Distribution and systematics of the freshwater red algal family Thoreaceae in North America

North American populations and type specimens of Thorea and Nemalionopsis were compared using multivariate morphometrics and image analysis. We continue to recognise the separation of the two genera based on spore-bearing branch-to-assimilatory filament length ratio and assimilatory filament density (≤0·3 and loose for Thorea and ≥0·6 and compressed for Nemalionopsis, respectively). Four species of Thorea were distinguished worldwide: T. hispida (syn. T. andina, T. lehmannii, T. ramosissima), T. violacea (syn. T. bachmannii, T. brodensis, T. gaudichaudii, T. okadae, T. prowsei and T. riekei), T. clavata and T. zollingeri. The former two species have variable branched, non-clavate assimilatory filaments, whereas the latter two have unbranched, clavate assimilatory filaments. Thorea hispida has copious secondary branches while T. violacea is sparsely branched. Thorea clavata is differentiated from T. zollingeri by having fewer monosporangia per cluster. Two of these species were found in North America: T. hispida in Mexico, Grenada and Jamaica, and T. violacea in Texas and Mexico. Two species of Nemalionopsis were differentiated: N. shawii with long assimilatory filaments composed of barrel-shaped cells and n. tortuosa (syn. N. shawii f. caroliniana) with short assimilatory filaments having cylindrical cells. Only N. tortuosa has been collected on the continent, from Florida, Louisiana and North Carolina.     

Three gene phylogeny of the Thoreales (Rhodophyta) reveals high species diversity

The freshwater red algal order Thoreales has triphasic life history composed of a diminutive diploid “Chantransia” stage, a distinctive macroscopic gametophyte with multi‐axial growth and carposporophytes that develop on the gametophyte thallus. This order is comprised of two genera, Thorea and Nemalionopsis. Thorea has been widely reported with numerous species, whereas Nemalionopsis has been more rarely observed with only a few species described. DNA sequences from three loci (rbcL, cox1, and LSU) were used to examine the phylogenetic affinity of specimens collected from geographically distant locations including North America, South America, Europe, Pacific Islands, Southeast Asia, China, and India. Sixteen species of Thorea and two species of Nemalionopsis were recognized. Morphological observations confirmed the distinctness of the two genera and also provided some characters to distinguish species. However, many of the collections were in “Chantransia” stage rather than gametophyte stage, meaning that key diagnostic morphological characters were unavailable. Three new species are proposed primarily based on the DNA sequence data generated in this study, Thorea kokosinga‐pueschelii, T. mauitukitukii, and T. quisqueyana. In addition to these newly described species, one DNA sequence from GenBank was not closely associated with other Thorea clades and may represent further diversity in the genus. Two species in Nemalionopsis are recognized, N. shawii and N. parkeri nom. et stat. nov. Thorea harbors more diversity than had been recognized by morphological data alone. Distribution data indicated that Nemalionopsis is common in the Pacific region, whereas Thorea is more globally distributed. Most species of Thorea have a regional distribution, but Thorea hispida appears to be cosmopolitan.     

Investigation of a freshwater acrochaetioid alga (Rhodophyta) with molecular and morphological methods

An enigmatic acrochaetioid alga was collected from Niangziguan spring in Shanxi Province, northern China. Morphological data indicated that this alga reproduces exclusively asexually by monosporangia and its morphological characteristics suggested that it might be referred to Audouinella heterospora. To ascertain its phylogenetic position, phylogenetic trees were reconstructed using partial sequences of the plastid‐encoded gene (rbcL) and the nuclear‐encoded gene (SSU rDNA) applying Bayesian inference (BI), maximum parsimony (MP) and maximum likelihood (ML). However, phylogenetic reconstructions showed that this acrochaetioid alga does not belong in a clade with the genus Audouinella, but forms a clade with Thorea hispida (Thoreales). Based on this analysis it is concluded that A. heterospora represents the ‘chantransia’ stage of T. hispida.     

New life cycles of <Emphasis Type="Italic">Porphyra katadae</Emphasis> var. <Emphasis Type="Italic">hemiphylla</Emphasis> in culture

Porphyra katadae Miura var. hemiphylla Tseng et T. J. Chang, a species distributed around the Liaodong and Shandong Peninsulas of China, produces gametophytes from late winter to early spring. These are monoecious with male and female reproductive tissues in distinct halves or sectors. Vegetative tissues from sectors expected to differentiate into sexual tissue were cultured in the laboratory. Male and female reproductive organs, as well as conchocelis and blades, were differentiated from these tissues. The male and female reproductive tissues were in patches and mixed on the cultured tissue pieces. This was quite different from the wild-type sectored individuals. The F₁ conchospore germlings also produced monospores, carposporangia, spermatangia and conchocelis. These carposporangia and spermatangia were in patches and were mixed on the F₁ fronds. The results imply that P. katadae var. hemiphylla is possibly sex-differentiated rather than sex-determined. This is the first report of such a dimorphic life history in the genus Porphyra.     

