Batrachospermum Section Research Articles

Paludicola gen. nov. and Revision of the Species Formerly in Batrachospermum Section Turfosa (Batrachospermales, Rhodophyta)

Since the first phylogenetic study of the order Batrachospermales, Batrachospermum was shown to be paraphyletic. Subsequently, sections of the genus have been methodically investigated using DNA sequences and morphology in order to propose new genera and delineate species. Batrachospermum section Turfosa is the last section with multiple species yet to be examined. New sequence data of specimens from Europe and the United States were combined with the sparse sequence data already available. Phylogenetic analyses using rbcL and COI-5P sequences showed this section to be a well-supported clade, distinct from Batrachospermum section Batrachospermum and its segregate genera. SectionTurfosa is raised to the generic rank as Paludicola gen. nov. Substantial genetic variation within the genus was discovered and 12 species are recognized based on DNA sequence data as well as morphological characters and geographic distribution. The following morphological characters were applied to distinguish species: branching pattern (pseudodichotomous or irregular), whorl size (reduced or well developed), primary fascicles (curved or straight), spermatangia origin (primary or secondary fascicles), and carposporophyte arrangement (loose or dense). Previously published species were transferred to the new genus: P.turfosa, P.keratophyta, P.orthosticha, P.phangiae, and P.periploca. Seven new species are proposed as follows: P.groenbladii from Europe; P.communis, P.johnhallii, and P.leafensis from North America; and P.aquanigra, P.diamantinensis, and P.turfosiformis from Brazil. In addition, three unsequenced species in the section, P.bakarensis, P.gombakensis, and P.tapirensis, were transferred to the new genus.

Current status of freshwater red algal diversity (Rhodophyta) of the African continent including description of new taxa (Batrachospermales)

ABSTRACT Freshwater red algae have been collected on the African continent since the early 1800s. However, the collections have been sparse and geographically restricted. The present study sought to bring together information from the literature, herbarium specimens, and newly collected specimens to provide an updated assessment of the freshwater red algal diversity of the African continent with a focus on the species-rich Batrachospermales. DNA sequence data and morphological observations were conducted for recently collected specimens. From these analyses, four new taxa are proposed: Kumanoa bouwmanii, Sheathia murpheyi, Sirodotia kennedyi, and the form taxon ‘Chantransia azurea’. DNA sequence data had been previously published for Kumanoa iriomotensis, Sirodotia aff. huillensis, and S. suecica. With this study, we have added sequence data for Torularia atra as well as a second location for S. suecica. In total, there are eight taxa with sequence data, of which five appear to be endemic. From our assessment of literature reports and herbarium specimens, we conclude that Kumanoa, Sirodotia, and Torularia have often been collected and are relatively geographically widespread with two or more species present. In addition, Montagnia, Nothocladus, Paralemanea, Sheathia, and Visia as well as Batrachospermum section Gonimopropagulum are represented in the flora. We estimate that 14 to 19 batrachospermalean taxa can be recognised for the African flora, and that with more study, that number could easily double or triple based on the diversity known from other well-studied continents.

Revision of Batrachospermum section Macrospora (Batrachospermales, Rhodophyta) with the establishment of the new genus Montagnia

ABSTRACTTo resolve the paraphyly of Batrachospermum, the sections of the genus have been methodically investigated using DNA sequence data and morphology; this has resulted in the raising of many sections to genus status. Phylogenetic analyses of combined rbcL and COI-5P showed Batrachospermum section Macrospora to be a well-supported clade. We propose Montagnia gen. nov. Montagnia is distinguished from other sections or genera of the Batrachospermales by the following characters: plants irregularly branched; carpogonial branches long and straight and well differentiated from fascicles, bearing involucral filaments in a crown pattern; enlarged pit connections in the cells of carpogonial branches; and pedunculate carposporophytes with large carposporangia. Within the new genus, we re-evaluated the characters used to circumscribe species by examining type specimens as well as samples from North and South America. Of the three currently accepted species attributable to Montagnia, we recognised two species: M. macrospora–type species (proposed synonyms Batrachospermum equisetifolium, B. hypogynum and B. macrosporum) and M. australis (synonym Batrachospermum australe). Morphological characters did not distinguish the two species due to variation within and among samples. The two species can be differentiated only using DNA sequence data and geographic distribution. Montagnia australis is restricted to North America; whereas, M. macrospora is a widespread pantropical species occurring in South America and Asia. Although the intraspecific divergence observed in M. macrospora is the highest reported for members of Batrachospermales, species delimitation methods did not suggest that more than one species is justified.

