Xuwulong

Norman, David B., 2015, On the history, osteology, and systematic position of the Wealden (Hastings group) dinosaur Hypselospinus fittoni (Iguanodontia: Styracosterna), Zoological Journal of the Linnean Society 173 (1), pp. 92-189 : 153-154

XUWULONG YUELUNI YOU, LI & LIU, 2011

Xuwulong is represented by a complete skull, most of the vertebral column, the ribcage, and the left pelvic girdle. The skeleton was collected from the Yujingzi Basin in Jinta County, north-western Gansu Province, China, and from the Xinminpu Group (Aptian−Albian), as does Jintasaurus (see above). The specimen has been described briefly, with some accompanying photographs and a simple interpretative outline of the skull.

Cranium

The skull, although slightly crushed, exhibits a flat skull roof and the frontal contributes to the dorsal margin of the orbit. A long, tapering palpebral crosses the orbit; the nasals form elongate rostral spines that are lodged against the mediodorsal premaxillary process; the external nares are enlarged; and the premaxilla appears to be ventrolaterally flared. The quadrate is pillarlike and its jugal wing is deeply notched to receive the quadratojugal (a paraquadrate foramen may be present).

Teeth and jaws

A single functional tooth and one replacement crown are present in each alveolus. The maxillary crowns are described as possessing a single prominent primary ridge that is slightly offset distally on the crown face; occasional smaller secondary ridges may also be present. The dentary crowns are described as bearing two low ridges, with some additional weak ridges. The margins of the maxillary and dentary crowns are denticulate. The dentary is robust and bears a prominent, laterally offset, and prominent coronoid process; the dentary ramus is robust and comparatively short, terminating in an obliquely positioned predentary, which bears a denticulate margin and a bifurcated ventral process.

Axial skeleton

A complete series of 11 cervicals is preserved, and it has been suggested that there are 16 dorsals; the sacral region is obscured by the pelvic bones, but it has been estimated that at least six sacrals are present. Nineteen caudals from the anterior and middle portion of the tail are preserved, along with their haemal spines. The dorsal vertebrae appear to support oblique, rectangular spines that are considerably shorter than those seen in Hypselospinus . Caudal vertebrae support narrower and taller neural spines.

Appendicular skeleton

The ilium is well preserved and resembles in the details of its form and proportions that of Hypselospinus . The pubis has an extremely elongate, expanded, and downturned prepubic blade and an elongate rodshaped posterior pubic ramus. The ischium has an elongate, somewhat angular-sided, shaft that is arched dorsally and terminates in an anteriorly expanded boot; this bone appears to resemble the ischium of Hypselospinus in its general shape and proportions. Taxonomic note

See Jintasaurus (above).