FIGURE 1

The zebrafish head has a complex anatomical organization (A, B) Schematics showing arrangement of craniofacial skeleton, muscle, and tendon in ventral and lateral planes (adapted from Schilling and Kimmel, 1997). (C, D) Schematics showing cranial nerves originating from rhombomere (r) 2, 3 & 4 innervating the branchial muscles in ventral and lateral planes. (E) 4dpf sox10:Kaede;unc:mCherry double transgenic fish showing musculoskeletal arrangement laterally. (F) 4dpf sox10:Kaede;scx:mCherry double transgenic fish showing tendons and cartilage laterally. (G) 4dpf sox10:Kaede;isl1:RFP double transgenic fish showing branchiomotor neurons and cartilage laterally. (H–J) Ventral view of developing zebrafish head at 56hpf showing craniofacial cartilage, muscle, tendons, and motor neurons emerge and integrate around the same developmental window. A (anterior), D (dorsal) L (lateral). r (rhombomere). Skeleton (grey)—BB (basibranchial), BH (basihyal), CB (ceratobranchial), CH (ceratohyal), CL (cleithrum), ETH (ethmoid), TB (trabecula), HH (hypohyal), HS (hyosymplectic), MC (Meckel’s cartilage), OP (opercle), PQ (palatoquadrate). Tendon (blue)—CHHT (ceratohyal hyohyoideus tendon), CHIT (ceratohyal interhyoideus tendon), HHJ (hyohyal junction), IMT (intermandibular tendon), MAT (Meckel’s adductor tendon), MHJ (mylohyoid junction), PQAT (palatoquadrate adductor tendon), SHT (sternohyoideus tendon). Muscle (pink)—M.AM (adductor mandibularis muscle), M. AO (adductor operculi muscle), M. DO (dilator operculi muscle), M. HH (hyohyoideus muscle), M. IH (interhyoideus muscle), M. IMA (Intermandibularis anterior muscle), M. IMP (Intermandibularis posterior muscle), M. LAP (levator arcus palatini muscle), M. LO (levator operculi muscle), M. SH (sternohyoideus muscle). Scale bar = 100 um.