LB 762), form a clade that is the sister group to a clade that includes Haematococcus spp., Chlamydomonas spp., and Stephanosphaera. Thus, the sequence data support the interpretations of ultrastructural evidence that described two distinct Carteria lineages. Moreover, the sequence data suggest that these two Carteria groups do not form a monophyletic assemblage. Parsimony analysis of a suite of organismal (morphological, ultra-structural, life history, and biochemical) character data also suggest two distinct lineages among the five Carteria taxa; however, the organismal data are ambiguous regarding monophyly of these Carteria taxa. When the two independent data sets are pooled, monophyly of Carteria is not supported; therefore, the weight of available evidence, both molecular and organismal, fails to support the concept of Carteria as a natural genus.     

PHYLOGENY OF THE CHLOROPHYCEAE WITH SPECIAL REFERENCE TO THE SPHAEROPLEALES: A STUDY OF 18S AND 26S rDNA DATA

Ultrastructural analyses of the flagellar apparatus suggested that Sphaeroplea , Atractomorpha , the Hydrodictyaceae, and the Neochloridaceae, all of which produce biflagellate motile cells with directly opposed (DO) basal bodies, are allied in an order Sphaeropleales. Recent studies of 18S rDNA sequence data supported an alliance of the DO group, but no data from Sphaeroplea and its allies were included. This investigation presented a test of the phylogenetic hypothesis suggested by the flagellar apparatus evidence using sequence data from the nuclear-encoded small-subunit rDNA (18S) and large subunit rDNA (26S) genes, combined with additional taxon sampling. Results from phylogenetic analyses weakly supported monophyly of biflagellate DO taxa and indicated that pyrenoids with cytoplasmic invaginations are present in numerous distinct lineages. Analysis of both molecular data sets supported a class Chlorophyceae comprised of at least six major groups that generally correspond to currently recognized orders or families: Chaetophorales, Chae- topeltidales, Chlamydomonadales, Sphaeropleales, Sphaeropleaceae, and Oedogoniales. In addition, Cylindrocapsa , Elakatothrix , Treubaria , and Trochiscia formed a seventh chlorophycean clade that is new to science. This investigation demonstrated that the 26S rDNA gene provides more phylogenetic signal, per unit sequence, than the 18S rDNA gene and that combined analysis yields topologies with more robust support than independent analysis of either data set.     

MORPHOLOGY,MOLECULAR PHYLOGENY AND TAXONOMY OF TWO NEW SPECIES OF PLEODORINA (VOLVOCEAE,CHLOROPHYCEAE)1

The volvocacean genus Pleodorina has been morphologically characterized as having small somatic cells in spheroidal colonies and anisogamous sexual reproduction with sperm packets. In this study we examined two new species that can be assigned to the genus Pleodorina based on morphology: P. starrii H. Nozaki et al. sp. nov. and P. thompsonii F. D. Ott et al. sp. nov. P. starrii was collected from Japan and had 32‐ or 64‐celled colonies with anterior somatic cells and spheroidal individual cellular sheaths that were weakly attached to each other within the colonial envelope. P. thompsonii from Texas (USA) exhibited four or 12 somatic cells in the anterior pole of 16‐ or 32‐celled colonies, respectively, and had a single large pyrenoid in the chloroplast of mature reproductive cells. The chloroplast multigene phylogeny placed P. starrii and P. indica (Iyenger) H. Nozaki in a clade that was robustly separated from the type species P. californica Shaw and P. japonica H. Nozaki. Pleodorina thompsonii was resolved as a basal branch within a large monophyletic group (Eudorina group) composed of Eudorina, Pleodorina and Volvox (excluding section Volvox). Thus, Pleodorina was found among three separate lineages within the Eudorina group in which Eudorina and Volvox were also resolved as nonmonophyletic. The DNA sequences from additional species/strains as well as recognition of morphological attributes that characterize the monophyletic groups within the Eudorina group are needed to construct a natural generic classification within these members of the Volvocaceae.     

CORRECTION OF THE NAME PSEUDOTETRAÉDRON POLYMORPHUM (CHLOROPHYCEAE)1

A unicellular chlorococcalean alga, Pseudotetraëdron polymorphum MacEntee, Bold & Archibald is renamed Chlorotetratëdron polymorphum (MacEntee, Bold & Archibald) MacEntee, Bold & Archibald became the former generic designation has been preempted by a xanthophycean alga.     