Revision ofBatrachospermumSectionVirescentia(Batrachospermales, Rhodophyta) with the Establishment of the New Genus,VirescentiaStat. nov.

In recent years, sections of the paraphyletic genus Batrachospermum have been investigated using DNA sequence data, as well as morphology and some have been raised to genera in order to resolve this paraphylly. The species of Batrachospermum section Virescentia form a well-supported clade and we propose the raising of this section to the genus Virescentia stat. nov. In addition, we re-evaluated the characters used to circumscribe species by reexamination of type specimens and new collections in historically important areas. Of the eleven previously accepted species, we recognize five species and a new species is proposed as follows: V. crispata, V. gulbenkiana (synomyms V. azeredoi and V. ferreri), V. helminthosa (type species), V. viride-americana sp. nov., V. viride-brasiliensis and V. vogesiaca. The species are circumscribed on the basis of morphological characteristics (shape of fascicles, occurrence of secondary fascicles, disposition of carpogonial branches and size of carpogonia), geographic distribution, and DNA sequence data (rbcL and COI-5P). Descriptions, identification key and photomicrographs are presented for each recognized species. Two potential species from Japan based on DNA sequence data remained undescribed due to lack of voucher specimens for morphological observation. Other species previously assigned to the section Virescentia are referred to other genera of Batrachospermales based on morphology (disposition of carpogonial branches, shape of trichogynes, types of gonimoblast filaments and arrangement of carposporophytes).

Nocturama gen. nov., Nothocladus s. lat. and other taxonomic novelties resulting from the further resolution of paraphyly in Australasian members of Batrachospermum (Batrachospermales, Rhodophyta)

The informal "Australasica Group" was established in 2009 to include several Australasian endemic Batrachospermum species, a few species of the cosmopolitan Batrachospermum section Setacea, and the South American endemic Petrohua bernabei. Although useful for communication purposes, no formal taxonomic designation was proposed due to weakly supported basal nodes. The present research took a two-pronged approach of adding more taxa (29 additional specimens) as well as more sequence data (LSU, cox1, psaA, and psbA markers added to rbcL data) to provide better resolution. The resulting tree showed improved statistical support values (Bayesian posterior probability and maximum likelihood bootstrap) for most nodes providing a framework for taxonomic revision. Based on our well-resolved phylogeny, a new genus, Nocturama, is proposed for a clade of Batrachospermum antipodites specimens. The circumscription of Nothocladus is expanded to include Batrachospermum section Setacea and four additional sections composed of at least 10 species, mostly from Australia and New Zealand. One new species added to the data set, N.diatyches, did not form a clade with the other species of section Setaceus, where it was classified previously, rendering that section paraphyletic. To resolve this, N.diatyches and the morphologically similar species N.latericius are included with N.theaquus, in the new section Theaquus within Nothocladus s.lat. A specimen from Australia unaligned to these clades was sister to the Australia-New Zealand genus Psilosiphon and the cosmopolitan B.cayennense, but lacked statistical support. This specimen has the gross morphology of Batrachospermum s. lat. and is here provisionally assigned to that genus, as B.serendipidum sp. nov.

Molecular and morphological evidence for Sheathia gen. nov. (Batrachospermales, Rhodophyta) and three new species.

