Zupaysaurus(/ˌzuːpeɪˈsɔːrəs/;"ZOO-pay-SAWR-us" ) is anextinctgenusof earlytheropoddinosaurliving during theNorianstage of theLate Triassicin what is nowArgentina.Fossils of the dinosaur were found in theLos Colorados Formationof theIschigualasto-Villa Unión Basinin northwestern Argentina. Although a full skeleton has not yet been discovered,Zupaysauruscan be considered abipedalpredator,up to 4 metres (13 ft) long. It may have had two parallel crests running the length of its snout.
| Zupaysaurus Temporal range:Norian
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| The skull ofZupaysaurus | |
Scientific classification
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Neotheropoda |
| Genus: | †Zupaysaurus Arcucci&Coria2003 |
| Species: | †Z. rougieri
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| Binomial name | |
| †Zupaysaurus rougieri Arcucci & Coria 2003
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Discovery
editDiscovered in May 1997 by Santiago Reuil ( "Vultur" ), part of the crew of Guillermo Rougier, it was later described by Arcucci and Coria and published in 2003. The nameZupaysaurusis composed of theQuechuawordsupaymeaning "devil" and theGreekwordsauros(σαυρος) meaning "lizard"; thus "devil lizard". In Incan mythology,supaywas both the god of death and ruler of theukhu pacha,the Incan underworld. Thetype specieswas namedZ. rougieriin the honor of Guillermo Rougier, the scientist who led the expedition which discovered and collected theholotype(original specimen) PULR-076.Zupaysauruswas first described and named in the scientific journalAmeghinianabyArgentinepaleontologistsAndrea Arcucci andRodolfo Coriain 2003.[1]
Description
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Zupaysauruswas a medium-sized theropod. An adultskull,measured approximately 450 mm (18 in) in length, suggesting a body length of approximately 4 m (13 ft) from its snout to the tip of its tail. In 2010Gregory S. Paulgave a length of 6 meters (20 ft) and a weight of 250 kg (550 lbs).[2]In 2016 it was given a much smaller size of 4.2 meters (14 ft) and 70 kg (154 lbs).[3]Like all theropods,Zupaysauruswalked only on its hindlegs, leaving its forelimbs free to grasp itsprey.The length of the neck bones recovered suggests that this genus has a rather long neck. Like thecoelophysoids,Zupaysaurushas a kink in its snout, between thepremaxillaryandmaxillarybones of the upper jaw. It is estimated thatZupaysaurushad 24 teeth and an intermandibular hinge is present in the lower jaw.[1]Only one specimen ofZupaysaurusis known to science. Theholotypespecimen was designated PULR-076, which consists of a nearly complete skull which was very well preserved, the rightshouldergirdle, the lower right leg andankle,and twelvevertebraefrom the neck, back, and hips. Additional material of a smaller individual found at the same site may or may not belong toZupaysaurus. AsZupaysauruswas originally described, the head bore two thin parallel crests on top of the skull, similar to theropods likeDilophosaurusandCoelophysis kayentakatae.These crests are thought to have been formed by thenasalbones solely, unlike those of many other theropods which also incorporated thelacrimalbones. Crests on the skull were pervasive among theropods and may have been used forcommunicative purposessuch as species or gender recognition.[4]However, more recent analysis of the skull has cast doubt on the presence of these crests inZupaysaurus.An unpublished abstract presented at a recent conference indicated the structures initially identified as crests were in fact the lacrimal bones displaced upwards during the process offossilization.[5]Other cranial ornamentation included a rugose laterally-projecting lacrimal ridge on the top of the skull.
A diagnosis is a statement of the anatomical features of an organism (or group) that collectively distinguish it from all other organisms. Some, but not all, of the features in a diagnosis are also autapomorphies. An autapomorphy is a distinctive anatomical feature that is unique to a given organism or group. According to Ezcurra (2006) and Ezcurra and Novas (2006),Zupaysauruscan be distinguished based on the following characteristics: the maxillary fenestra is within theantorbital fossa(according to Ezcurra, 2006), the rostral process of the lacrimal is ventrally bowed (according to Ezcurra, 2006), the ventral process of thesquamosalis kinked (according to Ezcurra, 2006), wide contact between squamosal andquadratojugal(according to Ezcurra, 2006). The maxillary-jugal ventral margin describes an obtuse angle in lateral view (according to Ezcurra and Novas, 2006), a notch on the dorsal margin of the ascending process of the maxilla, relating to horizontal ramus of the lacrimal is rostrally tapering onto the forked caudal tip of the ascending process of themaxilla;(according to Ezcurra and Novas, 2006), alacrimalwith a highlypneumatizedantorbital recess (according to Ezcurra and Novas, 2006), a short and square-shaped retroarticular process of themandible(according to Ezcurra and Novas, 2006), thecnemial crestis poorly developed (according to Ezcurra and Novas, 2006).
