Description: Dinophyte evolution is essentially inferred from the pattern of thecal plates, and two different labelling systems are used for the important subgroups Gonyaulacales and Peridiniales. The partiform hypotheca of cladopyxidoid dinophytes fits into the morphological concepts of neither group, although they are assigned to the Gonyaulacales. Here, we describe the thecate dinophyte Fensomea setacea, gen. & sp. nov., which has a cladopyxidoid tabulation. The cells displayed a Kofoidean plate formula APC, 3′, 4a, 7″, 7C, 6S, 6′′′, 2′′′′, and slender processes were randomly distributed over the echinate or baculate surface. In addition, we obtained rRNA sequences of F. setacea, gen. & sp. nov., but dinophytes that exhibit a partiform hypotheca did not show a close relationship to Gonyaulacales. Character evolution of thecate dinophytes may have progressed from the ancestral state of six postcingular plates, and two more or less symmetrically arranged antapical plates, towards patterns of only five postcingular plates (Peridiniales) or more asymmetrical configurations (Gonyaulacales). Based on our phylogenetic reconsiderations the contact between the posterior sulcal plate and the first postcingular plate, as well as the contact between an antapical plate and the distalmost postcingular plate, do not represent a rare, specialized gonyaulacoid plate configuration (i.e., the partiform hypotheca of cladopyxidoid dinophytes). Instead, these contacts correspond to the common and regular configuration of peridinioid (and other) dinophytes.

Description: Azaspiracids (AZA) are a group of food poisoning phycotoxins that are known to accumulate in shellfish. They are produced by some species of the planktonic dinophycean taxon Amphidomataceae. Azaspiracids have been first discovered in Ireland but are now reported in shellfish from numerous global sites thus showing a wide distribution. In shellfish samples collected in 2009 near Huelva (Spain),AZA was also found along the Andalusian Atlantic coast for the first time. Analysis using LC–MS/MS revealed the presence of two different AZA analogues in different bivalve shellfish species (Chamelea gallina, Cerastoderma edule, Donax trunculus, and Solen vagina). In a number of samples, AZA levels exceeded the EU regulatory level of 160 mg AZA-1 eq. kg�1 (reaching maximum levels of 〉500 mg AZA- 1 eq. kg�1 in Chamelea gallina and 〉250 mg AZA-1 eq. kg�1 in Donax trunculus) causing closures of some local shellfish production areas. One dinophyte strain established from the local plankton during the AZA contamination period and determined as Amphidoma languida was in fact toxigenic, and its AZA profile disclosed it as the causative species: it contained AZA-2 as the main compound and the new compound AZA-43 initially detected in the shellfish. AZA-43 had the same mass as AZA-3, but produced different collision induced dissociation (CID) spectra. High resolution mass spectrometric easurements indicated that there is an unsaturation in the H, I ring system of AZA-43 distinguishing it from the classical AZA such as AZA-1, -2, and -3. Furthermore, the Spanish strain was different from the previously reported AZA profile of the species that consist of AZA-38 and AZ-39. In molecular phylogenetics, the Andalusian strain formed a monophyletic group together with other strains of Am. languida, but ITS sequences data revealed surprisingly high intragenomic variability. The first Andalusian case of AZA contamination of shellfish above the EU regulatory limit reported here clearly revealed the risk of azaspiracid poisoning (AZP) for this area and also for the Atlantic coast of Iberia and North Africa. The present study underlines the need for continuous monitoring of AZA and the organisms producing such toxins.

