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1.
On the basis of LM, we isolated strains of two species of fusiform green flagellates that could be assigned to former Chlorogonium (Cg.) Ehrenb. One species, “Cg.”heimii Bourr., lacked a pyrenoid in its vegetative cells and required organic compounds for growth. The other was similar to Cg. elongatum (P. A. Dang.) Francé and “Cg.”acus Nayal, but with slightly smaller vegetative cells. Their molecular phylogeny was also studied based on combined 18S rRNA, RUBISCO LSU (rbcL), and P700 chl a‐apoprotein A2 (psaB) gene sequences. Both species were separated from Chlorogonium emend., Gungnir Nakada and Rusalka Nakada, which were formerly assigned to Chlorogonium. They were accordingly assigned to new genera, Tabris Nakada gen. nov. and Hamakko (Hk.) Nakada gen. nov. as T. heimii (Bourr.) Nakada comb. nov. and Hk. caudatus Nakada sp. nov., respectively. Tabris is differentiated from other genera of fusiform green flagellates by its vegetative cells, which only have two apical contractile vacuoles and lack a pyrenoid in the chloroplast. Hamakko, on the other hand, is distinguishable by the fact that its pyrenoids in vegetative cells are penetrated by flattened thylakoid lamellae.  相似文献   

2.
We examined the molecular phylogeny and ultrastructure of Chlorogonium and related species to establish the natural taxonomy at the generic level. Phylogenetic analyses of 18S rRNA and RUBISCO LSU (rbcL) gene sequences revealed two separate clades of Chlorogonium from which Chlorogonium (Cg.) fusiforme Matv. was robustly separated. One clade comprised Cg. neglectum Pascher and Cg. kasakii Nozaki, whereas the other clade included the type species Cg. euchlorum (Ehrenb.) Ehrenb., Cg. elongatum (P. A. Dang.) Francé, and Cg. capillatum Nozaki, M. Watanabe et Aizawa. On the basis of unique ultrastructural characteristics, we described Gungnir Nakada gen. nov. comprising three species: G. neglectum (Pascher) Nakada comb. nov., G. mantoniae (H. Ettl) Nakada comb. nov., and G. kasakii (Nozaki) Nakada comb. nov. We also emended Chlorogonium as a monophyletic genus composed of Cg. euchlorum, Cg. elongatum, and Cg. capillatum. Because Cg. fusiforme was distinguished from the redefined Chlorogonium and Gungnir by the structure of its starch plate, which is associated with pyrenoids, we reclassified this species as Rusalka fusiformis (Matv.) Nakada gen. et comb. nov.  相似文献   

3.
Mazoyerella gen. nov., based on Corynospora arachnoidea Harvey from Tasmania, is placed provisionally in the Compsothamnieae tribe of the Ceramiaceae. All plants can produce elongate-ovoid monosporangia which reproduce the same phase. Sporophytes also bear polysporangia and sexual plants are dioecious, bearing either spermatangial heads or subterminal procarps followed by carposporophytes with nearly all gonimoblast cells becoming carposporangia and an involucrum of sterile filaments developing from sterile cells associated with the procarp. The life-history has been followed through successive generations in culture.  相似文献   

4.
A new genus and species of heterotrophic dinoflagellate, Cryptoperidiniopsis brodyi gen. et sp. nov., are described. This new species commonly occurs in estuaries from Florida to Maryland, and is often associated with Pfiesteria piscicida Steidinger et Burkholder, Pseudopfiesteria shumwayae (Glasgow et Burkholder) Litaker et al., and Karlodinium veneficum (Ballantine) J. Larsen, as well as other small (<20 μm) heterotrophic and mixotrophic dinoflagellates. C. brodyi gen. et sp. nov. feeds myzocytotically on pigmented microalgae and other microorganisms. The genus and species have the enhanced Kofoidian plate formula of Po, cp, X, 5′, 0a, 6″, 6c, PC, 5+s, 5″′, 0p, and 2″″ and are assigned to the order Peridiniales and the family Pfiesteriaceae. Because the Pfiesteriaceae comprise small species and are difficult to differentiate by light microscopy, C. brodyi gen. et sp. nov. can be easily misidentified.  相似文献   

