Gargoyleosaurus

Gargoyleosaurus (meaning "gargoyle lizard") is one of the earliest ankylosaurs known from reasonably complete fossil remains. Its skull measures 29 centimetres (11 in) in length, and its total body length is an estimated 3 to 4 metres (9.8 to 13.1 ft). It may have weighed as much as 1 tonne (2,200 lb). The holotype was discovered at the Bone Cabin Quarry West locality, in Albany County, Wyoming in exposures of the Upper Jurassic (Kimmeridgian to Tithonian stages) Morrison Formation.[1]

Gargoyleosaurus
Temporal range: Late Jurassic, 154–150 Ma
↓
Fossil skeleton, Denver Museum of Nature and Science
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: †Ornithischia
Family: †Nodosauridae
Genus: †Gargoyleosaurus
Carpenter et al. 1998
Species:
†G. parkpinorum
Binomial name
†Gargoyleosaurus parkpinorum
Carpenter et al. 1998

The type species, G. parkpinorum (originally G. parkpini) was described by Ken Carpenter et al. in 1998. A mounted skeletal reconstruction of Gargoyleosaurus parkpinorum can be seen at the Denver Museum of Nature and Science and, alongside a couple skeletons of baby Stegosaurus, has been on display there since 2002. Gargoyleosaurus was present in stratigraphic zone 2 of the Morrison Formation.[2]

Holotype
Gargoyleosaurus skeleton cast, Museum of Ancient Life - Thanksgiving Point.

The holotype specimen of Gargoyleosaurus parkpinorum was collected by Western Paleontology Labs in 1996 and is currently held in the collections of the Denver Museum of Nature and Science, Denver, Colorado. Besides the holotype, two other partial skeletons are known (although not yet described). The holotype consists of most of the skull and a partial postcranial skeleton. The specimen was originally described as Gargoyleosaurus parkpini by Carpenter, Miles and Cloward in 1998, then renamed G. parkpinorum by Carpenter et al. in 2001, in accordance with ICZN art. 31.1.2A.

Classification
Size comparison

Much of the skull and skeleton has been recovered, and the taxon displays cranial sculpturing, including pronounced deltoid quadratojugal and squamosal bosses. The taxon is further characterized by a narrow rostrum (in dorsal view), the presence of seven conical teeth in each premaxilla, an incomplete osseous nasal septum, a linearly arranged nasal cavity, the absence of an osseus secondary palate, and, as regards osteoderms, two sets of co-ossified cervical plates and a number of elongate conical spines.[1] A very unusual feature is the sagittal (midline) osteoderm on the first set of cervical plates; in most other ankylosaurs, these osteoderms are bilateral, i.e. paired with one on each side of the midline.[3]

Vickaryous et al. (2004) place Gargoyleosaurus parkpinorum within the family Ankylosauridae of the Ankylosauria and are in agreement with most previous phylogenetic hypotheses, which place the genus as the sister group to all other ankylosaurids (i.e., members of the Ankylosauridae). These studies however, only utilized the skull, whereas many of the distinctive features of the family Polacanthidae are in the postcranial skeleton.

See also

References
  • Carpenter, K., Miles, C. and Cloward, K. (1998). "Skull of a Jurassic ankylosaur (Dinosauria)." Nature 393: 782-783.
  • Carpenter, K. (ed.) The Armored Dinosaurs. pp. 454–483. Indiana University Press, Bloomington.
  • Vickaryous, Maryanska, and Weishampel (2004). "Ankylosauria". in The Dinosauria (2nd edition), Weishampel, D. B., Dodson, P., and Osmólska, H., editors. University of California Press.
  • Killbourne, B. and Carpenter, K. (2005). "Redescription of Gargoyleosaurus parkpinorum, a polacanthid ankylosaur from the Upper Jurassic of Albany County, Wyoming". Neues Jahrbuch für Geologie und Paläontologie, 237, 111-160.
  1. Benton, Michael J. (2012). Prehistoric Life. Edinburgh, Scotland: Dorling Kindersley. p. 278. ISBN 978-0-7566-9910-9.
  2. Foster, J. (2007). "Appendix." Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. pp. 327-329.
  3. Kilbourne, B. and Carpenter, K. 2005. "Redescription of Gargoyleosaurus parkpinorum, a polacanthid ankylosaur from the Upper Jurassic of Albany County, Wyoming". N. Jb. Geol. Palaont. Abh. 237: 111-160
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.