the same year, Agassiz proposed that the name derives from the Ancient Greek πλατη (platê – "paddle", "rudder"; Agassiz translates this as Latin pala = "spade") and σαυρος (sauros – "lizard"). Agassiz consequently renamed the genus Platysaurus, probably from Greek πλατυς (platys – "broad, flat, broad-shouldered"), creating an invalid junior synonym. Later authors often referred to this derivation, and the secondary meaning "flat" of πλατυς, so that Plateosaurus is often translated as "flat lizard". Often, claims were made that πλατυς is supposed to have been intended as a reference to flat bones, for example the laterally flattened teeth of Plateosaurus, but the teeth and other flat bones such as the pubic bones and some skull elements were unknown at the time of description. In 1855, von Meyer published a detailed description of Plateosaurus with illustrations, but again gave no details on the etymology. He repeatedly referred to its gigantic size ("Riesensaurus" = giant lizard) and massive limbs ("schwerfüssig"), comparing Plateosaurus to large modern land mammals, but did not describe any important features that fit the terms "flat" or "shaped like an oar." Paleontologist Ben Creisler therefore concluded that "broad lizard" is the most suitable translation, and possibly was intended to emphasise the giant size of the animal. Valid species The taxonomic history of Plateosaurus is "long and confusing", a "chaotic tangle of names". As of 2019, only three species are universally accepted as valid: the type species P. trossingensis, P. longiceps, and P. gracilis, previously assigned to its own genus Sellosaurus. Moser performed the most extensive and detailed investigation of all plateosaurid material from Germany and Switzerland, concluding that all Plateosaurus and most other prosauropod material from the Keuper stems from the same species as the type material of Plateosaurus engelhardti. However, this is problematic due to the undiagnostic state of the lectotype. Moser considered Sellosaurus to be the same genus as Plateosaurus, but did not discuss whether S. gracilis and P. engelhardti belong to the same species. Palaeontologist Adam Yates of the University of the Witwatersrand cast further doubt on the generic separation. He included the type material of Sellosaurus gracilis in Plateosaurus as P. gracilis and reintroduced the old name Efraasia for some material that had been assigned to Sellosaurus. In 1926, von Huene had already concluded the two genera were the same. Yates has cautioned that P. gracilis may be a metataxon, which means that there is