ULTRASTRUCTURE AND LSU rDNA–BASED REVISION OF PERIDINIUM GROUP PALATINUM (DINOPHYCEAE) WITH THE DESCRIPTION OF PALATINUS GEN. NOV.1

The name Peridinium palatinum Lauterborn currently designates a freshwater peridinioid with 13 epithecal and six cingular plates, and no apical pore complex. Freshwater dinoflagellate floras classify it in Peridinium group palatinum together with P. pseudolaeve M. Lefèvre. General ultrastructure, flagellar apparatus, and pusular components of P. palatinum were examined by serial section TEM and compared to P. cinctum (O. F. Müll.) Ehrenb. and Peridiniopsis borgei Lemmerm., respectively, types of Peridinium and Peridiniopsis. Partial LSU rDNA sequences from P. palatinum, P. pseudolaeve and several peridinioids, woloszynskioids, gymnodinioids, and other dinoflagellates were used for a phylogenetic analysis. General morphology and tabulation of taxa in group palatinum were characterized by SEM. Differences in plate numbers, affecting both the epitheca and the cingulum, combine with differences in plate ornamentation and a suite of internal cell features to suggest a generic‐level distinction between Peridinium group palatinum and typical Peridinium. The branching pattern of the phylogenetic tree is compatible with this conclusion, although with low support from bootstrap values and posterior probabilities, as are sequence divergences estimated between species in group palatinum, and typical Peridinium and Peridiniopsis. Palatinus nov. gen. is proposed with the new combinations Palatinus apiculatus nov. comb. (type species; syn. Peridinium palatinum), P. apiculatus var. laevis nov. comb., and P. pseudolaevis nov. comb. Distinctive characters for Palatinus include a smooth or slightly granulate, but not areolate, plate surface, a large central pyrenoid penetrated by cytoplasmic channels and radiating into chloroplast lobes, and the presence of a peduncle‐homologous microtubular strand. Palatinus cells exit the theca through the antapical‐postcingular area.     

Ultrastructure and large subunit rDNA-based phylogeny of Sphaerodinium cracoviense, an unusual freshwater dinoflagellate with a novel type of eyespot

Sphaerodinium cracoviense was collected near Cracow, Poland, and analysed by light microscopy, scanning electron microscopy, and serial-section transmission electron microscopy. Thecae showed a peridinioid type of plate arrangement with unusual numbers in the anterior intercalary and postcingular plate series: 4 and 6, respectively. The apical pore of S. cracoviense differed from the typical arrangement seen in many thecate forms and included a furrow with knob-like protuberances reminiscent of the apical area of some woloszynskioids. The flagellar apparatus included the three microtubular roots that extend to the left of the basal bodies and a striated root connective between the transverse striated root and the longitudinal microtubular root. Both the single-stranded root that associates with the right side of the longitudinal basal body in peridinioids and gonyaulacoids, and the layered connective typical of peridinioids were absent. The eyespot was formed by a layer of vesicle-contained crystal-like units underlain by layers of variably fused globules not bounded by membranes, and represents a novel type. The pusular system included a long canal with a dilated inner portion with radiating tubules. Bayesian and maximum likelihood analyses based on large subunit rDNA placed Sphaerodinium as a sister taxon to a group of woloszynskioids and relatively far from Peridinium and its allies.     

Transferring the freshwater dinoflagellate Peridinium wisconsinense (Dinophyceae) to the family Thoracosphaeraceae,with the description of Fusiperidinium gen. nov.

Distinctive spindle‐shaped thecae first described by Samuel Eddy in 1930 and assigned to the genus Peridinium Ehrenberg are commonly reported from freshwater environments in eastern North America. We demonstrate that thecae incubated from cysts of Peridinium wisconsinense Eddy have six cingular plates and a protuberant apical pore complex characteristic of the family Thoracosphaeraceae Schiller 1930 emend. Tangen in Tangen et al . 1982. Small subunit ribosomal DNA (SSU rDNA) and internal transcribed spacer (ITS) sequences confirm the close genetic similarity with Chimonodinium lomnickii (Wo?oszyńska) Craveiro, Calado, Daugbjerg, Gert Hansen & Moestrup and with species recently reassigned to the genus Apocalathium Craveiro, Daugbjerg, Moestrup & Calado that was inferred from previously published LSU rDNA analysis of cysts of P. wisconsinense . Despite sharing identical tabulation with the thoracosphaeracean genera Chimonodinium Craveiro, Calado, Daugbjerg, Gert Hansen & Moestrup and Apocalathium , substantial morphological differences in the morphology of both the thecate and cyst stages of P. wisconsinense led us to reassign this species to the genus Fusiperidinium gen. nov. The phylogenetic position of Fusiperidinium wisconsinense comb. nov., inferred from concatenated data of SSU and LSU sequences, suggests that it evolved from the brackish Scrippsiella lineage, independently of the transition that produced the family Peridiniaceae. Cysts described as Geiselodinium tyonekensis Engelhardt from nonmarine strata from Alaska are apparently identical to the resistant cysts produced by F. wisconsinense . The palynologically‐constrained late Middle Miocene age for the Tyonek Formation provides a minimum age of 11.6 Ma for the evolution of this lineage, coinciding with a rapid glacioeustatic decline in sea level. Our findings also call into question the inclusion of the family Thoracosphaeraceae within the order Peridiniales Haeckel.     

