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DNA sequences were analyzed for three groups of species from the Lepocinclis genus (L. acus‐like, L. oxyuris‐like, and L. tripteris‐like) along with cellular morphology. Phylogenetic analyses were based on nuclear SSU rDNA, LSU rDNA, and plastid‐encoded LSU rDNA. DNA sequences were obtained from species available in culture collections (L. acus SAG 1224‐1a and UTEX 1316) and those isolated directly from the environment in Poland (48 isolates), resulting in 79 new sequences. The obtained phylogenetic tree of Lepocinclis included 27 taxa, five of which are presented for the first time (L. convoluta, L. gracillimoides, L. longissima, L. pseudospiroides, and L. torta) and nine taxonomically verified and described. Based on morphology, literature data, and phylogenetic analyses, the following species were distinguished: in the L. acus‐like group, L. longissima and L. acus; in the L. tripteris‐like group, L. pseudospiroides, L. torta, and L. tripteris; in the L. oxyuris‐like group, L. gracillimoides, L. oxyuris var. oxyuris, and L. oxyuris var. helicoidea. For all verified species, diagnostic descriptions were emended, nomenclatural adjustments were made, and epitypes were designated. [ABSTRACT FROM AUTHOR]

Genera and species of the tribes Rhipileae and Rhipiliopsideae are abundant in most coral reef ecosystems worldwide. However, the group has been largely overlooked, and very little genetic data is available to accurately assess its diversity, phylogenetic relationships, and geographic distribution. Our study provided an in‐depth reassessment of tribes Rhipileae and Rhipiliopsideae based on a species‐rich dataset and the combination of molecular species delimitation, multilocus phylogenetic analyses (tufA, rbcL, and 18S rDNA), and morpho‐anatomic observations. Our results revealed an unexpected diversity of 38 morphologically validated species hypotheses, including 20 new species, two of which are described in this paper and one resurrected species (Rhipilia diaphana). Based on our phylogenetic results we proposed to redefine the genera Rhipilia and Rhipiliopsis and described two new genera, Kraftalia gen. nov. (Rhipileae) and Rhipiliospina gen. nov. (Rhipiliopsideae). Finally, we validated Rhipiliella Kraft and included it in the tribe Rhipileae. Although Rhipilia and Rhipiliopsis have a pantropical distribution, none of the species studied here appeared cosmopolitan; instead, they have restricted distributions. [ABSTRACT FROM AUTHOR]

Marine-freshwater and freshwater-marine transitions have been key events in the evolution of life, and most major groups of organisms have independently undergone such events at least once in their history. Here, we first compile an inventory of bidirectional freshwater and marine transitions in multicellular photosynthetic eukaryotes. While green and red algae have mastered multiple transitions in both directions, brown algae have colonized freshwater on a maximum of six known occasions, and angiosperms have made the transition to marine environments only two or three times. Next, we review the early evolutionary events leading to the colonization of current habitats. It is commonly assumed that the conquest of land proceeded in a sequence from marine to freshwater habitats. However, recent evidence suggests that early photosynthetic eukaryotes may have arisen in subaerial or freshwater environments and only later colonized marine environments as hypersaline oceans were diluted to the contemporary level. Although this hypothesis remains speculative, it is important to keep these alternative scenarios in mind when interpreting the current habitat distribution of plants and algae. Finally, we discuss the roles of structural and functional adaptations of the cell wall, reactive oxygen species scavengers, osmoregulation, and reproduction. These are central for acclimatization to freshwater or to marine environments. We observe that successful transitions appear to have occurred more frequently in morphologically simple forms and conclude that, in addition to physiological studies of euryhaline species, comparative studies of closely related species fully adapted to one or the other environment are necessary to better understand the adaptive processes. [ABSTRACT FROM AUTHOR]

Chlamydomonas ( Cd.) is one of the largest but most polyphyletic genera of freshwater unicellular green algae. It consists of 400-600 morphological species and requires taxonomic revision. Toward reclassification, each morphologically defined classical subgenus (or subgroup) should be examined using culture strains. Chlamydomonas subg. Amphichloris is characterized by a central nucleus between two axial pyrenoids, however, the phylogenetic structure of this subgenus has yet to be examined using molecular data. Here, we examined 12 strains including six newly isolated strains, morphologically identified as Chlamydomonas subg. Amphichloris, using 18S rRNA gene phylogeny, light microscopy, and mitochondria fluorescent microscopy. Molecular phylogenetic analyses revealed three independent lineages of the subgenus, separated from the type species of Chlamydomonas, Cd. reinhardtii. These three lineages were further distinguished from each other by light and fluorescent microscopy-in particular by the morphology of the papillae, chloroplast surface, stigmata, and mitochondria-and are here assigned to three genera: Dangeardinia emend., Ixipapillifera gen. nov., and Rhysamphichloris gen. nov. Based on the molecular and morphological data, two to three species were recognized in each genus, including one new species, I. pauromitos. In addition, Cd. deasonii, which was previously assigned to subgroup ' Pleiochloris,' was included in the genus Ixipapillifera as I. deasonii comb. nov. [ABSTRACT FROM AUTHOR]

