Avisauridae leg formed by fused metatarsals (the bones which comprise the foot in humans). As a result, members of this family are distinguished from other enantiornitheans exclusively by features of the tarsometatarsal and pedal phalanges (toe bones). Unlike in some prehistoric birds, avisaurid tarsometatarsals were not completely fused, with the distal (outer) parts of the metatarsals being separate from each other. The proximal (near) half of metatarsal III (the long bone in the middle of the tarsometatarsus) is convex from the front. The inside edge of this bone's trochlea (toe joint) has a bony tab which points downward, known as a
Dianopachysaurus a triangular acetabulum, and a reduced but still quite robust dorsal process. The pubis is round, and has an open obdurator foramen, but the ischium is almost entirely hidden. The femurs are slender and slightly sigmoid, with distinct striations on both ends. They are 14 mm long. The fibulae are slightly longer than the tibiae, at 6.5 rather than 6 mm long. The astragali are larger than the calcanea, but both have flat proximal margins. The first metatarsals are distinctly shorter than the others, and many metatarsals are covered by phalanges and so not fully visible. Enough phalanges are preserved