Origin of the phylum was Cambrian period about more

than 500 million years ago

Arthropoda
 Specific Characteristics

▪ Arthropods are considered the most successful and largest

animals on the earth.
▪ Words arthro meaning joints and poda meaning foot refers to
unique feature of the group –jointed legs called appendages
(which vary widely in number and function.
• Appendages are used for eating, feeling, sensing, mating, walking
or defence. Arthropods are characterized by a chitinous
exoskeleton (outer shell).
• Arthropods body is segmented, and with a variety of respiratory
structures depending on the habitat.
. Proportion of species in the kingdom
Animalia, which are arthropods versus
all other animals. The vast majority of
arthropods are insects.
 General characters of Arthropoda

▪ The body is triploblastic, true coelomate, bilaterally symmetrical and segmented animals .
▪ Animal with hard exoskeleton (chitin) and jointed appendage (which help in locomotion).
▪ They exhibit organ system level of organization.
▪ The body is divided into head (bears a pair of compound eyes), thorax, and abdomen.
▪ They have an open circulatory system and well-developed digestive system.
▪ The terrestrial Arthropods excrete through Malpighian tubules while the aquatic ones
excrete through green glands or coaxal glands.
▪ They are unisexual and fertilization is either external or internal.
▪ They respire through the general body surface or trachea.
▪ They contain sensory organs like hairs, antennae, simple and compound eyes, auditory
organs, and statocysts
 Sub-Phylum

Trilobitomorpha

Chelicerata
Phylum

Arthropoda
Crustacea
The trilobites are an extinct group of
arthropods (e.g., Elrathia sp) that lived in the
seas of the world for about 380 million years,
from the Precambrian 610 million years ago to Tracheata
around the end of the Permian.
 Class
Xiphosura

- Cephalothorax with large extended,

convex, horse shoe shaped carapace.
- Abdomen unsegmented with long e.g. Limulus
terminal telson.

Phylum Sub-phylum Class

Arthropoda Chelicerata Arachnida

- Cephalothorax with 2 chelicerae, 2

pedipalps, and 4 pairs of walking legs e.g. Palamnaeus
- Body divided into an anterior cephalothorax
- Abdomen without appendages.
(Prosoma) and a posterior abdomen (Opisthosoma)
- Prosomatic appendages 6 pair,
- First pair chelicerae with claws
- Followed by postoral pedipalps
- 4 pairs of walking legs
Class
- Antennae and true jaws absent
Pycnogonida
Pycnogonids, also known as sea spiders, are arthropods
with long legs, a proboscis, and a reduced
abdomen. They are found in all oceans and are predators
of soft-bodied invertebrates.
 • Small crustaceans, trunk short 10 or fewer
segments • Adults sessile or parasitic.
• Small eye with 3 ocelli.
• May cephalothorax present Super-class Class
• Thorax bears biramous appendages Maxillopoda Cirripedia e.g. Balanus,
• Abdomen lacks appendages

e.g. Daphnia
Sub-phylum
Arthropoda Class Sacculina
Crustacea
Phyllopoda
• Head and thorax fused to form
cephalothorax covered with • Includes clamshrimps and water
fleas.
carapace. • Body laterally compressed.
• Appendages biramous.
• Antennae 2 pairs.
Class Carapace covers head and thorax.
Malacostraca Trunk contains 8 thoracic and 6 abdominal segments

e.g. Palaemon, Cancer, Eupagurus

• Myriapods have a single pair of antennae and, in most
cases, simple eyes.
• The mouthparts with an "epistome" and labrum Class
forming the upper lip, and a pair of maxillae Chilopoda
forming the lower lip. A pair of mandibles lie inside the
mouth.
• Myriapods are arthropods with many pairs of legs, a head,
and a multi-segmented trunk. They are wingless and live Super-class
on land. Myriapoda
• Myriapods have multiple pairs of legs running down either
side of their body. The number of legs varies by Class
species and can range from nine pairs to nearly 200.
Diplopoda
Phylum Infra-phylum
Arthropoda Uniramia/ Tracheata

