This video shows the life cycle of the sea biscuit Clypeaster subdepressus and is part of my master's thesis project at the Biosciences Institute of University of São Paulo.
We collected adults from sand beds of São Sebastião Channel (São Sebastião, SP, Brazil) and induced gamete release (eggs and sperm). We did the fertilization in vitro and followed the embryonic development in the laboratory, under light microscopy. Embryos become swimming larvae, approximately 0.2 mm wide, which we fed with microalgae until metamorphosis. A diminute sea biscuit grows inside the larva. When the minuscule podia and spines are formed the larva sinks and undergoes metamorphosis. The juvenile sea biscuit resorbs the larval tissue and begins to explore its new habitat, between sand grains.
The formal description was published in 2010:
We did the footage in the Marine Biology Center of University of São Paulo (CEBIMar-USP), located in São Sebastião, SP, Brazil, northern shore of State of São Paulo.
You can find more information about this project in the website.
Download the soundtrack from the netlabel AEROTONE.
This video is under a Creative Commons by-nc-sa license.