Seaweeds of the Southeastern United States: Cape Hatteras to Cape Canaveral
... Epiphytes classification was performed according to the work of Abbott and Hollenberg [32], Burrows [33], Cho et al. [34], Guimarães et al. [35], Littler and Littler [36], Schneider and Searles [37] Taylor [38], Hoek [39], and Won et al. [40]. The taxonomic determination of cyanobacteria was performed according to the work of Anagnostidis and ...
... Epiphytes classification was performed according to the work of Abbott and Hollenberg [32], Burrows [33], Cho et al. [34], Guimarães et al. [35], Littler and Littler [36], Schneider and Searles [37] Taylor [38], Hoek [39], and Won et al. [40]. The taxonomic determination of cyanobacteria was performed according to the work of Anagnostidis and Komárek [41][42][43][44][45][46]. ...
... The dry season had the highest epiphytic specific richness with 61 species; the rainy season had 53 species; and the winter rain season had the lowest number of species (37). ...
The leaves of Thalassia testudinum provide an ideal substrate for the establishment of small-sized algae with different morphologies that are abundant and diverse. There are few studies on epiphytism in Mexico, and most of them are floristic lists. The objective of this study was to analyze the taxonomic and morphofunctional composition of epiphytes in three climatic seasons, and their relationship with the phorophyte T. testudinum in two localities, El Uvero and Santa Rosa, in the south of Quintana Roo; three transects and fifteen quadrants were set in June and December (2014) and April (2015). A total of 84 epiphytic species were identified: 27 corresponded to Cyanobacteria, 10 to Phaeophyceae, 9 to Chlorophyta, and 38 to Rhodophyta. The highest specific richness was observed in Santa Rosa (73 species). The dry and summer rains seasons share a higher number of species compared to the winter rainy season. The crusty algae Hydrolithon farinosum was the dominant and most persistent species; in addition, filamentous algae presented great specific richness and coverage due to their morphology and reproductive strategies, which allowed them to successfully establish themselves on the phorophyte. This is related to the ecological succession of the epiphytes and seagrass phenology.
... Several authors have provided descriptions of A. fistulosus, A. ensiformis, A. bullosus and A. scaber (Greville 1830;Sauvageau 1895;Fritsch 1945;Asensi 1972;Womersley 1987;Schneider and Searles 1991;Nelson and Knight 1995;D'Archino and Nelson 2006;Cormaci et al. 2012;Bárbara et al. 2015), whereas little is known about A. tortilis and A. norvegicus, of which only the original description is available. ...
... Asperococcus fistulosus (Hudson) W.J. Hooker (Greville 1830;Fritsch 1945;Womersley 1987;Schneider and Searles 1991;Cormaci et al. 2012). ...
... Asperococcus fistulosus is widely distributed. This species was reported in the Arctic (Caram andJónsson 1972), northeast Atlantic (Adams 1907;Cotton 1912Cotton , 1913Newton 1931;De Valéra et al. 1979;Maggs 1983;Whelan and Cullinane 1985;Fletcher 1987;Morton 1994;Bartsch and Kuhlenkamp 2000;Hardy and Guiry 2003;Brodie et al. 2015;Bunker et al. 2017), West Atlantic (Neto et al. 2001;Haroun et al. 2002;Gil-Rodríguez et al. 2003;John et al. 2004;Moro et al. 2011;Afonso-Carrillo 2014;Ferreira et al. 2018), Mediterranean (Gerloff and Geissler 1974;Ribera et al. 1992;Furnari et al. 1999;Rindi et al. 2002;Taşkin et al. 2008), Baltic Sea (Nielsen et al. 1995;Kontula and (Schneider and Searles 1991), in the northwest Atlantic from Virginia to New Hampshire (Humm 1979;Schneider et al. 1979), in the northeast Pacific (Pedroche et al. 2008), and on the Australia and New Zealand coasts (Womersley 1987). ...
Asperococcus J.V. Lamouroux is a genus of brown algae in the Chordariaceae family (Order Ectocarpales). This concise review compiles the published literature on Asperococcus taxonomy, morphology, geographical distribution, ecology, life cycles, cultivation, biochemical composition and bioactive properties, emphasizing its commercial potential. This genus, which is mainly distributed in temperate-cold latitudes, is represented by six species of which A. fistulosus, A. ensiformis and A. bullosus have been the most studied. Species of this genus have membranous saccate or filiform thalli with prominent sori protruding from the surface. The life cycle is heteromorphic, alternating between a macroscopic sporophyte and a microscopic branched gametophyte. They inhabit tidal pools or different depths in the subtidal zone. Some species have been reported as epiphytic and epizoic organisms. Although there is no record of the commercialization of Asperococcus species, the cultivation of A. ensiformis from the Argentine Patagonian coasts was recently assessed and the biochemical composition of some species was studied, revealing a commercial potential.
... However, Harvey (1853) was the first to describe Grateloupia gibbesii, focusing on the large size of fronds that taper both towards the base and apex and that are typically proliferous, coriaceous-membranaceous, with a dark, blackish purple color, changing more or less completely to a vivid green when dried. Based on specimens from the type locality, Schneider and Searles (1991) offered additional information on the habit and the inner structure of the thallus, but they did not characterise female reproductive structures or early postfertilization stages. The habit of the Egyptian Mediterranean specimens (Grateloupia gibbesii) coincided with the description by Schneider and Searles (1991), except that the overall size of the plants and blade width were considerably smaller in the Mediterranean Sea. ...
... Based on specimens from the type locality, Schneider and Searles (1991) offered additional information on the habit and the inner structure of the thallus, but they did not characterise female reproductive structures or early postfertilization stages. The habit of the Egyptian Mediterranean specimens (Grateloupia gibbesii) coincided with the description by Schneider and Searles (1991), except that the overall size of the plants and blade width were considerably smaller in the Mediterranean Sea. Rodriguez-Prieto et al. (2021) investigated in details the pre-and postfertilisation stages of the female reproductive structures (Table 4.7). ...
Chapter 1:
The Mediterranean Sea:
The Mediterranean Sea is one of the most highly valued seas in the world. The region comprises a vast set of coastal and marine ecosystems that provide a variety of different services that are crucial for human well-being. Since the mid-twentieth century, water pollution became a serious problem due to increasing of industrialisation, coastal population, and tourism along several Mediterranean coastal areas. Pollution in the Mediterranean tends to persists near its source of discharge due to relatively weak tidal and current movements. Likewise, the Egyptian Mediterranean coastal areas suffer from degradation of water quality, and many hot spot areas are designated there, which had drastic effects on seaweeds biodiversity and other marine organisms. This chapter attempts to track changes that happened in the seaweeds community over more than 60 years along the coast of the Egyptian Mediterranean Sea.
Chapter 1:
Red Sea:
Seaweeds (marine macroalgae) are a group of photosynthesizing organ-isms that are attached to the rock or another hard substrate in coastal areas. Ecologically, many species provide protective habitats for a wide range of flora and fauna preserve the coastal community and act as the primary producers and carbon sinks. The distribution and abundance of seaweeds are governed at a global scale by their sensitivity and ability to tolerate different natural ecological conditions. The Red Sea is a diverse and rich ecosystem, the rich diversity is in part due to the 2000 km of coral reef extending from the Gulfs of Suez and Aqaba in the north to Bab El-Mandab and Gulf of Aden in the south. It provides habitats for a wide range of marine species and it received its algae from nearby African and Arabian coasts mainly occupied by members of the widespread tropical Indo-Pacific marine flora. There are more efforts on seaweed biodiversity studies in the Red Sea are required, including topics such as taxonomy, genetic diversity, or biogeography. Moreover, many anthropogenic disturbances such as pollution, introduction of non-native species, or global warming change the macroalgal biodiversity patterns.
