Main Difference – Chilopoda vs Diplopoda
Chilopoda and Diplopoda are two classes of the phylum Arthropoda. Both Chilopoda and Diplopoda belong to the subphylum Myriapoda. Chilopoda consists of centipedes while Diplopoda consists of millipedes. Both Chilopoda and Diplopoda consist of arthropods with a segmented body and jointed legs. Both types of arthropods breathe through spiracles. However, both types of arthropods lack direct copulatory organs. The main difference between Chilopoda and Diplopoda is that Chilopoda consists of one pair of legs in each body segment whereas Diplopoda consists of two pairs of legs in each body segment.
Key Areas Covered
1. What is Chilopoda
– Definition, Characteristics, Behavior
2. What is Diplopoda
– Definition, Characteristics, Behavior
3. What are the Similarities Between Chilopoda and Diplopoda
– Outline of Common Features
4. What is the Difference Between Chilopoda and Diplopoda
– Comparison of Key Differences
Key Terms: Arthropoda, Chilopoda, Diplopoda, Legs, Myriapoda, Segmented Body, Venomous Fangs
What is Chilopoda
Chilopoda refers to a class of Myriapod arthropods having a trunk composed of numerous body segments (somites), each bearing one pair of legs. The arthropods of Chilopoda are commonly called centipedes. Centipedes have a dorsoventrally flattened body divided into head and trunk. The head of centipedes consists of a pair of simple eyes and antenna. The legs of the first body segment are developed into venomous fangs. A centipede is shown in figure 1.
Figure 1: Centipede
As centipedes are carnivores (insectivores), they use venom to capture insects as well as for defence. Male centipedes spin a small web to deposit the sperms in the form of spermatophores, which is then picked up by the female centipedes. The young centipedes molt several times until they reach sexual maturity.
What is Diplopoda
Diplopoda refers to a class of myriapod arthropods bearing two pairs of legs per body segment. As Diplopoda consists of scavengers, they can be found in the decaying organic matter. The arthropods in the class Diplopoda is commonly called millipedes. Generally, millipedes have more legs than centipedes. A millipede is shown in figure 2.
Figure 2: Millipede
Typically, the body of millipedes is cylindrical. It is also divided into head and trunk. The trunk is segmented, and the first three body segments lack legs. Each body segment is a fusion of two body segments. The head of the millipedes consists of chewing mouthparts.
The sexual reproduction of millipedes occurs by mating. The seventh body segment contains mating legs that transfer sperms to the genital opening of the female.
Similarities Between Chilopoda and Diplopoda
- Chilopoda and Diplopoda are two classes of the subphylum Myriapoda under the phylum Arthropoda.
- Both Chilopoda and Diplopoda are terrestrial arthropods.
- Both Chilopoda and Diplopoda consist of invertebrates with jointed legs and a segmented.
- The body of both Chilopoda and Diplopoda is covered by a chitinous exoskeleton.
- The body of both Chilopoda and Diplopoda is divided into the head and trunk.
- Both Chilopoda and Diplopoda consist of arthropods with multi-legs.
- Both Chilopoda and Diplopoda consist of arthropods with simple eyes and a single pair of antenna.
- The mouthparts of both chilopods and diplopods occur in the underside of the head.
- The upper lip of the mouth of both Chilopoda and Diplopoda consist of epistome and labrum while the lower lips consist of maxillae.
- A pair of mandibles can be identified inside the mouth in both Chilopoda and Diplopoda.
- The respiration of both Chilopoda and Diplopoda occur through the trachea. The spiracles are the external respiratory opening in both types of arthropods.
- The excretion of both Chilopoda and Diplopoda occurs through malpighian tubules.
Difference Between Chilopoda and Diplopoda
Definition
Chilopoda: Chilopoda refers to a class of myriapod arthropods bearing a pair of legs per body segment.
Diplopoda: Diplopoda refers to a class of myriapod arthropods bearing two pairs of legs per body segment.
Common Name
Chilopoda: Chilopoda is commonly called centipedes.