MOLECULAR PHYLOGENY,ULTRASTRUCTURE, AND TAXONOMIC REVISION OF CHLOROGONIUM (CHLOROPHYTA): EMENDATION OF CHLOROGONIUM AND DESCRIPTION OF GUNGNIR GEN. NOV. AND RUSALKA GEN. NOV.1

We examined the molecular phylogeny and ultrastructure of Chlorogonium and related species to establish the natural taxonomy at the generic level. Phylogenetic analyses of 18S rRNA and RUBISCO LSU (rbcL) gene sequences revealed two separate clades of Chlorogonium from which Chlorogonium (Cg.) fusiforme Matv. was robustly separated. One clade comprised Cg. neglectum Pascher and Cg. kasakii Nozaki, whereas the other clade included the type species Cg. euchlorum (Ehrenb.) Ehrenb., Cg. elongatum (P. A. Dang.) Francé, and Cg. capillatum Nozaki, M. Watanabe et Aizawa. On the basis of unique ultrastructural characteristics, we described Gungnir Nakada gen. nov. comprising three species: G. neglectum (Pascher) Nakada comb. nov., G. mantoniae (H. Ettl) Nakada comb. nov., and G. kasakii (Nozaki) Nakada comb. nov. We also emended Chlorogonium as a monophyletic genus composed of Cg. euchlorum, Cg. elongatum, and Cg. capillatum. Because Cg. fusiforme was distinguished from the redefined Chlorogonium and Gungnir by the structure of its starch plate, which is associated with pyrenoids, we reclassified this species as Rusalka fusiformis (Matv.) Nakada gen. et comb. nov.     

TAXONOMIC STUDY OF TWO NEW GENERA OF FUSIFORM GREEN FLAGELLATES,TABRIS GEN. NOV. AND HAMAKKO GEN. NOV. (VOLVOCALES,CHLOROPHYCEAE)1

On the basis of LM, we isolated strains of two species of fusiform green flagellates that could be assigned to former Chlorogonium (Cg.) Ehrenb. One species, “Cg.”heimii Bourr., lacked a pyrenoid in its vegetative cells and required organic compounds for growth. The other was similar to Cg. elongatum (P. A. Dang.) Francé and “Cg.”acus Nayal, but with slightly smaller vegetative cells. Their molecular phylogeny was also studied based on combined 18S rRNA, RUBISCO LSU (rbcL), and P700 chl a‐apoprotein A2 (psaB) gene sequences. Both species were separated from Chlorogonium emend., Gungnir Nakada and Rusalka Nakada, which were formerly assigned to Chlorogonium. They were accordingly assigned to new genera, Tabris Nakada gen. nov. and Hamakko (Hk.) Nakada gen. nov. as T. heimii (Bourr.) Nakada comb. nov. and Hk. caudatus Nakada sp. nov., respectively. Tabris is differentiated from other genera of fusiform green flagellates by its vegetative cells, which only have two apical contractile vacuoles and lack a pyrenoid in the chloroplast. Hamakko, on the other hand, is distinguishable by the fact that its pyrenoids in vegetative cells are penetrated by flattened thylakoid lamellae.     

MOLECULAR PHYLOGENY OF DISCOSPORANGIUM MESARTHROCARPUM (PHAEOPHYCEAE) WITH A REINSTATEMENT OF THE ORDER DISCOSPORANGIALES1

