Pelvic musculature development in the axolotl. Immunostained larvae of Ambystoma mexicanum showing the developing pelvic musculature. All stages were incubated in a primary antibody against skeletal muscle and were visualized with a secondary anti-IgG1(γ1) 568 Alexa antibody. v, ventral view and l, lateral view; ld, lateral view, detail; d, dorsal view. A) Stage 55, B) 1.5 cm, C) 2.0 cm, D) 2.5 cm, *E) 3.0 cm. Cfe, caudofemoralis; Cpist, caudopuboischiotibialis; Ilfe, iliofemoralis; Isfe, ischiofemoralis; Isfl, ischioflexorius; Pisfe ext, puboischiofemoralis externus; Pisfe int, puboischiofemoralis internus; Pist, puboischiotibialis; Pop, popliteus; Pt, pubotibialis; R.a., rectus abdominis; S. e., shank extensors; S. f., shank flexors. Anterior to the left. *Shank extensors and flexors are absent because the distal part of the limb has been bitten of by another individual.