Biology of Finfish and Shellfish (2+1)

4.12.5. Nauplius IV

MTL: 0.36 mm (0.34-0.38 mm); MW: 0.17 mm (0, 15-0, 18 mm); MFS: 0.20 mm (0.19-0.21 mm).

The furcal lobes become more distinct and bear 4 setae each, outermost seta smallest and being dorsally placed not clearly visible in ventral view; rudiments of developing Mx1, Mx2, Mxp1, Mxp3 seen inside cuticle; A1 outer lateral seta lost and one very small seta added on inner lateral aspect proximally; proximal portion with indistinct segmentation; exopod of A2 with 6 long plumose setae and one rudimentary spine-like seta distally, indistinct segmentation seen in exopod, inner terminal seta on A2 endopod longer. Duration of this sub stage is 3 to 4 hours.