A molecular phylogenetic analysis of the little‐studied filamentous brown alga Discosporangium mesarthrocarpum (Meneghini) Hauck using rbcL and partial 18S rDNA sequences revealed that the species forms a monophyletic clade with Choristocarpus tenellus (Kütz.) Zanardini that is sister to all other brown algae. Although D. mesarthrocarpum has unique disk‐shaped plurilocular reproductive organs, D. mesarthrocarpum and C. tenellus share the following basic morphological features, which are considered to be plesiomorphic characters in the brown algae: (1) apical (and diffuse) growth; (2) uniseriate, subdichotomously branched filaments; (3) multiple chloroplasts per cell without pyrenoids; and (4) lack of heterotrichy and of phaeophycean hairs. The rbcL DNA sequence of an Australian D. mesarthrocarpum specimen showed considerable deviation from Mediterranean and Macaronesian specimens. Therefore, the presence of a second species in the genus is suggested; however, the taxonomic treatment of this putative species is not pursued in the present report. Regarding the higher‐ranking systematic position of D. mesarthrocarpum, reinstatement of Discosporangiaceae and Discosporangiales is proposed, and the inclusion of Choristocarpaceae in the order is also suggested. Under short‐day and long‐day culture conditions at 15°C–25°C, Mediterranean D. mesarthrocarpum exhibited a direct type of life history, with a succession of uniseriate filamentous thalli bearing characteristic disk‐shaped plurilocular zoidangia, but thalli did not survive at 10°C and below.     

PHYLOGENETIC RELATIONSHIPS AMONG LINEAGES OF THE CERAMIACEAE (CERAMIALES,RHODOPHYTA) BASED ON NUCLEAR SMALL SUBUNIT rDNA SEQUENCE DATA1

Phylogenetic relationships among 69 species of the Ceramiales (51 Ceramiaceae, six Dasyaceae, seven Delesseriaceae, and five Rhodomelaceae) were determined based on nuclear SSU rDNA sequence data. We resolved five strongly supported but divergent lineages among the included Ceramiaceae: (i) the genus Inkyuleea, which weakly joins other orders of the Rhodymeniophycidae rather than the Ceramiales in our analyses; (ii) the tribe Spyridieae, which is sister to the remainder of the included ceramialean taxa; (iii) the subfamily Ceramioideae, weakly including the tribe Warrenieae; (iv) the subfamily Callithamnioideae; and (v) the subfamily Compsothamnioideae, which emerges as sister to the Dasyaceae/Delesseriaceae/Rhodomelaceae complex, thus rendering the Ceramiaceae sensu lato unequivocally paraphyletic, as has been argued separately on anatomical grounds by Kylin and Hommersand. Our data support a restricted concept of the Ceramiaceae that includes only one of the five lineages (Ceramioideae) that we have resolved. In addition to failing to ally with the Ceramiales in our molecular analyses, species of Inkyuleea differ substantially from other Ceramiaceae sensu lato in details of pre‐ and postfertilization development. The genus Inkyuleea is here assigned to the Inkyuleeaceae fam. nov., which we provisionally retain in the Ceramiales. Species of Spyridia also differ from the remaining Ceramiaceae in their postfertilization development, and, in light of our molecular data, the genus Spyridia is assigned to the Spyridiaceae. The Callithamnioideae is strongly monophyletic (100% in all analyses), which, in combination with key anatomical differences, supports elevation to family status for this lineage as the Callithamniaceae. Similarly, the Compsothamnioideae is solidly monophyletic in our molecular trees and has a unique suite of defining anatomical characters that supports family status for a complex that we consider to include the tribes Compsothamnieae, Dasyphileae, Griffithsieae, Monosporeae, Ptiloteae, Spermothamnieae, Sphondylothamnieae, Spongoclonieae, and Wrangelieae, for which the reinstated family name Wrangeliaceae is available.     

HYPERSALINE SOIL SUPPORTS A DIVERSE COMMUNITY OF DUNALIELLA (CHLOROPHYCEAE)1

Numerous isolates of the green halophile Dunaliella were studied as part of a survey of microbial diversity at the Great Salt Plains (GSP) in Oklahoma, USA. The GSP is a large (～65 km²) salt flat with extreme temporal and spatial fluctuations in salinity and temperature. Although the flagellate halophile Dunaliella is common worldwide, nearly all cultured isolates are from saline habitats that are primarily aquatic rather than primarily terrestrial. The diverse GSP Dunaliella strains exhibit three morphotypes: a predominantly motile form, a motile form with a prominent palmelloid phase (nonmotile, mucilage rich), and a palmelloid form with a weakly motile phase. All had broad salinity optima well below typical in situ salinities at the GSP, and two of the palmelloid isolates grew as well in freshwater as in highly saline media. Molecular phylogenetic and evolutionary analyses revealed that Dunaliella from the GSP (and two similar habitats in the Great Basin, USA) are allied with D. viridis Teodor. but possess phylogenetic diversity in excess of existing global isolates from aquatic habitats. In addition, isolates from primarily terrestrial habitats exhibit statistically higher rates of nucleotide substitution than the phylogenetically homogeneous set of primarily aquatic Dunaliella taxa. We hypothesize that dynamically extreme saline soil habitats may select for different and more diverse Dunaliella lineages than more stable saline aquatic habitats. We also propose Dunaliella as a tractable microbial model for in situ testing of evolutionary and phylogeographic hypotheses.     