5.
A new ceramiaceous alga, Sciurothamnion stegengae De Clerck et Kraft, gen. et sp. nov., is described from the western Indian Ocean and the Philippines. Sciurothamnion appears related to the tribe Callithamnieae on the basis of the position and composition of its procarps and by the majority of post‐fertilization events. It differs, however, from all current members of the tribe by the presence of two periaxial cells bearing determinate laterals per axial cell. Additionally, unlike any present representative of the subfamily Callithamnioideae, no intercalary foot cell is formed after diploidization of the paired auxiliary cells. The genus is characterized by a terminal foot cell (“disposal cell”), which segregates the haploid nuclei of the diploidized auxiliary cell from the diploid zygote nucleus. The nature of three types of foot cells reported in the Ceramiaceae (intercalary foot cells containing only haploid nuclei, intercalary foot cells containing haploid nuclei and a diploid nucleus, and terminal foot cells containing only haploid nuclei) is discussed.  相似文献   

6.
Dicroglossum gen. nov. (Delesseriaceae, Ceramiales) is a monotypic genus based on Delesseria crispatula, a species originally described by Harvey for plants collected from southwestern Western Australia. Distinctive features of the new genus include exogenous indeterminate branches; growth by means of a single transversely dividing, apical cell; absence of intercalary divisions in the primary, secondary, and tertiary cell rows; lateral pericentral cells not transversely divided; not all cells of the secondary cell rows producing tertiary cells rows; all tertiary initials reaching the thallus margin; midrib present but lateral nerves absent; determinate lateral bladelets arising endogenously; blades monostromatic, except, at the midrib; carpogonial branches restricted to primary cell rows, on both surfaces of unmodified blades; procarps produced on both blade surfaces, each procarp consisting of a supporting cell that bears two four-celled carpogonial branches and one sterile-cell group of three to four cells; and tetrasporangia borne in two layers, separated by a central row of sterile cells. The combination of exogenous indeterminate branching and bicarpogonial procarps is considered to warrant the recognition of a new tribe, the Dicroglosseae, within the subfamily Delesserioideae.  相似文献   

7.
Chrysolepidomonas gen. nov. is described for single-celled monads with two flagella, a single chloroplast, and distinctive canistrate and dendritic scales. The type species, Chrysolepidomonas dendrolepidota sp. nov., is described for the first time. The canistrate scales bear eight “bumps” on the top surface, and the dendriticscales have a tapered base with a quatrifid tip. These organic scales are formed in the Golgi apparatus and storred in a scale reservoir. The scale reservoir is bounded on two sides by the R1 and R2 in microtubular roots of the basal apparatus. The cyst (=stomatocyst, statospore) forms endogenously by means of a silica deposition vesicle. The outer cyst surface is smooth, and the pore region is unornamented. Two other organisms bearing canistrate and dendritic scales, previously assigned to the genus Sphaleromants, are transferred to the genus Chrysolepidomonas. They are C.angalica sp. nov. and C. marine(Pienaar) comb. nov. The distinguishing features of Chrysolepidomonas and Sphaleromantis are discussed. A new family, Chrysolepidomonadceae fam. noc., is described for flagellates covered with organic scales.  相似文献   

8.
A new filamentous bluegreen alga Starria zimbabweënsis gen. nov. et sp. nov. isolated from a soil sample collected near Zimbabwe, Southern Rhodesia, has a unique triradiate morphology. In transverse section each narrow cell possesses three arm-like projections, separated by 120° and in which pigment is concentrated. Filaments may be straight or twisted and various clonable biradiate forms have originated in cultures initiated from the triradiate type. Cell ultra-structure is typical of the Oscillatoriaceae except that 70 nm pit-like pores occur throughout the L-II layer of the longitudinal walls. Wall structure of deviant forms is identical to that of the triradiate “wild type.” The organism is assigned to the Oscillatoriaceae rather than to the Gomontiellaceae or to a new family.  相似文献   

