Classification in Outline:
The following classification is based on Honigberg Report.
It is subdivided into four subphyla— Sarcomastigophora, Sporozoa, Cnidospora and Ciliophora.
Phylum Protozoa:
I. Subphylum: Sarcomastigophora
1. Locomotory structures are present ei¬ther in the form of flagella, pseudopodia, or both.
2. Nucleus is usually of single type(monomorphic).
3. Asexual reproduction by binary fission and multiple fission.
4. Sexual reproduction by syngamy.
5. There is no spore formation.
6. Sarcodes= fleshy, mastix= whip, phoros= bearing.
It includes three super-classes—Mastigophora, Opalinata and Sarcodina.
A. Superclass: mastigophora: .
1. They are commonly called flagellates.
2. Body is covered by pellicle.
3. Locomotory organs are flagella.
4. Asexual reproduction by binary fission.
5. Either solitary or colonial.
6. Presence of one or more flagella in trophozoite stage.
7. Sexual reproduction is uncommon.
8. Nutrition may be either phototrophic or heterotrophic or both.
9. Ex. Volvox, Noctiluca, Trichomonas, Trypanosoma, Giardia.
It is subdivided into two classes— Phytomastigophorea and Zoomastigophorea.
(i) Class Phytomastigophorea
1. Chlorophyll containing chromatophores are present.
2. Presence of one or two emergent flagella.
3. Nutrition mostly holophytic (by photosynthesis)
4. Reserve food is starch or paramylon.
5. Most members are free-living.
6. Ex. Euglena, Noctiluca.Volvox, Chlamydomonas.
(ii) Class Zoomastigophorea:
1. Chlorophyll containing Chromatophores are absent.
2. Presence of one-to-many flagella.
3. Nutrition holozoic or saprozoic.
4. Reserve food is glycogen.
5. Parasitic, commensal, symbiotic.
6. Ex. Trypanosoma, Leishmania, Giardia, Trichonympha, Trichomonas
B. Superclass: opalinata: .
1. Presence of cilium-like organelles in oblique rows over entire body surface.
2. Cytostome is absent, Saprozoic nutrition.
3. One or more monomorphic nuclei.
4. Asexual reproduction by binary fission.
5. Sexual reproduction happens involves syngamy with flagellated gametes.
6. Always live in association.
7. Examples. Opalina, Zelleriella, cepedea.
C. Superclass: sarcodina:
1. Locomotion by pseudopodia.
2. Nutrition is holozoic or saprozoic.
3. Pseudopodia may be lobopodian, filopodia or reticulopodia.
4. Flagella appear in some forms dur¬ing development.
5. Body may not or may have various types or exo or endoskeleton.
6. Asexual reproduction occurs by fission.
7. Sexual reproduction by flagellate gametes.
(iii) Class Rhizopodea:
1. Free living or endoparasite.
2. Contractile vacuole is present or absent.
3. Body is without a pellicle and has no fixed shape.
4. Protoplasm is differentiated into ectoplasm and endoplasm.
5. Locomotary organelles are pseudopodia (lobopodian, filopodia, reticulopodia) which also help in food capturing.
6. Single nucleus is present in the endoplasm.
7. Nutrition is holozoic and parasitic.
8. Reproduction takes place by fission.
9. Ex. Amoeba, Entamoeba, Elphidium.
(iv) Class Piroplasmea: (pear shaped)
1. Small round rod shaped or amoeboid organisms.
2. Parasites in red blood cells of vertebrates.
3. Locomotory structures are absent.
4. Binary fission takes place.
5. Ex. Babesia
(iv) Class Actinopodea:
1. Usually floating with spherical body and delicate pseudopodia.
2. Pseudopodia may be axopodia, filose or reticulate.
3. Usually naked when test present it is either membranous or chitonid or silicious or strontium.
4. Both asexual and sexual reproduc¬tion occur.
5. Gametes are flagellated.
6. Ex. Collozoum, Actinophrys, Acanthometra.
II. Subphylum sporozoa:
1. All are endoparasites.
2. Body covered with thick pellicle.
3. Locomotary organs are absent in adults.
4. Nucleus is of single type.
5. Saprozoic nutrition.
6. Contractile vacuole is absent.
7. Cilia absent but flagellated gametes may occur.
8. Asexual reproduction by multiple fission.
9. Sexual reproduction by syngamy followed by spore formation.
10. Spore contains one to many sporozoites.
11. Ex. Gregarina, Monocystis, Nematocystis, Plasmodium, Nosema.
It is subdivided into three classes— Telosporea, Toxoplasmea and Hoplosporea.
(v) Class Telosporea:
1. Spores are seen.
2. Both asexual and sexual reproduc¬tion take place.
3. Locomotion by gliding or body flexion.
4. Pseudopodia are usually absent but sometimes used only for food capture.
5. Spores are without capsules, naked or encysted.
6. Microgametes are flagellated in some.
7. They are blood and gut parasites of vertebrates.
8. Ex. Monocyctis, Plasmodium
(vi) Class Toxoplasmea:
1. No spore formation.
2. Asexual reproduction by binary fis¬sion.
3. Locomotion is affected by gliding or body flexion.
4. Structures like pseudopodia and flagella are absent.
5. Cysts include naked trophozoites.
6. Examples. Toxoplasma, Sarcocystis.
(vii) Class Haplosporea:
1. Presence of spores(amoeboid), only asexual re¬production takes place by schizogony.
2. Schizogony is present.
3. Pseudopodia may be present, but flagella are absent.
4. Parasite of fish and invertebrates.
5. Examples. Haplosporidium, Coelosporidium.
III. Subphylum cnidospora:
1. All are parasitic.
2. Spores have one to many cells. Presence of spores having one or more spore filaments and sporoplasms.
3. Without sporogony, zygote gives rise to one or more trophozoites, each with many nuclei.
Two classes—Myxosporidea and Microsporidea are present.
(viii) Class Myxosporidea:
1. The spores are large and develop from several nuclei.
2. The spores have two polar filaments and have two to three valves.
3. They are extra cellular parasities of cold-blooded vertebrates such as fish.
4. Ex. Myxobolus, Ceratomyxa, Helicosporidium, Myxidium.
(ix) Class Microsporidea:
1. The spores are small and are developed from only one nucleus. These spores have single valve.
2. There is one long tubular polar filament through which the sporoplasm emerges.
3. They are intracellular parasites in arthropoda.
4. Ex. Nosema, Caudospora
IV. Subphylum Ciliophora:
1. Most species are free living, commensal, parasitic.
2. Body organisation complex.
3. Presence of simple cilia as locomotory organelles.
4. Nucleus dimorphism occurs. They have two nuclei. Macronucleus and a small micronucleus.
5. Nutrition heterotrophic.
6. Contractile vacuole present.
7. Asexual reproduction by binary fission, budding or multiple fission.
8. Sexual reproduction by conjunction.
9. Gametes are absent.
10. They have a cytostome.
(xi) Class Ciliatea:
1. Body organisation is complex.
2. Body shape and size is definite and covered with pellicle.
3. Free living forms with cilia or cili¬ated organelle at least in some part of the life cycle.
4. Sub-pellicular infra-ciliature always present, even during the absence of cilia.
5. Locomotory and feeding organelles are numerous hairs like cilia.
6. One or more contractile vacuoles are present.
7. Most ciliates possess a cell mouth called cytostome.
8. Anal aperture cytopyge permanent.
9. Usually, two types of nuclei are seen large vegetative macronucleus and small reproductive micronucleus.
10. Both asexual and sexual reproduc¬tions occur.
11. Sexual reproduction involves either conjugation or autogamy or cytogamy.
12. Nutrition is heterotrophic.
13. Holozoic mode of nutrition.
14. Ex. Opalina,Paramecium, Vorticella, Balatidium, Halteria.