NEW GENERA AND SPECIES OF CERAMIACEAE (RHODOPHYTA) FROM THE SOUTHEASTERN UNITED STATES1

Five Ceramiaceae (Rhodophyta) are reported from the offshore waters of the southeastern, warm temperate coast of the United States. These include two new monotypic genera, Calliclavula trifurcate Schneider in the Griffithsieae and Nwynea grandispora Searles in the Sphondylothamnieae, and three new species, Callithamniella silvae Searles, Ptilothamnion occidentale Searles, and Lejolisia exposita Schneider et Searles.     

A NEW SPECIES OF VOLVOX SECT. MERRILLOSPHAERA (VOLVOCACEAE,CHLOROPHYCEAE) FROM TEXAS1

Smith (1944) divided the familiar genus Volvox L. into four sections, placing seven species that lacked cytoplasmic bridges between adult cells in the section Merrillosphaera. Herein, we describe a new member of the section Merrillosphaera originating from Texas (USA): Volvox ovalis Pocock ex Nozaki et A. W. Coleman sp. nov. Asexual spheroids of V. ovalis are ovoid or elliptical, with a monolayer of 1,000–2,000 somatic cells that are not linked by cytoplasmic bridges, an expanded anterior region, and 8–12 gonidia in the posterior region. Visibly asymmetric cleavage divisions do not occur in V. ovalis embryos as they do Volvox carteri F. Stein, Volvox obversus (W. Shaw) Printz, and Volvox africanus G. S. West, so the gonidia of the next generation are not yet recognizable in V. ovalis embryos prior to inversion. Molecular phylogenetic analyses of the five chloroplast genes and the internal transcribed spacer (ITS) regions of nuclear rDNA indicated that V. ovalis is closely related to Volvox spermatosphaera Powers ( Powers 1908 , as “spermatosphara”) and/or Volvox tertius Art. Mey.; however, V. ovalis can be distinguished from V. spermatosphaera by its larger gonidia, and from V. tertius by visible differences in gonidial chloroplast morphology.     

PHYLOGENY OF THE EUGLENOID LORICATE GENERA TRACHELOMONAS AND STROMBOMONAS (EUGLENOPHYTA) INFERRED FROM NUCLEAR SSU AND LSU rDNA1

Previous studies using the nuclear SSU rDNA and partial LSU rDNA have demonstrated that the euglenoid loricate taxa form a monophyletic clade within the photosynthetic euglenoid lineage. It was unclear, however, whether the loricate genera Trachelomonas and Strombomonas were monophyletic. In order to determine the relationships among the loricate taxa, SSU and LSU nuclear rDNA sequences were obtained for eight Strombomonas and 25 Trachelomonas strains and combined in a multigene phylogenetic analysis. Conserved regions of the aligned data set were used to generate maximum‐likelihood (ML) and Bayesian phylogenies. Both methods recovered a strongly supported monophyletic loricate clade with Strombomonas and Trachelomonas species separated into two sister clades. Taxa in the genus Strombomonas sorted into three subclades. Within the genus Trachelomonas, five strongly supported subclades were recovered in all analyses. Key morphological features could be attributed to each of the subclades, with the major separation being that all of the spine‐bearing taxa were located in two sister subclades, while the more rounded, spineless taxa formed the remaining three subclades. The separation of genera and subclades was supported by 42 distinct molecular signatures (33 in Trachelomonas and nine in Strombomonas). The morphological and molecular data supported the retention of Trachelomonas and Strombomonas as separate loricate genera.     