The freshwater red algal genus Batrachospermum has been shown to be paraphyletic since the first molecular studies of the Batrachospermales. Previous research, along with this study, provides strong support for the clade Batrachospermum section Helminthoidea. This study has found that heterocortication, the presence of both cylindrical and bulbous cells on the main axis, is an underlying synapomorphy of this clade. Based on support from DNA sequences of the rbcL gene, the COI barcode region and the rDNA ITS 1 and 2, along with morphological studies, the new genus Sheathia is proposed. Seven heterocorticate species were recognized from the molecular clades. Sheathia boryana and S.exigua sp. nov. appear to be restricted to Europe, whereas S.confusa occurs in Europe and New Zealand. Sheathia involuta is widespread in the USA and reported for the first time from Europe. Sheathia americana sp. nov., has been collected in the USA and Canada, and S.heterocortica and S.grandis sp. nov. have been collected only in the USA. Sheathia confusa and S.grandis can be distinguished based on morphological characters, whereas DNA sequence data are required to conclusively distinguish the other species. Sheathia fluitans and S.carpoinvolucra also are placed within this genus based on the presence of heterocortication. These data also hint at greater diversity among non-heterocorticate Sheathia than is recognized by the single species name S.arcuata.

Molecular systematics of four endemic Batrachospermaceae (Rhodophyta) species in China with multilocus data

Four endemic Batrachospermaceae species in China, Batrachospermum hongdongense Xie & Feng, Batrachospermum longipedicellatum Hua & Shi, Kumanoa curvata (Shi) Vis et al., and Kumanoa intorta (Jao) Entwisle et al., were analyzed with multilocus data in order to assess their phylogenetic placement. Multilocus molecular data from one nuclear gene (the ribosomal SSU), one chloroplast gene (rbcL), and two mitochondrial genes (COI and the cox2-3 spacer) as well as morphological studies were used to determine the phylogenetic relationships of these endemic species within the Batrachospermales. Batrachospermum hongdongense and B. longipedicellatum had previously been placed in Batrachospermum section Batrachospermum, but based on the data from this study they should be transferred into section Helminthoidea. Kumanoa curvata and K. intorta clearly belong to the newly established genus Kumanoa.

Investigation of two species complexes in Batrachospermum section Batrachospermum (Batrachospermales, Rhodophyta)

S.A. Stewart and M.L. Vis. 2007. Investigation of two species complexes in Batrachospermum section Batrachospermum (Batrachospermales, Rhodophyta). Phycologia 46:380–385. DOI: 10.2216/06-86.1Within Batrachospermum section Batrachospermum, there are two putative species complexes with members that only differ by breeding system alone or this trait with a single vegetative character. New sequence data for the rbcL gene were generated from specimens of B. anatinum, B. arcuatum, B. boryanum, B. confusum and B. heterocorticum in order to assess the phylogenetic value of heterocortication on the main axis of the thallus and further explore the taxonomic utility of breeding system. The presence of heterocortication in B. involutum was confirmed, and this character served as a synapomorphy for a clade containing this taxon and B. anatinum, B. boryanum, B. confusum and B. heterocorticum. The rbcL sequences were identical for the two monoecious species: B. anatinum with spermatangia confined to the tips of vegetative branches and B. confusum with spermatangia on involucral filaments of the carpogonial branches as well as the vegetative ones. It is argued that knowledge of spermatangia placement is of ecological importance, and B. anatinum f. confusum is proposed rather than simply placing the two entities in synonymy. There was no clear support for or against the use of breeding system as a taxonomic character, with pairs of morphologically similar species differing primarily by breeding system grouped together. Batrachospermum gelatinosum and B. gelatinosum f. spermatoinvolucrum from North America were not part of the clade formed by the other taxa studied. In fact, they were nested distantly in a clade containing other genera in the Batrachospermaceae. Among the taxa with heterocortication, B. anatinum, B. boryanum, B. heterocorticum and B. involutum, each was at least 1.4% different in its rbcL sequence from its closest neighbor. The present research provides more evidence that section Batrachospermum will need to be split with the potential of resurrecting section Helminthoidea and that the generic classification needs revision.