Studies on Woloszynskioid Dinoflagellates X: Ultrastructure,Phylogeny and Colour Variation in Tovellia rubescens n. sp. (Dinophyceae)

The external morphology and internal cell fine structure of a new species of Tovelliaceae, Tovellia rubescens n. sp., is described. Phylogenetic analyses based on partial LSU rDNA sequences place the new species in a clade containing Tovellia species that accumulate red pigments and identify T. aveirensis as its closest known relative. Cells of T. rubescens n. sp. were mostly round and had the cingulum located near the middle, with its ends displaced about one cingular width. Small numbers of distinctly flat cells appeared in culture batches; their significance could not be determined. Cells of the new species in culture batches progressively changed from a yellowish‐green, mainly due to chloroplast colour, to a reddish‐brown colour that appeared associated with lipid bodies. The switch to a reddish colour happened earlier in batches grown in medium lacking sources of N or P. Pigment analyses by HPLC‐MS/MS revealed the presence of astaxanthin and astaxanthin‐related metabolites in the new species, but also in T. aveirensis, in which a reddish colour was never observed. The chloroplast arrangement of T. rubescens n. sp. resembled that of T. aveirensis, with lobes radiating from a central pyrenoid complex. The flagellar apparatus and pusular system fell within the general features described from other Tovelliaceae. A row of microtubules interpretable as a microtubular strand of the peduncle was present. Spiny resting cysts with red contents and an ITS sequence identical to that of cultured material of the new species were found in the original locality.     

Study on freshwater genus Peridinium (Dinophyta) from China

Peridinium is an important genus of freshwater armoured dinoflagellates with two more intercalary plates (sensu Bourrelly). A few species of Peridinium were known from China heretofore. The plate pattern is one of the important criteria for the taxonomy of Peridinium, and it was difficult to visualize their plate patterns under normal light microscope. For editing of Flora Algarum Sinicarum Aquae Dulcis, 11 species of Peridinium col-lected from various freshwater habitats of China are described. Among them, 6 species are first reported from China. They are P. gatunense Nygaard, P. gutwinskii Woloszynska, P. lomnickii Woloszynska, P. palatinum Lauterborn, P. striolatum Playfair, and P. zonatum Playfair. Epifluorescence microscopy and scanning electron microscopy, and also light microscopy were employed for their structure and patterns of thecal plates.     

Scrippsiella trochoidea and scrippsiella regalis, nov. comb. (peridiniales, dinophyceae): a comparison

Culture experiments on dinoflagellates from the Atlantic Ocean revealed Scrippsiella regalis (Gaarder) Janofske, nov. comb., a calciodinelloid species with a spherical spiny calcareous cyst. This calcareous cyst was collected previously from plankton and sediment samples, where it was described as the coccolithophorid Discosphaera regalis Gaarder or was often mistaken for the cyst of Scrippsiella trochoidea (von Stein) Loeblich III. The morphological features of both the cellulosic theca and the calcareous cyst of S. trochoidea and S. regalis were compared with respect to their systematic position and the emendation of taxa. Both species were found to have different distribution patterns. Scrippsiella trochoidea is known only from the neritic environment, whereas S. regalis has been found mostly in oceanic samples. The preservation of these spiny calcareous dinocysts in the (fossil) sediment was dependent on the ultrastructure of the calcareous layer of the cyst wall.     

