Along with many other flagellum-bearing protists, euglenoids and kinetoplastids were once lumped in the now-defunct, polyphyletic taxon
"Mastigophora" (mastig = "whip"; phor = "to bear").
This should serve as a reminder about that symplesiomorphies are not informative when one is trying to construct monophyletic taxa.
The flagellum is a very ancient, widespread eukaryotic structure. Its presence provides no information useful for classifying anything with a flagellum into a less
Side note: The flagellum of the euglenozoans has a unique feature: a spiral or crystalline rod inside the protein filaments. Its function is unknown, but this unique feature of the flagellum is derived. Its presence can be used as a synapomorphy that links the Euglenoids into a single monophyletic taxon.
Also unique to euglenoids are disk-shaped cristae in the mitochondria.
These two very basic characters suggest monophyly of the euglenoids, kinetoplastids, and a few other small groups of euglenozoans with these synapomorphies.
This diverse group includes both some of the most important photoautotrophs in the biosphere (diatoms; macroalgae such as "brown algae"), and economically important pathogens. It is currently divided into two clades
These are linked by the presence of alveoli under the plasma membrane,
which is highly complex in function and anatomy.
Important Alveolates include
These organisms are responsible for seasonal red tides that can cause massive die-offs of fish and other marine animals.
They are also indirectly responsible for the most common form of non-bacterial seafood poisoning in the U.S., ciguatera.
Gregarines are parasites of mollusks and annelids.
Commonly known as ciliates, these are among the most complex of all protists--and possibly all cell types, in general.
covered in shortened flagella called cilia
one small, diploid micronucleus for reproduction only; its genes are not expressed
one large, polyploid macronucleus for regulation of cell functions. Produced by the micronucleus, it is not passed on to daughter cells.
This are the most diverse protist group, with over 8000 species.
Their name comes from the Latin stramen ("straw") and pilos ("hair")). The taxon gets its name from its fuzzy flagellum, which is often paired with a smooth one. Flagellated cells occur in all members of this taxon, though in some highly derived groups, they occur only during reproductive cycles and function as gametes.
This group includes the
Also nestled within this clade are the haptophytes, unicellular algae that produce plated shells (coccoliths) that presumably protect them from predators. The calcium carbonate "skeletons" of a famous haptophyte, Emiliana huxleyi are the primary component of the White Cliffs of Dover
Many of these aquatic Chromalveolate amoebas secrete ornate shells, through which highly derived, threadlike pseudopods emerge. The pseudopods facilitate movement, may be involved in prey capture, and also provide buoyancy via greatly increased surface area.
They are some of the most beautiful protists.
This clade includes the Red Algae (Rhodophyta) and the Green Plants.
The Rhodophyta form a monophyletic clade united by the synapomorphic appearance of pigments known as
all contained in specialized light-collecting systems known as phycobilisomes. These are found elsewhere only in the cyanobacteria, strongly suggesting that a secondary endosymbiosis involving cyanobacteria gave rise to the Rhodophytes.
These pigments absorb blue wavelengths, transmitting their energy to the photosynthetic cycle.
Thus, Rhodophytes can live in relatively low light conditions where other algae cannot
very deep water
under algal mats of other types of algae
They are a diverse and beautiful group, and are economically important as the source of