CLASSIFICATION OF RHABDOPLEURA

PHYLUM :-  HEMICHORDATA ( Marine, enterocoelous coelomate. Notochord confined to head region).

CLASS :- PTEROBRANCHIA (Small hemichordates with encased body. U-shaped intestine).

FAMILY :- RHABDOPLEURIDA (Colonial, no gil-slits; 1 gonad).

Genus : Rhabdopleura

GEOGRAPHICAL DISTRIBUTION

  • It is mainly found in southern hemisphere especially reported from Norway and Ireland coasts.

HABIT AND HABITAT

  • It is a marine and colonial hemichordate, found 5 to 6 meters deep. The colony is formed on hard substratum and also in association with mollusc shells, bryozoans and tunieates.

RHABDOPLEURA DIAGRAM HEMICHORDATA

GENERAL CHARACTERSTICS OF RHABDOPLEURA

  • Colony consists of zooids enclosed into erect tubes which are much more elongated than zooids. 
  • Colony contains erect coenoecium extended zooids, contractile stalk, decumbent coenoecium, retracted zooids, pectocaulus and young buds. 
  • Each zooid is composed of stalk, trunk sac, oral lamella, pigment stripe, cephalic shield, arms and tentacles. 
  • There is a lophophore with one pair of arms, one gonad, but without gill-slits. 
  • Alimentary canal is V-shaped. 
  • Most of the zooids are sterile, but male and female specimens may be observe. 
  • Sexes united. Development includes a free-swimming larva.
  • Zooids are formed by budding, but the buds do not break off from the stolon and remain permanently attached to form a colony.
RHABDOPLEURA HEMICHORDATA

SPECIAL FEATURES

  • Rhabdopleura is a colonial hemichordate with organic continuity between individuals that are produced by a sexual budding from one individual.

IDENTIFICATION

  • It contains extended zooids and all above features, hence it is Rhabdopleura.

REFERENCES

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