Swiss Journal of Geosciences

, Volume 103, Issue 2, pp 187–198

Species of plated dinosaur Stegosaurus (Morrison Formation, Late Jurassic) of western USA: new type species designation needed



Stegosaurus armatus Marsh 1877, based on a partial tail and a very large dermal plate from the Morrison Formation (Late Jurassic) of Morrison, Wyoming, USA, is a nomen dubium. Valid Morrison stegosaur species (with possible autapomorphies, dermal “armor” considered if present), with most holotypes consisting of a disarticulated partial postcranial skeleton at most, include: Hypsirhophus discurus Cope 1878 (characters of incomplete vertebrae, a dorsal and a caudal; Garden Park near Cañon City, Colorado); Stegosaurus ungulatus Marsh 1879 (half skeleton with partial skull; three pairs of small flat dermal spines adjacent to terminal tail spikes; Quarry 12, Como Bluff near Como station, Wyoming; syntype is holotype of S. duplex Marsh 1887, half skeleton lacking armor; Quarry 11, Como Bluff); Diracodon laticeps Marsh 1881b (just partial dentaries with few teeth, diastema between predentary and tooth 1; Quarry 13, Como Bluff); Stegosaurus sulcatus Marsh 1887 (pair of ?tail spikes with greatly enlarged base; Quarry 13, Como Bluff); S. longispinus Gilmore 1914 (characters of distal caudal vertebrae, tail spikes: two pairs, sub-equal bases, transversely flattened, very elongate; Alcova, Wyoming); and Hesperosaurus mjosi Carpenter, Miles & Cloward, 2001 (?Stegosaurus mjosi; partial articulated skeleton with skull, no limbs, several plesiomorphic and autapomorphic characters, dorsal plates longer than tall; Wyoming). However, the well known valid nominal species, S. stenops Marsh 1887 (12 autapomorphies, three alternating flat plates adjacent to terminal tail spikes; Garden Park), is based on a virtually complete articulated skeleton lacking only the terminal caudal vertebrae and first pair of tail spikes. It includes 17 dermal plates, is still exposed as preserved on the block, and is the current basis for Stegosaurus. The International Commission on Zoological Nomenclature (ICZN) will be petitioned to designate S. stenops Marsh 1887 as the new type species of Stegosaurus Marsh 1877 in order to conserve Stegosauria Marsh 1877 and Stegosauridae Marsh 1880 (also Stegosauroidea, Stegosaurinae).


Ornithischia Stegosauria Stegosaurus Hesperosaurus Late Jurassic Taxonomy 

Institutional abbreviations


American Museum of Natural History, New York, USA


Denver Museum of Nature & Science (formerly Denver Museum of Natural History), Colorado, USA


Hayashibara Museum of Natural History, Okayama, Japan


Morrison Natural History Museum, Morrison, Colorado, USA


Sauriermuseum Aathal, Switzerland


National Museum of Natural History (formerly United States National Museum), Washington DC, USA


Department of Geology and Geophysics, University of Wyoming, Laramie, USA


Peabody Museum of Natural History, Yale University, New Haven, Connecticut, USA

Copyright information

© Swiss Geological Society 2010

Authors and Affiliations

  1. 1.College of Naturopathic MedicineUniversity of BridgeportBridgeportUSA
  2. 2.Peabody Museum of Natural HistoryYale UniversityNew HavenUSA
  3. 3.Rio VistaUSA

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