Nematodes vs Cestodes
Nematodes and Cestodes are worm groups. The key difference between Nematodes and Cestodes is that Nematodes are roundworms whereas Cestodes are flatworms.
The kingdom Animalia is comprised of several phyla. Phylum Nematoda includes round worms, which are pseudocoelomates. Phylum Platyhelminthes includes worms that are flattened dorsoventrally and acoelomates. Cestoda is parasitic worm class of phylum Platyhelminthes.
CONTENTS
1. Overview and Key Difference
2. What is Nematodes
3. What is Cestodes
4. Similarities Between Nematodes and Cestodes
5. Side by Side Comparison – Nematodes vs Cestodes in Tabular Form
6. Summary
What are Nematodes?
Nematoda is a phylum of Kingdom Animalia that comprises of cylindrically shaped worms or the round worms. Nematodes are bilaterally symmetrical, long and thin, hair like worms. They are triploblastic and have a short body cavity (pseudocoelom) that is not a true coelom. Nematodes are free living or parasitic worms. They are found in aquatic environments, terrestrial habitats, bodies of animal and plants etc. Parasitic round worms are caused by several diseases such as elephantiasis, etc. Round worms or pin worms in the human intestine are also causing various diseases.
Figure 01: Nematodes
Nematodes sexes are separated, and distinct male, female can be identified. Female worms are longer than the male worms. Class Enoplea and class chromadorea are two classes of nematodes.
What are Cestodes?
Cestoda is a class of phylum Platyhelminthes of Kingdom Animalia. Cestodes are parasitic flatworms or tapeworms. Cestodes are obligate parasites in the gut of vertebrates. They are bilaterally symmetrical, and they are triploblastic. Thus, they don’t have a complete digestive system. Cestodes possess unique extensions called microtriches.
Figure 02: Cestodes
Microtriches help cestodes in the absorption of nutrients from the host. Cestodes possess a variety of attachment structures such as hooks, tentacles, and suckers.
What are the Similarities Between Nematodes and Cestodes?
- Both Nematodes and Cestodes are groups of Kingdom Animalia.
- Nematodes and Cestodes show bilateral symmetry.
- Both are worms.
- Both worm types: Nematodes and Cestodes are multicellular eukaryotes.
- These phyla Nematodes and Cestodes do not have a true coelom.
- Both are invertebrates. Hence, do not have a backbone.
- Both Nematodes and Cestodes are triploblastic.
- Nematodes and Cestodes are parasitic.
- Fertilization is internal in both Nematodes and Cestodes.
What is the Difference Between Nematodes and Cestodes?
Chasmogamous vs Cleistogamous |
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| Nematodes are a phylum of kingdom Animalia comprising round worms. | Cestodes are a class of phylum Platyhelminthes including obligate parasitic flatworms. |
| Type of Worms | |
| Nematodes are round worms. | Cestodes are flat worms. |
| Shape | |
| Nematodes are cylindrical in shape. | Cestodes are flattened dorsoventrally in shape. |
| Class/Phylum | |
| Nematodes are a phylum of Kingdom Animalia. | Cestodes are a class of phylum Platyhelminthes of Kingdom Animalia. |
| Digestive System | |
| Nematodes alimentary canal is complete. | Cestodes digestive system is incomplete. |
| Sexes | |
| Nematodes sexes are separate. | Cestodes sexes are not separate. |
| Nature | |
| Nematodes are free living or parasitic. | Cestodes are obligate parasites of vertibrates. |
| Coelom | |
| Nematodes are pseudocoelomates. They possess a false coelom. | Cestodes are acoelomates. They don’t have a coelom. |
| Examples | |
| Ascaris suum, Ascaris lumbricoides, filarias, hookworms, pinworms (Enterobius), and whipworms (Trichuris trichiura) are examples of Nematodes. | Taenia solium, Taenia saginata, Diphyllobothrium latum, Hymenolepis nana, Hymenolepis diminuta, Echinococcus granulosus, Echinococcus multilocularis , Spirometra are examples of Cestodes. |
Summary – Nematodes vs Cestodes
Nematodes and Cestodes are worm groups. Nematoda is a phylum comprised of round worms that are pseudocoelomates. Cestodes are tapeworms or flatworms, which are acoelomates and obligates parasites. This is the difference between nematodes and cestodes.
Reference:
1.“Animal Kingdom Classification.” Animal Kingdom Classification | Chart | Biology@TutorVista.com. Available here
2.“Cestoda.” Wikipedia, Wikimedia Foundation, 12 Apr. 2018. Available here
Image Courtesy:
1.’CSIRO ScienceImage 2818 Group of Nematodes’By CSIRO, (CC BY 3.0) via Commons Wikimedia
2.’Taenia saginata adult 5260 lores’ (Public Domain) via Commons Wikimedia