Main evolutionary patterns of the pelvic and femoral structures through the probainognathian evolution.

The right pelvis and femora are respectively represented in lateral and posterior view (with exception of the femur of Irajatherium, which is represented in anterior view*). 1, reduced postacetabular region of the iliac blade; 2, medial projection of the lesser trochanter; 3, distinct greater trochanter; 4, head set-off from the shaft by a short femoral neck; 5, confluent acetabular facets of the three bones composing the acetabulum; 6, hemispherical femoral head; 7, narrow intertrochanteric fossa instead of wide and circular; 8, well-marked intertrochanteric crest; 9, presence of the fovea capitis; 10, narrow distal end of the femur; 11, rim of the acetabulum without dorsal emargination; 12, femoral head strongly projected medially and long femoral neck. The hemispherical femoral head is only present in Tritylodon among Tritylodontidae, but it is not represented in this phylogeny. Abbreviations: ac, acetabulum; f.h, femoral head; gr.tr, greater trochanter; int.cr, intertrochanteric crest; int.f, intertrochanteric fossa; l.tr, lesser trochanter; ob, obturator foramen; post.ac, postacetabular region of the iliac blade; pre.ac, preacetabular region of the iliac blade; p.tb, pubic tuberosity.