Four Stages of Parhyale Germband Elongation
The amphipod crustacean Parhyale hawaiensis has germband formation that is different from the long-germ type of Drosophila. Germband formation in Parhyale is sequential like in short-germ insects.
(1) At the earliest stage, the germband comprises only the head segments.
(2) Next, the ectoderm of the trunk segments is set up in a grid-like arrangement. The grid has straight rows and columns that emerge by self-organization.
(3) The grid is maintained during two longitudinal divisions.
(4) Later, the intersegmental furrows become visible.
Courtesy of Matthias Gerberding
[Not a valid template]