Phylogeny and morphology of the freshwater red alga Nemalionopsis shawii (Rhodophyta,Thoreales) from Nepal

Phylogenetic relationships and morphological characters are presented for a population of Nemalionopsis shawii Skuja collected from Nepal. Molecular data (sequences of rbcL and cox1) were generated and morphological characters were described in detail. The rbcL sequence analyses showed that specimens from Nepal are most similar to N. shawii from Indonesia and Japan and that these entities form a clade with high support (>95% bootstrap and 0.95 posterior probability). The cox1 barcode sequence, however, only had 90.9–91.9% identity with specimens of N. shawii from Hawaii. The rbcL sequence of the specimen from Nepal was positioned in a clade having sequence identity of 99.3–99.7% with three samples: N. shawii from Indonesia and two from Japan identified as N. tortuosa. The comparison of morphological characters of Nemalionopsis from Nepal allowed unequivocal identification with N. shawii. Identifications from previous studies using molecular data were mistaken since most reports of N. shawii are actually of N. tortuosa or vice‐versa. This confusion of names presumably occurred because most specimens previously sequenced were from culture collections or from ‘Chantransia’ stages. Small tufts of ‘Chantransia’ stage were observed growing epiphytically on gametophytes and on the basal system. Carpogonia and spermatangia were fully described in specimens from Nepal. Monosporangia were not observed, whereas carposporangia were unequivocally described for the first time in the genus. An unusual flat strap‐like basal system was observed, interpreted as an additional mode of maintenance in nature under unfavorable environmental conditions.     

MORPHOLOGY AND REPRODUCTION OF THE RED ALGA ACROCHAETIUM PECTINATUM IN CULTURE12

The life history of the marine red alga Acrochaetium pectinatum (Kylin) Hamel was studied in unialgal culture using supplemented natural seawater media. The tetrasporophytes are larger than the gametophytes, have a compact filamentous basal system, and produce monosporangia and tetrasporangia. Mono-spores give rise to tetrasporophytes. Tetraspores develop into small gametophytes with unicellular bases. The gametophytes are heterothallic when small (usually less than 500 μ) but as some females become larger (2-3 mm) they produce spermatangia as well as carpogonia. Gametophytes may bear mono-sporangia in addition to carpogonia or spermatangia. These monospores give rise to gametophytes. Fertilization of the carpogonia has not been observed. The tetrasporophytes produce only monosporangia in day-lengths of 12-16 hr, but both tetrasporangia and monosporangia are formed in daylengths of 6–10 hr. Tetrasporangial production is reduced at 15 C compared with 10 C. Light intensity in the range of 5-200 ft-c (cool white fluorescent lighting) has no apparent influence on induction of tetrasporangia. Induction of tetrasporangia is not a photoperiodic response because their development is not inhibited by a brief light break in the middle of the dark period in short daylengths. Plastid morphology, origin, and frequency of sporangia and vegetative branching are variable during the ontogeny, and consequently are somewhat unreliable as taxonomic criteria. Differences in basal systems between gametophytes and tetrasporophytes also indicate that this feature, which is used to distinguish major subgeneric groupings in Acrochaetium, may not be as useful as previously thought.     

Microhabitat and plant structure of Batrachospermum (Batrachospermales, Rhodophyta) populations in four streams of São Paulo State, southeastern Brazil

Microhabitat and plant structure of seven Batrachospermum populations (four of Batrachospermum delicatulum (=Sirodotia delicatula), one of Batrachospermum macrosporum and two of the ‘Chantransia’ stage), including the influence of physical variables (current velocity, depth, irradiance and substratum), were investigated in four streams of São Paulo State, southeastern Brazil. The populations of B. delicatulum and the ‘Chantransia’ stage occurred under very diverse microhabitat conditions, which probably contributes to their wide spatial and seasonal distribution in Brazilian streams. Results suggest branch reconfiguration as a probable mechanism of adaptation to current velocity based on the occurrence of: (i) B. macrosporum (a large mucilaginous form with presumably little ability for branch reconfiguration) under lower current velocity than B. delicatulum; (ii) only dense plants in populations with high current velocities (> 60 cm s^?1), whereas 53–77% of dense plants were seen in populations exposed to lower currents (< 40 cm s^?1); (iii) positive correlations of plant length with internode length in populations under low current velocities and negative correlation in a population with high velocity (132 cm s^?1); and (iv) negative correlations of current velocity with plant diameter and internode length in a population under high flow. This study, involving mainly dioecious populations, revealed that B. delicatulum displayed higher fertilization rates than B. macrosporum. A complementary explanation for a dioecious species to increase fertilization success was proposed consisting of outcrossing among intermingled male and female adjacent plants within an algal spot.     