Description: Arctic regions have experienced pronounced biological and biophysical transformations as a result of global change processes over the last several decades. Current hypotheses propose an elevated impact of those environmental changes on the biodiversity, community composition and metabolic processes of species. The effects on ecosystem function and services, particularly when invasive or toxigenic harmful species become dominant, can be expressed over a wide range of temporal and spatial scales in plankton communities. Our study focused on the comparison of molecular biodiversity of three size-fractions (micro-, nano-, picoplankton) in the coastal pelagic zone of West Greenland and their association with environmental parameters. Molecular diversity was assessed via parallel amplicon sequencing the 28S rRNA hypervariable D1/D2 region. We showed that biodiversity distribution within the area of Uummannaq Fjord, Vaigat Strait and Disko Bay differed markedly within and among size-fractions. In general, we observed a higher diversity within the picoplankton size fraction compared to the nano- and microplankton. In multidimensional scaling analysis, community composition of all three size fractions correlated with cell size, silicate and phosphate, chlorophyll a (chl a) and dinophysistoxin (DTX). Individually, each size fraction community composition also correlated with other different environmental parameters, i.e. temperature and nitrate. We observed a more homogeneous community of the picoplankton across all stations compared to the larger size classes, despite different prevailing environmental conditions of the sampling areas. This suggests that habitat niche occupation for larger-celled species may lead to higher functional trait plasticity expressed as an enhanced range of phenotypes, whereas smaller organisms may compensate for lower potential plasticity with higher diversity. The presence of recently identified toxigenic harmful algal bloom (HAB) species (such as Alexandrium fundyense and A. ostenfeldii) in the area points out the potential risk for this vulnerable ecosystem in a changing world.

Description: Amphidoma is an old though poorly studied thecate dinophyte that has attracted attention recently as a potential producerof azaspiracids (AZA), a group of lipophilic phycotoxins. A new species, Amphidoma parvula, sp. nov. is described from theSouth Atlantic shelf of Argentina. With a Kofoidean thecal plate pattern Po, cp, X, 6′, 6′′, 6C, 5S, 6′′′, 2′′′′, the cultivatedstrain H-1E9 (from which the type material of Am. parvula, sp. nov. was prepared) shared the characteristic platearrangement of Amphidoma each with six apical, precingular and postcingular plates. Amphidoma parvula, sp. nov. differs from other species of Amphidoma by a characteristic combination of small size (10.7–13.6 μm in length), ovoid shape, high length ratio between epitheca and hypotheca, and small length ratio between apical and precingular plates. Other morphological details, such as the number and arrangement of sulcal plates and the fine structure of the apical pore complex support the close relationship between Amphidoma and the other known genus of Amphidomataceae, Azadinium. However, Am. parvula, sp. nov. lacks a ventral pore, a characteristically structured pore found in all contemporary electron microscopy studies of Amphidoma and Azadinium. As inferred from liquid chromatography coupled with tandem mass spectrometry, Am. parvula, sp. nov. did not produce AZA in measurable amounts. Molecular phylogenetics confirmed the systematic placement of Am. parvula, sp. nov. in Amphidoma (as sister species of Amphidoma languida) and the Amphidomataceae. The results of this study have improved the knowledge of Amphidomataceae biodiversity.

Description: One of the most common marine dinophytes is a species known as Heterocapsa triquetra. When Stein introduced the taxon Heterocapsa, he formally based the type species H. triquetra on the basionym Glenodinium triquetrum. The latter was described by Ehrenberg and is most likely a species of Kryptoperidinium. In addition to that currently unresolved nomenclatural situation, the thecal plate composition of H. triquetra sensu Stein (1883) was controversial in the past. To clarify the debate, we collected material and established the strain UTKG7 from the Baltic Sea off Kiel (Germany, the same locality as Stein had studied), which was investigated using light and electron microscopy, and whose systematic position was inferred using molecular phylogenetics. The small motile cells (18–26 µm in length) had a biconical through fusiform shape and typically were characterized by a short asymmetrically shaped, horn-like protuberance at the antapex. A large spherical nucleus was located in the episome, whereas a single pyrenoid laid in the lower cingular plane. The predominant plate pattern was identified as apical pore complex (Po, cp?, X), 4', 2a, 6'', 6c, 5s, 5''', 2''''. The triradiate body scales were 254–306 nm in diameter, had 6 ridges radiating from a central spine, 9 peripheral and 3 radiating spines, and 12 peripheral bars as well as a central depression in the basal plate. Our work provides a clarification of morphological characters and a new, validly published name for this important but yet formally undescribed species of Heterocapsa: H. steinii sp. nov.

