CLASSIFICATION OF PENTACEROS (SEA PENTAGON)
KINGDOM :- ANIMALIA (Multicellular eukaryotic organisms)
PHYLUM :- ECHINODERMATA (Coelomate, pentaradiate and spiny skinned animals with vascular system.)
SUB-PHYLUM :- ELEUTHEROZOA (Non-pedicellate and free-living.)
CLASS :- ASTEROIDEA (Central disc and arms fused.)
ORDER :- PHANEROZONIA (Marginal plates distinct.)
GENUS :- Pentaceros
It is found in U. K., U.S.A., India, Panama and South America.
HABIT AND HABITAT
Pentaceros is the most common eleutherozoan echinoderm found in sea from shallow water to 1,000 fathoms.
GENERAL CHARACTERSTICS OF PENTACEROS (SEA PENTAGON)
- Commonly called as sea pentagon or starfish.
- Body is enclosed in a tough, hard and leathery integument containing several ossicles.
- Central disc and the arms are fused together. Arms contain extension of gonad, coelom and the gut.
- Arms are 5 in number and symmetrically arranged in the form of star around the central disc. Body is differentiated into oral and aboral surfaces.
- Aboral surface is brown and convex, containing rows of definitely arranged spines. The marginal plates are large and distinct.
- There is a rounded sieve plate or madreporite plate in one of the inter-radii. It forms the first part of the water vascular system which is well developed.
- Oral surface is concave, dark brown, having a centrally-placed mouth or actinostome. Mouth is 5-angled and each angle is continued into the ambulacral groove up to the tip of an arm.
- Ambulacral groove contain double rows of locomotory organs of tube foot.
- Sexes are separate. Development indirect which includes bipinnaria larva.
- Pentaceros is the most familiar seashore animals.
The animal contains leathery surface and all above features, hence, it is Pentaceros.