Phylum-Echinodermata - Chart

Sea Cucumber

Classification:

Phylum-            Echinodermata           Presence of spines on body

Class -               Holothuroidea             Body cylindrical with bilateral symmetry

Order-               Aspidochirotida          Body wall tough and muscular

Type-                Sea Cucumber             Body elongated with bilateral symmetry

Characters:

1.      Body elongated, vermiform and bilaterally symmetrical.

2.      Tube feet scattered all over the body.

3.      Dorsal tube feet pointed.

4.      20-30 oral tentacles are present anteriorly.

5.      Ventral tube feet with suckers.

Brittle Star

 

Classification:

Phylum-            Echinodermata           Presence of spines on body

Class -               Stelleroidea                 Long slender arm containing open ambulacral groove

Order-               Oegophiurida              Presence of five simple, slender, jointed and brittle arms

Type-                Brittle Star                  Flat disc covered by scales and radial shields.

Characters:

1.      Body flattened, pentamerous and star shaped.

2.      It shows 5 long, slender, brittle arms

3.      Spines on the body are short, cilia like and downwardly directed.

4.      Arms bear open ambulacral grooves on ventral side.

5.      Oral and aboral surfaces are distinct.

Sea Star

Classification:

Phylum-            Echinodermata                       Presence of spines on body

Class -               Asteroidea                               Pentagonal body with flattened central disc

Order-               Forcipulata                              Marginal plates not prominent

Genus-              Asterias                                   Body star shaped with radial symmetry

Species-            rubencs                                    Ambulacral spines with pedicellariae

Characters:

1.      Commonly called as star fish.

2.      Body pentagonal star shaped with radial symmetry.

3.      Ambulacral grooves are open and bear tube feet in 2 rows.

4.      Mouth is on the oral surface and anus is on the aboral surface.

5.      Tube feet are provided with the terminal suckers hence they act as locomotary organs. 

Sea Urchin

Classification:

Phylum-            Echinodermata           Presence of spines on body

Class -               Echinoidea                  Body globular, oval

Order-               Echinoida                    Testa globular and rigid

Type-                Sea urchin                   Body with flat oral and dome

                                                  shaped aboral surface

Characters:

1.      Body nearly spherical with flat oral and dome shaped aboral surface.

2.      Calcareous plates are present on body surface which act as exoskeleton called as test.

3.      Whole surface of test is covered with movable spines except mouth and anal region.

4.      Tube feet are arranged in rows in ambulacral grooves

5.      External gills are present.

6.      Spines are of same size.

Sea Lily/ Feather Star

Classification:

Phylum-            Echinodermata           Presence of spines on body

Class -               Crinoidea                    Presence of stalk and branched arms

Order-               Commatulida              Arms usually branched bearing pinnules

Type-                Sea lily                        Arms 10, elongated and slender

Characters:

1.      These animals are usually stalked with movable and branched arms.

2.      Generally 10 long, slender arms are present.

3.      Both mouth and anus are present on oral surface.

4.      Oral surface is leathery and with numerous calcareous plates.

5.      Each arm contains the double series of pinnules.

6.      Young stages are stalked while later stages are free swimming.