Collected zooplankton of Investigated pond (Khutabandh, Dumka Jharkhand)

                                                       Smriti Singh 

                                                   Research Scholar 

                                          S.K.M.U, Dumka (Jharkhand)

                                   Email ID- smriti22071991@gmail.com  
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                                              1. Daphnia

                                              2. Moina  

Moina (captured by me in s.k.m.u zoology lab with bright field light microscope)

Above mentioned, both of the zooplankton comes under-

Phylum- Arthropoda

Class- Crustacea

Order- Cladocera (water fleas)

Phylum- Arthropoda

• ‘Arthron’ means jointed and ‘podon’ means foot, it means they have jointed appendages.
• The animals possess a covering of chitin which is made harder by further deposition of calcium salts. This external covering termed exoskeleton.
• It is segmented and each segment possesses a pair of jointed appendages.
• It is one of the most widely represented phyla in fresh water habitat and different groups have different ecological adaptations.

Class- Crustacea

• Crustaceans having two pairs of antennae of which one pair is called the antennules.
• The body is divided into head and trunk which is divisible into thorax and abdomen.
• In many cases, one or more of the anterior thoracic segments are fused with head to form the cephalothorax.
• The last segment of abdomen is telson.
• The appendages of the crustaceans are biramous.
• Order- Cladocera
• It is about 0.2mm - 3.0mm in size.
• The shell may appear round or oval e.g. Gurneyella odiosa (Gurney) or polygonal e.g. Daphnia (O.F.Muller), or rhomboidal e.g. Moina (Baird).
• The head and the trunk are clearly distinguished by a notch.
• The head has a large compound eye which is movable by the muscles.
• The first antennae or antennules are small and bear basal olfactory setae.
• The large second antennae are biramous and have setae.
• The trunk has five to six pairs of foliaceous thoracic legs.
• The terminal part of the body ends into an enlargement of post- abdominal segment called abreptor.
• There are two long setae on the dorsal side of the abdomen.
• Usually at the end of the post-abdomen there are two terminal claws which bear denticles and spines of various arrangements and sizes.

3. Mesocyclops

Phylum- Arthropoda

Class- Crustacea

Order- Copepoda

Order- Copepoda

• The copepods inhabit many of the fresh water habitats such as lakes, reservoirs, tanks, ponds, and pools.
• Many of the copepods are pelagic and so are abundant in the plankton of both the limnetic as well as littoral regions of the fresh water.
• It is about 0.3mm – 3.5mm.
• The first segment of thorax is fused with head to form a compound cephalic somite.
• The body seems to be divided in two parts – (a) Metasome, which is unmovable portion and it consists of head and most of the thoracic segments which are six in number.

                                                                                              (b) Urosome, which is movably articulated with the metasoma and consists of last one or two thoracic and all the abdominal segments.

• The front part of metasome is produced into a rostrum.
• The head bears first and second pairs of antennae, mandibles, first and second pairs of maxillae.
• There are two small median eyes in free living copepods.
• The antennules are uniramous.
• The last abdominal segment is with caudal rami and setae.
• The development is through various larval moults.   

                                                                           

Mesocyclops (captured by me under bright field light microscope at s.k.m.u, Dumka zoology lab)

  

searching and capturing zooplankton 

Mesocyclops ( captured by me under bright field light microscope at s.k.m.u, Dumka zoology lab)

 

(Captured with the help of compound microscope)