was a large, sculptured and concave surface that likely worked as the insertion for the m. iliofemoralis internus in life, and the lesser trochanter had the insertion for the m. pubo ischio femoralis on the lower edge. On the upper lateral surface of the femur, bottom-oriented to the greater trochanter, there was a tubercle that formed the attachment for the m. iliofemoralis. Insertions for m. ilio trochantericus and ischio trochantericus were located on the posterolateral surface at the proximal end of the femur. In the inner side, on the proximal third part of the shaft, a coarse, concave area likely attached m. pubo ischio femoralis externus-3. Below this area, a small, convex tubercle attended the insertion for m. pubo ischio femoralis-2. The tibia was less robust than the femur, but straighter, measuring in length. The surface of the shaft center was smooth, without traces of muscles. In front and towards the back surface of the cnemial crest, however, a coarse and microsculptured area worked as the attachment for m. ilio tibialis and ambiens. Additional tissue traces in the tibia were located on the lower surface and towards the posterior aspect. Here, a depression with a somewhat coarse surface likely attached prominent aponeurosis of the connected ligaments to the tibia and fibular head in life. Metatarsals III and IV were stocky, measuring and , respectively, indicating that the length of the metatarsus was under the 50% of the tibial length. As in other maniraptorans, the metatarsals were closely united. The top end of metatarsal III was side-to-side flattened and not pinched at the upper end, thus lacking an arctometatarsalian (pinched upper end) condition. The lower end of metatarsal IV had a joint where motion was restricted to one plane, and the lateral condyle was short. The pelvis was formed by the pubis, ilium, and ischium bones. The ilium was prominently tall, measuring in length and in height with the preacetabular process situated from top to bottom. Both insertions for the m. caudofemoralis were located at the inner surface of the ilium. On the anterior edge were microstriations that likely gave form to the m. iliofemoralis in life, behind to this area, traces of the m. ilio tibialis-2 were also present. The pubis measured long and is very straight, having a large pubic boot (a wide expansion at the end). While other dromaeosaurids had a very opisthopubic pelvic configuration, Achillobator had a