Ptilothamnion richardsii (Rhodophyta) is a chantransia stage of Batrachospermum

Four specimens attributable to the freshwater red algal taxon, Ptilothamnion richardsii, were examined from locations in Australia and French Guiana, and partial rbcL gene sequence data were obtained. Phylogenetic analyses showed these specimens to be allied to taxa in the Batrachospermales. The two specimens from Australia were determined to be Batrachospermum antipodites, differing from that taxon by only 15 bp (1.2%). The two specimens from French Guiana were within the Batrachospermum section Contorta clade, but differed considerably (≥8%) from the taxa for which there are presently rbcL gene data. The sequence data clearly show these specimens to be chantransia stages of Batrachospermum taxa. Recently, other described freshwater Audouinella taxa have also been shown to be chantransia stages. Like previous authors, we argue that it is useful to continue to recognize entities with particular morphological characters and propose the form taxa Chantransia richardsii, C. macrospora and C. pygmaea. A key to these is provided.

INSIGHTS INTO THE PHYLOGENY OF THE BATRACHOSPERMALES (RHODOPHYTA) FROM rbcL SEQUENCE DATA OF AUSTRALIAN TAXA

Thirteen representatives of the freshwater red algal order Batrachospermales from Australia were analyzed with previously published sequences in a phylogenetic analysis of RUBISCO large subunit (rbcL) gene sequence data. The newly sequenced taxa represented putative endemics to the Australia–New Zealand region (Batrachospermum antipodites, B. deminutum, B. discors, B. kraftsii, B. theaquum, B. wattsii, and Nothocladus lindaueri) and more cosmopolitan species (B. ambiguum, B. atrum, B. cayennense, B. gelatinosum[two samples], and Sirodotia suecica). From parsimony, distance, and maximum likelihood analyses, three clades of batrachospermalean taxa were suggested: a “mixed” clade composed of taxa sampled from Australia and North America, a clade of primarily Australian collections, and a clade of predominantly North American samples. The latter two clades appeared to be more closely related to each other than to the mixed clade. It is hypothesized that the Australian clade may be of Gondwanic origin, but more sampling of other continents is needed to confirm this statement. The collections of B. gelatinosum from Australia did not form a monophyletic clade with B. gelatinosum from North America, and a new species, B. pseudogelatinosum, is proposed for the Australian collections. Unlike the B. gelatinosum results, B. atrum and S. suecica samples from Australia were very closely related to collections of the same species from other continents. With the addition of B. deminutum and B. ambiguum to the analysis, Batrachospermum section Contorta is shown to be monophyletic if section Hybrida is included. The expansion of the description for section Contorta is proposed to accommodate species from section Hybrida. The validity of Batrachospermum section Aristata is questioned based on the distant relationship of B. macrosporum and B. cayennense.

Phenology of a Batrachospermum population in a boreal pond and its implications for the systematics of section Turfosa (Batrachospermales, Rhodophyta)

Phenology of a population of the freshwater rhodophyte genus Batrachospermum section Turfosa was examined in a small pond in Newfoundland, Canada from November 1993 to November 1994. The gametophyte was perennial; percent cover peaked in summer and was correlated with maximal water temperature and day length. Carpogonia and spermatangia were confined largely to the upper half of the branches and were observed throughout the year, except in October and November 1994 when monospore production predominated. Spermatangia were observed to occur only on the involucral filaments of the carpogonial branch, indicating a high probability of self-fertilization. The density of carposporophytes reached a peak in January, followed by maximum incidence of chantransia germlings in February and May. None of the phenological features of Batrachospermum was significantly correlated with temperature or photoperiod. Gametangia and monosporangia were always on separate thalli. Chromosome counts and relative fluorescence measurements of DNA were made for vegetative and reproductive cells. Analysis of the nuclear rDNA internal transcribed spacer (ITS) 1 and 2 sequences in gametangial and monosporangial plants showed an overall sequence divergence between the two types of only 0.009%. Therefore, these two types of thalli appear to represent the same species. This finding alters the present taxonomic scheme for section Turfosa, and B. keratophytum Bory de Saint-Vincent is synonymized with B. turfosum Bory de Saint-Vincent.

