The plated dinosaur Stegosaurus longispinus Gilmore, 1914 (Dinosauria: Ornithischia; Upper Jurassic, western USA), type species of Alcovasaurus n. gen.
Galton, Peter M.; Carpenter, Kenneth
published: Feb 17, 2016
published online: Feb 1, 2016
ArtNo. ESP155027902004, Price: 29.00 €
The plated dinosaur Stegosaurus longispinus came from the Morrison Formation (Upper Jurassic) near Alcova, Wyoming, USA. Only the femur and plaster casts of the posterior pair of long dermal tail spines survived destructive water damage in the 1920s. This surviving material and archival photographs showing the bones in the quarry and as exhibited allow us to expand the original description. S. longispinus Gilmore, 1914 is made the type species of Alcovasaurus n. gen. as A. longispinus (Gilmore, 1914). Autapomorphies include the continuation of transverse processes to the distal caudal vertebrae; distal caudal centra anteroposteriorly short so height exceeds length; both distal dermal spine pairs with a very long slender shaft at ~90% of femoral length, and posterior pair widest at 25% of length. Natronasaurus longispinus was proposed by Ulansky (2014) for S. longispinus. However this failed to meet the requirements of the International Code of Zoological Nomenclature, as is also true for 17 other names proposed for basal thyreophorans and stegosaurs.