IDENTIFICATION (with reason) OF Asterias sp. (B.Sc. ZOOLOGY_CCF-CC5_SEM4)

  Identifying features are:

1. Multicellular heterotroph.
2. embryonic development, preceded by heterogametic fertilization.

            Hence, the specimen belongs to the Kingdom Animalia.

1. Usually exhibit pentamerous symmetry.
2. Presence of external spines.
3. Oral surface directed downward.
4. Tube foot is present.
5. Five grooves named ambulacra are usually present.

           Hence, the specimen belongs to the Phylum Echinodermata

1. Star-shaped body.
2. Ambulacral grooves are present on the oral surface bearing double series of tube feet with suckers.
3. Mouth is directed downwards.

               Hence, the specimen belongs to the Sub Phylum Asterozoa

1. Arms are not sharply set off from the central disc.
2. Madreporite is on the oral surface.
3. Pedicellariae is present.
4. Ambulacral grooves are open & a large coelomic cavity is present in the arms.

              Hence, the specimen belongs to Class Asteroidea

1. Five radiating arms arise from  the pentagonal central disc.
2. On the convex aboral surface anus is eccentrically placed.
3. From mouth to the tip of each arm Ambulacral groove extends.

           Hence, the specimen seems to be Asterias sp.

Systematic Position (Ruppert & Barnes 1994)

 Kingdom: Animalia

   Phylum: Echinodermata

         Sub Phylum:Asterozoa

                 Class: Asteroidea

                     Genus: Asterias