{{Short description|Extinct genus of thyreophoran dinosaurs}} {{Speciesbox | fossil_range = Early Toarcian<br/>~{{fossil_range|183|182}}<small>Tenuicostatum</small> | image = Emausaurus dentary.png | image_caption = Dentary bone of ''Emausaurus ernsti'' | display_parents = 3 | genus = Emausaurus | parent_authority = Haubold, 1990 | species = ernsti | authority = Haubold, 1990 }}
'''''Emausaurus''''' is a genus of thyreophoran or armored dinosaur from the Early Jurassic (Early Toarcian). Its fossils have been found in the Lehmhagen Member, in Mecklenburg-Vorpommern, northern Germany. ''Emausaurus'' is the only known Toarcian thyreophoran, as well as the only dinosaur from the zone of the same age with a formal name.<ref name=Haubold2>{{cite journal |last1=Haubold |first1=H. |title=Der Greifswalder Dinosaurier ''Emausaurus'' |journal=Fundgrube |date=1991 |volume=27 |issue=2 |pages=51–60}}</ref>
==Discovery and naming== thumb|245x245px|Profile at Grimmen with Emausaurus horizon marked The type and only species, ''E. ernsti'', was named and described by Hartmut Haubold in 1990.<ref name="Haubold1990">{{cite journal |last1=Haubold |first1=H. |title=Ein neuer Dinosaurier (Ornithischia, Thyreophora) aus dem Unteren Jura des nördlichen Mitteleuropa |journal=Revue de Paléobiologie |date=1990 |volume=9 |issue=1 |pages=149–177 |url=https://www.researchgate.net/publication/281199000 |access-date=24 October 2021}}</ref> The generic name is composed of an acronym of Ernst Moritz Arndt University of Greifswald and the Greek ''{{lang|grc-Latn|sauros}}/{{lang|grc|σαυρος}}'' (lizard). The specific name is derived from the name of geologist Werner Ernst, who acquired the holotype specimen, '''SGWG 85''', in the summer of 1963 from foreman Werner Wollin at a loam pit 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.<ref name="Haubold2" />
==Description== left|thumb|Size compared to a human ''Emausaurus'' was probably a semi-bipedal to quadrupedal animal, being covered in an armor of osteoderms across the body. Like other thyreophorans, it probably was an herbivore, specifically a low dwelling one, with a diet associated with ground flora, such as cycads and Bennettitales.<ref name=Haubold2/> The body length of the holotype juvenile individual of ''Emausaurus'' has been estimated at {{cvt|2|-|2.5|m|ft}}, with a body mass of {{cvt|50|–|90|kg|lbs}}.<ref>{{cite book |last=Holtz |first=Thomas R. Jr. |year=2012 |title=Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages |url=http://www.geol.umd.edu/~tholtz/dinoappendix/HoltzappendixWinter2011.pdf |quote=Winter 2011 Appendix}}</ref><ref name=Paul2016>{{Cite book|last=Paul|first=Gregory S.|title=The Princeton Field Guide to Dinosaurs|year=2016|publisher=Princeton University Press|isbn=978-1-78684-190-2|oclc=985402380|page=242}}</ref><ref name=Haubold2/> The adult length has been estimated at {{cvt|3|-|4|m|ft}}, with a body mass up to {{cvt|240|kg|lbs}}.<ref name=Haubold2/> Some recent data suggest the holotype may be from a subadult rather than a juvenile.<ref name=Thyreo/> 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 were more quadrupedal. Unfortunately, the type specimen is too incomplete to infer a mode of locomotion.<ref name=Scutello>{{cite journal |last1=Breeden III|first1=B. T |last2=Raven |first2=T. J |last3=Butler |first3=R. J. |last4=Rowe |first4=T. B. |last5=Maidment |first5=S. C. |title=The anatomy and palaeobiology of the early armoured dinosaur ''Scutellosaurus lawleri'' (Ornithischia: Thyreophora) from the Kayenta Formation (Lower Jurassic) of Arizona |journal=Royal Society Open Science |date=2021 |volume=8 |issue=7 |article-number=201676 |pmid=34295511 | doi=10.1098/rsos.201676 | doi-access=free|pmc=8292774 |bibcode=2021RSOS....801676B }}</ref> Armor includes three conical scutes and one tall, spiny element.