page_title: Kwanasaurus
section_title: Hip and hindlimbs
hierarchical_section_title: Kwanasaurus / Description / Hip and hindlimbs
caption_attribution_description: English: Figure 20: Kwanasaurus williamparkeri distal femur DMNH EPV.67956. (A) Distal view, (B) lateral view, (C) anterior view, (D) medial view, (E) posterior view. Scale bar = 2 cm. lc = lateral condyle mc = medial condyle sul = sulcus tb = crista tibiofibularis
context_page_description: Kwanasaurus is an extinct genus of silesaurid dinosauromorph reptiles from the Late Triassic of Colorado. It is known from a single species, Kwanasaurus williamparkeri. Kwanasaurus had a deeper, stronger skull and greater specialization for herbivory compared to other silesaurids. It also possessed many unique characteristics of the snout, ilium, and lower part of the femur. It was described along with new specimens of Dromomeron from the Eagle Basin, the northernmost extent of the Chinle Formation.
context_section_description: The hip is only represented by the ilium, which had a low, saddle-shaped upper blade like silesaurids such as Silesaurus, Eucoelophysis, and Ignotosaurus. It also resembles these taxa in its elongated and expanded preacetabular process. Kwanasaurus takes this trend further, lengthening the preacetabular process so that it projects further forwards than the pubic peduncle, an adaptation otherwise only seen in several lineages of dinosaurs among dinosauromorphs. The postacetabular process is large and possesses a well-developed brevis shelf and brevis fossa, traits standard for sulcimentisaurians. Like many basal dinosauromorphs, the brevis shelf merges with the edge of the acetabulum and the rear edge of the postacetabular process has a small pointed extension. The acetabulum is deep and has a very thin and concave lower edge. This contrasts with other silesaurids, which have a straight lower edge to the acetabulum, and instead may suggest a partially perforated acetabulum akin to that of dinosaurs. The inner surface of the ilium has several facets for the sacral ribs. The second facet is twice as long as the first and may have encompassed two sacral ribs, suggesting that Kwanasaurus possessed three sacral vertebrae.
  Multiple femora of various sizes and conditions have been referred to Kwanasaurus. The femoral head was similar to that of other advanced silesaurids, according to several traits. These include a longitudinal groove on its upper surface, a straight (rather than rounded) articular facet on the medial surface, a distinct notch on its underside, and an overall triangular cross section due to the lack of a distinct posteromedial tuber. Directly below the head extends a ridge known as a dorsolateral trochanter. Adjacent to it is the anterior trochanter, a pronounced vertical crest characteristic of dinosauriforms (and a few Dromomeron specimens). The crest was blade-like, triangular, and straight-edged, proportionally most similar to Silesaurus among dinosauriforms. Only one femur referred to Kwanasaurus (DMNH EPV.125924) possessed additional muscle attachment structures such as a trochanteric shelf and a swelling that likely represented the iliotrochanteris caudalis attachment site. Asilisaurus and Silesaurus are the only other silesaurids with trochanteric shelves, and its development is sometimes considered to be related to skeletal maturity. However, the largest Kwanasaurus femur (DMNH EPV.34579) lacks a trochanteric shelf, despite its presence in the smaller 125924 specimen. All specimens had a low fourth trochanter, sometimes edged by an anterior depression as in Sacisaurus and Diodorus. The distal portion of the femur possessed several unique features. The medial condyle was a sharp flange, notably thinner than the lateral condyle and crista tibiofibularis. This is similar to lagerpetids but in contrast to the broader medial condyle of all other silesaurids. Kwanasaurus also possesses a characteristic depression on the distal surface of the femur, in front of the crista tibiofibularis. Nevertheless, the notably deep and extensive sulcus present between the medial and lateral condyles is in line with that of other silesaurids.
caption: Referred distal femur DMNH EPV.67956
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