FishFace

By 32 hpf, pharyngeal arches 1 and 2 (pa1, pa2) continue to extend (lengthen) along the dorsal-ventral axis. Pharyngeal pouch 1 (pp1), which is GFP-negative in fli1a:EGFP transgenic fish, maintains the dorsal separation between pharyngeal arches 1 and 2, while the oral ectoderm (oe), which also is GFP-negative in fli1a:EGFP transgenic fish, continues to separate dorsal and ventral cells in the anterior region of pharyngeal arch 1. Pharyngeal arch 1 has expanded further anteriorly along both dorsal and ventral surfaces of the oral ectoderm, compared to that seen at 28 hpf. Also, some neural crest cells abutting pharyngeal pouch 1 appear to be aligning with the endodermal surface.