Chapter3:
Suez canal:
The Suez Canal is an artificial sea-level waterway in Egypt, connecting the Mediterranean Sea to the Red Sea through the Isthmus of Suez and dividing Africa and Asia. The canal occupies a strategic position and is considered as the shortest route of trade between Europe and Asia. In 2015 the Egyptian government finished a nearly $8.5 billion project to improve the canal and significantly increase its capacity; nearly 29 km (18 miles) were added to its original length of 164 km (102 miles). The importance of Suez Canal augmented with the enlargement process which changes many aspects in its characteristics particularly, the biological ones. This chapter aim to have reliable information based on seaweeds biodiversity from the beginning of the last century till this time to register any potential changes in seaweeds biodiversity after the enlargement and create a snapshot of the benthic flora inhabiting the Canal.
Chapter 4:
Recent Introduced Algal Species in the Egyptian Marine Waters:
Marine non-indigenous species (NIS) pose considerable threats and rep-resent a significant risk to the receiving environments. They could exhibit invasive behavior and cause changes to ecosystem structure and function, prohibit the delivery of ecosystem services, or even result in detrimental socioeconomic implications in coastal areas. The increased globalization and rising tendencies in human activities including shipping, aquaculture, fishing, tourism, and the aquarium trade have hastened the introduction of new NIS in recent decades. In addition, climatic change is one of the most important factors that have severe impacts on the marine ecosystems, including fauna and flora biodiversity. This chapter deals with the problem of the introduction of non-indigenous species (NIS) and their effect on native seaweeds and their biodiversity in the Egyptian waters. This chapter is also monitoring their presence which is essential for marine environmental management and sustainable development.
... Taylor (1979), Hollenberg (1968a), Abbott (1999), Schneider & Searles (1997, Kapraun & Norris (1982) Taylor (1945,1979), Schneider & Searles (1991), Guimarâes et al. ...
A new red algal species (Polysiphonia iberica) is described from the Atlantic Iberian Peninsula (Basque country, Galicia and South of Portugal), based on morphology and molecular evidence. It is confined to sciaphilic subtidal rocky bottoms and can be distinguished by its erect habit, 5–7 orders of dichotomous branching, axes 350–900 mm in diameter at the base, segments composed by 9–11 pericentral cells and 0.5–2 diametres long. Plants are bright red to brown-red in colour, 3–6 cm high, firm at the base but ultimate divisions are soft and flaccid. Cortication is only restricted to the base of large thalli. Plants are initially attached to substrate by a discoid holdfast with the tips of decumbent branches reattaching with secondary discoid holdfasts or rhizoids, which are cut off from pericentral cells. Lateral branches develop independently from trichoblasts or scar cells, which are absent. Tetrasporangia (25–40 mm in diameter) are placed in straight series of up to 15 segments. Sexual structures are unknown, even by culture in
laboratory. The new species is assigned to Polysiphonia sensu lato based on these morphological features, but it shows intermediate characters between Neosiphonia and Polysiphonia sensu stricto. It resembles Neosiphonia in having holdfast discoid, erect indeterminate branches developed from the main axes and rhizoids cut off from pericentral cells, however P. iberica has lateral branch initials separated by naked internodal segments, trichoblasts absent and tetrasporangia in straight series, as it occurs in Polysiphonia sensu stricto. On the basis of the morphological features, it is
assigned to Polysiphonia sensu lato, but it is not possible to include it in Neosiphonia neither Polysiphonia. Molecular data also indicate that P. iberica is closely related to the ‘‘multipericentral’’ group and/or ‘‘Neosiphonia’’ group rather than Polysiphonia group.
... [43], considered C. aerea and C. linum to be different forms of the same taxon, with the latter name taking precedence. Cytological studies [80] [81], either using morphological attributes [30] [82] [83] [84] or molecular techniques [85], confirmed these as distinct species. The main difference between these taxa is related to the habit. ...
The results obtained in this study highlight that further the macroalgae diversity in this region is even higher than what is reported to date. Here we present eight new records of marine macroalgae collected from the Caribbean coast of Costa Rica between March 2011 and May 2019. The morphological characteristics of Bryocladia cuspidata, Ceratodictyon variabile, Gracilaria hayi, Padina boergesenii, Zonaria tournefortii, Sargassum furcatum, Chaetomorpha aerea, and Bryopsis pennata var. secunda are described. The genera Bryocladia and Zonaria are reported for the first time for this region.
... What is presently known as Champia parvula and C. parvula var. prostrata L.G. Williams from Cape Hatteras, N.C. to the greater Caribbean Sea and Brazil (Harvey 1853, Schneider & Searles 1991, Lozada-Troche & Ballantine 2010) needs molecular investigation. Whether these warm temperate populations are C. parvula, C. farlowii or other entities in this complex of species remains to be determined. ...
Using mitochondrial COI-5P and plastid rbcL genetic markers, the red algal species historically known in southern New England, USA, as Champia parvula is found to be genetically distinct from the species to which it has historically been aligned. This necessitates the description of a new species, C. farlowii, for plants from Rhode Island, Massachusetts, Connecticut and New York, USA. The new species is morphologically compared with true European C. parvula and congeners, especially those with similar features previously aligned under the same species name. Champia farlowii is a morphologically cryptic species, the sixth in the expanding C. parvula complex, with overlapping characteristic measurements despite differences at the range extremes, when compared to C. parvula.
... Taylor (1979), Hollenberg (1968a), Abbott (1999), Schneider & Searles (1997, Kapraun & Norris (1982) Taylor (1945,1979), Schneider & Searles (1991), Guimarâes et al. ...
During a genetic analysis of western Atlantic Wrangeliaceae J.Agardh, specimens closely related to the generitype of Lophothamnion J.Agardh fell into a clade including the generitype of the earlier described Pleonosporium Nägeli, causing us to subsume the former genus. Two new species are described, P. novae-angliae G.W.Saunders & C.W.Schneider, sp. nov. for specimens from southern New England and New York, United States, formerly identified there as P. borreri (Smith) Nägeli, and P. ricksearlesii C.W.Schneider & G.W.Saunders, sp. nov. from Bermuda. The relationship of Pleonosporium with its sister genus Spongoclonium Sonder is discussed with the transfer of Spongoclonium australicum Womersley to Pleonosporium.
Le genre australasien Lophothamnion J.Agardh se révèle génétiquement aligné avec Pleonosporium Nägeli (Wrangeliaceae, Spongoclonieae): nouvelles espèces de l'Atlantique occidental.
Au cours d'une analyse génétique des Wrangeliaceae J.Agardh de l'Atlantique occidental, des spécimens étroitement liés au généritype de Lophothamnion J.Agardh sont tombés dans un clade comprenant le généritype de Pleonosporium Nägeli décrit précédemment, nous obligeant à englober le premier genre. Deux nouvelles espèces sont décrites, P. novae-angliae G.W.Saunders & C.W.Schneider, sp. nov. pour les spécimens du sud de la Nouvelle-Angleterre et de New York, États-Unis, anciennement identifiés là-bas sous le nom de P. borreri (Smith) Nägeli, et P. ricksearlesii C.W.Schneider & G.W.Saunders, sp. nov. des Bermudes. La relation entre Pleonosporium et son genre frère Spongoclonium Sonder est discutée avec le transfert de Spongoclonium australicum Womersley dans Pleonosporium.
