Larval forms of Crustacea.pptx

Larval forms of Crustacea.

1. Larval forms of Crustacea K.Kamatchi Assistant Professor Department of Zoology Vivekananda College Tiruvedakam West

2. Direct or indirect Egg – hatches – young one – resemble – adult Egg – hatches – larval stages – adult

3. Nauplius First larva Free swimming Minute and microscopic Oval – shape Cephalothorax, abdomen Simple median eye 3 pairs of appendages Uniramous Biramous – antenna, mandible Caudal fork Under goes moults- metanaupilus .

4. Metanauplius Second larva Develops from nauplius Cephalothorax, abdomen Caudal fork Frontal sense organ Median eye.

5. Protozoea Larva of prawn Develops – metanauplius Cephalothorax, abdomen Cepha – covered – carapace 5 pairs of appendages Throax – 2 Abdomen – no Telson

6. Zoea Developes – protozoea Free swimming Minute, microscopic Cephalothorax, abdomen Carapace Rostrum 5 cephalic app 3 thoracic app Remain 5 buds Abdomen – no – app Telson

7. Mysis Develops – zoea Elongated, laterally compresed Cephalothroax , abdomen Carapace Rostrum All appendages developed Differ from adult by brood pouch.

8. Cypris Develops – nauplius Triangular Bivalved shell 7 pairs of app Caudal spines Terminal end – antennules – hooked Median eye Germ cells Short free swimming – attached – crab – kentrogen larva.

9. Kentrogen Develops – cypris Attached to crab Like sac – cuticle Chitinous tube – dart Later stage – pierces – body of crab

10. Alima Modified zoea Hatches out direct form egg. Pelagic larva Glass like transparency. Slender body Cephalothorax, abdomen Carapace Rostrum All – cepha 2 – thorax 4 – abdo

11. Megalopa larva Larva of crab Develops – zoea Pelagic larva Cepha , abdo Carapace, rostrum Median spine Eyes – compound Megalopa - crab

12. Phyllosoma larva Directly – egg Glass –crab Modified Mysis Cepha , abdo Carapace Compound eye