Shuvosaurus inexpectatus Chatterjee 1993
Creators: name: Rauhut, Oliver W. M.
Publisher: name: Zenodo
Year: 2003
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Saurischia
Shuvosauridae
Shuvosaurus
Shuvosaurus inexpectatus

description: <i>Shuvosaurus inexpectatus</i> Chatterjee, 1993 <i>Age.</i> Norian. <i>Occurrence.</i> Cooper Canyon Formation of the Dockum Group, exas and New Mexico, USA. <i>Diagnosis.</i> Maxilla block-like, strongly reduced in length and almost entirely excluded from the ventral rim of the antorbital fenestra; nasal forms the dorsal rim of the internal antorbital fenestra anteriorly; jugal elongated underneath the antorbital fenestra and forms a peg-and-socket articulation with the maxilla anteriorly; jugal without posterior quadratojugal process; quadratojugal with two anterior process, which subdivide the infratemporal fenestra in a smaller ventral and a larger dorsal part; postorbital with broad posterior process, overlapping the anterior end of the squamosal; dentary with medial platform anteriorly. <i>Remarks. Shuvosaurus</i> is one of the most bizarre of supposed theropods described recently (Text-fig. 4h). The taxon is based on a fairly well-preserved skull of a juvenile individual, to which additional skull elements and a few postcranial bones were referred (Chatterjee 1993). However, only the cranial parts that show some overlap with the holotype are accepted here as belonging to this taxon, since all the material came from the Post Quarry in the Dockum Group of Texas, which has yielded hundreds of specimens of all kinds of Triassic vertebrates (e.g. Chatterjee 1985, 1991, 1993; Long and Murry 1995), and thus the association of isolated postcranial material is rather questionable. The genus was originally referred to the O rnithomimosauria by Chatterjee (1993). Long and Murry (1995) tentatively referred the holotype skull of <i>Shuvosaurus</i> to the genus <i>Chatterjeea,</i> a taxon of a possible poposaurian archosaur they named from the same locality. The reasons for this referral were the matching size of the specimens, the comparable preservation, and the lack of other cranial material that could have been referred to the otherwise common crurotarsan (Long and Murry 1995, p. 162). However, <i>Shuvosaurus</i> is radically different from all known crurotarsans in skull morphology (see e.g. Walker 1964; Krebs 1976; Chatterjee 1985; Parrish 1993; Long and Murry 1995), including the edentulous crurotarsan archosaur <i>Lotosaurus</i> (Zhang 1975; pers. obs. of a mounted skeleton in the IVPP). Rauhut (1997) presented a new reconstruction of the skull (Text-fig. 4h) and listed the following characters in favour of dinosaurian, saurischian, and theropodan affinities for <i>Shuvosaurus:</i> lack of postfrontal (convergent in crocodiles), paroccipital processes directed ventrolaterally rather than laterally or dorsolaterally as in other archosaurs, lacrimal elongated dorsoventrally and in the shape of an inverted L, presence of a deep basisphenoid recess, and possibly the presence of a deep ventral recess in the ectopterygoid (the identification of this element is questionable). Therefore, <i>Shuvosaurus</i> is included in the analysis here, although the highly apomorphic cranial morphology of this taxon makes it difficult to establish its theropod affinities beyond doubt, unless more material becomes available. As noted above, it might be possible that <i>Gojirasaurus</i> represents a junior synonym of <i>Shuvosaurus.</i>
description: Published as part of <i>Rauhut, Oliver W. M., 2003, The interrelationships and evolution of basal theropod dinosaurs, pp. 1-213 in Special papers in palaeontology 69</i> on page 18, DOI: 10.5281/zenodo.3382576
description: {"references": ["------ 1993. Shuvosaurus, a new theropod. National Geographic Research and xploration, 9, 274 - 285.", "------ 1985. Postosuchus, a new thecodontian reptile from the riassic of Texas and the origin of tyrannosaurs. Philosophical Transactions of the Royal Society of London, B, 309, 395 - 460.", "------ 1991. Cranial anatomy and relationships of a new riassic bird from exas. Philosophical Transactions of the Royal Society of London, B, 332, 277 - 342.", "WALKER, a. D. 1964. riassic reptiles from the Elgin area: Ornthosuchus and the origin of camosaurs. Philosophical Transactions of the Royal Society of London, B, 248, 53 - 134.", "KREBS, B. 1976. Pseudosuchia. 40 - 98. In kuhn, o. (ed.). Handbuch der Palaoherpetologie, Teil 13, Thecodontia. Gustav Fischer Verlag, Stuttgart, 137 pp.", "PARRISH, J. M. 1993. Phylogeny of the Crocodylotarsi, with reference to archosaurian and crurotarsian monophyly. Journal of Vertebrate Paleontology, 13, 287 - 308."]}