Marine non-indigenous species (NIS) pose considerable threats and represent a significant risk to the receiving environments. They could exhibit invasive behavior and cause changes to ecosystem structure and function, prohibit the delivery of ecosystem services, or even result in detrimental socioeconomic implications in coastal areas. The increased globalization and rising tendencies in human activities including shipping, aquaculture, fishing, tourism, and the aquarium trade have hastened the introduction of new NIS in recent decades. In addition, climatic change is one of the most important factors that have severe impacts on the marine ecosystems, including fauna and flora biodiversity. This chapter deals with the problem of the introduction of non-indigenous species (NIS) and their effect on native seaweeds and their biodiversity in the Egyptian waters. This chapter is also monitoring their presence which is essential for marine environmental management and sustainable development.KeywordsNon-indigenous speciesMarine ecosystemHuman activitiesClimatic changeBiodiversity
DNA sequence analyses have demonstrated that Gelidium as currently circumscribed is not monophyletic and has three distinctive lineages: Gelidium sensu stricto that includes the generitype Gelidium corneum, the Capreolia group, and another lineage that includes two distinct clades formed by species from the eastern Pacific and western Atlantic Oceans. A new genus of small gelidioid algae, Gelidiorariphycus, is described to accommodate one of the clades in this latter lineage. Four species (Gelidiorariphycus loratus, G. gahunbooi, G. stipitatus and G. sungminbooi) segregated into this genus in single- and multi-gene phylogenies. Gelidiorariphycus is sister to a clade formed by an unidentified eastern Pacific species and Gelidium lingulatum. These clades are closely related to a clade formed by Gelidiophycus and the Capreolia group. All four Gelidiorariphycus species were morphologically similar with small thalli that have simple and distally flattened erect axes. Fertile tetrasporophytes were found to have sori with sterile margins that are acutely tapered, which may be morphologically distinctive, but determining this requires additional study. These species were rare, with only one or two samples of each collected despite Gelidiales surveys having been done in the areas where they are known. They were mainly found growing on shallow subtidal rocky shores, but a G. gahunbooi specimen was also collected at more than 30 m depth. Their small size and preference for subtidal habitats may explain the small number of specimens collected. The recognition of this new genus is a further step in the establishment of a natural classification system for genera within the Gelidiaceae.
In marine systems, behaviorally-mediated indirect interactions between prey, mesopredators, and higher trophic-level, large predators are less commonly investigated than other ecologic interactions, likely because of inherent difficulties associated with making observations. Underwater videos ( n = 216) from SharkCam, a camera installation sited beneath Frying Pan Tower, a decommissioned light house and platform, on a natural, hard bottom site approximately 50 km off Cape Fear, North Carolina, were used to investigate association behavior of round scad Decapterus punctatus around sand tiger sharks Carcharias taurus . Videos containing sand tiger sharks were analyzed for the simultaneous presence of round scad, and six species of scad mesopredators, with scad-shark interactions assigned to one of three categories of association: no visible interaction, loosely associated, or tightly associated. The likelihood of scad being loosely or tightly associated with sharks was significantly higher in the presence of scad mesopredators, suggesting that sharks provide a predation refuge for scad. This behaviorally-mediated indirect interaction has important implications for trophic energy transfer and mesopredator control on hard bottoms, as scad are one of the most abundant planktivorous fish on hard bottoms in the western Atlantic Ocean. Although we were not able to provide statistical evidence that sand tiger sharks also benefit from this association behavior, we have clear video evidence that round scad association conceals and attracts mesopredators, enhancing predation opportunities for sand tiger sharks. These interactions potentially yield additional trophic consequences to this unique association and highlight the value of exploring behaviorally-mediated interactions in marine communities.
Twenty-one samples belonging to species of Spyridia Harvey with uncinate (= hook-shaped) spines on determinate lateral branches were investigated for their morphology with a focus on the structure of determinate branches, and for comparative chloroplast-encoded rbcL and nuclear LSU rDNA sequence analysis to elucidate their taxonomy and phylogeny. Currently, four Spyridia species with uncinate spines are recognized worldwide: S. alternans, S. cupressina, S. horridula and S. hypnoides. Of them, S. hypnoides has been recognized as the most common species with uncinate spines. In this study, we show that S. aculeata needs to be resurrected from S. hypnoides, and recognized as a distinct species based on samples from Israel, Red Sea, near the type locality. Spyridia aculeata is characterized by the spiral arrangement of determinate branches, incompletely corticated determinate branches, naked basal segment of determinate branches, by the presence of only acropetal cortication in the nodes of determinate branches, and by uncinate spines at the terminal node and on the first and second nodes of determinate branches. In our molecular analyses based on rbcL and LSU rDNA, although four Spyridia species with uncinate spines are supported on phylogenetic trees, they are not a monophyletic group. The feature of uncinate spines in Spyridia is recognized as a polyphyletic character. Our phylogenetic analysis using rbcL and LSU rDNA sequences reveals high gene sequence divergence (6.8–7.0% for rbcL and 1.2–1.3% for LSU rDNA) between samples of S. aculeata and S. hypnoides. Therefore, the distribution of S. hypnoides may be restricted to the Indian Ocean, whereas S. aculeata is widely distributed in the Atlantic Ocean including the Mediterranean Sea and the Red Sea. Another Spyridia species with uncinate spines, S. alternans, is recognized as a synonym of S. horridula by our detailed morphological observations of its type specimen.
The Mediterranean Sea is a hotspot for introduced marine species, including seaweeds. Among red algae, Grateloupia, with no less than eight introduced species, occupies a prominent position. Here, we
report a large foliose Grateloupia species collected in Eastern Harbour, Alexandria, Egypt, which had previously been reported as G. acuminata and G. doryphora. Comparison of rbcL gene sequences revealed that the specimens represent G. gibbesii, a species originally described from Charleston, South Carolina, and potentially distributed in the warm temperate and tropical western Atlantic
Ocean. The species has been known only from a single location in Alexandria since the early 90s, it has not been reported in extensive surveys prior to that date, and there are no reports from other Mediterranean sites. This indicates a recent introduction, with shipping the likely vector. We describe the vegetative and reproductive morphology of G. gibbesii as the basis for evaluating variation in female reproductive structures and generic concepts in Grateloupia
The mesophotic zone off the coast of Bermuda has been explored for macroalgae beginning with the R/V Seahawk cruises of the 1980s and most recently on the Nekton XL Catlin cruise of the R/V Baseline Explorer in 2016. In this paper, we present two new members of the Halymeniaceae discovered on these missions based upon a combined ML analysis of mitochondrial (COI-5P), plastid (rbcL) and nuclear genes (LSU), as well as morphological and anatomical characteristics. Howella gorgoniarum gen. et sp. nov. grows conspicuously on the base of soft corals, and represents one of the three species in the new genus. Two species of the non-monophyletic Thamnoclonium, T. latifrons Endlicher & Diesing and T. lemannianum Harvey from South Africa and Australia, are moved to Howella based upon their molecular phylogenetic placements. First collected offshore of Bermuda in 1960 and misidentified as Halymenia hancockii, Galene leptoclados sp. nov. represents the first species in its genus collected outside of the western Pacific.
The red algal genus Hypnea has a wide geographical distribution along the coast of Brazil, where it has economic and ecological importance. The relatively simple and plastic morphology, often influenced by the conditions of its habitat, complicates the identification of Hypnea species. In the past years, several studies dealing with the taxonomy of Hypnea on the coast of Brazil have changed considerably the known diversity of species in the region. Studies using molecular markers led to the description of new species, while other names were placed in synonymy. In this review, revaluation of the morphology and the addition of new sequences for COI-5P, UPA and rbcL-3P markers were used in order to better understand the diversity of Hypnea species and their range of distribution. An identification key is presented for eleven species of the genus Hypnea occurring on the coast of Brazil: H. brasiliensis P.B. Jesus, Nauer & J.M.C. Nunes, H. cervicornis J. Agardh, H. cornuta (Kützing) J. Agardh, H. cryptica P.B. Jesus & J.M.C. Nunes, H. edeniana Nauer, Cassano & M.C. Oliveira, H. flava Nauer, Cassano & M.C. Oliveira, H. pseudomusciformis Nauer, Cassano & M.C. Oliveira, H. platyclada P.B. Jesus & J.M.C. Nunes, H. spinella (C. Agardh) Kützing, H. yokoyana Nauer, Cassano & M.C. Oliveira and H. wynnei Nauer, Cassano & M.C. Oliveira. Of all taxonomic characteristics proposed by earlier studies, the only ones that have taxonomic value considering the species analyzed in this work were: (1) habit of the thallus, (2) main axis, (3) apex shape, (4) form of the branchlets and (5) tetrasporangial sori position in the branches. However, the identification of the species based only on morphological characteristics should be made with caution, once phenotypic plasticity and convergent morphologies are present in the group. The DNA barcode technique, especially the COI-5P marker, proved to be very effective in the identification and delimitation of the species, revealing scenarios that would go unnoticed by morphology alone.