The genus Glochidinium gen. nov., with two species: G. penardiforme comb. nov. and G. platygaster sp. nov. (Peridiniaceae)

Glochidiniumgen. nov., a ncw genus of Peridiniaceae based on Peridinium penardiforme Lindemann, is herewith erected. Its plate formula is: Po+X+4′+6′′+3C+4S+5′′′+2′′′′ Main diagnostic characters of this new genus are the presence of only 3 cingular plates (it lacks the transitionalone), the third cingular contacting the anterior sulcal plate, and an unusual sulcus holding a small triangular posterior sulcal plate. The thecal morphology and structure of two freshwater planktic species of the genus are described on the basis of LM and SEM observations. G. penardiforme comb. nov. is an infrequent species, albeit widely distributed world-wide. It has been recorded under the names of Peridinium, Glenodinium and Peridiniopsis. Peculiar features in the tabulation of the furrows and of the surface sculpture show that the species does not fit any of the known genera, for which reason the new genus Glochidinium is established. G. platygaster sp. nov., the second species included in the genus, differs from the former by its elongated body, the regular pentagonal shape of its large first apical plate, an equally large sulcal anterior plate, and well developed sculpture, chiefly on the antapical plates. Glochidinium penardiforme and G. platygaster were found in some reservoirs from central and northern Argentina. G. penardiforme was also found in several Argentine rivers and ponds.     

Phylogeny of calcareous dinoflagellates as inferred from ITS and ribosomal sequence data

The phylogenetic relationships of calcareous dinoflagellates (i.e., Calciodinellaceae and Thoracosphaera) are investigated. Molecular data from the ribosomal 5.8S rRNA and highly conserved motifs of the ITS1 show Calciodinellaceae s.l. to be monophyletic when few non-calcareous taxa are included. They segregate into three monophyletic assemblages in a molecular analysis that considers the 5.8S rRNA and both the Internal Transcribed Spacer regions ITS1 and ITS2: a clade comprising species of Ensiculifera and Pentapharsodinium (E/P-clade), Scrippsiella s.l. (including fossil-based taxa such as Calciodinellum and Calcigonellum), and a heterogeneous group (T/P-clade) of calcareous (e.g., Thoracosphaera) and non-calcareous taxa (e.g., the highly toxic Pfiesteria). The potential to produce calcareous structures is considered as apomorphic within alveolates, and non-calcareous taxa nesting with calcareous dinoflagellates may have reduced calcification secondarily. Molecular results do not contradict general evolutionary scenarios provided by previous morphological (mainly paleontological) investigations.     

GENERAL ULTRASTRUCTURE AND FLAGELLAR APPARATUS ARCHITECTURE OF WOLOSZYNSKIA LIMNETICA (DINOPHYCEAE)

The ultrastructure of Woloszynskia limnetica Bursa was examined using serial thin section electron microscopy. Sections of W. limnetica reveal numerous chloroplast profiles without any obvious pyrenoids. The extensive pusular complex consists of a "smooth" part and a part lined with electron-dense particles. The nucleus is located in the episome. A stigma (= eyespot) consisting of numerous electron-dense globules is situated beneath the amphiesmal vesicles of the sulcal groove. The longitudinal microtu-bular root extends between the stigma and the amphiesma vesicles. Subthecal fibers occur in conjunction with the microtubules and the stigma. Both flagellar exit apertures are encircled by a broad striated collar, each giving rise to a fiber that extends along the pusular canal opening. The striated collars are interconnected by the ventral ridge fiber. The basal part of the transverse flagellum has, in addition to the normal paraxonemal rod (= striated strand or fiber), a semicircular structure consisting of fibrils. The flagellar apparatus is complex but possesses components typically found in the Dinophyceae. The longitudinal mi-crotubular root is broad and is connected to both striated collars. The transverse basal body gives rise to the transverse microtubular root, which in turn is associated with microtubules that extend to the interior of the cell and with the transverse striated root. The transitional region of both basal bodies possesses a distinctive fibrous ring attached to each microtubular triplet by short fibers that collectively appear as spokes of a wheel. Not unexpectedly, the flagellar apparatus of Woloszynskia limnetica is much like that of the related Woloszynskia sp.; however, some dif ferences were discovered. A phylogenetic relationship between Woloszynskia limnetica, W. coronata ( Wolosz.) Thompson, and W. sp. is indicated based on similarities in pusule and stigma structure .     

