Emausaurus is a genus of thyreophoran from the Early Jurassic (Toarcian). Its fossils have been found in Mecklenburg-Vorpommern, northern Germany. Emausaurus is the only known Toarcian thyreorphoran and it is also the only dinosaur from the zone of the same age with a formal name.[1][2]
Discovery and naming[]
The type and only species, E. ernsti, was named and described by Harmut Haubold in 1990. The generic name is composed of an acronym of Ernst Moritz Arndt University of Greifswald and Greek 'sauros/σαυρος' (lizard). The specific name is derived from the name of geologist Werner Ernst, who acquired the fossil, holotype SGWG 85, in the summer of 1963 from foreman Werner Wollin at a loampit near Grimmen, in strata dating from the Toarcian. It is known by the right side of the skull, the right lower jaw, caudal vertebrae, neural arches, a radius, a metatarsal, a claw, fragments of ribs, scutes and plates, known as EMAU SGWG 85.
Description[]
Emausaurus was probably a semibipedal to quadrupedal animal, being covered on a armor of osteoderms across the body. Like other thyreorphora, probably was hervivore, concretely a low dwelling one, with a diet more related with ground flora, such as Cycads and Bennnetitales. The body length of the holotype of Emausaurus has been estimated at around 2.5 m, with a weight of 70–90 kg. This was based on a juvenile individual though; adult length has been estimated at three to four metres, with a weight up to 240 kg.[3]
Most of the reconstruction has been based on Scelidosaurus, although it is possible that Emausaurus was a more bipedal animal, as some of the young specimens of Scelidosaurus were thought to be. Adult forms probably where more quadrupedal. Armor includes three conical scutes and one tall, spiny element. David Norman in 2019 examined the morphology of Scelidosaurus, comparing it with Emausaurus. In Emausaurus the maxilla has, overall, a similar morphology to that seen in Scelidosaurus.
Paleoecology[]
Emausaurus has a sinuous jaw profile, more advanced in ankylosauromorphans, unlike the rectilinear morphology seen in the more basal genus Scutellosaurus. The changes on the jaw is considered a series of modifications due to changes on the Diet and evolution of the food procesation of this dinosaurs, where it seems to be adapted to eat Coriaceous flora, such as Bennetites and Cycads, abundant on the coeval Ciechocinek Formation Lublin Coal Basin and specially on the Sorthat Formation.
Paleoenvironment[]
The holotype of Emausaurus was found on the so-called "Emausaurus type site", that represents a shale ingression from the Posidonia Shale, dated from the Lower Toarcian (Tenuicostatum).
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