Identification of small Gelidium species based on morphology is difficult; as a consequence, the name Gelidium pusillum has been used for many small gelidiacean taxa throughout the world. Molecular-assisted identifications, however, are demonstrating that G. pusillum has a more restricted distribution than previously recognised. We used detailed morphological analyses combined with rbcL and cox1 sequence analyses to identify and assess the phylogenetic relationships of small Mediterranean Gelidium species. These analyses revealed the presence of two new species, G. adriaticum sp. nov. and G. carolinianum sp. nov. Gelidium adriaticum is a closely related sister species to G. pusillum, which was not found amongst our Mediterranean specimens. Gelidium carolinianum has been previously collected outside the Mediterranean, but it was misidentified as G. americanum. Morphological observations and sequence data generated from G. americanum types and other historical specimens clarified the status and distribution of this species. Phylogenetic analyses resolved G. carolinianum as a species in the Mediterranean and warm-temperate northwest Atlantic; whereas, G. americanum occurs in the Caribbean and tropical western Atlantic, and is sister to G. calidum from Brazil and closely related to G. crinale.
Lobophora is a common tropical to temperate genus of brown algae found in a plethora of habitats including shallow and deep‐water coral reefs, rocky shores, mangroves, seagrass beds and rhodoliths beds. Recent molecular studies have revealed that Lobophora species diversity has been severely underestimated. Current estimates of the species numbers range from 100‐140 species with a suggested center of diversity in the Central Indo‐Pacific. This study used three molecular markers (cox3, rbcL, psbA), different single‐marker species delimitation methods (GMYC, ABGD, PTP), and morphological evidence to evaluate Lobophora species diversity in the Western Atlantic and the Eastern Pacific Oceans. Cox3 provided the greatest number of Primary Species Hypotheses, followed by rbcL and then psbA. GMYC species delimitation analysis was the most conservative across all three markers, followed by PTP, and then ABGD. The most informative diagnostic morphological characters were thallus thickness and number of cell layers in both the medulla and the dorsal/ventral cortices. Following a consensus approach, 14 distinct Lobophora species were identified in the Western Atlantic and five in the Eastern Pacific. Eight new species from these two oceans were herein described: L. adpressa sp. nov., L. cocoensis sp. nov., L. colombiana sp. nov., L. crispata sp. nov., L. delicata sp. nov., L. dispersa sp. nov., L. panamensis sp. nov., and L. tortugensis sp. nov. This study showed that the best approach to confidently identify Lobophora species is to analyze DNA sequences (preferably cox3 and rbcL) followed by comparative morphological and geographical assessment.
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A molecular survey of red algae collected by technical divers and submersibles from 90 m in the mesophotic zone off the coast of Bermuda revealed three species assignable to the Kallymeniaceae. Two of the species are representative of recently described genera centered in the western Pacific in Australia and New Zealand, Austrokallymenia and Psaromenia and the third from the Mediterranean Sea and the eastern Atlantic, Nothokallymenia. A phylogenetic analysis of concatenated mitochondrial (COI‐5P) and chloroplast (rbcL) genes, as well as morphological characteristics, revealed that two are shown to be new species with distant closest relatives (N. erosa and P. septentrionalis), while the third represents a deep water western Atlantic species now moved to an Australasian genus (A. westii).
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Se presentan diez nuevos reportes de especies de macroalgas rojas para la Reserva Internacional de la Biosfera Seaflower en el Mar Caribe. Cuatro taxones fueron previamente citados para el Caribe colombiano: Dohrniella antillarum, Halydictyon mirabile, Taenioma nanum y Aglaothamnion cordatum. Las restantes seis especies son nuevos registros para el país: Callithamniella tingitana, Frikkiella searlesii, Lejolisia exposita, Melanothamnus gorgoniae, Monosporus indicus y Wrangelia gordoniae. Todas las algas fueron colectadas en hábitat de arrecife coralino (9–17 m de profundidad), y todas las especies menos una son algas de tamaño diminuto, creciendo principalmente sobre coral muerto o como epifitas de algas más grandes. Se discuten las características morfológicas y reproductivas de cada especie, así como las novedades de su distribución.
Macroalgae are a natural, common feature of inland waters as well as estuaries, coastal waters, and oceanic waters particularly the Gulf of Mexico, North Atlantic Ocean, and Caribbean Sea where pelagic Sargassum is distributed. As the causes and effects of macroalgal blooms are similar in many ways to those associated with harmful phytoplankton species, scientists use the term harmful algal bloom (HAB) to describe this diverse array of bloom phenomena. Many studies have addressed the importance of nutrient loading to the development of macroalgal HAB. Unlike toxic phytoplankton blooms, macroalgal blooms usually lack direct chemical toxicity, but typically have a broader range of distribution and ecological impacts. Because of the negative environmental and economic impacts that are often associated with harmful macroalgal blooms, government agencies and private stakeholders have increasingly sought various strategies for management and mitigation, although the main historic approaches, physical removal and herbicide treatment, remain common.
Cryptonemia specimens collected in Bermuda over the past two decades were analysed using gene sequences encoding the large subunit of the nuclear ribosomal DNA and the large subunit of RuBisCO as genetic markers to elucidate their phylogenetic positions. They were additionally subjected to morphological assessment and compared with historical collections from the islands. Six species are presently found in the flora including C. bermudensis comb. nov., based on Halymenia bermudensis, and the following five new species: C. abyssalis, C. antricola, C. atrocostalis, C. lacunicola and C. perparva. Of the eight species known in the western Atlantic flora prior to this study, none is found in Bermuda. Specimens reported in the islands in the 1900s attributed to C. crenulata and C. luxurians are representative of the new species, C. antricola and C. atrocostalis, respectively.
Sequence data generated during a Canadian barcode survey (COI-5P) of the tribes Polysiphonieae and Streblocladieae, a large and taxonomically challenging group of red algae, revealed significant taxonomic confusion and hidden species diversity. Polysiphonia pacifica Hollenberg, P. paniculata Montagne, P. stricta (Dillwyn) Greville and Vertebrata fucoides (Hudson) Kuntze were all complexes of two or more genetically distinct yet overlooked species. One variety of P. pacifica was elevated to the rank of species as P. determinata (Hollenberg) Savoie & Saunders, stat. nov. Several new additions to the Canadian flora were recorded including P. kapraunii Stuercke & Freshwater and P. morrowii Harvey. Subsequent multi-gene (COI-5P, LSU and rbcL) phylogenetic analyses confirmed that the genus Polysiphonia Greville was polyphyletic, and currently assigned species resolved with many other genera. Polysiphonia sensu stricto was restricted to a group of species that formed a monophyletic lineage with the type, Polysiphonia stricta. Carradoriella P.C.Silva was resurrected based on the South African species Carradoriella virgata (C.Agardh) P.C.Silva. Species previously attributed to Polysiphonia were transferred to Carradoriella, Leptosiphonia and Vertebrata as well as to three new genera described here: Acanthosiphonia gen. nov., based on A. echinata (Harvey) comb. nov.; Eutrichosiphonia gen. nov. for E. confusa (Hollenberg) comb. nov. and E. sabulosia (B.Kim & M.S.Kim) comb. nov.; and Kapraunia gen. nov., which includes K. schneideri (Stuercke & Freshwater) comb. nov. and three additional species.
