Ankylosaurus

Abstract: A new nodosaurid specimen from the Upper Cretaceous Naashoibito Member of the Ojo Alamo Formation in the San Juan Basin, New Mexico is assigned to Glyptodontopelta mimus Ford, 2000 based on characters of internal (histological) and external osteoderm morphology. This specimen is from the same stratigraphic horizon as the holotype (USNM 8610), and because it displays a wide range of osteoderm morphotypes, it can be used as a basis for comparison of osteoderm shape and sculpturing among different ankylosaur taxa. Its unique surface texture differentiates it from other Upper Cretaceous ankylosaurids and nodosaurids (Ankylosaurus, Nodocephalosaurus, Edmontonia, Euoplocephalus, and Panoplosaurus) and demonstrates that G. mimus is a valid taxon. The nodosaurid Edmontonia australis Ford, 2000 is considered a subjective junior synonym of G. mimus based on having the same surface texture and shape of the medial cervical osteoderms. Ankylosaur osteoderms are distinctive to at least the genus level and are ...

Abstract: A new large nodosaurid ankylosaur, Peloroplites cedrimontanus, is described from a partial skull and postcranial skeleton found at the PR-2 Quarry located at the base of the Mussentuchit Member of the Cedar Mountain Formation in central Utah. The specimen is about the same size as the contemporary nodosaurid Sauropelta edwardsorum from the Cloverly Formation of Montana, and is of an individual approximately 5–5.5 m long. The skull of Peloroplites differs from that of Sauropelta in the vertical orientation of the suspensorium, non-domed cranium and broad, square premaxillary beak. The quarry is near and roughly at the same level as the CEM Quarry that produced the holotype of the ankylosaurid Cedarpelta bilbeyhallorum. The postcrania of Cedarpelta is described and illustrated based on the paratype and new material. These elements clearly establish that Cedarpelta is closer to Ankylosaurus than to Sauropelta. As a primitive ankylosaurid, there is no a priori reason to assume that the tail club was ...

Abstract: A new ankylosaurid (Ankylosauria: Dinosauria), Ziapelta sanjuanensis, gen. et sp. nov., is based on a complete skull, an incomplete first cervical half ring, a possible fragment of the second cervical half ring, and additional fragmentary osteoderms. The holotype specimen is from the Upper Cretaceous (Upper Campanian, Kirtlandian Land-Vertebrate Age) Kirtland Formation (De-na-zin Member) at Hunter Wash, San Juan Basin, in northwestern New Mexico, USA. Diagnostic characters of Ziapelta include: a large, prominent triangular median nasal caputegulum; a mixture of flat and bulbous frontonasal caputegulae; ventrolaterally oriented squamosal horns with a sharp, prominent dorsal keel; and the ventral surface of basicranium with three prominent anteroposteriorly oriented fossae. A phylogenetic analysis suggests that Ziapelta is not closely related to the other ankylosaurid from the De-na-zin Member, Nodocephalosaurus, but allies it to the northern North American ankylosaurids Ankylosaurus, Anodontosaurus, Euoplocephalus, Dyoplosaurus, and Scolosaurus.

Abstract: A new dinosaur,Taohelong jinchengensis gen.et sp.nov.,is described based on material(a proximo-middle caudal vertebra,three dorsal ribs,an almost complete left ilium,and several armors including a partial sacral shield) from the Lower Cretaceous Hekou Group in Lanzhou-Minhe Basin,north-central China.Taohelong jinchengensis possesses three autapomorphies:neural canal of proximo-middle caudal inverted trapezium,lateral edge of preacetabular process inverted "S"-shaped in dorsal view,and sacral shield composed of varioussized and irregularly-arranged osteoderms.Cladistic analysis shows that Taohelong is a member of polacanthine nodosaurid ankylosaur,and is the sister taxon of Polacanthus foxii from the Early Cretaceous Barremian of England.Here Polacanthinae is defined as the most inclusive clade containing Polacanthus foxii Owen,1865 but not Ankylosaurus magniventris Brown,1908 or Panoplosaurus mirus Lambe,1919.Taohelong represents the frst occurrence of polacanthine in Asia,and indicates again the existence of a rich and unique dinosaur assemblage in the Lower Cretaceous Hekou Group in the Lanzhou-Minhe Basin.