9.
Morphological and molecular studies demonstrate that the tribe Ptiloteae (Ceramiaceae, Ceramiales) is polyphyletic. The Ptiloteae, sensu stricto, occur only in the Northern Hemisphere and all Southern Hemisphere representatives belong in other tribes. Three genera (Euptilota, Seirospora, and Sciurothamnion) are transferred to the Euptiloteae Hommersand et Fredericq, trib. nov., and the Callithamnieae is revised to include three Ptilota‐like genera, Georgiella, Falklandiella, and Diapse, and two new genera. Heteroptilon Hommersand, gen. nov. is erected to receive Euptilota pappeana Kützing 1849 and Aglaothamnion rigidulum De Clerck, Bolton, Anderson et Coppejans 2004 from South Africa, and Aristoptilon Hommersand et W. A. Nelson, gen. nov. is established to receive Euptilota mooreana Lindauer 1949 from New Zealand. The principal difference between the Euptiloteae and the Callithamnieae is seen in the earliest stages after fertilization. The fertilized carpogonium enlarges and forms a pair of tube‐like protuberances directed toward the auxiliary cells that are cut off as connecting cells in the Euptiloteae, whereas in the Callithamnieae the carpogonium usually divides into two cells, each of which cuts off a small connecting cell that fuses with an adjacent enlarging auxiliary cell. Nuclei are terminal in spermatangia of the Euptiloteae, subtended by mucilaginous vesicles, and are medial in the Callithamnieae situated between apical and basal vesicles. The Euptiloteae and Callithamnieae (including the Ptilota‐like members) are each strongly supported in maximum‐likelihood tree topologies resulting from analyses of combined 18S rDNA, 28S rDNA, 16S rDNA, and rbcL data sets. Their sister relationship is also well supported.  相似文献   

10.
A diminutive, distromatic ulvaceous green alga was collected in southern California and studied in culture. The initial stages of development resemble those found in the Ulvaceae sensu Bliding. Germlings pass through a uniseriate filamentous stage, a multiseriate stage and a monostromatic saccate stage. At this stage the development departs from the developmental patterns found in the Ulvaceae. Each cell of the monostromatic upright portion of the germling undergoes a single division in a plane parallel to the surface of the germling to form a distromatic saccate germling. Rupture of the apical end of the germling and continued growth eventually results in a peltate distromatic alga superficially resembling Ulva. Based on the developmental pattern, which is unique to the green algae, the new genus Chloropelta gen. nov. and new species Chloropelta caespitosa sp. nov. are proposed for this alga.  相似文献   

11.
本文对禽棒恙螨属Ornithogastia的属征提出商榷,并建立肩棒恙螨属,新属Omogastia gen.nov.来安置Neoschoengastia riversi Wharton et Hardcastle,1946。  相似文献   

12.
On the basis of comparative morphology and phylogenetic analyses of rbcL and LSU rDNA sequence data, a new genus, Gayliella gen. nov., is proposed to accommodate the Ceramium flaccidum complex (C. flaccidum, C. byssoideum, C. gracillimum var. byssoideum, and C. taylorii), C. fimbriatum, and a previously undescribed species from Australia. C. transversale is reinstated and recognized as a distinct species. Through this study, G. flaccida (Kützing) comb. nov., G. transversalis (Collins et Hervey) comb. nov., G. fimbriata (Setchell et N. L. Gardner) comb. nov., G. taylorii comb. nov., G. mazoyerae sp. nov., and G. womersleyi sp. nov. are based on detailed comparative morphology. The species referred to as C. flaccidum and C. dawsonii from Brazil also belong to the new genus. Comparison of Gayliella with Ceramium shows that it differs from the latter by having an alternate branching pattern; three cortical initials per periaxial cell, of which the third is directed basipetally and divides horizontally; and unicellular rhizoids produced from periaxial cells. Our phylogenetic analyses of rbcL and LSU rDNA gene sequence data confirm that Gayliella gen. nov. represents a monophyletic clade distinct from most Ceramium species including the type species, C. virgatum. We also transfer C. recticorticum to the new genus Gayliella.  相似文献   