• uniramous (single-branching)
Class
appendages, Entognatha
Super-class
• one pair of antennae and two
pairs of mouthparts (single pairs
Hexapoda
of mandibles and maxillae).
• Hexapods are a group of invertebrates with a
segmented body, six legs, and three body Class
parts: a head, thorax, and abdomen. Insecta
• They have a thick chitinous exoskeleton.
• Hexapods have three sets of jaws called
mandibles, maxillae, and labium.
• Myriapods have a single pair of antennae and, in most cases,
simple eyes.
• The mouthparts with an "epistome" and labrum forming the Class
upper lip, and a pair of maxillae forming the lower lip. A pair of Chilopoda
mandibles lie inside the mouth.
• Myriapods are arthropods with many pairs of legs, a head, and a Body divided into head and trunk.
multi-segmented trunk. They are wingless and live on land.
• Myriapods have multiple pairs of legs running down either side
Super-class Each trunk segment bears 1 pair of legs.
Ex. Centipedes, Scolopendra,
of their body. The number of legs varies by species and can Myriapoda
range from nine pairs to nearly 200.

Phylum Infra-phylum
Arthropoda Uniramia/ Tracheata
Super-class Class
• uniramous (single-branching)
Hexapoda Diplopoda
appendages, Body divided into head and trunk.
• one pair of antennae and two Each trunk segment bears 2 pairs of
• Hexapods are a group of invertebrates with a
pairs of mouthparts (single pairs legs. Ex. Millepedes, Julus,
segmented body, six legs, and three body
of mandibles and maxillae). parts: a head, thorax, and abdomen.
• They have a thick chitinous exoskeleton.
• Hexapods have three sets of jaws called
mandibles, maxillae, and labium.
• Myriapods have a single pair of antennae and, in most cases,
simple eyes.
• The mouthparts with an "epistome" and labrum forming the
upper lip, and a pair of maxillae forming the lower lip. A pair of Super-class
mandibles lie inside the mouth. Myriapoda
• Myriapods are arthropods with many pairs of legs, a head, and a
multi-segmented trunk. They are wingless and live on land.
• Myriapods have multiple pairs of legs running down either side
of their body. The number of legs varies by species and can
range from nine pairs to nearly 200. Class
Entognatha

Phylum Infra-phylum
Arthropoda Uniramia/ Tracheata
Super-class
Hexapoda
• uniramous (single-branching)
appendages, Class
• one pair of antennae and two • Hexapods are a group of invertebrates with a Insecta
segmented body, six legs, and three body
pairs of mouthparts (single pairs
parts: a head, thorax, and abdomen. Body divided into head thorax and
of mandibles and maxillae). • They have a thick chitinous exoskeleton. abdomen.
• Hexapods have three sets of jaws called Thorax contains 3 pairs of legs and
mandibles, maxillae, and labium. 1 or 2 pairs of wings.
 Super-class
Phylum Infra-phylum Myriapoda Order
Class
Arthropoda Uniramia/ Entognatha Archaeognath
Tracheata Super-class a
Hexapoda Order
Class Order
Insecta Zygentoma Ephemroptera

Sub-class Order
Pterygota Odonata

Infra-class
Neoptera
 1. Order
Orthoptera
Super-class
Phylum Infra-phylum Myriapoda Order 2. Order
Class
Arthropoda Uniramia/ Entognatha Archaeognatha Phasmida
Tracheata Super-class
Hexapoda Order
Class 3. Order
Insecta Zygentoma Grylloblattaria
Sub-class Infraclass 4. Order
Pterygota Neoptera Mantophasmatodea
5. Order
Dermaptera
6. Order
Plecoptera
7. Order
Embioptera
 8. Order 16. Order 23. Order
Isoptera
e.g. Termites e.g. Bombyx
Thysanoptera Lepidoptera

9. Order 17. Order 24. Order

Mantoidea Coleoptera Mecoptera

18. Order
10. Order e.g. Periplaneta 25. Order
Neuroptera
Blattaria Siphonoptera

11. Order 19. Order 26. Order

Zoraptera Megaloptera Strepsiptera

12. Order 27. Order

20. Order e.g. Musca
Psocoptera Diptera
Raphidioptera

13. Order
21. Order
Phthiraptera e.g. Apis
Hymenoptera

14. Order
22. Order
Hemiptera
Trichoptera