The biodiversity, geographic distribution, and community parameters of the benthic tanaidaceans associated with three coral reefs along the SW and SE Gulf of Mexico were analysed. A total of 15,525 specimens were grouped in 36 species. The highest value of abundance was found in the PNSAV with 6382 tanaidaceans. The PNSAV presented 30 species, the ANPT-L 16 species, and the SABS 17 species. The species with the widest distribution were Pseudonototanais sp., Condrochelia dubia, Leptochelia forresti, Synapseudes sp., Haplopolemius propinquus, Alloleptochelia longimana, and Paradoxapseudes bermudeus. In the Veracruz System Reef, the highest abundance was recorded for Condrochelia dubia and Pseudonototanais sp. The highest value of diversity was obtained in the SABS (3.08 bits/ind in the reef Bajo Diez), and the lowest value was found in the PNSAV (0.07 bits/ind in the reef Isla de Enmedio). The highest value of abundance was found in coral rubble and macroalgae. A significant relationship between depth and specific richness was found in the three reef systems. Using cluster analysis, three groups were found in each system, mainly related to the proximity to the coast and to urban areas. This is one of the first studies to show the specific substrate and attributes of three communities of tanaidaceans along the SE–SW coast of the Gulf of Mexico.
The current identification of crustose coralline algae from North Carolina is based on a few morphoanatomical studies from the last century. We reassessed the type specimens of the two Lithophyllum species historically reported from offshore communities in North Carolina, L. intermedium with a Caribbean Sea type locality and L. subtenellum with an Atlantic southern France type locality, using scanning electron microscopy images and diagnostic rbcL sequences. Neither of the sequences generated from the type specimens matched rbcL sequences from contemporary specimens collected from subtidal North Carolina epibenthic communities. On the basis of analyses of rbcL and other loci (psbA, UPA, and COI), we instead found L. atlanticum, recently described from Brazil, and L. searlesii sp. nov. from Onslow Bay, North Carolina. These sequence data show that L. atlanticum is related to northeast Pacific species, whereas L. searlesii is related to Mediterranean species.
Polysiphonia is the largest genus of red algae, and several schemes subdividing it into smaller taxa have been proposed since its original description. Most of these proposals were not generally accepted, and currently the tribe Polysiphonieae consists of the large genus Polysiphonia (190 species), the segregate genus Neosiphonia (43 species) and 13 smaller genera (< 10 species each). In this paper, phylogenetic relationships of the tribe Polysiphonieae are analysed, with particular emphasis on the genera Carradoriella, Fernandosiphonia, Melanothamnus, Neosiphonia, Polysiphonia sensu stricto, Streblocladia and Vertebrata. We evaluated the consistency of 14 selected morphological characters in the identified clades. Based on molecular phylogenetic (rbcL and 18S genes) and morphological evidence, two speciose genera are recognized: Vertebrata (including the type species of the genera Ctenosiphonia, Enelittosiphonia, Boergeseniella and Brongniartella) and Melanothamnus (including the type species of the genera Fernandosiphonia and Neosiphonia). Both genera are distinguished from other members of the Polysiphonieae by synapomorphic characters, the emergence of which could have provided evolutionarily selective advantages for these two lineages. In Vertebrata trichoblast cells are multinucleate, possibly associated with the development of extraordinarily long photoprotective trichoblasts. Melanothamnus has 3-celled carpogonial branches and plastids lying exclusively on radial walls of the pericentral cells, which similarly may improve resistance to damage caused by excessive light. Other relevant characters that are constant in each genus are also shared with other clades. The evolutionary origin of the genera Melanothamnus and Vertebrata is estimated as 75.7–95.78 and 90.7–138.66 Ma, respectively. Despite arising in the Cretaceous, before the closure of the Tethys Seaway, Melanothamnus is a predominantly Indo-Pacific genus and its near-absence from the north-eastern Atlantic is enigmatic. The nomenclatural implications of this work are that 46 species are here transferred to Melanothamnus, six species are transferred to Vertebrata, and 13 names are resurrected for Vertebrata.
Identification of Cladophora species is challenging due to conservation of gross morphology, few discrete autapomorphies, and environmental influences on morphology. Twelve species of marine Cladophora were reported from North Carolina waters. Cladophora specimens were collected from inshore and offshore marine waters for DNA sequence and morphological analyses. The nuclear-encoded rRNA internal transcribed spacer regions (ITS) were sequenced for 105 specimens and used in Molecular Assisted Identification (MAI). The ITS1 and ITS2 region was highly variable, and sequences were sorted into ITS Sets of Alignable Sequences (SASs). Sequencing of short hyper-variable ITS1 sections from Cladophora type specimens was used to positively identify species represented by SASs when the types were made available. Secondary structures for the ITS1 locus were also predicted for each specimen and compared to predicted structures from Cladophora sequences available in GenBank. Nine ITS SASs were identified and representative specimens chosen for phylogenetic analyses of 18S and 28S rRNA gene sequences to reveal relationships with other Cladophora species. Phylogenetic analyses indicated that marine Cladophorales were polyphyletic and separated into two clades, the Cladophora clade and the "Siphonocladales" clade. Morphological analyses were performed to assess the consistency of character states within species, and complement the DNA sequence analyses. These analyses revealed intra- and interspecific character state variation, and that combined molecular and morphological analyses were required for the identification of species. One new report, Cladophora dotyana, and one new species Cladophora subtilissima sp. nov., were revealed, and increased the biodiversity of North Carolina marine Cladophora to 14 species. This article is protected by copyright. All rights reserved.
Hypnea musciformis is one of the most studied species of the genus Hypnea. It has a wide geographic range along the Atlantic, Pacific and Indian Oceans that would be consistent with an extensive intraspecific variation in morphology. Hypnea musciformis has been previously reported on coasts of the Yucatan Peninsula; however, neither morphological characterization nor molecular studies have been done for Gulf of Mexico or Mexican Caribbean populations. For the first time, we present a detailed morphoanatomical description of the tetrasporophytic, gametophytic and carposporophytic phases and its reproductive structures for this region, including the description of the male gametophyte. Mexican Caribbean samples showed morphological variation in branching pattern, branch abundance and branchlet types, and this was attributed to life-history phase and the reproductive status of the thalli. Molecular analysis of ribulose-1,5-bisphosphate carboxylase/oxygenase gene and the 5′ region of the mitochondrial cytochrome C oxidase subunit I gene markers allows us to confirm the unique genetic identity of Mexican specimens. The analysis of H. musciformis collected in different tropical areas showed a high degree of intraspecific variation and suggested the necessity of a combined analysis of morphology and different gene markers for a better understanding of its taxonomy and phylogeny.
The diversity of many communities is changing due to local extinctions and invasions. Understanding the consequences of these changes is vital to their successful conservation, yet few studies have experimentally investigated how producer diversity affects the stability of higher trophic levels. Here, we show that producer diversity, when manipulated as the only independent variable in the presence of natural top‐down forces, increases the stability of consumer abundance, biomass and diversity in a benthic marine community.
Using four macroalgal species ( Codium fragile , Gracilaria tikvahiae , Gracilaria vermiculophylla and Gymnogongrus griffithsiae ), we manipulated producer diversity (identity and richness) in a substitutive design to create seven treatments. Our treatments included four monocultures, two 3‐species mixtures that differed only by including either the native or invasive Gracilaria and the complete four‐species mixture. We followed the week‐to‐week dynamics of producer and consumer communities in each treatment concurrently for 12 weeks and quantified their temporal stability.
We found that higher producer diversity increased the stability of a diverse, productive consumer community. Producer biomass production did not affect consumer production or diversity, suggesting that producer diversity was solely responsible for driving the mechanisms underlying the observed multitrophic diversity–stability relationships. Taken together, our results indicate that higher producer diversity directly increased consumer diversity by increasing overyielding and decreasing the temporal variance of this response variable and that this increased consumer diversity enhanced consumer stability via increased asynchrony among consumers.
Synthesis . Our results suggest that the effects of producer diversity propagate upwards to maintain diversity and productivity at higher trophic levels, and thereby enhance the overall stability of food webs.