13.
A previously unknown species of kelp was collected on Kagamil Island, Aleutian Islands. The species can be easily distinguished from any known laminarialean alga: the erect sporophytic thallus is composed of a thin lanceolate blade attaining ~2 m in height and ~0.50 m in width, without midrib, and the edge of the blade at the transition zone is thickened to form a V‐shape; the stipe is solid and flattened, slightly translucent, attaining ~1 m in length; the holdfast is semidiscoidal and up to 0.15 m in diameter. Anatomically, the blade has the typical trumpet‐shaped hyphae characteristic of the Chordaceae and derived foliose laminarialean species (i.e., Alariaceae/Laminariaceae/Lessoniaceae). No hair pits or mucilaginous structures were observed on the blade or stipe. No fertile sporophytes were collected, but abundant juvenile sporophytes were observed in the field. In the molecular phylogenetic analyses using chloroplast rbcL gene, nuclear ITS1‐5.8S‐ITS2 rDNA, and mitochondria nad6 DNA sequences, the new species (Aureophycus aleuticus gen. et sp. nov.) showed a closer relationship with Alariaceae of conventional taxonomy, or the “Group 1” clade of Lane et al. (2006) including Alaria and related taxa than with other groups, although the species was not clearly included in the group. Aureophycus may be a key species in elucidating the evolution of the Alariaceae within the Laminariales. Because of the lack of information on reproductive organs and insufficient resolution of the molecular analyses, we refrain from assigning the new species to a family, but we place the new species in a new genus in the Laminariales.  相似文献   

14.
The phylogenetic position of an oxygenic photosynthetic prokaryote containing chl d as a major pigment, which have been tentatively named “Acaryochloris marina,” was analyzed using small subunit rDNA sequences. Phylogenetic relationships inferred among A. marina, selected strains from the Cyanobacteria, and plastids showed that A. marina was within the cyanobacterial radiation. The A. marina lineage diverged independently from other phylogenetic subgroups of the Cyanobacteria. No organism was found to be identical or related closely to A. marina by a similarity search and phylogenetic analysis. Based on these results, in addition to the reported characteristics of the cell morphology, pigment composition, and photosynthesis, a new taxon, Acaryochloris marina Miyashita et Chihara gen. et sp. nov., is formally proposed for the oxy‐genic photosynthetic prokaryote.  相似文献   

15.
A chlorarachniophycean alga, Lotharella amoebiformis, which has been classified in the genus Lotharella is placed into a new genus Amorphochlora gen. nov., based on its phylogenetic position, which has been clarified by the recently accumulated molecular phylogenetic information, and the morphological difference between the vegetative cells of the Lotharella species. Following this taxonomic treatment, a new combination Amorphochlora amoebiformis comb. nov., is proposed.  相似文献   

16.
This study indicates that bilaterally flattened, armored, benthic dinoflagellates are more diverse in morphology than previously known. A new species, Plagiodinium belizeanum Faust et Balech gen. et. sp. nov., is described in floating detritus from Twin Cays, Belize, mangrove habitats. Plagiodinium belizeanum cells are small, with dimensions of 26.5–30.5 μm in length, 20–24.5 μm in width, and 6.5–8.5 μm in depth. Cells are oblong and bilaterally compressed with a posteriorly located, spherical nucleus, many chloroplasts, and spherical starch granules. The epitheca descends ventrally, is cap-shaped, and is composed of five plates and a very small platelet provisionally named P0 situated in the center. The epitheca is narrowly oval in apical view with a pointed truncated ventral side and a rounded dorsal side. The cingulum is composed of five plates. The hypotheca is constructed of five posteriorly elongated postcingular plates and one antapical plate. The sulcus is very short and narrow, comprised of five very small plates. The thecal plate arrangement of P. belizeanum is P0, 5′, O″, 5C, 5″′, 1″″, 5S. No lists are present. Thecal plates have a smooth surface with small and irregularly scattered pores. The intercalary band is smooth on outer cell surface and broadly striated on its inner surface. We conclude that P. belizeanum represents a new, benthic, peridinioid, armored genus, Plagiodinium gen. nov. The taxonomic position of P. belizeanum sp. nov. is compared to related sand-dwelling and bilaterally flattened benthic dinoflagellates.  相似文献   