Distribution and systematics of Batrachospermum (Batrachospermales, Rhodophyta) in North America. 9. Section Batrachospermum: description of five new species

Five new species belonging to Batrachospermum section Batrachospermum are described from North America. B. spermatoinvolucrum sp. nov. is distinguished by the combination of spermatangia on the inv...

DISTRIBUTION AND SYSTEMATICS OF BATRACHOSPERMUM(BATRACHOSPERMALES, RHODOPHYTA) IN NORTH AMERICA. 6. SECTION TURFOSA1

ABSTRACTTwenty‐one populations of Batrachospermum section Turfosa from North America were compared to nine type and two historically important specimens using multivariate morphometrics and image analysis. The protologues of six other infrageneric taxa were also compared. From this analysis, six species are recognized worldwide: B, de‐sikacharyi Sankaran, B. gombakense Kumano et Ratnasabapathy, B. keratophytum Bory de Saint‐Vincent [syn. B. vagum var. keratophytum (Bory de Saint‐Vincent) Sirodot, B. gulbenkianum Reis, and B. suevorum Kützing nom. Meg.], B. sinense Jao, B. turfosum Bory de Saint‐Vincent [syn. B. vagum (Roth) C. Agardh and B. vagum var. undulato‐pedicellatum Kumano et Watanabe], and B. vogesiacum F. G. Schultz ex Skuja [syn. B. vagum var. flagelliforme Sirodot, B. flagelliforme (Sirodot) Necchi], These species are distinguished on the basis of carposporophyte‐bearing branch cortication, secondary fascicle development, monoecy or dioecy, presence of spermatangia on involucral filaments and monosporangia, and dimensions of trichogynes and carposporangia. Peripheral cortication has been previously used to separate species in this section, but we observed that this feature is quite widespread in the section. Presence of indeterminate gonimoblast filaments has been reported for some taxa in section Turfosa, but no such structures were seen in any of the specimens examined. Only B. keratophytum has been collected in North America, ranging from southwestern Greenland (64°N) to Louisiana (30° N).

DISTRIBUTION AND SYSTEMATICS OF BATRACHOSPERMUM (BATRACHOSPERMALES, RHODOPHYTA) IN NORTH AMERICA. 4. SECTION VIRESCENTIA1

ABSTRACTThirty‐nine populations of Batrachospermum section Virescentia from North America were compared to eight type specimens and two historically important specimens using multivariate morphometrics and image analysis. From this analysis, two species are recognized: B. helminthosum Bory de Saint‐Vincent (syn. B. bruziense Sirodot, B. graibussoniense Sirodot, B. sirodotii Skuja ex Flint, B. testale Sirodot, B. virgatum Sirodot nom. illeg., and B. viride Sirodot) and B. elegans Sirodot (syn. B. coerulescens Sirodot nom. illeg.). In B. helminthosum trichogynes are cylindrical to slightly club‐shaped with few to no protuberances, whereas in B. elegans half to all of the trichogynes have one to three basal knobs or branches. None of the qualitative features previously used to separate species in this section were found to be of taxonomic value due to their universal presence; quantitative characteristics were highly variable and overlapped among specimens examined. Emended descriptions of both species are provided. Batrachospermum elegans was collected in northeastern U.S.A. and central Costa Rica, whereas B. helminthosum ranged from Nova Scotia to Louisiana and was collected in central Mexico, Costa Rica, and northwestern U.S.A. Batrachospermum julianum Arcangeli and B. transtaganum Reis, previously classified in section Virescentia, were observed to have twisted carpogonial branches and, therefore, should be placed in section Contorta. Sections Setacea and Virescentia of Batrachospermum differ in whorl size, ratio of carposporophyte height to whorl diameter, and trichogyne stalking; hence, we continue to recognize them as being distinct taxonomic entities as originally described.