<ref name=NWW04>{{cite book|title=The Dinosauria, 2nd Edition|url=https://archive.org/details/dinosauriandedit00weis|url-access=limited|year=2004|chapter=Basal Thyreophora|editor1=Weishampel, D.B. |editor2=Dodson, P. |editor3=Osmólska, H. |author1=Norman, D.B. |author2=Witmer, L.M. |author3= Weishampel, D.B. |name-list-style=amp|pages=[https://archive.org/details/dinosauriandedit00weis/page/n353 335]–342|publisher=University of Californian Press|isbn=0-520-24209-2}}</ref> In 2019, David Norman examined the morphology of ''Scelidosaurus'', comparing it with ''Emausaurus''. In ''Emausaurus'', the maxilla has, overall, a similar morphology to that seen in ''Scelidosaurus''. The disarticulated maxilla of ''Emausaurus'' exhibits an anteromedially directed robust process with which it met its counterpart in the midline, creating a wedge-like structure, with no obvious offset between the alveolar margins. In ''Emausaurus'', the structure of the frontals is not well preserved. In outline, its proportions resemble those of ''Scelidosaurus'', but the same is true of many Ornithischia. The lacrimal bone of ''Emausaurus'' is incomplete, but includes a long, curved jugal process that evidently wrapped itself around the anterior tip of the jugal.<ref>{{cite journal |last1=Norman |first1=D. B. |title=''Scelidosaurus harrisonii'' from the Early Jurassic of Dorset, England: cranial anatomy. |journal=Zoological Journal of the Linnean Society |date=2019 |volume=188 |issue=1 |pages=1–81 |doi=10.1093/zoolinnean/zlz074 |doi-access=free|url=https://royalsocietypublishing.org/doi/10.1098/rsos.201676 |access-date=17 November 2021|url-access=subscription }}</ref> Very little is known of the postcranium ''Emausaurus'', recovering parts like a multipartite odontoid (sutured to the axis centrum), similar to that of ''Scelidosaurus''.<ref>{{cite journal |last1=Norman |first1=D. B. |title=''Scelidosaurus harrisonii'' from the Early Jurassic of Dorset, England: postcranial skeleton |journal=Zoological Journal of the Linnean Society |date=2019 |volume=189 |issue=1 |pages=47–157 |doi=10.1093/zoolinnean/zlz078 |url=https://academic.oup.com/zoolinnean/article/189/1/47/5679623 |access-date=17 November 2021|url-access=subscription }}</ref> ''Emausaurus'' has a series of assigned osteoderms, but lacks like ''Scutellosaurus'' 'scapular osteoderms'. The major series of osteoderms found appear to come from the tail or the dorsal section.<ref>{{cite journal |last1=Norman |first1=D. B. |title=''Scelidosaurus harrisonii'' from the Early Jurassic of Dorset, England: the dermal skeleton |journal=Zoological Journal of the Linnean Society |date=2020 |volume=190 |issue=1 |pages=1–53 |doi=10.1093/zoolinnean/zlz085 |url=https://academic.oup.com/zoolinnean/article/190/1/1/5716282 |access-date=17 November 2021|doi-access=free }}</ref>
==Classification== Cladistic analyses have shown that ''Emausaurus'' was a basal member of the Thyreophora, more derived than ''Scutellosaurus'', but less than ''Scelidosaurus''.<ref>{{cite journal |last1=Sereno |first1=P. C. |title=The origin and evolution of dinosaurs |journal=Annual Review of Earth and Planetary Sciences|date=1997 |volume=25 |issue=1 |pages=435–489|doi=10.1146/annurev.earth.25.1.435 |bibcode=1997AREPS..25..435S |url=http://doc.rero.ch/record/15399/files/PAL_E2750.pdf }}</ref> ''Scelidosaurus'', ''Emausaurus'', and ''Scutellosaurus'' cluster at the base of most trees because they can be scored for only a restricted number of anatomical characters.