Morphological aspects of the embryonic development of Aegla platensis (Decapoda, Aeglidae)

The present study characterizes the embryonic development of Aegla platensis Schmitt, 1942 by means of optical microscopy and electron microscopy. The sequence of morphological changes observed in the egg allowed to describe ten embryonic stages: the unsegmented egg, cleavage, blastula, gastrula, nauplius, metanauplius, early zoea, late zoea, decapodid, and juvenile. Cleavage was centrolecithal and the blastula was regular. The nauplius stage was transient. The development of the gut could be observed during the zoea stages. At the late zoea stage the posterior midgut was well developed showing chromophobous cells. The dark eye pigmentation started to develop at the early zoea stage and was completed at the decapodid stage. Newly hatched juveniles exhibit some yolk incorporation in the cephalothorax and do not need food during the first days after hatching. The morphological changes observed during the development of this anomuran are discussed in relation to patterns of development reported for other allegedly allied decapods.