| Synurids | |
|---|---|
 | |
| A colony of Synura sp. | |
Scientific classification  | |
| Domain: | Eukaryota |
| Clade: | Diaphoretickes |
| Clade: | SAR |
| Clade: | Stramenopiles |
| Phylum: | Gyrista |
| Subphylum: | Ochrophytina |
| Class: | Chrysophyceae |
| Order: | Synurales Andersen, 1987 |
| Genera [1] | |
The synurids (order Synurales) are a small group of heterokont algae, found mostly in freshwater environments, characterized by cells covered in silica scales. [2]
They are covered in silicate scales and spines. In Synura, these are formed on the surface of the chloroplasts, [3] two of which are usually present, but sometimes only one divided into two lobes is seen. The cells have two heterokont flagella, inserted parallel to one another at the anterior, whose ultrastructure is a distinguishing characteristic of the group. Both asexual and isogamous sexual reproduction occur.
Synurales are divided into three families, each with one genus: [4]
The genus Synura was proposed in 1834 by the German microscopist Christian Gottfried Ehrenberg (1795–1876). [5]
The synurids were originally included among the golden algae in the order Ochromonadales as the family Mallomonadaceae or as the family Synuraceae . They were formally defined as a separate group by Andersen in 1987, who placed them in their own class Synurophyceae, based on an earlier approach of more narrowly defining major lineages of chrysophyte algae by British phycologist David Hibberd. [6] [7]
The Chrysophyceae and Synurophyceae are currently recognized as closely related taxa within the Stramenopiles. [8] [9] Present classifications include the synurids as an order (Synurales) within Chrysophyceae. [2] [10]
The Stramenopiles, also called Heterokonts, are a clade of organisms distinguished by the presence of stiff tripartite external hairs. In most species, the hairs are attached to flagella, in some they are attached to other areas of the cellular surface, and in some they have been secondarily lost. Stramenopiles represent one of the three major clades in the SAR supergroup, along with Alveolata and Rhizaria.
The haptophytes, classified either as the Haptophyta, Haptophytina or Prymnesiophyta, are a clade of algae.
Pedinellales (ICN) or Pedinellida (ICZN) is a group of single-celled algae found in both marine environments and freshwater.
The axodines are a group of unicellular stramenopiles that includes silicoflagellate and rhizochromulinid algae, actinomonad heterotrophic flagellates and actinophryid heliozoa. Alternative classifications treat the dictyochophytes as heterokont algae, or as Chrysophyceae. Other overlapping taxonomic concepts include the Actinochrysophyceae, Actinochrysea or Dictyochophyceae sensu lato. The grouping was proposed on the basis of ultrastructural similarities, and is consistent with subsequent molecular comparisons.
Chromista is a proposed but polyphyletic biological kingdom, refined from the Chromalveolata, consisting of single-celled and multicellular eukaryotic species that share similar features in their photosynthetic organelles (plastids). It includes all eukaryotes whose plastids contain chlorophyll c and are surrounded by four membranes. If the ancestor already possessed chloroplasts derived by endosymbiosis from red algae, all non-photosynthetic Chromista have secondarily lost the ability to photosynthesise. Its members might have arisen independently as separate evolutionary groups from the last eukaryotic common ancestor.
The Chrysophyceae, usually called chrysophytes, chrysomonads, golden-brown algae or golden algae, are a large group of algae, found mostly in freshwater. Golden algae is also commonly used to refer to a single species, Prymnesium parvum, which causes fish kills.
Bicosoecida (ICZN) or Bicosoecales/Bicoecea (ICBN) is an order of Bikosea, a small group of unicellular flagellates, included among the stramenopiles. Informally known as bicosoecids, they are a small group of unicellular flagellates. The cells are free-living, with no chloroplasts, and in some genera are encased in a lorica.
