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

Classification of Phylum Platyhelminthes

Phylum :-  Platyhelminthes

Characters :- 

(i) Body bilaterally symmetrical & dorsoventrally flattened.

(ii) Digestive system had a single opening or mouth, that leads to a well developed gastrovascular cavity absent & anus absent.

Class :- Tubellaria

Characters :-

(i) Turbellarian are mainly free living, aquatic, but there are some terristrial sp.

(ii) Hermaphrodite, with internal fertilization.

Example :- Planeria (free living)

Fig :- Planeria

Fig :- Planeria anatomy

Class :- Trematoda

Characters :-

(i) Body cylindrical or leaf shaped & parasitic.

(ii) Body is covered by cuticle, which provides protection against host enzyme action & defence mechanism.

Examples :- Fasciola; Schistosoma; Aspidogaster;

Fig :- Fasciola

Fig :- Schistosoma

Fig :- Aspidogaster

Class :- Cestoidea

Characters :-

(i) Endoparasitic helminth, whose body is covered by a syncytial tegument.

(ii) Organs of attachment in the form of hooks & suckers are present.

Examples :- Taenia; Echinococcus;

Fig :- Taenia

Fig :- Echinococcus

Classification of Phylum Echinodermata

Phylum :- Echinodermata

Characters :- 

(i) Adult with radial & five rayed symmetry, while the larvae are bilaterally symmetrical.

(ii) The body is covered by calcareous ossicles or plates, often bearing projecting tubercles or spines.

SubPhylum :- Crinozoa

Characters :-

(i) Madriporite absent.

(ii) Radially symmetrical, possessing a cup shaped theca.

Class :- Crinoidea

Characters :-

(i) Arms are branched & bearing pinnules.

(ii) The ambulacral grooves radiates from the mouth & extend to the tip of the pinnules.

Examples :- Antedon (sea lily); Metacrinus;

Fig :- Antedon

Fig :- Metacrinus

SubPhylum :- Asterozoa

Characters :-

(i) Body is star shaped & remain unattached.

(ii) On the oral surface in the ambulacral groove, tube feet are present.

Class :- Asteroidea

Characters :-

(i) Arms are not sharply set off from the cetral dosc.

(ii) Anus & madriporite are present on the aboral surface.

Examples :- Asterias ; Asteropectin;

Fig :- Asterias

Class :- Ophiuroidea

Characters :-

(i) Arm sharply set off from the central disc.

(ii) Absence of ambulacral groove & arms are filled by vertebral ossicles.

Example :- Ophiura

Fig :- Ophiura

SubPhylum :- Echinozoa

Characters :-

(i) Radially symmetrical, globoid or discoid without arms or brachioles.

(ii) Madriporite & anus remain on the aboral surface.

Class :- Echinoidea

Characters :-

(i) Body more or less spherical, flattened orally/ aborally.

(ii) Aristotle's lantern, a apparatus used in feeding is mostly present.

Examples :- Echinus ; Arbacia;

Fig :- Echinus

Fig :- Arbacia

Class :- Holothuroidea

Characters :-

(i) Body elongated along oral/ aboral axis.

(ii) The surface of body may exhibit five ambulacral groove.

Examples :- Holothuria; Cucumaria;

Fig :- Holothuri

Fig :- Cucumaria

Classification of Phylum Nematoda according to Ruppert & Barnes(1994)

Phylum :- Nematoda

Characters :- 

(i) They have perfectly cylindrical body adapted for living in minutes place.

(ii) Body cavity is pseudocoel, Cuticle thick & tough.

(iii) Circular muscle is absent, longitudinal muscles in 4 groups.

(iv) Anterior end bear sense organ amphid & posterior phasmid present.

Class :- Aphasmida

Characters :-

(i) Anterior end of body bear chemo receptor amphids, phasmid absent posteriorly.

(ii) Most are free living animal.

(iii) Excretory system relatively simple types.

(iv) Presence of cephalic setae & papillae.

Examples :- Trichurus; Trichenella;

Fig :- Trichenella

Fig :- Trichurus

Class :- Phasmida

Characters :-

(i) Possess anteriorly Amphids & posteriorly Phasmid.

(ii) Most are parasitic.

(iii) In the caudal region there is the presence of a pair of Phasmid.

 Examples :- Ascaris; Wuchereria; Ancylostoma;

Fig :- Ascaris

Fig :- Wuchereria bancrofti

Fig :- Ancylostoma

Classification of Phylum Cnideria according to Ruppert & barnes(1994)

Phylum :- Cnideria

Character :- 

(i) Body diploblastic i.e, composed of two tissue layers, an outer epidermal (ectoderm) & an inner gastrodermis (endoderm) with several to many cell types & a less cellular mesoglea at the centre.

                   

(ii) Two different body forms may exist a 'medesa' (sexual) adapted for pelagic existence & a polyp(asexual) adapted for benthic existence.

                   

(iii)Short & slender tentacles encircles the mouth in one or more whorls.

                  

 (iv)The body composed of a special types of cell, called of Cnidocytes, containing stinging organelles called Nematocysts.

                   

(v) In the body there is an internal space for digestion, the gastrovascular cavity with the mouth as the only opening.

Class:- Hydrozoa

Characters :-

(i) Individuals are either exclusively polypoid or medusoid or constituted by both forms in the life cycle.

(ii) Mesoglea acellular.

(iii)Cnidocytes are confined to the epidermal layer.
                 
(iv)Gonads are usually ectodermal in origin.

Examples :- Hydra; Obelia; Physalia; Velella; Porpita;

Fig :- Obelia

Fig :- Hydra

Fig :- Porpita

Fig :- Physalia

Class:- Scyphozoa

Characters :- 

(i) Medusoid form is dominant in the life cycle, polypoid forms is very insufficant.
               
(ii) Mesoglea is cellular.
               
 (iii)Gonads are endodermal.
               
 (iv)The endodermal gastric tentacles are present.

 Examples :- Aurelia; Pilema; Pericolpa;

Fig :- Aurelia

Pilema

Class:- Cubozoa

Characters :- 

(i) Medusoid cnidarians with bells.
               
(ii) Body is distinctly flattened to form four sides.
                 
(iii) Bell margin simple.
                 
(iv) Presence of velum along the margin of the medusa.

Examples :- Carybdea; Chironex; Chiropsalmus;

Fig :- Carybdea

Fig :- Chirinex

Class:- Anthozoa

Characters :-

(i) Exist only in the polypoid form.
                 
(ii) Gonads are endodermal.
               
(iii) Stomodium strongly developed.
                 
(iv) Extending between the stomodaeum & the body wall there are mesenteries.


Examples :- Gorgonia(sea-fan); pennatulla(sea-pen); Corallium; Fungia;

Fig :- Gorgonia

Fig :- Pennatulla

Fig :- Corallium

Fig :- Fungia