PHAGOTROPHY IN GYMNODINIUM FUNGIFORME (PYRRHOPHYTA): THE PEDUNCLE AS AN ORGANELLE OF INGESTION1

The non-photosynthetic phagotrophic dinoflagellate, Gymnodinium fungiforme Anissimova, ingests prey cytoplasm through a highly extensible structure called the peduncle. Although the peduncle is not observable when G. fungiforme is swimming, it protrudes 8–12 μm from the sulcal-angular vicinity of the cell during feeding, and is approximately 3.3 μm wide when the cytoplasm of its prey is flowing through it. A circular-oval ring of overlapping microtubules, the ‘microtubular basket’ may be seen in transmission electron microscope sections of G. fungiforme and it is inferred that this structure is a cross section of a retracted peduncle. The microtubular basket-peduncle complex is discussed in relation to similar structures in other dinoflagellates and to the tentacle of the suctorian ciliates which have a homologous ingestion system.     

ULTRASTRUCTURE OF GYMNODINIUM AUREOLUM (DINOPHYCEAE): TOWARD A FURTHER REDEFINITION OF GYMNODINIUM SENSU STRICTO

Examination of the ultrastucture of the unarmored dinoflagellate Gymnodinium aureolum (Hulburt) G. Hansen (syn: Gyrodinium aureolum Hulburt) revealed the presence of nuclear chambers, which are specialized differentiations of the nuclear envelope, similar to those described in the type species of Gymnodinium , G. fuscum (Ehrenberg) Stein and certain other Gymnodinium species. The nuclear pores were restricted to these chambers. In the flagellar apparatus a nuclear fibrous connective linked the longitudinal microtubular root and the nucleus. This structure had so far been observed only in Gymnodinium spp. and in the heterotrophic species Actiniscus pentasterias (Ehrenberg) Ehrenberg, Nematodinium armatum (Dogiel) Kofoid et Swezy and Polykrikos kofoidii Chatton. Another unusual feature of G. aureolum was the presence of a striated fiber in the longitudinal flagellum, a feature previously only found in Ceratium furca (Ehrenberg) Claparède et Lachmann and C. tripos (O.F. Müller) Nitzsch. Gymnodinium aureolum also possessed a prominent ventral protrusion associated with the peduncle and containing electron opaque material. It is concluded that G. aureolum belongs to the Gymnodinium sensu stricto group. This may be a temporary classification, however, because G. aureolum and its allies differ from the type species G. fuscum by the presence of a transverse striated root, striated collars, trichocysts, and a peduncle.     

An Early Cretaceous fruit with affinities to Ceratophyllaceae

A new genus and species with affinities to Ceratophyllaceae from the Lower Cretaceous of Kansas, USA is reported. The fruits of Donlesia dakotensis gen. et sp. nov. are smooth achenes with two winged lateral spines, two winged facial spines, one stylar spine, and a long peduncle with a distinctive groove. The facial spines are arranged perpendicular to the lateral spines. The seed contains two cotyledons and a central plumule. Dichotomous leaves associated with Donlesia dakotensis fruits are whorled, petiolate, and lack denticles. The fruit morphology of D. dakotensis differs from extant and fossil members of Ceratophyllaceae in its tetra-radial symmetry, the presence of two winged facial spines, a long peduncle, and the lack of other appendages on the fruit surface. It seems to be more closely related to section Ceratophyllum of extant Ceratophyllum. This relationship suggests that section Ceratophyllum of extant Ceratophyllum may represent the ancestral members of the ancient Ceratophyllum lineage. The presence of this species in the Dakota Formation further confirms that there were diverse aquatic plants living in freshwater lakes along the eastern margin of the Western Interior Seaway during the Early Cretaceous.     

Didymocarpus tonghaiensis sp. nov. (Gesneriaceae) from Yunnan,China

Didymocarpus tonghaiensis J. M. Li & F. S. Wang sp. nov. from Yunnan, China, is illustrated and described. It is morphologically similar to D. stenanthos C. B. Clarke, but differs by having a densely glandular peduncle, 5‐lobed calyx with lobes that are free to the base, larger corolla, anther with white woolly hairs and a densely glandular‐hairy capsule.     