Ochrophytes, also known as heterokontophytes or stramenochromes, are a group of algae. They are the photosynthetic stramenopiles, a group of eukaryotes, organisms with a cell nucleus, characterized by the presence of two unequal flagella, one of which has tripartite hairs called mastigonemes. In particular, they are characterized by photosynthetic organelles or plastids enclosed by four membranes, with membrane-bound compartments called thylakoids organized in piles of three, chlorophyll a and c as their photosynthetic pigments, and additional pigments such as β-carotene and xanthophylls. Ochrophytes are one of the most diverse lineages of eukaryotes, containing ecologically important algae such as brown algae and diatoms. They are classified either as phylum Ochrophyta or Heterokontophyta, or as subphylum Ochrophytina within phylum Gyrista. Their plastids are of red algal origin.
Phaeothamniophycidae is a subclass of heterokont algae. It contains two orders, Phaeothamniales and Pleurochloridellales, and consists of species separated from Chrysophyceae.
Mallomonas lacuna is a species of heterokont algae. It is a tiny free-living cell, about the width of a human hair. It has ornate scales and bristles, as well as long spines. It is a relatively common part of lake or pond plankton. It differs from its cogenerates by the number, distribution, and size of its base plate pores, the secondary structures on the scale surfaces, together with characteristics of its bristles.
Mallomonas hexareticulata is a species of heterokont algae. It is a tiny free-living cell, about the width of a human hair. It has ornate scales and bristles, as well as long spines. It is a relatively common part of lake or pond plankton. It differs from its cogenerates by the number, distribution, and size of its base plate pores, the secondary structures on the scale surfaces, together with characteristics of its bristles.
Mallomonas pseudomatvienkoae is a species of heterokont algae. It is a tiny free-living cell, about the width of a human hair. It has ornate scales and bristles, as well as long spines. It is a relatively common part of lake or pond plankton. It differs from its cogenerates by the number, distribution, and size of its base plate pores, the secondary structures on the scale surfaces, together with characteristics of its bristles.
Mallomonas sorohexareticulata is a species of heterokont algae. It is a tiny free-living cell, about the width of a human hair. It has ornate scales and bristles, as well as long spines. It is a relatively common part of lake or pond plankton. It differs from its cogenerates by the number, distribution, and size of its base plate pores, the secondary structures on the scale surfaces, together with characteristics of its bristles.
Mallomonas pleuriforamen is an extinct species of heterokont algae. It was first found in Middle Eocene lacustrine deposits from northwestern Canada. It was a tiny free-living cell, about the width of a human hair. It had ornate scales and bristles, as well as long spines. It was a relatively common part of lake or pond plankton. It differs from its cogenerates by the number, distribution, and size of its base plate pores, the secondary structures on the scale surfaces, together with characteristics of its bristles.
Picophagea, also known as Synchromophyceae, is a class of photosynthetic stramenopiles. The chloroplast of the Synchromophyceae are surrounded by two membranes and arranged in a way where they share the outer pair of membranes. The entire chloroplast complex is surrounded by an additional two outer membranes.
Mallomonas is a genus comprising unicellular algal eukaryotes and characterized by their intricate cell coverings made of silica scales and bristles. The group was first named and classified by Dr. Maximilian Perty in 1852. These organisms live in freshwater and are widely distributed around the world. Some well known species include Mallomonas caudata and Mallomonas splendens.
Synura is a genus of colonial chrysomonad algae covered in silica scales. It is the most conspicuous genus of the order Synurales.
Ultrastructural identity is a concept in biology. It asserts that evolutionary lineages of eukaryotes in general and protists in particular can be distinguished by complements and arrangements of cellular organelles. These ultrastructural components can be visualized by electron microscopy.
Gyrista is a phylum of heterokont protists containing three diverse groups: the mostly photosynthetic Ochrophyta, the parasitic Pseudofungi, and the recently described group of nanoflagellates known as Bigyromonada. Members of this phylum are characterized by the presence of a helix or a double helix/ring system in the ciliary transition region.
Ochromonadales is an order of single-celled algae belonging to the class Chrysophyceae, also known as golden algae. Species of this order are flagellates, composed of cells capable of swimming by using two flagella. Though ancestrally photosynthetic, some species have secondarily lost this ability, and appear colourless. These are heterotrophic, and can be phagotrophic. Some are mixotrophic, capable of both photosynthesis and phagotrophy, such as Poterioomonas and Ochromonas.
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