Fig. 7

Gastrulation at two distinct loci in Cheiracanthium mildei. A1–E1, A2–E2 External view of two representative embryos show internalization of different cell populations at two distinct loci. First, cumulus cells (red and pink) internalize through a central blastopore; then generalized mesendoderm (yellow) internalizes in situ at a separate ring outside the blastopore. Some mesendoderm likely internalizes at the original blastopore as well, see text. Times in min. Scale bars 200 µm. Timelapse movie of Cm embryo 1 is shown in Additional file 8: Movie 5. A3–E3 Representation of gastrulation in C. mildei from our timelapse and histological data (not shown). Diagrammatic midsagittal sections. Ectoderm is blue, cumulus is red, mesendoderm is yellow