Classification
editZupaysauruswas classified as the earliest knowntetanurantheropod due to several features of its skull, dentition, and hindlimb. However, several features typical of morebasaltheropods were also noted by the original authors.[1]Analyses by Carano (2005), Tykoski (2005), and Ezcurra and Novas (2005) have classifiedZupaysaurusas acoelophysoidrelated toSegisaurusand probablyLiliensternus,though more basal thanCoelophysis.[5][6][7]Yates (2006) foundZupaysaurusto form a group withDilophosaurusandDracovenator,placing it in a monophyleticDilophosauridae.[8]But later studies foundZupaysaurusto be a sister taxon sister to a clade containingdilophosaurids,ceratosaursandtetanurans.[9][10]
Below is acladogrambased on the phylogenetic analysis conducted by Sues et al. in 2011, showing the relationships ofZupaysaurus:[11]
| Theropoda |
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Paleoecology
editZupaysauruswas discovered in red siliciclastic sediments at the "Quebrada de los Jachaleros" locality within theLos Colorados Formationof theLa Riojaprovince in Argentina. Thisformationhas been shown by magnetostratigraphy to date to theNorianstage of theLate Triassicperiod, approximately 228 to 208 million years ago.[12]but has also been assigned to the slightly youngerRhaetianstage, which was approximately 208 to 201 million years ago.[13]Both specimens assigned to this genus are housed in the collection of the National University of La Rioja inLa Rioja, Argentina.[1]
TheLos Colorados Formationwas interpreted as an ancient floodplain and it was home to several types of earlysauropodomorphdinosaurs (includingRiojasaurus,Coloradisaurus,andLessemsaurus), all of which shared the samepaleoenvironmentwithZupaysaurus.[12]It is recognized as one of the earliest known faunal assemblages dominated by dinosaurs, which were 43% of the number of tetrapod species currently known. The non-dinosaurs that inhabited this locality includedpseudosuchians,therapsidslikeCynodontia,other early reptiles, and possiblearchosaurs.
References
edit- ^abcdArcucci, A.B. & Coria R.A. 2003. A new Triassic carnivorous dinosaur from Argentina.Ameghiniana40(2):217-228.
- ^Paul, Gregory S. (2010).The Princeton Field Guide to Dinosaurs.New Jersey: Princeton University Press. pp.75.
- ^Molina-Pérez & Larramendi (2016).Récords y curiosidades de los dinosaurios Terópodos y otros dinosauromorfos.Spain: Larousse. p. 253.
- ^Currie, P.J. & Zhao X. 1993. A new carnosaur (Dinosauria, Theropoda) from the Jurassic of Xinjiang, People's Republic of China.Canadian Journal of Earth Sciences30: 2037-2081.
- ^abEzcurra, M.D. & Novas, F.E. 2005. Phylogenetic relationships of the Triassic theropodZupaysaurus rougierifrom NW Argentina. Presented in August 2005 during theII Latin American Congress of Vertebrate PaleontologyArchivedMay 4, 2006, at theWayback MachineinRio de Janeiro,Brazil.This analysis will be published in peer-reviewed print form later in 2006. A summary of the talk can be seenhere.
- ^Carrano, M.T., Hutchinson, J.R., & Sampson, S.D. 2005. New information onSegisaurus halli,a small theropod dinosaur from the Early Jurassic of Arizona.Journal of Vertebrate Paleontology25(4): 835-849.
- ^Tykoski, 2005. Anatomy, ontogeny and phylogeny of coelophysoid theropods. PhD Dissertation. University of Texas at Austin. 553 pp.
- ^Yates, A.M., 2006 (for 2005). "A new theropod dinosaur from the Early Jurassic of South Africa and its implications for the early evolution of theropods."Palaeontologia Africana,41:105-122.
- ^Smith N.D., Makovicky P. J., Hammer W. R. & Currie P. J. 2007 Osteology of Cryolophosaurus ellioti (Dinosauria: Theropoda) from the Early Jurassic of Antarctica and implications for early theropod evolution. Zool. J. Linn. Soc. 151, 377–421.
- ^Nesbitt, S. J., Smith, N. D., Irmis, R. B., Turner, A. H., Downs, A., & M. A. Norell. 2009. A complete skeleton of a Late Triassic saurischian and the early evolution of dinosaurs. Science 326:1530-1533.
- ^Hans-Dieter Sues, Sterling J. Nesbitt, David S. Berman and Amy C. Henrici (2011). "A late-surviving basal theropod dinosaur from the latest Triassic of North America". Proceedings of the Royal Society B 278 (1723): 3459–3464
- ^abWeishampel, D.B., Barrett, P.M., Coria, R.A., Le Loueff, J., Xu X., Zhao X., Sahni, A., Gomani, E.M.P., & Noto, C.R. 2004. Dinosaur distribution. In: Weishampel, D.B., Dodson, P., & Osmólska, H. (Eds.).The Dinosauria(2nd Edition). Berkeley: University of California Press. Pp. 517-606.
- ^Heckert, A.B. & Lucas, S.G. 1998. Global correlation of the Triassic theropod record.Gaia15: 63-74. [not printed until 2000]
External links
edit- Zupaysaurusentry in The Theropod Database.