New Record of Red Alga <Emphasis Type="Italic">Thorea Hispida</Emphasis> (Thore) Desv. (Rhodophyta) in Moscow River,Russia

In Moscow oblast, Thorea hispida (Thore) Desv. was first recorded at the beginning of the 20th century. Subsequently, T. hispida was found in 2004 in Moscow River within the territory of Moscow, where it still occurs. This species is included in the Red List of the Russian Federation, the Red List of Moscow oblast, and the Red Lists of some European countries. The new data on the distribution of T. hispida in Moscow River is presented in the paper, and some problems concerning the morphology and conservation status of this species are discussed.     

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

Twenty-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).     

Electron microscopical studies ofThorea ramosissima (Thoreaceae,Rhodophyta): Taxonomic implications ofThorea pit plug ultrastructure

The thallus ofThorea ramosissima was studied electron microscopically. The cells of the medulla, the cortex and the assimilatory hairs differ not only in size and number of plastids and their equipment with thylakoids but also in cell wall structure, the number of mitochondria and the activity of the Golgi apparatus, with dictyosomes transforming complete cisternae into Golgi vesicles with mucilaginous contents in the outer region of the cortex. The pit connections have plugs with a distinct plate—like (not dome-like) outer cap layer. BecauseT. riekei was reported to have dome-like outer cap layers and because this character was the main reason to place theThoreaceae into theBatrachospermales (Pueschel & Cole 1982),T. riekei was reinvestigated, too. A distinct outer cap could not be detected. The reliability of pit plug structure as a taxonomic character and the taxonomic position ofThorea is discussed.     

中国的红索藻属植物

记述了中国产红索藻属Thtorea Bory emend．Necchi的2种2变种,即棘刺红索藻T．hispida(Thorea)Desvaux emend,Sheath,Vis et Cole,棘刺红索藻小孢变种T．hispida var,microspora S．L．Xie et Z．X．Shi,蓝色红索藻T．vio—lacea Bory emend．Sheath,Vis et Cole和蓝色红索藻长毛变种T．violacea var．longipilosa S．L．Xie et Z．X．Shi．其中,蓝色红索藻T．violacea Bor yemend．Sheath,Vis et Cole为中国新记录,棘刺红索藻小孢变种T．hispida var．microspora S．L．Xie et Z．X．Shi和蓝色红索藻长毛变种T．violacea var,longipilosa S．L Xie et Z．X．Shi为新变种。     

AN UNUSUAL PHYCOCYANOBILIN-CONTAINING PHYCOERYTHRIN OF SEVERAL BLUISH-COLORED,ACROCHAETIOID, FRESHWATER RED ALGAL SPECIES1

The reproductive biology and phycobiliproteins of four different culture isolates of the freshwater algae Audouinella and‘Chantransia’were investigated.‘Chantransia’sp. (3585/UTEX 2623) and Audouinella macrospora (Wood) Sheath et Burkholder (3394,3395) from California and Minnesota reproduced only by monospores. However, A. macrospora (3603/Necchi 1) reproduced by monosporangia that formed successive generations of the Audouinella phase, and Batrachospermum shoots developed from the basal and erect systems. The major light-harvesting phycobiliprotein in all of these isolates was a phycocyanobilin-containing phycoerythrin not previously detected in red algae or cyanobacteria. As in the commonly found R- and B-phycoerythrins, Audouinella phycoerythrin had a native molecular mass of ～ 240,000 and was made up of α, β, and γ subunits. Audouinella phycoerythrin carried two phycoerythrobilins on the α subunit; one phycourobilin, one phycoerythrobilin, and one phycocyanobilin on the β subunit; and one phycourobilin and two phycoerythrobilins on the γ subunit. With excitation at 495, 563, or 603 nm, the fluorescence emission peak of Audouinella phycoerythrin was at 626 nm, showing that phycocyanobilin was the terminal energy acceptor.     

