PHYLUM – ARTHROPODA -GENERAL CHARACTERS
1. Arthropoda means jointed legs. It includes individuals with jointed appendages.
2. It is the largest phylum in the animal kingdom, and comprises 80 percent of animal species.
3. Found in a cosmopolitan area.
4. They are omnivorous in feeding habit Some forms are carnivorous (Scorpion)
5. Some organisms are ectoparasite
6. The digestive system is complete and well developed
7. They are triploblastic and bilaterally symmetrical.
8. The body is divisible into the head thorax and abdomen.
9. The exoskeleton is made up of a chitinous cuticle and protein.
10. Presence of a pair of antennae.
11. Molting or ecdysis is the most common phenomenon, which facilitates growth.
12. Presence of the true haemo-coelomic cavity filled with hemolymph or
haemocoel omic fluid.
13. Respiratory pigment if present is hemocyanin (few are with hemoglobin).
14. Respiratory pigment hemocyanin contains copper.
15. The sensory organs are compound eyes, anal cirri, bristles, statocyst, antenna, etc.
16. Excretory organs are green glands or coxal glands. In terrestrial arthropods malphigian
tubules.
17. They are mostly unisexual i. e. Sexes are separate.
18. Sexual dimorphism is occurs
19. Internal fertilization occurs in aquatic forms. Internal fertilization occurs in terrestrial
forms.
20. Development is direct or indirect.
21. Egg is centrolecithal.
22. Cleavage is meroblastic and superficial.
Phylum Arthropods Chart
Balanus
Kingdom Animalia Eukaryotic, heterophic animal.
Phylum: Arthropoda Jointed appendages
Class Crustacea Head and thorax fused (cephalothorax)
Order: Thoracica Six pair of thoracic appendages called cirri.
Genus : Balanus
Species amphitrite
Characters
1. It is commonly known as acorn or rock barnacle.
2. It is sessile and marine animal.
3. It found attached to the rock.
4. Presence of 6 pairs of thoracic appendages.
5. Heart and blood vessels absent.
6. Hermaphrodite animal.
Prawn
Kingdom Animalia Eukaryotic, heterophic animal.
Phylum: Arthropoda Jointed appendages.
Class Crutacea Head and thorax fused (cephalothorax).
Order: Decapoda Presence of 10 pairs of appendages.
Genus : Penaeus
Species : monodon
Characters:
- 1. It is freshwater as well as marine water.
- 2. Presence of 10 pairs of appendages.
- 3. Head fused with thorax forming ephalothorax.
- 4. Cephalothorax is covered by carapace.
- 5. Presence of telson.
King crab
Kingdom Animalia Eukaryotic, heterophic animal.
Phylum: Arthropoda Jointed appendages.
Class Merostomata Aquatic form and compound eyes are well developed.
Order: xiphosurida prosoma coveed with horse shoe shaped carapace.
Genus Limulus
Species: polyphemus
Characters.
1. It is commonly called as King krab
2. Body is divided into prosoma,
mesosoma and metasoma.
3. It is living fossil.
4. Body is covered with carapace.
5. 6 pair of movable spins on mesoma.
6. Respiratory organs are book lung.
7. Presence of telson.
8. Sexes are separate.
Scorpion
Kingdom Animalia Eukaryotic, heterophic animal.
Phylum: Arthropoda Jointed appendages.
Class Arachnida 4 pairs of thoracic legs.
Order: Scorpinoida Presence of sting apparatus.
Genus Palamnaeus
Species bengalensis
Characters.
1. It is living fossil.
2. It is nocturnal animal.
3. It has poisonous sting at its end.
4. Body divisible into prosoma, mesosoma and metasoma
5. Chelacera are small.
6. Pedipalp is much larger.
7. Four pairs of walking legs.
8. Five pairs of lateral eyes
9. Respiratory organs are book lungs.
10. Scorpions is poisonous animal.
11. Sexes are separate.
Grasshopper
Kingdom Animalia Eukaryotic, heterophic animal.
Phylum: Arthropoda Jointed appendages.
Class Insecta Body divided into head, thorax and abdomen.
Order: Orthoptera Prothorax large.
Genus: Schistocerca
Species gregarian
Characters:
1. Thorax bears 3 pairs of walking legs.
2. Two pairs of wings.
3. Abdomen is segmented and cylindrical.
4. Male has anal style.
5. Female has ovipositor.
6. It is serious crop pest.
7. Sexes are separate.
Butterfly
Kingdom Animalia Eukaryotic, heterophic animal.
Phylum: Arthropoda Jointed appendages.
Class Insecta Body divided into head, thorax and abdomen.
Order Lepidoptera compound eyes are very large./
Genus : Raphicera
Species: satricus
Characters
1. Thorax bears 3 pairs of walking legs.
2. Two pairs of wings.
3. Abdomen is segmented and cylindrical.
4. Antennae shows terminals enlargement.
5. Wing are colourfull and attractive.
6. Metamorphosis is complete.
7. Larva is called catrpiller.
8. Sexes are separate.
Centipede
Kingdom Animalia Eukaryotic, heterophic animal.
Phylum: Arthropoda Jointed appendages.
Class Chilopoda Body is divided into head and trunk.
Order: scolopendromorpha body elongated dorso- ventrally flattened.
Genus : Scholopendra
Species: subspinipes
Characters:
1. Centipeds are 100 leggers.
2. Body is segmented.
3. Each segment has a pair of walking legs.
4. 1st five pairs are curved act as poison glands.
5. Anus is in the last body segment.
6. Presence of anal style.
7. It is carnivorous.
Millipede
Kingdom Animalia Eukaryotic, heterophic animal.
Phylum: Arthropoda Jointed appendages.
Class Diplopoda two pairs of walking legs to each segment.
Order: Julida Spinneretes absent in last segment.
Genus: Cylindroiulus
Species :londinensis
Characters:
1. Commonly called as Julus.
2. It is also called 1000 leggers.
3. Body is segmented.
4. Each segment has two pairs of leg.
5. Simple eyes.
6. Antenna 7 segmented.
7. Julus is herbivorous.
Peripatus
Kingdom Animalia Eukaryotic, heterophic animal.
Phylum: Arthropoda Jointed appendages.
Class: Onychophora Exoskeleton absent, parapodia with claws
Genus Peripatus ,
Species capensis
Characters
1. It is connecting link between annelid and arthropod.
2. Body is caterpillar like.
3. Body is segmented.
4. Alimentary canal is straight.
5. Presence of segmented antenna.
6. Presence of Chitenous jaw.
7. Parapodia terminates into claws.
