Name: Alcovasaurus ‭(‬Alcova lizard‭)‬.
Phonetic: Al-co-vah-sor-us.
Named By: Peter M.‭ ‬Galton‭ & ‬Kenneth Carpenter‭ ‬-‭ ‬2016.
Synonyms: Stegosaurus longispinus.
Classification: Chordata,‭ ‬Reptilia,‭ ‬Dinosauria,‭ ‬Ornithischia,‭ ‬Thyreophora,‭ ‬Stegosauria,‭ ‬Stegosauridae.
Species: A.‭ ‬longispinus‭ (‬type‭)‬.
Diet: Herbivore.
Size: Roughly estimated at about‭ ‬5.7‭ ‬meters long.
Known locations: USA,‭ ‬Wyoming‭ ‬-‭ ‬Morrison Formation.
Time period: Late Jurassic.
Fossil representation: Partial post cranial skeleton including vertebrae,‭ ‬ribs,‭ ‬ischia,‭ ‬partial pubis,‭ ‬right femur,‭ ‬and four tail spines.

       In‭ ‬1914‭ ‬the palaeontologist Charles Whitney Gilmore described a new species of Stegosaurus which he named S.‭ ‬longispinus.‭ ‬The name was chosen as a reflection of the unusually large tail spines that were much longer than those seen in other Stegosaurus fossils.‭ ‬For many years however the validity of S.‭ ‬longispinus was called into question with the long spines possibly representing a case of sexual dimorphism and there for display.‭ ‬However others such Olshevsky and Ford in‭ ‬1993‭ ‬speculated that Stegosaurus longispinus may in fact be an American species of Kentrosaurus which is known from Africa.‭ ‬Studies were hampered however when the type specimen was damaged by water from a burst pipe at the University of Wyoming and was thought lost,‭ ‬though fossils are now known again.‭
       In‭ ‬2014‭ ‬a freelance palaeontologist named Roman Ulansky self-published an article online of his own opinion that Stegosaurus longispinus was not a valid species of Stegosaurus,‭ ‬and agreeing with the previous interpretation that S.‭ ‬longispinus was more similar to Kentrosaurus,‭ ‬created a new genus name for S.‭ ‬longispinus.‭ ‬This new genus name was called Natronasaurus,‭ ‬after Natrona County which is the generic location where the type fossils of S.‭ ‬longispinus had been found.‭ ‬Problems soon arose however as even though the new name gained quick popularity on the internet,‭ ‬it was never officially valid.‭ ‬The problem was that the paper describing Natronasaurus was self-published without peer review association,‭ ‬and on top of this the paper didn’t have a valid ISSN number.‭ ‬Therefore,‭ ‬while the paper made a clear and valid point about S.‭ ‬longispinus,‭ ‬it could never be accepted as scientifically valid without those two things.

       In‭ ‬2016‭ ‬yet another new name for S.‭ ‬longispinus was proposed,‭ ‬this time by veteran palaeontologists Peter M.‭ ‬Galton and Kenneth Carpenter,‭ ‬and this time in a peer reviewed journal.‭ ‬Their new name for S.‭ ‬longispinus was Alcovasaurus which means‭ ‘‬Alcova lizard‭’‬,‭ ‬after the Alcova Quarry in Natrona County in Wyoming which is the specific location in Natrona County where fossils of Alcovasaurus were found.‭ ‬Stegosaurus is still a valid genus in its own right,‭ ‬but the former species S.‭ ‬longispinus is now a synonym to Alcovasaurus,‭ ‬with the species name used to establish the new type species,‭ ‬Alcovasaurus longispinus.‭ ‬Because Natronasaurus was never officially documented it is now seen as an invalid name,‭ ‬and because it is invalid,‭ ‬it cannot even exist as a synonym to Alcovasaurus.
       With an estimated length of about‭ ‬5.7‭ ‬meters for the holotype individual,‭ ‬Alcovasaurus would have been a medium sized stegosaurid dinosaur,‭ ‬and one speculated to be more like Kentrosaurus than Stegosaurus.‭ ‬However,‭ ‬at the time of writing only four tail spines are known,‭ ‬and the full pattern of spines and possible plates along the back is still unknown.‭ ‬For this reason reconstructions are usually based upon Kentrosaurus which is known to have small plates on the anterior‭ (‬front‭) ‬half of the body,‭ ‬and long spines on the posterior‭ (‬rear‭) ‬half of the body.‭ ‬Like all stegosaurid dinosaurs,‭ ‬Alcovasaurus would have been a browser of low growing vegetation while ornithopod and sauropod dinosaurs would have browsed the medium and high levels.
       Possible predatory threats to Alcovasaurus include Allosaurus,‭ ‬Torvosaurus,‭ ‬Fosterovenator and possibly also Ceratosaurus.

Further reading
-‭ ‬Osteology of the armoured Dinosauria in the United States National Museum,‭ ‬with special reference to the genus Stegosaurus.‭ ‬-‭ ‬United States National Museum Bulletin‭ ‬89:‭ ‬1‭–‬143.‭ ‬-‭ ‬Charles Whitney Gilmore‭ ‬-‭ ‬1914.
-‭ ‬The origin and evolution of the stegosaurs.‭ ‬-‭ ‬Gakken Mook,‭ ‬Dinosaur Frontline,‭ ‬v.‭ ‬4,‭ ‬p.‭ ‬65-103.‭ ‬-‭ ‬G.‭ ‬Olshevsky‭ & ‬T.‭ ‬L.‭ ‬Ford‭ ‬-‭ ‬1993.
-‭ ‬Evolution of the stegosaurs‭ (‬Dinosauria‭; ‬Ornithischia‭)‬.‭ ‬-‭ ‬Dinologia,‭ ‬35‭ ‬pp.‭ [‬in Russian‭]‬.‭ ‬-‭ ‬Roman E.‭ ‬Ulansky‭ ‬-‭ ‬2014.
-‭ T‬he plated dinosaur Stegosaurus longispinus Gilmore,‭ ‬1914‭ (‬Dinosauria:‭ ‬Ornithischia‭; ‬Upper Jurassic,‭ ‬western USA‭)‬,‭ ‬type species of Alcovasaurus n.‭ ‬gen.‭ ‬-‭ ‬Neues Jahrbuch für Geologie und Paläontologie‭ ‬-‭ ‬Abhandlungen‭ ‬279‭(‬2‭)‬:‭ ‬185-208.‭ ‬-‭ ‬Peter M.‭ ‬Galton‭ & ‬Kenneth Carpenter‭ ‬-‭ ‬2016


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