<ref>{{cite journal |last1=Butler |first1=R.J. |last2=Upchurch |first2=P. |last3=Norman |first3=D.B. |title=The phylogeny of the ornithischian dinosaurs |journal=Journal of Systematic Palaeontology |date=2008 |volume=6 |issue=1 |pages=1–40|doi=10.1017/S1477201907002271 |bibcode=2008JSPal...6....1B |s2cid=86728076 }}</ref> The cladistic status of the specimen is relatively controversial due to its young nature. It is clearly a member of the Thyreophora, but its position may be modified if an adult specimen is found. ''Emausaurus'' may be more derived than ''Scelidosaurus'', or even be a sister taxon to Stegosauria.<ref name="NorDino">{{cite journal |last1=Stumpf |first1=S. |last2=Meng |first2=S. |title=Dinosaurier aus Nordostdeutschland: Verschleppt |journal=Biologie in unserer Zeit |date=2013 |volume=43 |issue=6 |pages=362–368 |doi=10.1002/biuz.201310521 |s2cid=83200480 |url=https://www.researchgate.net/publication/259535946 |access-date=24 October 2021}}</ref> The general consensus has established ''Emausaurus'' as a non-eurypodan stem thyreophoran, along with Scutellosaurus and ''Scelidosaurus'' reinforced by almost all subsequent systematic reviews of ornithischian–thyreophoran relationships.<ref name=Dinzau>{{cite journal |last1=Coombs|first1=W.P. |last2=Maryańska |first2=T. |title=Ankylosauria. |journal=The Dinosauria|date=1990 |volume=1 |issue=1 |pages=456–483}}</ref> Being ''Emausaurus'' and ''Scutellosaurus'' more basal than ''Scelidosaurus''.<ref name=Dinzau/> ''Emausaurus'' has been put on an outgroup to Ankylosauria, with ''Scelidosaurus'' and the basal stegosaur ''Huayangosaurus''.<ref>{{cite journal |last1=Witmer |first1=Hill R.V. |last2=Norell |first2=L.M. |title=A new specimen of Pinacosaurus grangeri (Dinosauria: Ornithischia) from the Late Cretaceous of Mongolia: ontogeny and phylogeny of ankylosaurs |journal=American Museum Novitates |date=2003 |issue=1 |pages=1–29}}</ref> Vickaryous et al. (2004), did the default phylogenetic analysis for ingroup ankylosaurs, due to including cranial and postcranial characters, a wide range of taxa and made no in-group relationships, although this analysis used the holotype ''Lesothosaurus'' and ''Huayangosaurus'' as outgroups, ignoring ''Scelidosaurus'' and ''Emausaurus''.<ref name=Dinzau/> In 2020, Norman found that ''Scelidosaurus'', along with ''Scutellosaurus'' and ''Emausaurus,'' are positioned on the stem of Ankylosauria, rather than on the stem of Thyreophora, with ''Emausaurus'' as the basal sister-taxon to ''Scelidosaurus''.<ref name="phylo">{{cite journal |last1=Norman |first1=D. B. |title=''Scelidosaurus harrisonii'' (Dinosauria: Ornithischia) from the Early Jurassic of Dorset, England: biology and phylogenetic relationships |journal=Zoological Journal of the Linnean Society |date=2020 |volume=192 |issue=1 |pages=1–86 |url=https://academic.oup.com/zoolinnean/article-abstract/191/1/1/5893854?redirectedFrom=fulltext |access-date=17 November 2021}}</ref> This is because ''Emausaurus'' possesses a dorsal margin of the dentary sinuous in lateral view and neither elongated nor squat proportions of metacarpal 1 'medium'.<ref name=phylo/> Alternatively, ''Emausaurus'' may be a basal sister-taxon to ''Scutellosaurus'', but taking the similarities between ''Emausaurus'' and ''Scelidosaurus'' this is less likely.<ref name=phylo/> Yet this was contested the same year with the description of +70 specimens of ''Scutellosaurus'', where ''Emausaurus'' was found as sister taxon of this last one and both with strong evidence for a phylogenetic placement within Thyreophora but outside of Thyreophoroidea.<ref name=Scutello/> A cladogram following the results of Norman (2020) is shown below:
{{clade| style=font-size:100%;line-height:80%;margin:1em auto; |label1='''Thyreophora''' |label2=Eurypoda |1={{clade |1=Stegosauria |label2=Ankylosauromorpha |2={{clade |1=''Scutellosaurus'' |2={{clade |1='''''Emausaurus''''' |2={{clade |1=''Scelidosaurus'' |label2=Ankylosauria |2={{clade |1=Ankylosauridae |2=Nodosauridae }} }} }} }} }} }}