Diplopoda: Diplopoda is commonly called millipedes.
Body Structure
Chilopoda: The body of Chilopoda is flat.
Diplopoda: The body of Diplopoda is cylindrical.
Flexibility
Chilopoda: The body of Chilopoda is flexible.
Diplopoda: The body of Diplopoda is not flexible.
Length
Chilopoda: The body of Chilopoda can be 4 to 5 inches long.
Diplopoda: The body of Diplopoda can be 1 to 8 inches long.
Body Color
Chilopoda: The color of the body of Chilopoda is yellowish-gray to brown.
Diplopoda: The color of the body of Diplopoda is dark reddish-brown to black.
Number of Body Segments
Chilopoda: The body of Chilopoda is divided into 15 to 100 segments.
Diplopoda: The body of Diplopoda is divided into 11 to 150 segments.
Monosegmentic/Diplosegmentic
Chilopoda: Chilopoda are monosegmentic.
Diplopoda: Diplopoda are diplosegmentic; each segment is formed by the fusion of two segments.
Number of Legs
Chilopoda: Chilopoda has an average number of 40 legs.
Diplopoda: Diplopoda has an average number of 300 legs.
Legs per Body Segment
Chilopoda: Chilopoda has a pair of legs per body segment.
Diplopoda: Diplopoda has two pairs of legs per body segment.
Length of the Legs
Chilopoda: Chilopoda has long legs extended sideways from the body.
Diplopoda: Diplopoda has short legs.
Legs in the First Segment
Chilopoda: The legs of Chilopoda start from the first body segment.
Diplopoda: The first three body segments lack legs.
Length of the Antenna
Chilopoda: Chilopoda has a long antenna on top of the head.
Diplopoda: Diplopoda has a short antenna.
Type of Locomotion
Chilopoda: Chilopoda treads forward swiftly using their legs.
Diplopoda: Diplopoda moves forward by the wave-like motion of the legs.
Speed of Locomotion
Chilopoda: Chilopoda moves very fast.
Diplopoda: Diplopoda moves slowly.
Mode of Nutrition
Chilopoda: Chilopoda consists of carnivorous arthropods that feed on insects and other small organisms.
Diplopoda: Diplopoda consists of scavengers that feed on decomposing organic matter.
Defense Mechanism
Chilopoda: Chilopoda has poison glands to attack and kill the prey.
Diplopoda: Diplopoda curl their body when threatened or squirt a corrosive liquids.
Sexual Reproduction
Chilopoda: The male Chilopoda deposits bundles of sperms known as spermatophores in the environment; they are engulfed by female Chilopoda.
Diplopoda: Diplopoda reproduces through mating.
Genital Openings
Chilopoda: Chilopoda is opisthogoneate, consisting a single genital opening at the posterior end of the body.
Diplopoda: Diplopoda is progoneate, consisting a single genital opening at the anterior end of the body.
Number of Eggs
Chilopoda: Chilopoda lays around 50 eggs at a time.
Diplopoda: Diplopoda lays around 300 eggs at a time.
Protecting Eggs and Nursing
Chilopoda: Chilopoda protects their eggs and nurses the young.
Diplopoda: Diplopoda does not protect their eggs.
Conclusion
Chilopoda and Diplopoda are two classes of arthropods. Both classes consist of terrestrial animals with a segmented body and jointed appendages. Chilopoda consists of a single pair of legs per body segment while Diplopoda consists of two pairs of legs per body segment. The main difference between Chilopoda and Diplopoda is the number of legs in each body segment.
Reference:
1. Chilopoda – centipedes, Ento. Csiro, Available here.
2. Animals, A-Z. “Millipede.” A-Z Animals – Animal Facts, Pictures and Resources, Available here.
Image Courtesy:
1. “Lithobius forficatus” (CC BY-SA 3.0) via Commons Wikimedia
2. “Brown Millipede (Diplopoda) (9598625908)”By Bernard DUPONT from FRANCE – Brown Millipede (Diplopoda) (CC BY-SA 2.0) via Commons Wikimedia
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