CLASSIFICATION OF UNIO (FRESH WATER MUSSEL)​

KINGDOM :- ANIMALIA (Multicellular eukaryotic organisms)

PHYLUM :- MOLLUSCA (Unsegmented bilaterally symmetrical and provided with visceral mass, foot and mantle.)

CLASS :- PELECYPODA OR BIVALVIA (Bivalve shell.)

ORDER :- UNIONIDA (Gill filaments united by inter-filament and inter-lamellar junctions.)

FAMILY :- UNIONIDAE

GENUS :- Unio (The Fresh water Mussel or Clam)

GEOGRAPHICAL DISTRIBUTION

  • It is commonly found in India, Europe, Atlantic slope and U.S.A.

HABIT AND HABITAT

  • Unio is the most familiar and very favourite pelecypod, found in ponds, lakes, rivers and streams. The animal is usually buried in the mud.

UNIO (FRESH WATER MUSSEL)​

GENERAL CHARACTERSTICS OF UNIO (FRESH WATER MUSSEL)​

  • Commonly called as fresh water mussel or clam.
  • Body is dark brown, unsegmented, bilaterally symmetrical and flattened from side to side measuring 5 to 10 cm in length. 
  • Animal is completely enclosed in equal bivalve shells. The periostracum is generally smooth and without rays.
  • Two valves are united together along the dorsal side in a straight hinge-line by hinge-ligament. Anteriorly, in front of the hinge, there is a whitish, knob-like swelling on each valve, called as umbo. Outer surface of each shell contains various lines of growth. Hinge is without teeth. 
  • Posteriorly, on lateral margins there are two openings; smaller one is exhalent siphon, while the larger one is inhalent siphon.
  • Mantle consists of two lobes, corresponding to two valves of the shell. Ctenidia are W-shaped and eulamellibranch.
  • Foot is large, muscular and wedge-shaped and is used for burrowing. 
  • Adductor muscles are of same size, i.e. isomyarian. 
  • Sexes are separate but the male and female shells are alike. Development includes glochidium larva.
UNIO (FRESH WATER MUSSEL)​

ECONOMIC IMPORTANCE

  • The shells are used in making buttons and animals are largely dissected for understanding nervous system and invertebrate anatomy.

IDENTIFICATION

  • The animal contains Umbo, hinge and all above characters, hence it is Unio.

UNIO (FRESH WATER MUSSEL)​
UNIO (FRESH WATER MUSSEL)​
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