==Paleoecology== [[File:Emausaurus_Hagen_Theropod.jpg|thumb|right|Restoration of ''Emausaurus'' being attacked by an unnamed theropod belonging to the Orionides]] left|thumb|214x214px|''Lehmhagen Member'' biota ''Emausaurus'' has a sinuous jaw profile, more advanced in ankylosauromorphs, unlike the rectilinear morphology seen in the more basal genus ''Scutellosaurus''.<ref name="phylo" /> The changes to the jaw are considered a series of modifications reflecting changes in the diet and evolution of the food processing of this dinosaur compared to its ancestors. It seems to be adapted to eat Coriaceous flora, such as bennettites and cycads, abundant on the coeval Sorthat Formation, where probably this taxon lived.<ref name="Kors">{{cite journal |last1=McElwain |first1=J. C. |last2=Wade-Murphy |first2=J. |last3=Hesselbo |first3=S. P. |title=Changes in carbon dioxide during an oceanic anoxic event linked to intrusion into Gondwana coals |journal=Nature |date=2005 |volume=435 |issue=7041 |pages=479–482 |doi=10.1038/nature03618 |pmid=15917805 |bibcode=2005Natur.435..479M |s2cid=4339259 |url=https://www.nature.com/articles/nature03618 |access-date=8 September 2021|url-access=subscription }}</ref> The rest of the skeleton of this genus is poorly presented, with for example the vertebrae showing no evidence of the proportional changes in the height of the neural arches and spines seen on stegosaurs.<ref name="phylo" /> The animal was covered in osteoderms, although the few found give no indication of how extensively they were distributed across the torso.<ref name="phylo" /> ''Emausaurus'', based on the proportions of the preserved metacarpals that the forelimb shows adaptations for weight support, rather than grasping, having ungual phalanges that are conical and only slightly decurved.<ref name="phylo" /> The partially known proximal pedal phalanges are short and block-like, with near the same proportions seen in the pes of ''Scelidosaurus''.<ref name="phylo" /> A series of characters that together are suggestive of graviportality and quadrupedality, making ''Emausaurus'' a low roaming herbivore. Pseudo-bipedality is not discarded, with the animal able to reach slightly taller flora.<ref name="phylo" /> Later works however have criticised this assumption given the relationships with ''Scutellosaurus'' are more likely and recommend to not infer bipedality or quadrupedality as the taxon is incomplete.<ref name="Scutello" />
==Paleoenvironment== The holotype of ''Emausaurus'' was found in the so-called "Emausaurus type site", which represents a shale ingression from the Lehmhagen Member, dated from the Lower Toarcian.<ref>{{cite journal |last1=Ernst |first1=W.|title=Die Liastongrube Grimmen. Sediment, Makrofauna und Stratigraphie. |journal=Ein Überblick Geologie|date=1967 |volume=16 |issue=1 |pages=550–569}}</ref> The site is a boundary composed of bituminous shale,<ref name="Haubold1990" /> representing an ancient seashore-influenced environment, probably lagoonal, and contemporaneous with the Sorthat Formation of the same region. Fossil wood has been found in the same location, including driftwood and others related to the Araucariaceae, present in other European environments of Toarcian age.<ref name="Haubold1990" /> The invertebrate fauna consists of insects, bivalves, sea snails and ammonites (''Tiltoniceras'', ''Eleganticeras'' and ''Lobolytoceras'').