Description: Toxic algae such as Alexandrium and Azadinium have an important ecological impact and have originated several times independently within the dinophytes. Their closest relatives, however, are mostly unknown at present. A new dinophyte species, Amphidoma languida sp. nov., was isolated from Bantry Bay (Ireland) during a period of elevated azaspiracid toxicity in mussels. The new species was described in detail, and its phylogenetic position was analysed, by using a combination of light and electron microscopy, chemical detection methods, and sequence comparison of concatenated ribosomal RNA sequence data. Morphological similarities, such as cingular and hypothecal plates, the number and arrangement of sulcal plates, and the characteristic apical pore complex with a small X-plate centrally invading the first apical plate, indicated a close relationship between Amphidoma and Azadinium. However, no known azaspiracid analogues were detected in A. languida by liquid chromatography coupled with tandem mass-spectrometry. In a molecular phylogeny, the Amphidomataceae including Amphidoma and Azadinium were an independent lineage among other monophyletic major groups of the dinophytes such as the Suessiales, Prorocentrales, Gonyaulacales, and Peridiniales. Thus, the taxonomic affiliation of Azadinium is clarified, and our data may prove helpful in the development of specific and reliable molecular detection methods of toxic Azadinium.

Description: The phylogenetic relationships of the Dinophyceae (Alveolata) are not sufficiently resolved at present. The Thoracosphaeraceae (Peridiniales) are the only group of the Alveolata that include members with calcareous coccoid stages; this trait is considered apomorphic. Although the coccoid stage appar- ently is not calcareous, Bysmatrum has been assigned to the Thoracosphaeraceae based on thecal morphology. We tested the monophyly of the Thoracosphaeraceae using large sets of ribosomal RNA sequence data of the Alveolata including the Dinophyceae. Phylogenetic analyses were performed using Maximum Likelihood and Bayesian approaches. The Thoracosphaeraceae were monophyletic, but included also a number of non-calcareous dinophytes (such as Pentapharsodinium and Pfiesteria) and even parasites (such as Duboscquodinium and Tintinnophagus). Bysmatrum had an isolated and uncertain phylogenetic position outside the Thoracosphaeraceae. The phylogenetic relationships among calcareous dinophytes appear complex, and the assumption of the single origin of the potential to produce calcareous structures is challenged. The application of concatenated ribosomal RNA sequence data may prove promising for phylogenetic reconstructions of the Dinophyceae in future.

Description: Species of dinophycean Amphidomataceae are producers of phycotoxins classified as azaspiracids. We provide the first records of two of their constituent species, Amphidoma languida and Azadinium dexteroporum, for the Irminger Sea off Iceland. Morphological examination and molecular characterization, including uncorrected mean pairwise distances between sequences of the Internal Transcribed Spacer (ITS), doubtlessly assigned the sub-Arctic strain 2A11 to the reference of Amphidoma languida. Strain 2A11 produced AZA-38 and AZA-39, corresponding to the toxin profile described for the type material. The sub-Arctic isolate 1D12 differed significantly in terms of ITS genetic distance (p = 0.04) from a Mediterranean Azadinium dexteroporum strain, but our morphological analysis did not reveal any major or stable diagnostic traits between the reference strain of Azadinium dexteroporum and the new strain described here. In contrast to the Mediterranean strain of Azadinium dexteroporum, the sub-Arctic strain 1D12 did not produce any known azaspiracids. The new records of Amphidoma languida and Azadinium dexteroporum from the Irminger Sea imply an important range extension of the species, formerly known from the northern and eastern Atlantic (Amphidoma languida) and from the Mediterranean area (Azadinium dexteroporum) only. Together with three new species of Azadinium recently described from the same expedition, the results clearly show that the biodiversity of the Amphidomataceae in the sub-Arctic is remarkably large.