Dendraster excentricus (otherwise known as a sand dollar) is a flattened, burrowing echinoid. Like traditional sea urchins, its rounded body is covered in spines. D. excentricus uses its spines to move sand grains over its body to bury itself into the substrate.
The Dendraster in the lab were fertilized on the fourth of April. By the 25th of April, we started to see the rudiment forming in the late pluteus larvae. The rudiment appeared on the left side of the larvae, taking up more than half of the space within the body.
The fenestrated spines and early tube feet of the juvenile sand dollar are visible even within the larva. The juvenile will emerge from its larval skeleton oral-side first so that it can orient itself correctly on the substrate.
Here is a metamorphosed juvenile Dendraster. It is extremely active as it moves along on its tube feet.
-Jacqueline and Monica
No comments:
Post a Comment