Moramonas marocensis gen. nov., sp. nov.: a jakobid flagellate isolated from desert soil with a bacteria-like,but bloated mitochondrial genome

A new jakobid genus has been isolated from Moroccan desert soil. The cyst-forming protist Moramonas marocensis gen. nov., sp. nov. has two anteriorly inserted flagella of which one points to the posterior cell pole accompanying the ventral feeding groove and is equipped with a dorsal vane—a feature typical for the Jakobida. It further shows a flagellar root system consisting of singlet microtubular root, left root (R1), right root (R2) and typical fibres associated with R1 and R2. The affiliation of M. marocensis to the Jakobida was confirmed by molecular phylogenetic analyses of the SSU rRNA gene, five nuclear genes and 66 mitochondrial protein-coding genes. The mitochondrial genome has the high number of genes typical for jakobids, and bacterial features, such as the four-subunit RNA polymerase and Shine–Dalgarno sequences upstream of the coding regions of several genes. The M. marocensis mitochondrial genome encodes a similar number of genes as other jakobids, but is unique in its very large genome size (greater than 264 kbp), which is three to four times higher than that of any other jakobid species investigated yet. This increase seems to be due to a massive expansion in non-coding DNA, creating a bloated genome like those of plant mitochondria.     

Dactylodinium pterobelotum gen. et sp. nov., a new marine woloszynskioid dinoflagellate positioned between the two families Borghiellaceae and Suessiaceae

A new marine woloszynskioid dinoflagellate Dactylodinium pterobelotum gen. et sp. nov., collected from a southern Vietnamese estuary, was described on the basis of LM, SEM, and TEM, and molecular phylogeny inferred from rDNA sequences. This species had the smallest number of amphiesmal vesicles (5 latitudinal series) in woloszynskioid dinoflagellates assigned to the Suessiaceae and Borghiellaceae. The eyespot was of type B, composed of osmiophilic globules and brick‐like material, located in‐ and outside of the chloroplast respectively. An apical structure comprised a pair of elongate anterior vesicles (PEV). A large peduncle was conspicuous, located in the sulcal extension in the epicone, and supported by a microtubular strand of ~140 microtubules. Ultrastructural features of trichocysts represent a novel type in the Dinophyceae, bearing lateral hairs besides anterior fibers. The molecular phylogeny based on partial LSU rDNA showed the species in a basal position in the family Suessiaceae; this indicates the eyespot type B and PEV of the Borghiellaceae are ancestral states of the eyespot comprising brick‐like material (type E) and an elongate apical vesicle of the Suessiaceae.     

Redefinition of Peridinium lomnickii Wołoszynska (Dinophyta) by scanning electronmicroscopical survey

Peridinium lomnickii Wo?oszynska was investigated by scanning electron microscopy with special attention to the importance of development of thecal plate during the life cycle. Different life cycle stages (gymnodinoid-, glenodinoid-, peridinioid) are described on the basis of development of cell wall, presence and development of sutures, appearance of pore and the change of the cell shape. Differences and possible relationships between the three existing varieties of the species are discussed. We suggest that the three varieties of P. lomnickii, P. lomnickii var. lomnickii, P. lomnickii var. wierzejskii and P. lomnickii var. splendida,represent the different life cycle stages of the species. These results and the known ontogenic cycle of dinophyta taxa should be taken into consideration, when a phylogenic tree of the dinophytes is constructed.     

Studies on woloszynskioid dinoflagellates IV: The genus Biecheleria gen. nov.

The well known freshwater dinoflagellate Woloszynskia pseudopalustris is transferred to the new genus Biecheleria , based on the very unusual structure of the eyespot (comprising a stack of cisternae), the apical apparatus of a single elongate amphiesma vesicle, the structure of the resting cyst, and molecular data. Biecheleria is phylogenetically related to Symbiodinium and Polarella of the family Suessiaceae. This family, which extends back to the Jurassic, is redefined with the eyespot (Type E sensu Moestrup and Daugbjerg) and apical apparatus as diagnostic features, unknown elsewhere in the dinoflagellates. Biecheleria also comprises the brackish water species Biecheleria baltica sp. nov. (presently identified as Woloszynskia halophila ) and the marine species Biecheleria natalensis (syn. Gymnodinium natalense ). Gymnodinium halophilum described in 1952 by B. Biecheler but apparently not subsequently refound, is transferred to Biecheleria . The Suessiaceae further includes the marine species Protodinium simplex , described by Lohmann in 1908 but shortly afterwards (1921) transferred to Gymnodinium by Kofoid and Swezy and subsequently known as Gymnodinium simplex . It only distantly related to Gymnodinium . A new family, the Borghiellaceae, is proposed for the sister group to the Suessiaceae, based on eyespot structure (Type B of Moestrup and Daugbjerg), the morphology of the apical apparatus (if present), and molecular data. It presently comprises the genera Baldinia and Borghiella . Cells of Biecheleria pseudopalustris and B. baltica contain a microtubular strand (msp) associated with vesicles containing opaque material. Such structures are known in other dinoflagellates to serve as a peduncle, indicating that the two species may be mixotrophic.     