PHYLOGENETIC POSITION OF KOLIELLA (CHLOROPHYTA) AS INFERRED FROM NUCLEAR AND CHLOROPLAST SMALL SUBUNIT rDNA

The phylogenetic position of Koliella , a chlorophyte characterized by Klebsormidium type cell division, was inferred from analyses of partial 18S rDNA and partial 16S rDNA. Parsimony and distance analyses of separate and combined data sets indicated that the members of Koliella belonged to Trebouxiophyceae, and high decay indices and bootstrap values supported this affinity. However, the genus appeared to be polyphyletic. Koliella spiculiformis , the nomenclatural type of the genus, was allied with Nannochloris eucaryota and the "true" chlorellas ( Chlorella vulgaris , C. lobophora , C. sorokiniana , and C. kessleri ). The close relatives of Koliella longiseta (≡ Raphidonema longiseta ) and Koliella sempervirens appeared to be Stichococcus bacillaris and some species traditionally classified in Chlorella that were characterized by the production of secondary carotenoids under nitrogen-deficient conditions. This clade was also supported by the presence of a relatively phylogenetically stable group I intron (1506) in the 18S rRNA gene. Because of the presence of Klebsormidium type cell division, some authors regarded the members of Koliella as closely related to charophytes. Molecular analyses, however, did not confirm this affinity and suggested that a Klebsormidium type cell division is homoplastic in green plants.     

SYSTEMATIC REVISION OF THE GENERA LIAGORA AND IZZIELLA (LIAGORACEAE,RHODOPHYTA) FROM TAIWAN BASED ON MOLECULAR ANALYSES AND CARPOSPOROPHYTE DEVELOPMENT,WITH THE DESCRIPTION OF TWO NEW SPECIES1

Some Liagora and Izziella distributed in Taiwan display a wide range of morphological variation and can be difficult to distinguish. To clarify species concepts, we applied DNA sequence analyses and examined carposporophyte development in detail. These studies revealed two new species, which are described herein as Izziella hommersandii sp. nov. and Izziella kuroshioensis sp. nov. I. kuroshioensis superficially resembles Izziella formosana and Izziella orientalis in that its involucral filaments subtend rather than surround the lower portion of the gonimoblast mass (= Izziella type) and a fusion cell is formed from cells of the carpogonial branch, but it can be separated by differences in the cell numbers and branching pattern of the involucral filaments, as well as thallus morphology. In contrast to other species that also bear short lateral branchlets, I. hommersandii is unique in possessing a mixture of short and long involucral filaments, a phenomenon not reported before. The length of the involucral filaments is species specific among species of Izziella and contrasts to the behavior of the involucral filaments after fertilization in species such as “Liagora”setchellii [= Titanophycus setchellii comb. nov.], in which the filaments completely envelop the gonimoblast. In addition, the cells of the carpogonial branch in Titanophycus do not fuse after fertilization to form a fusion cell. Thus, a combination of characters with respect to the behavior of the carpogonial branch and the involucral filaments after fertilization is very useful for delineating species boundaries in Izziella and for separating Titanophycus from Izziella and Liagora.     

粒毛盘菌属及其相关属的分子系统学研究*

晶杯菌科的分类目前主要基于子囊盘外囊盘被表面毛状物的形态学特征,在系统演化关系上十分不清楚。本研究利用18SrRNA基因核苷酸序列分析方法探讨该科粒毛盘菌属及其相关属间的系统发育关系。以Saccharomycescerevisiae为外群的严格合意树和最简约树表明,粒毛盘菌属与其相关的属形成三个分支。Lachnumhyalopus,L.nudipes和L.virgineum代表一个分支。L.brasiliense,L.sclerotii,L.singerianum,Albotrichaguangxiensis,Calycellinapopulina.,Cistellagrevillei,Hyaloscyphaaureliella,Lachnellulacalyciformis,Parachnopezizaguangxiensis和Trichopezizasulphurea聚在一起(支持率为57%),为另一个分支。上述两个姊妹分支的支持强度为76%。与Lachnum在形态上有些相似的Cistella和Lachnum聚在一起的支持强度为51%。传统上纳入Arachnopezizoideae的Parachnopeziza与该亚科的模式属Arachnopeziza的关系较远。Arachnopezizaaurata是供试的14个种中距离最远的一个,位于系统发育树的最外侧,与上述两个分支的亲缘关系较远,这对Arachnopezizoideae在晶杯菌科中的地位提出了质疑。