The morphology and life history of Mazoyerella gen. nov. (M. arachnoidea (Harvey) comb. nov.)—Rhodophyta,Ceramiaceae—from Southern Australia

Mazoyerella gen. nov., based on Corynospora arachnoidea Harvey from Tasmania, is placed provisionally in the Compsothamnieae tribe of the Ceramiaceae. All plants can produce elongate-ovoid monosporangia which reproduce the same phase. Sporophytes also bear polysporangia and sexual plants are dioecious, bearing either spermatangial heads or subterminal procarps followed by carposporophytes with nearly all gonimoblast cells becoming carposporangia and an involucrum of sterile filaments developing from sterile cells associated with the procarp. The life-history has been followed through successive generations in culture.     

White mullet Mugil curema population structure from Mexico and Brazil revealed by otolith chemistry

The white mullet Mugil curema supports several fisheries in the neotropical region; nevertheless, the population structure is still elusive. The aim of this study was to assess the presence of adult management units and nursery areas from five sampling sites throughout the Gulf of Mexico and northern Brazil using otolith microchemistry. The Li/Ca, Na/Ca, Mn/Ca, Sr/Ca, Ba/Ca and Pb/Ca ratios were measured in otolith core (juvenile stage) and edge (adult stage) (N = 131) using laser ablation–inductively coupled plasma–mass spectrometry. Several ratios were significantly different between sampling sites for core and edge (P < 0.05). For otolith edge, permutational multivariate analysis of variance showed significant differences (P < 0.05) between all sampling sites from Mexico (except between Mecoacán and Tamiahua, P > 0.05) and between Mexico (pooled samples) and Brazil. Quadratic discriminant analyses showed jackknifed classification higher in the edge (66.6% and 99.5% for Mexico and Brazil plus Mexico, respectively) than in the core (46.3% and 76.5% Mexico and Brazil plus Mexico, respectively). The two cluster analyses based on the core microchemistry (Mexico and Brazil plus Mexico) produced three main clusters, which did not coincide with catchment areas. These results support the segregation of the M. curema adult life stages among several sampling sites from Mexico and Brazil; moreover, core analysis suggested that the nursery areas did not correspond to the capture sites or adults stocks.     

Characterization of the crustose red alga Peyssonnelia japonica (Rhodophyta,Gigartinales) and its taxonomic relationship with Peyssonnelia boudouresquei based on morphological and molecular data

The vegetative and reproductive morphology of the crustose red alga Peyssonnelia japonica (Segawa) Yoneshigue was re‐examined based on the holotype specimen and recent collections from various localities in Japan, including the type locality, and Hawaii. This species is characterized by the following features: thallus with appressed margins, perithallial filaments arising from the entire upper surface of each hypothallial cell (the Peyssonnelia rubra‐type), easily separable perithallial filaments in a gelatinous matrix, hypothallial filaments arranged in parallel rows, unicellular rhizoids, hypobasal calcification, gonimoblasts derived mainly from connecting filaments, and spermatangia produced in a series of whorls comprised of one to four paired spermatangia surrounding each central cell (the Peyssonnelia dubyi‐type). In addition to these features, the dimensions of the vegetative and reproductive structures of Peyssonnelia boudouresquei Yoneshigue described from Brazil were consistent with those of P. japonica. Molecular phylogenetic analyses using partial 26S rDNA, rbcL, and cox2‐3 spacer DNA sequences also supported the monophyly of P. japonica (from 16 localities in Japan and one locality in Hawaii) and P. boudouresquei (from two localities in Brazil). Therefore, P. boudouresquei may be a taxonomic synonym of P. japonica. However, considering the relatively high sequence divergences between the two taxa (2.1–2.5% in partial 26S rDNA, 5.9–6.7% in rbcL, and 5.8–6.7% in cox2‐3 spacer), and the relatively limited geographic sampling ranges, we reserve the taxonomic conclusion until further morphological and genetic data of the specimens from other geographic areas connecting Japan and Brazil become available.     

Life history in culture of the obligate epiphyte Porphyra subtumens (Bangiales, Rhodophyta) endemic to New Zealand

This is the first report of the growth in culture of Porphyra subtumens J. Agardh ex Laing (Bangiales, Rhodophyta), an obligate epiphyte of Durvillaea species and endemic to New Zealand waters. Archeospores, previously observed on field material, develop directly into the blade phase. Spores released from field collected blades form conchocelis. Conchospores develop into new blades, completing the life history in culture. Earlier reports of reproduction in P. subtumens gave conflicting accounts with some authors citing this species as having an asexual, monophasic life history with an unusual form of spore production, while others described spermatangia and carposporangia on the blade phase.     