A new photosynthetic, sand-dwelling marine dinoflagellate, Ailadinium reticulatum gen. et sp. nov., is described from the Jordanian coast in the Gulf of Aqaba, northern Red Sea, based on detailed morphological and molecular data. A. reticulatum is a large (53-61 μm long and 38-48 μm wide), dorsoventrally compressed species, with the epitheca smaller than the hypotheca. The theca of this new species is thick and peculiarly ornamented with round to polygonal depressions forming a foveate-reticulate thecal surface structure. The Kofoidian thecal tabulation is APC (Po, cp), 4′, 2a, 6′′, 6c, 4s, 6′′′, 1p, 1′′′′ or alternatively it can be interpreted as APC, 4′, 2a, 6′′, 6c, 4s, 6′′′, 2′′′′. The plate pattern of A. reticulatum is noticeably different from described dinoflagellate genera. Phylogenetic analyses based on the SSU and LSU rDNA genes did not show any supported affinities with currently known thecate dinoflagellates. [ABSTRACT FROM AUTHOR]

Gambierdiscus is a genus of benthic dinoflagellates found worldwide. Some species produce neurotoxins (maitotoxins and ciguatoxins) that bioaccumulate and cause ciguatera fish poisoning ( CFP), a potentially fatal food-borne illness that is common worldwide in tropical regions. The investigation of toxigenic species of Gambierdiscus in CFP endemic regions in Australia is necessary as a first step to determine which species of Gambierdiscus are related to CFP cases occurring in this region. In this study, we characterized five strains of Gambierdiscus collected from Heron Island, Australia, a region in which ciguatera is endemic. Clonal cultures were assessed using (i) light microscopy; (ii) scanning electron microscopy; (iii) DNA sequencing based on the nuclear encoded ribosomal 18S and D8-D10 28S regions; (iv) toxicity via mouse bioassay; and (v) toxin profile as determined by Liquid Chromatography-Mass Spectrometry. Both the morphological and phylogenetic data indicated that these strains represent a new species of Gambierdiscus, G. lapillus sp. nov. (plate formula Po, 3′, 0a, 7″, 6c, 7-8s, 5‴, 0p, 2″″ and distinctive by size and hatchet-shaped 2′ plate). Culture extracts were found to be toxic using the mouse bioassay. Using chemical analysis, it was determined that they did not contain maitotoxin ( MTX1) or known algal-derived ciguatoxin analogs ( CTX3B, 3C, CTX4A, 4B), but that they contained putative MTX3, and likely other unknown compounds. [ABSTRACT FROM AUTHOR]

Foliicolous lichens are formed by diverse, highly specialized fungi that establish themselves and complete their life cycle within the brief duration of their leaf substratum. Over half of these lichen-forming fungi are members of either the Gomphillaceae or Pilocarpaceae, and associate with Trebouxia-like green algae whose identities have never been positively determined. We investigated the phylogenetic affinities of these photobionts to better understand their role in lichen establishment on an ephemeral surface. Thallus samples of Gomphillaceae and Pilocarpaceae were collected from foliicolous communities in southwest Florida and processed for sequencing of photobiont marker genes, algal cultivation and/or TEM. Additional specimens from these families and also from Aspidothelium (Thelenellaceae) were collected from a variety of substrates globally. Sequences from rbcL and nu SSU regions were obtained and subjected to Maximum Likelihood and Bayesian analyses. Analysis of 37 rbcL and 7 nu SSU algal sequences placed all photobionts studied within the provisional trebouxiophycean assemblage known as the Watanabea clade. All but three of the sequences showed affinities within Heveochlorella, a genus recently described from tree trunks in East Asia. The photobiont chloroplast showed multiple thylakoid stacks penetrating the pyrenoid centripetally as tubules lined with pyrenoglobuli, similar to the two described species of Heveochlorella. We conclude that Heveochlorella includes algae of potentially major importance as lichen photobionts, particularly within (but not limited to) foliicolous communities in tropical and subtropical regions worldwide. The ease with which they may be cultivated on minimal media suggests their potential to thrive free-living as well as in lichen symbiosis. [ABSTRACT FROM AUTHOR]