Symbiomonas scintillans gen. et sp. nov. and Picophagus flagellatus gen. et sp. nov. (Heterokonta): two new heterotrophic flagellates of picoplanktonic size

Two new oceanic free-living heterotrophic Heterokonta species with picoplanktonic size (< 2 microm) are described. Symbiomonas scintillans Guillou et Chrétiennot-Dinet gen. et sp. nov. was isolated from samples collected both in the equatorial Pacific Ocean and the Mediterranean Sea. This new species possesses ultrastructural features of the bicosoecids, such as the absence of a helix in the flagellar transitional region (found in Cafeteria roenbergensis and in a few bicosoecids), and a flagellar root system very similar to that of C. roenbergensis, Acronema sippewissettensis, and Bicosoeca maris. This new species is characterized by a single flagellum with mastigonemes, the presence of endosymbiotic bacteria located close to the nucleus, the absence of a lorica and a R3 root composed of a 6+3+x microtubular structure. Phylogenetical analyses of nuclear-encoded SSU rDNA gene sequences indicate that this species is close to the bicosoecids C. roenbergensis and Siluania monomastiga. Picophagus flagellatus Guillou et Chrétiennot-Dinet gen. et sp. nov. was collected in the equatorial Pacific Ocean. Cells are naked and possess two flagella. This species is characterized by the lack of a transitional helix and lateral filaments on the flagellar tubular hairs, the absence of siliceous scales, two unequal flagella, R1 + R3 roots, and the absence of a rhizoplast. SSU rDNA analyses place this strain at the base of the Chrysophyceae/Synurophyceae lineages.     

Phototactic responses of four marine dinoflagellates with different types of eyespot and chloroplast

Great structural variety is seen in the eyespot of dinoflagellates, a structure involved in phototaxis. Although there are several works on the phototactic responses in some species of dinoflagellates, none of the dinoflagellates used in these studies possessed an eyespot and, therefore, we have no knowledge of the relationship between eyespot type and phototactic response. In this study, we determined wavelength dependency curves for phototaxis in four marine dinoflagellates that possess a different type of either eyespot or chloroplast. These include: (i) a dinoflagellate possessing a peridinin-containing ohioroplast with an eyespot (Scrippsiella hexapraecingula Horiguchi et Chihara); (ii) a dinoflagellate containing a diatom endosymbiont and with the type B eyespot sensu Dodge (1984; (Peridinium foli-aceum (Stein) Biecheler); (iii) a dinoflagellate with peri-dinin-containing chloroplasts, but lacking an eyespot (Atexandrium hiranoi Kita et Fukuyo); and (iv) a dinoflagellate with fucoxanthin, 19′-hexanoyloxyfucoxanthin and 19′-butanoyloxyfucoxanthin, but lacking an eyespot (Gymnodinium mikimotoi Miyabe et Kominami ex Oda), Regardless of the eyespot or the chloroplast type, all four dinoflagellates showed similar wavelength dependency curves for phototaxis, with sensitivity between 380 and 520 nm, the highest peak at approximately 440 or 460 nm and smaller peaks or shoulders at 400–420 nm and 480–500 nm. Substantial peaks have also been noted in the ultraviolet range (260–280 nm). The ultrastructural study of the eye-spot of Scrippsiella hexapraecingula revealed that the eyespot consists of two layers of lipid globules and probably acts as a quarter-wave stack antenna.     

Durinskia baltica (Dinophyceae), a newly recorded species and genus from China, and its systematics

A freshwater dinoflagellate was identified as Durinskia baltica (Levander) Carty & Cox by morphological characteristics,with the plate formula:Po,x,4',2a,6',5c,4s,5',2'.Durinskia was a newly recorded dinoflagellate genus for China with two anterior intercalary plates and six characteristic precingular plates.Partial sequences of the small and large subunit ribosomal DNA and internal transcribed spacer sequences for the dinoflagellate cells were obtained from field samples.Molecular phylogenetic results indicated Durinskia species could cluster into a monophyletic group,which were distinct from Peridinium species.According to morphological and molecular evidence,it was agreed that the genus Durinskia was separated from the genus Peridinium,which could be a polyphyletic group.In addition,D.baltica was an infrequent diatom-harboring dinoflagellate which was known to possess an endosymbiotic diatom or diatom-like alga.The phylogenetic analyses indicated that D.baltica had a close affinity with Peridiniopsis penardii and P.niei,common freshwater bloom-forming species in China.