17.
The red alga Cenacrum subsutum gen. et sp. nov. is described from material collected at Macquarie Island in the subantarctic between November 1977 and February 1978. The habit and carposporophyte development are similar to members of the family Rhodymeniaceae (Rhodymeniales), but certain vegetative features are unique. The frond is a variously incised or lobed foliose blade with hollow apices above and a medulla which becomes progressively filled basipetally with ingrowing rhizoidal filaments. Details of carpogonial branch, auxiliary cell, connecting cell and gonimoblast anatomy are given, as well as observations on the habitats and distribution of the species.  相似文献   

18.
The tiny jumping flagellate originally described as Pedinomonas mikron Throndsen was isolated into pure culture from Australian waters and its ultrastructure critically examined. Pedinomonas mikron differs in behavior and in features of the flagellar apparatus from P. minor, the type species from freshwater, and is referred to the new genus Resultor. The two genera are closely related and form the new class Pedinophyceae, which is characterized by features of the flagellar apparatus, mitosis, and cytokinesis. The flagella show the 11/5 orientation otherwise characteristic of Ulvophyceae and Pleurastrophyceae, but they are arranged end to end as in the Chlorophyceae. The flagellar root system is asymmetric and includes a rhizoplast that emerges from the base of one flagellum but subsequently associates with a microtubular root from the second basal body. Mitosis studied previously by Pickett-Heaps and Ott in Pedinomonas is closed, unlike in other green algae, and the spindle is persistent. No phycoplast or phragmoplast is formed during cytokinesis. The eyespot of the Pedinophyceae is located at the opposite end of the cell from the flagella and adjacent to the pyrenoid, as in the most primitive members of the Prasinophyceae. Members of the Pedinophyceae lack prasinoxanthin and Mg 2,4D, characteristic of certain other primitive green algae. The primitive green algae include the classes Prasinophyceae and Pedinophyceae. Micromonadophyceae Mattox et Stewart is considered a synonym of Prasinophyceae. Two new orders are established, Pedinomonadales, containing all known members of the Pedinophyceae, and Scourfieldiales, with the single family Scourfieldiaceae fam. nov. and the single genus Scourfieldia.  相似文献   

19.
Bipolar asymmetry has been considered a morphological characteristic sufficient for differentiation of genera among the Desmidiaceae. Therefore, Micrasterias sudanensis Grönbl., Prowse & Scott, the only species of Micrasterias showing such asymmetry, is made the type of a new genus, Prescottiella, gen. nov.  相似文献   

20.
Cyrtophorids are a specialized group of ciliated protozoa with multitudinous morphotypes. In the present work, the morphology and infraciliature of two new and three rarely known species, including two new genera of cyrtophorid ciliates, Heterohartmannula fangi gen. et sp. nov. , Aporthotrochilia pulex (Deroux, 1976) gen. et comb. nov. , Trochilia alveolata sp. nov. , Trochochilodon flavus Deroux, 1976, and Hypocoma acinetarum Collin, 1907, are described. Heterohartmannula gen. nov. is mainly characterized by a combination of features: two circumoral kineties obliquely arranged, podite not surrounded by somatic kineties, and no distinct gap between left and right ciliary field. Aporthotrochilia gen. nov. is diagnosed mainly by: podite present, oral ciliature reduced to two fragments, several kinety fragments positioned on the right posterior of frontoventral kineties and several terminal fragments. Phylogenetic analyses based on the small subunit rRNA (SSU rRNA) gene sequences support the establishment of two new genera and indicate that Heterohartmannula is most closely related to Hartmannula, and Aporthotrochilia is basal to the Cyrtophoria‐Chonotrichia clade. Trochilia alveolata sp. nov. differs from its congeners mainly by having a conspicuous alveolar layer. In addition, detailed live and infraciliature data of Hypocoma acinetarum and Trochochilodon flavus are supplied. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 1–17.  相似文献   

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