Dicynodon njalilus von Huene 1942 Tetragonias is an extinct genus of dicynodont from the Anisian Manda Beds of Tanzania.

[6] As for Cruickshank's specific diagnosis, T. njalilus was described as a “medium sized dicynodont, tusked in both sexes" with an overall rectangular skull shape in dorsal view.

He included details about the maxillary processes surrounding the tusks differently in males and females, the fact that the postorbital bones do not meet the squamosals at the back of the temporal fenestrae, information about the size of the interpterygoid space in relation to the length of the internal nares, and most significantly, that the intertemporal bar is “drawn out into low parietal crest.”[2] T. njalilus skull bones are quite large.

However, T. njalilus has much larger temporal fenestrae than Lystrosaurus murrayi, as well as a shallower skull, no postfrontals,  a parietal crest, and differences in size of some parts of the palate.

In Tetragonias the straight medial margins of the puboischiadic suggest an articulation which is supported by ligaments or cartilage, although there's no evidence for a suture or fusion along the midline.

As mentioned earlier concerning the biomechanical strain on the hind limb, most of Tetragonias's body weight would have been carried by the adducted hind limb rather than pelvis: “In this orientation of the pelvic girdle, the supraacetabular crest is strongly overhanging the acetabulum, forming a well-developed dorsal roof to the laterally pointing articulation surface.

This feature emphasizes a direct transmission of the body load from the pelvis to the femur, resulting in a more adducted position of the hind limb.”[8] This inhibits Tetragonias from sprawling motion,[9] but rather, a parasaggital gait.

This is likely attributable to the trend of growing body size observed throughout dicynodont evolutionary history, which positively correlates with an increase in sacral vertebrae number.