AimFor over 80 years, the Maine baitworm trade has shipped live polychaete worms and packing algae ‘wormweed’ to distributors world-wide, while also consistently transferring a wide diversity and abundance of hitchhiking organisms of all life stages to numerous recipient communities. Here, we investigate this potent, yet underestimated, invasion vector using an important recipient region (the Mid-Atlantic) to examine the stepwise species transfer and survival along four stages of the vector.LocationMaine and Mid-Atlantic region (New Jersey, Delaware, Maryland, Virginia and North Carolina), USA.Methods
We quantified taxonomic identities and abundances of organisms associated with packing algae at four stages along the vector pathway during summer 2011: (1) Maine source habitats; (2) bait boxes from Maine distributors; (3) bait boxes from distributors in five Mid-Atlantic States; and (4) bait bags from retailers in five Mid-Atlantic States. We also examined functional diversity based on significant physical and life history characteristics and assessed genetic diversity for two common hitchhiking snail species.ResultsWe identified 17,798 live macro-organisms across 58 taxa, including marine macro-invertebrates, macroalgae, vascular plants and semi-terrestrial or aquatic invertebrates, present in bait boxes and bags. In all measures of diversity and abundance, we observed decreases of live marine macro-invertebrates across sequential stages of the vector from source to recipient regions. Significant differences in community composition were also observed between stages and were driven by isopods (taxonomic diversity) and isopods, amphipods and some gastropods (functional diversity).Main conclusionsThe lack of management in the face of the sheer magnitude and diversity of organisms that are transported via the live marine bait trade underscores how this is an underappreciated vector that could be a considerable source of successful invasions globally.
Species recognition in algae is often extremely difficult due to the paucity of morphological characters and high
environmental plasticity. If environment is important to morphology, then related species growing in sympatry are good candidates to discover diagnostic characters. We studied algae collected in sympatric populations in tropical Atlantic Mexico. Hydropuntia cornea and H. usneoides have high morphological variation and have been difficult to diagnose morphologically. We used four molecular markers (RuBisCo spacer, cox2–3 spacer, rbcL and COI) to investigate the genetic relationship between samples that correspond to either H. cornea or H. usneoides; in addition, we determined if molecular-characterized groups were morphologically distinguishable. RuBisCo and cox2–3 spacers revealed low genetic variation but showed two genetic groups: groups I and II. rbcL and COI phylogenies also showed a separation into two groups, corresponding with cox2–3 spacer groups I and II. Group I matched sequences in GenBank of H. usneoides and group II with H. cornea. Populations were mixed for these genetic groups, with group I prominent in Quintana Roo populations. Morphological analysis of samples in both genetic clades showed that they are not distinguishable. As the difference between the two groups is only genetic, they are, consequently, cryptic species. While the extremes of morphology in allopatric populations may be distinguishable, we do not feel that in most cases these species can be recognized. Therefore, we propose that these two ‘species’ should be designated as a species complex (the Hydropuntia
cornea/H. usneoides complex).
Cormaci, M., Furnari, G. & Pizzuto, F.: Taxonomic and nomenclatural notes on Anotrichium tenue and related species (Ceramiaceae, Rhodophyta). – Taxon 43: 633‐637. 1994. – ISSN 0040‐0262.
Two distinct species, differing mainly in tetrasporangial features, have been confused under the name Anotrichium tenue. In true A. tenue the tetrasporangia are borne terminally on a small number (5‐8) of whorled pedicels. In the other, A. secundum, comb, nov., the tetrasporangia are borne subterminally and adaxially on a relatively large number (8‐50) of whorled pedicels.
A recent collection of a red alga from Bermuda showed great similarities to Leptofauchea brasiliensis from Brazil, providing the impetus for a morphological and anatomical evaluation of the two. Based on these studies, the two appear to be congeneric. Molecular phylogenetic analyses of the Bermudian plants showed them to be to be a new genus and species of the Phyllophoraceae (Gigartinales), Archestenogramma profundum C.W. Schneider, Chengsupanimit & G.W. Saunders. In light of our anatomical observations, our phylogenetic results also proved instructive as to the disposition of L. brasiliensis, a species that was suggested to be incorrectly assigned to the Rhodymeniales for over a quarter of a century and even recently excluded from Leptofauchea. The morphological and anatomical similarity of L. brasiliensis to A. profundum suggested its movement from the Faucheaceae to a new taxonomic placement in the Phyllophoraceae, as A. brasiliense (A.B. Joly) C.W. Schneider, Chengsupanimit & G.W. Saunders, comb. nov.
The green marine alga Pseudendoclonium submarinum (Willie 1901) occurs on hard substratum in the upper littoral in the North Atlantic Ocean. In recent field and laboratory studies, Pseudendoclonium submarinum grew normally in situ but declined in vitro. Microscopic examination showed the alga inoculum to be associated with a filamentous fungus, where the fungus grew in close association with the alga. Pseudendoclonium samples collected from Ipswich, MA during a two-year period were consistently associated with the fungus. In cultures with the fungus present, algal thalli declined and became necrotic, while the fungus produced hyphae and conidia. The fungus failed to grow in sterile algal medium in the absence of Pseudendoclonium but could be isolated and grown on standard mycological culture media. Light and scanning electron microscopy showed fungal hyphae infiltrated intercellular areas of the algal filaments but did not penetrate algal cell walls. Pathogenicity is apparently a result of the in vitro environment, and it is hypothesized that the fungus produces one or more secondary metabolites, which accumulate in culture. These metabolites produced by the fungus eventually killed algal cells. Fungal ribosomal DNA sequences were compared to Cladasporium sp. in GenBank, indicating that the fungus is Cladosporium cladosporioides (Fresenius) de Vries. Widely distributed, Cladosporium cladasporioides has been shown to be a facultative parasite, endophyte and saprophyte on terrestrial plants and some algae. The fungus has not been described in association with an ulvophyte, a green marine alga.
A new red algal species, Crassitegula laciniata (Sebdeniaceae, Sebdeniales), was described from recent collections made on offshore Bermuda reef habitats, and it was distinguished morphologically and molecularly (COI-5P, LSU gene sequences) from congeners in Bermuda and Australia. In addition, four other species were reported as new members of the growing Bermuda macroalgal flora: the chlorophytes Anadyomene lacerata and Codium carolinianum and the rhodophytes Gracilaria occidentalis and Predaea goffiana.
Biology Taxonomic identity and the effect of temperature and irradiance on the photosynthesis of an indoor tank-cultured red alga Agardhiella subulata from Japan Abstract We determined through morphological and rbcL phylogenetic analyses that a previously unidentified, but introduced species of macroalga, which has been easily cultivated in indoor tanks in Japan, is Agardhiella subulata (Solieriaceae). Additionally, the photosynthetic biology of this alga was examined by inducing photo-synthetic activity under a variety of water temperatures and photosynthetic active radiation (PAR) to clarify the optimal conditions needed for its efficient cultivation. Photosynthetic activity was evaluated by using both dis-solved oxygen (DO) and pulse amplitude modulated-chlorophyll fluorometric (PAM) techniques, and focused on elucidating temperature and PAR levels that would potentially maximize productivity. The DO method revealed that the net photosynthetic rates at 24 °C quickly increased as PAR increased, and approached a P max of 27.8 mg O 2 g ww -1 min -1 (95 % Bayesian credible interval, BCI 23.8–32.1). The maximum gross photo-synthetic rate occurred at 26.7 °C (BCI 24.4–28.3 °C). However, PAM experiments indicated that for the max-imum quantum yield, the optimal temperature was 23.7 °C (BCI 22.7–24.6) and the maximum relative electron rates occurred when the water temperature was 31.0 °C (BCI 30.6–31.5). This study suggests that the broad tolerance of maximal photosynthetic activity to temperature (22.7–31.5 °C) is one of the main reasons why this alga can be successfully cultivated year-round.
