Ornithosuchus longidens (Huxley 1877) Late Triassic ~210mya, 4 m in length, was derived from a sister to Euparkeria and was a sister to Riojasuchus.
Overall the proportions of Ornithosuchus resembled those of the much smaller Euparkeria.
The skull had an elongated naris and an expanded antorbital fossa and orbit. The skull was more angular. Ornithosuchus retained the distinct notch in the jawline characteristic of all basal euarchosauriformes beginning with Proterosuchus. The quadratojugal and squamosal further invaded the lateral temporal fenestra. The mandibular fenestra was larger and the posterior mandible turned down.
The cervicals were relatively smaller, little different from the dorsals. The caudal series included many more vertebrae, each one with a taller neural spine and deeper chevron.
The scapula was gracile as were the forelimb elements. Furhter reduction of the lateral metacarpals and digits continued.
The pubis was greatly deepened, which would have expanded the torso. The hind lmbs were longer and less robust. The calcaneum developed a distinct process, a "heel" that curved posteriorly. The pedal elements were all longer with less difference between the medial and lateral element diameters. However, digit I was much shorter and digit V was not hooked. |