<ref name=Haubold1990 /> The vertebrate fauna is also diverse, with fossils of the fish genera ''Saurorhynchus'',<ref>{{cite journal |last1=Maxwell |first1=E. E. |last2=Stumpf |first2=S. |title=Revision of ''Saurorhynchus'' (Actinopterygii: Saurichthyidae) from the Early Jurassic of England and Germany |journal=European Journal of Taxonomy |date=2017 |issue=321 |pages=1–29 |doi=10.5852/ejt.2017.321 |url=https://europeanjournaloftaxonomy.eu/index.php/ejt/article/view/446/961 |access-date=24 October 2021|doi-access=free }}</ref> ''Grimmenichthys'',<ref>{{cite journal |last1=Konwert |first1=M. |last2=Hörnig |first2=M. |title=''Grimmenichthys ansorgei'', gen. et sp. nov. (Teleostei, "Pholidophoriformes"), and other "pholidophoriform" fishes from the early Toarcian of Grimmen (Mecklenburg-Western Pomerania, Germany) |journal=Journal of Vertebrate Paleontology |date=2018 |volume=38 |issue=3 |pages=1–16 |doi=10.1080/02724634.2018.1451872 |s2cid=90344418 |url=https://www.tandfonline.com/doi/abs/10.1080/02724634.2018.1451871 |access-date=24 October 2021|hdl=11336/84457 |hdl-access=free |url-access=subscription }}</ref> and ''Grimmenodon''.<ref>{{cite journal |last1=Stumpf |first1=S. |last2=Ansorge |first2=J. |last3=Pfaff |first3=C |last4=Kriwet |first4=J. |title=Early Jurassic diversification of pycnodontiform fishes (Actinopterygii, Neopterygii) after the end-Triassic extinction event: evidence from a new genus and species, Grimmenodon aureum |journal=Journal of Vertebrate Paleontology |date=2017 |volume=37 |issue=4 |article-number=e1344679 |doi=10.1080/02724634.2017.1344679 |pmid=29170576 |pmc=5646184 |bibcode=2017JVPal..37E4679S }}</ref> Reptile fossils include indeterminate ichthyosaurs and plesiosaurs, rhomaleosaurid plesiosaurs, indeterminate mesoeucrocodylians (probably related to ''Sichuanosuchus''), indeterminate thalattosuchians,<ref>{{cite thesis |last1= Stumpf |first1=Sebastian |title=A synoptic review of the vertebrate fauna from the "Green Series"(Toarcian) of northeastern Germany with descriptions of new taxa: A contribution to the knowledge of Early Jurassic vertebrate palaeobiodiversity patterns|type=PhD Thesis |publisher=Greifswald University |date=2017 |pages=1–47|url=https://epub.ub.uni-greifswald.de/frontdoor/deliver/index/docId/1941/file/STUMPF2017DISS.pdf|access-date=9 September 2021}}</ref> a possible pterosaur,<ref>{{Cite journal |last1=Schade |first1=Marco |last2=Ansorge |first2=Jörg |date=2024 |title=Enigmatic fragment possibly marks the first pterosaur record from the Lower Toarcian of Grimmen, NE Germany |journal=PalZ|doi=10.1007/s12542-024-00698-6 |doi-access=free }}</ref> and theropod and gravisaurian sauropod material, the latter related to the north African ''Tazoudasaurus''.<ref name="Gravisa">{{cite journal |last1=Stumpf |first1=Sebastian |last2=Ansorge |first2=Jörg|last3=Krempien |first3=Wilfried |title=Gravisaurian sauropod remains from the marine late Early Jurassic (Lower Toarcian) of North-Eastern Germany |journal=Geobios |date=2015 |volume=48 |issue=3 |pages=271–279 |doi=10.1016/j.geobios.2015.04.001 |bibcode=2015Geobi..48..271S |url=https://www.sciencedirect.com/science/article/pii/S0016699515000297 |access-date=30 July 2021|url-access=subscription }}</ref> A later discovery includes a thyreophoran osteoderm, interpreted as representing a lateral of the neck or shoulder region.<ref name=Thyreo>{{cite journal |last1=Schade |first1=Marco |last2=Ansorge |first2=Jörg |title=New thyreophoran dinosaur material from the Early Jurassic of northeastern Germany |journal=Paläontologische Zeitschrift |date=2022 |volume=96 |issue=1–14 |pages=303–311 |doi=10.1007/s12542-022-00605-x |s2cid=246040635 |doi-access=free |bibcode=2022PalZ...96..303S }}</ref>
== References == {{Reflist}}
==External links== * [https://pbs.twimg.com/media/CzOqGdZWgAAA54O.jpg An image of the skull of the holotype, published by the twitter account of Susie Maidment]
{{Ornithischia|H.}} {{Taxonbar|from=Q133065}}
Category:Thyreophora Category:Dinosaur genera Category:Toarcian dinosaurs Category:Fossil taxa described in 1990 Category:Dinosaurs of Germany