The Mediterranean red algal flora is diverse but current knowledge of its diversity is at best fragmentary. Here, a new species of Kallymenia from Croatia is described based on morphological and molecular data. Members of the genus Kallymenia share similar morphology making their generic identification relatively easy, whereas species level identification is notoriously difficult. In this paper an integrative systematics study using three gene markers, cox1 (COI), rbcL and nuclear LSU, allowed us to (i) confirm the identity of four existing members of this genus inhabiting the Mediterranean Sea: K. feldmannii, K. lacerata, K. patens and K. requienii; (ii) detect the presence of K. reniformis only in the Atlantic, and (iii) reveal the presence of a new member of Kallymenia from the Mediterranean Sea, K. ercegovicii Vergés & Le Gall, sp. nov., which is described based on distinctive morphological and molecular characters. Kallymenia ercegovicii is distinguished, using three molecular markers, from all Kallymenia species for which these sequences are available. Morphologically, the new species can be distinguished from other polycarpogonial Kallymenia by a set of characters including a deeply lobed thallus, large inner cortical cells, stellate but non-glanglionic medullary cells and non-ostiolate cystocarps surrounded by a filamentous net composed of elongated cells forming fascicles. An initial phylogeny of the genus Kallymenia was inferred from cox1 (COI), rbcL and nuclear LSU sequences. Kallymenia ercegovicii was resolved with full support within the same lineage as K. reniformis (the generitype), K. feldmannii and K. patens, whereas K. lacerata and K. requienii were only distantly related.
This work presents a taxonomic, floristic and chorological account of the most representative turf-forming species from sand-covered rocks along the Atlantic Iberian Peninsula, including in this Part 2 species belonging to six orders of the Rhodophyta and one of the Phaeophyceae. For each species are provided morphological descriptions, distribution maps, and/or COI-5P sequences, as well as taxonomic notes. The species studied are: Rhodothamniella floridula, Ceramium ciliatum, Erythroglossum lusitanicum, Hypoglossum hypoglossoides, Ptilothamnion sphaericum, Spermothamnion repens, Tiffaniella capitata, Gelidium crinale, G. spathulatum, Pterocladiella melanoidea, Calliblepharis hypneoides, Gymnogongrus griffithsiae, Plocamium maggsiae, Gastroclonium reflexum and Bachelotia antillarum.
We propose the new genus Melyvonnea to accommodate species previously included in Mesophyllum having: a) perithallial protuberances that may branch and dominate over the encrusting base, b) monoecious gametophytes with gametangial conceptacles occasionally developed in superimposition, c) spheroid carposporangial chambers (lacking a central pedestal), and d) filaments lining canals of multiporate roofs composed of 3 to 5 cells with distinctively elongate basal cells. The new genus shares with Mesophyllum the development of a predominantly coaxial hypothallium. Melyvonnea presently accommodates three species in the Central Atlantic, viz. the generitype Melyvonnea canariensis (Foslie) comb. nov. from the Canary Islands, Melyvonnea erubescens (Foslie) comb. nov. ( =Mesophyllum incertum; type locality: Bermuda) from the western Atlantic, Melyvonnea aemulans (Foslie & Howe) comb. nov. from Puerto Rico, and one Indo-Pacific species, Melyvonnea madagascariensis (Foslie) comb. nov. We also emend Mesophyllum Lemoine to encompass Northern Hemisphere species that lack the above apomorphies of Melyvonnea and in addition develop a central pedestal in carposporangial conceptacles (via dissolution of the surrounding cells) with gonimoblasts bending down to fill the empty space. Mesophyllum sensu stricto currently includes six species in the northeast Pacific (M. aleuticum, M. conchatum, M. crassiusculum, M. lamellatum, M. megagastri, M. vancouveriense), two species in the western Atlantic (M. mesomorphum and M. syntrophicum), and three species in the northeast Atlantic and the Mediterranean Sea (M. expansum, M. lichenoides, M. philippii). Gametophytic species of each genus show a mainly disjunct distribution being restricted to the tropics–subtropics (Melyvonnea) and the temperate waters of the Northern Hemisphere (Mesophyllum s.s.). This classification is supported by a consensus of studies of all well-known species of Mesophyllum sensu Adey (1970), and is based on a phylogenetic analysis of morphological and anatomical characters in addition to molecular evidence.
The presence of tetrahedrally divided tatrasporangia in Ceramium bisporum Ballantine is reported for the first time. The plant was found as epiphytic on calcareous Halimeda tuna in coral reef environment in Caribbean Colombia. The taxon represents a new record for the country.Presencia de tetrasporangios en Ceramium bisporum(Ceramiales, Rhodophyta)Se reporta por primera vez la presencia de tetrasporangios divididos tetrahedricamente para la especie Ceramium bisporum. El alga fue encontrada epífita del alga calcárea Halimeda tuna en arrecifes coralinos en el Caribe colombiano. El taxón representa un nuevo registro para el país.
Sand-covered rocks provide a particular habitat to benthic seaweeds, which must
tolerate the stressful conditions imposed by the presence of sediments. Turf assemblages are
dominant in this habitat, which is widely distributed along the Atlantic Iberian Peninsula,
neverthelss their flora remained poorly known. This work presents a taxonomic, floristic
and chorological account of the most representative Rhodomelaceae from sand-covered
rocks along the Atlantic Iberian Peninsula. For each species we provided morphological
descriptions, distribution maps, and/or COI-5P sequences, as well as taxonomic notes. The
species studied are: Chondria coerulescens, Ctenosiphonia hypnoides, Herposiphonia cf.
secunda f. tenella, Leptosiphonia schousboei, Lophosiphonia reptabunda, L. simplicissima
sp. nov., Ophidocladus simpliciusculus, Polysiphonia caespitosa, P. devoniensis, P. foeti-
dissima, P. fucoides, P. nigra, P. stricta, P. tripinnata, Pterosiphonia ardreana, P. parasitica,
P. pennata and Streblocladia collabens. Among our taxonomical conclusions, we herein
proposed a novel species Lophosiphonia simplicissima as well as the transfer of Streblo-
cladia collabens to the genus Neosiphonia. Furthermore, the parasitic species Aiolocolax
pulchellus is described and its taxonomic position is discussed.
A new red alga, Dasya enomotoi, is described from Japan. This species is characterized by having a large thallus consisting of an elongated axis and many, radially arranged, polysiphonous branches both of which are heavily corticated and densely covered with numerous, soft monosiphonous filaments. It is distinguished from several similar species by the combination of the following: (i) indistinct pericentral cells in transverse sections except near the apices, (ii) the presence of enlarged, inner cortical cells, (iii) radially arranged adventitious monosiphonous filaments, (iv) three-celled carpogonial branches, (v) six (sometimes five) tetrasporangia in each fertile segment of the stichidia, and (vi) three tetrasporangial cover cells that are not elongated longitudinally and usually not divided transversely. This species may have been identified as D. villosa Harvey by previous investigators in Japan.
The red alga Chrysymenia divaricata Durant, described from New York Harbor, is shown to belong to Lomentaria. The binomial Lomentaria divaricata (Durant) M.J. Wynne comb. nov. is proposed. This name includes the taxonomic synonyms L. baileyana (Harvey) Farlow and Chondrothamnion divaricatum Bailey ex Kützing.
Fronds of Ulva spp. from Patagonian Atlantic coasts exhibited brown spots produced by the presence of Myrionema strangulans (Chordariales, Phaeophyceae). The occurrence of M. strangulans on Ulva spp. is widely reported from several regions of the world, but there were no detailed studies about the subject. In the present study, we describe the morphology and interactions of M. strangulans with Ulva spp. as observed under light and electron microscopes, and we reconstruct all stages of its life cycle based upon in vitro experiments. The prevalence of infection by M. strangulans was 100%. In case of the strongest epiphytism, the host cuticle exhibited perforations, massive depigmentation, cellular disorganization, and cuticle rupture. It was possible to demonstrate a purely epiphytic life strategy of the organism by transmission electron microscopy. M. strangulans formed discoid thalli constituted by vegetative filaments and radiating from a central zone to a peripheral zone. Transversally, the discs were formed by two strata: a basal monostromatic and a filamentous erect stratum. From the monostromatic stratum, hyaline hairs and reproductive structures were produced. Both plurilocular and unilocular sporangia were present. Zoids from both plurilocular and unilocular sporangia were able to germinate in culture. M. strangulans exhibited a haploid–diploid, heteromorphic life cycle with thalli with three different morphologies. The haploid chromosome number was 12 ± 2 chromosomes.
