Classification of Phylum Arthropoda

Phylum :- Arthropoda

Characters :- 

(i) A pair of externally jointed appendages is usually present in each segment.

(ii) Body is externally covered by thick, tough & chitinous cuticle, forming the exoskeleton.

SubPhylum :- Crustacea

Characters :- 

(i) Head bears five pairs of appendages which comprises of two pairs of antennae & two pairs of maxilla.

(ii) Respiration usually through gills.

Class :- Branchiopoda

Characters :- 

(i) Trunk appendages are flattened leaf like structure.

(ii) Coxa is provided with a flattened epipod.

Examples :- Triopes(tadpole shrimp); Daphnia; Artemia;

Fig :- Triopes

Fig :- Daphnia

Fig :- Artemia

Class :- Ciripedia

Characters :-

(i) Body enclosed within a bivalve carapace.

(ii) Body is poorly segmented & most lack abdomen.

Examples :- Lepas; Balanus; Sacculina;

Fig :- Balanus

Fig :- Lepas

Fig :- Sacculina

Class :- Malacostraca

Characters :-

(i) Body comprises of head, an eight segmented thorax & six segmented abdomen.

(ii) The posterior thoracic limbs being walking legs, the 1st five pairs of abdominal ones forming swimming organs.

Examples :- Squilla; Hippa; Macrobrachium(prawn); Cancer;

Fig :- Squilla

Fig :- Macrobrachium

SubPhylum :- Uniramia

Characters :-

(i) Appendages are uniramous

Class :- Diplopoda

Characters :- 

(i) Presence of double trunk segments, which are either cylindrical or somewhat flattened.

(ii) Presence of calcified exoskeleton.

Example :- Julus

Fig :- Julus

Class :- Insecta

Characters :- 

(i) Head formed by the fusion of 6 segments, typically bears a single pairs of antennae & two pairs of maxillae.

(ii) The trunk in insects subdevided into three segmented thorax & an abdomen of 11 segments without walking legs.

Examples :- Lepisma(silver fish); Periplaneta; Carausias(stick insect);Bombyx; Anopheles;

Fig :- Lepisma

Fig :- Periplaneta

Bombyx

Fig :- Anopheles

SubPhylum :- Chelicerata

Characters :- 

(i) Body divided into an anterior cephalothorax or prosoma, which wholly or partially covered by a dorsal carapace  & a posterior abdomen or opsthosoma.

(ii) Lack of antennae.

Class :- Merostomata

Characters :- 

(i) A prominent spike like caudal spine or telson is present at the end of the body.

(ii) Prosoma is covered by a large, horse shoe shaped carapace.

  

Example :- Limulus

Fig :- Limulus