Differentiation in the ability to utilize Pterostyrax hispida (Ebenales: Styracaceae) among four local populations of the phytophagous ladybird beetle Henosepilachna yasutomii (Coleoptera: Coccinellidae)

The oligophagous ladybird beetle Henosepilachna yasutomii Katakura (Coleoptera: Coccinellidae) shows inter-population differences in its host-use. In this beetle, populations using the deciduous tree Pterostyrax hispida Sieb. et Zucc. (Styracaceae) were recently rediscovered in the Kanto districts of central Honshu, Japan. In the present study, the ability to utilize P. hispida and other host plants was compared among four populations of H. yasutomii occurring on P. hispida and Scopolia japonica Maxim. (Solanaceae), Chelidonium japonicum Thunb. (Papaveraceae), and Solanum tuberosum L. (Solanaceae). As regards the feeding habits of adult beetles, only the populations occurring on P. hispida accepted this plants leaves, which differed distinctly from the feeding habits of the other populations, although the differences among the four populations were not readily apparent with respect to the leaf amounts consumed. The larvae from the populations occurring on P. hispida showed significantly higher survivorship on this plant than did the larvae from the other populations. Considering the host use patterns and the life cycles of beetles under natural conditions, the large abundance of P. hispida leaves throughout the season may have played an important role in selection for the ability to utilize P. hispida observed in the H. yasutomii populations occurring on this woody host.     

Ecology and morphological characterization of gametophyte and 'Chantransia' stages of Sirodotia huillensis (Batrachospermales, Rhodophyta) from a stream in central Mexico

The morphology and phenology of Sirodotia huillensis was evaluated seasonally in a central Mexican first‐order calcareous stream. Water temperature was constant (24–25°C) and pH circumneutral to alkaline (6.7–7.9), and calcium and sulfates were the dominant ions. The gametophyte stages were characterized by the presence of a distinctive mucilaginous layer, a marked difference in phycocyanin to phycoerythrin ratio between female and male plants, and the presence of a carpogonia with a large trichogyne (>60 µm). Occasionally three capogonia were observed on a single basal cell. The ‘Chantransia’ stages were morphologically similar to those described for the other members of Batrachospermales. A remarkable observation was the formation of dome‐shaped structures, consisting of prostrate filaments that are related with the development of new gametophytes. Chromosome numbers were n = 4 for fascicle cells, cortical filament cells and dome‐shaped cells, and 2n = 8 for gonimoblast filament cells and ‘Chantransia’ stage filaments. Gametophytes and ‘Chantransia’ stages occurred in fast current velocities (60–170 cm/s) and shaded (33.1–121 µmol photons/m²/s) stream segments. The population fluctuated throughout the study period in terms of percentage cover and frequency: the ‘Chantransia’ stages were most abundant in the rainy season, whereas gametophytic plants had the highest frequency values during the dry season. These results were most likely a result of fluctuations in rainfall and related changes in current velocity. Some characteristics of this population can be viewed as probable adaptations to high current velocities: the mucilaginous layer around plants that reduces drag; potential increase in fertilization by the elongate and plentiful trichogynes and abundant dome‐shaped structures producing several gametophytes.     

Beiträge zur kenntnis der süsswasserrotalge thorea ramosissima bory

Zusammenfassung In dem ungarischen Fluss T i s z a lebt die Rotalge Thorea ramosissima in der unteren Schicht der Cladophora-Zone von Schwimmbalken. Es sind hier Exemplare von einer Länge von über 2 m vorgekommen; somit ist dieser Organismus als die grösste Süsswasseralge zu betrachten. Es hat sich herausgestellt, dass diese Alge eine ausdauernde Pflanze ist, die mit ihrem ganzen Thallus überwintert.Die sporangientragenden Zellfäden lassen drei Typen erkennen. Die Bildung von Tochterthallus ist als eine wahrscheinliche weitere Form der vegetativen Vermehrung im Aufsatz eingehender geschildert worden.An den basalen Teilen älterer Thallusachsen entwickelt sich ein epibiontischer Kieselalgenaufwuchs, dessen Zusammensetzung vor allem durch die Standortbedingungen beeinflusst wird.Auch im B a l a t o n (Plattensee) kommt Thorea vor. Die Wellenbegung wirkt bei diesen Exemplaren als limitierender Faktor.