The eukaryotic alga Ostreobium quekettii (Ostreobiaceae: Chlorophyceae) is reported from Fiji for the first time. It is found creeping over the calcareous plates of dead specimens of species of a barnacle genus Acasta (Pendunculata: Acastinae), which was endozoic in the gorgonian Rumphella suffruticosa. The barnacles are lodged in cavities in the coenenchyme of the gorgonian, mostly in the vicinity of colonial branching points. There is little external evidence of the location of the barnacles where the gorgonian tissue is thick, but where it is thin, prominent galls are visible. There is no evidence that the barnacle or algal association causes stress to the host, which was otherwise healthy in appearance. The presence of the algae would appear to be associated with the occurrence of the barnacles.
Six species of Porphyra have commonly been recognized in the north-western Atlantic from Long Island Sound to the Canadian Maritimes: P. amplissima, P. leucosticta, P. linearis, P. miniata, P. purpurea, and P. umbilicalis. Distinguishing them with certainty has been problematic. A DNA-based system of molecular identification was developed using partial sequences of the nuclear small subunit ribosomal RNA gene (SSU) or the plastid ribulose-1,5-bisphosphate carboxylase-oxygenase large subunit gene (rbcL). Multiple samples of each taxon were surveyed for intraspecific variation. Intraspecific SSU divergences for Porphyra 'leucosticta', P. 'miniata', P. 'umbilicalis', and P. 'purpurea' ranged from 0% to 1%. There was more variation for P. 'amplissima' (0-2.1%) and P. 'linearis' (0-3.5%); however, each taxon was monophyletic. No intraspecific differences were observed for these taxa in rbcL (one to eight samples per taxon). These sequences were compared with P. yezoensis U51, introduced to Maine, and with P. 'dioica', a north-east Atlantic Porphyra easily confused with P. 'purpurea'. To discriminate between P. 'purpurea, P. 'umbilicalis', and A 'leucosticta', SSU variation was used to design primers for the Allele-Specific Polymerase Chain Reaction(TM). With molecular tools, we could classify over 80% of the monostromatic specimens surveyed, but the residue of unidentifiable specimens may indicate the existence of further monostromatic species in the north-west Atlantic. Porphyra 'purpurea' was found to occur further south than previously recorded. A morphologically cryptic Porphyra was discovered at Herring Cove, Nova Scotia, Canada. dagger Phylogenetic analyses using SSU or rbcL sequences showed 'soft incongruence' between gene trees, i.e. the topologies of the phylograms were similar but not identical, with only weak to moderate bootstrap support for the nodes that differed. Both trees strongly supported a clade including P. 'purpurea', P. 'umbilicalis', P. 'linearis', and P. 'dioica'. Porphyra sp. Herring Cove was allied with the remaining Porphyra taxa in the SSU tree. The rbcL phylogeny was less well resolved, consisting of a polytomy of a P. 'purpurea'-P. 'umbilicalis'-P. 'linearis'-P. 'dioica' clade, Porphyra sp. Herring Cove, a clade comprising P. 'amplissima' and P. 'miniata', and a P. 'suborbiculata'-P. 'leucosticta'-P. yezoensis clade.
The genus Cladosiphon is represented in the Canary Islands by three species, C. contortus, C. occidentalis, and the new species C. cymodoceae. Vegetative and reproductive morphology of macrosporophytes, as well as habitat and phenology of the Canarian individuals, are described in detail. The southern limit of distribution of the northeastern Atlantic and Mediterranean species, C. contortus, is extended to the Canary Islands, and some anatomical features that previous descriptions had apparently overlooked (large inner medullary cells and rhizoid-like perimedullary filaments, longer cortical filaments, sheathed hairs, adventitious cortical filaments, and hairs often formed from inside empty plurilocular sporangia) are documented. Unilocular sporangia of C. contortus are described here for the first time, and they agree with the characteristics of the genus. Cladosiphon occidentalis is reported for the first time in the eastern Atlantic Ocean. Specimens previously reported from the Canary Islands as Cladosiphon zosterae were found to be misidentifications of C. occidentalis. Cladosiphon cymodoceae sp. nov., known only from the Canary Islands, is an epiphytic species on leaves of the warm temperate seagrass Cymodocea nodosa. Cladosiphon cymodoceae differs from the remaining species of the genus in a unique combination of characteristics: very irregularly branched habit with relatively thick axes and abundant short branchlets, long and thin cortical filaments (to 425 mu m long and 5-8 mu m lower diameter), sheathed hairs, and plurilocular sporangia with few-celled outgrowths of mature sporangia commonly at the apices of inrolled cortical filaments. Young thalli of C. occidentalis and C. cymodoceae were observed arising from myrionematoid crusts on leaves of Cymodocea nodosa as a juvenile stage in the development of the macroscopic sporophytes.
Temperature tolerances were determined for isolates belonging to three distributional groups: species confined to the tropical W Atlantic amphi-Atlantic species with a (sub)tropical distribution; and species with an amphi-Atlantic tropical to warm-temperate distribution also occurring in the Mediterranean. Tolerance to high temperatures was correlated with vertical position in the intertidal/subtidal zone rather than biogeographic grouping. Species restricted to the subtidal were the least tolerant. Tolerance to low temperatures was not different in subtidal and intertidal species but was significantly better in amphi-Atlantic than in W Atlantic species. It is proposed that these differences in low-temperature tolerances reflect adaptations to glacial cold-stress in the tropical E Atlantic and subsequent trans-Atlantic dispersal. -from Authors
Thirty-two isolates of four amphi-Atlantic seaweed species with a tropical to subtropical distribution (Dictyopteris delicatula, Ceratodictyon intricatum, Ernodesmis verticillata and Lophocladia trichoclados) have been investigated for their temperature responses. Long (8 week) incubation times at 15–18°C caused damage or death in all isolates. Lower temperatures were tolerated only for shorter incubation times or caused severe damage. High temperatures in the range 30–35°C were tolerated. For L. trichoclados growth response curves were also determined which showed growth at temperatures ranging from 18/20 to 30°C, with optimum growth rates at 25–30°C. Crossing experiments with isolates of L. trichoclados showed that no reproductive barrier exists between isolates from opposite sides of the Atlantic. Comparison of upper and lower tolerance limits and growth response curves showed no indication of ecotypic differentiation between isolates from different localities on eastern and western Atlantic coasts, despite different local seawater temperature regimes. These results indicate that (long-range) dispersal events are likely to have overruled older, vicariant patterns. This is further supported by Random Amplified Polymorphic DNA analysis in L. trichoclados, which showed that one of the Canary Islands isolates has an intermediate position between an isolate from the Caribbean and two other isolates from the Canary Islands. Based on palaeoclimatic evidence and temperature tolerance data, it is suggested that the populations on the Canary Islands became extinct during Pleistocene glaciations and that the islands were subsequently repopulated by means of dispersal from tropical donor populations.
L-systems provide a method for modelling seaweed branching patterns in terms of simple rules. These rules can be used to generate computer graphics images of an alga's basic architecture, which, of course, is often obscured by adventiltious growth in living plants. L-systems provide a mathematical abstraction that allows us to compare species by focusing on essential differences in their substitution rules rather than relying entirely on the visual appearance of branching patterns. Two species of red algae from closely related genera in the Dasyaceae—Dasya rigidula and Dasysiphonia concinna—are virtually identical in pseudolateral branching detail and appear to diverge solely in terms of pseudolateral position. L-systems models and their graphical representations are presented to demonstrate that the two-dimensional, alternate-distichous pattern of pseudolateral position for Dasysiphonia concinna can be derived in a straightforward way from that of the three-dimensional, spiralled pattern of Dasya rigidula. These models illustrate a case in which generic distinction is based upon an easily observable but relatively trivial feature, differences other than branching pattern being quite subtle.
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