Notes on plated dinosaurs (Ornithischia: Stegosauria), mostly on dermal armor from Middle and Upper Jurassic of England (also France, Iberia), with a revised diagnosis for Loricatosaurus priscus (Callovian, England)
Galton, Peter M.
published: Oct 1, 2016
ArtNo. ESP155028201000, Price: 29.00 €
In basal thyreophorans there is no equivalent to the small based slender dermal tail spines of stegosaurs, which differ in several respects from the lateral dorsal spines of nodosaurid ankylosaurs, and large based stocky spikes are restricted to a few genera of stegosaurs. Several isolated spines and spikes from England (Middle and Upper Jurassic), Portugal (Upper Jurassic) and Spain (Lower Cretaceous), previously re-identified as Thyreophora indet., are Stegosauria indet. Where available, cross-sections shows a thick layer of compact bone with a well-defined central canal as in old adult individuals of Stegosaurus (Upper Jurassic, USA) in which, in addition to display, they functioned as weapons. This stronger construction also favored their preservation as isolated bones. It contrasts with a thin layer of compact bone filled with cancellous bone for the spines of adult and younger individuals of Stegosaurus and of ankylosaurs. The preservation of an isolated pair of spines and of spikes indicates that their bases were bound together. Two columnar femora with a finger-like anterior trochanter from England (Middle and Upper Jurassic) are also re-identified as Stegosauria indet., as are the remains of a juvenile individual from Portugal (Upper Jurassic). The autapomorphies of Lori- catosaurus priscus (Nopcsa, 1911) (England, Middle Jurassic: Middle Callovian) include characters observed in the anterior and mid-caudal vertebrae, posterior pubic process and dermal armor (spine plate, small based body spine).