Abstract
The rhynchosaur previously referred to as the “Mariante Rhynchosaur” is here formally described as a new genus and species based on two specimens: a complete skull (without the lower jaw) articulated with the three first cervical vertebrae and a set of right maxilla and dentary. Both specimens were collected at the same site in Rio Grande do Sul, Brazil, from deposits of the Santa Maria Formation considered of Ladinian (Middle Triassic) age. Diagnostic characters include the contact between prefrontal and postfrontal, a pair of deep frontal grooves, and a very deep skull. A new phylogenetic analysis recovered the new taxon as a member of the Stenaulorhynchinae, a relatively diverse clade of Middle Triassic rhynchosaurs, with records in India, east Africa, and the Americas. Evidence suggests that the extinction of that clade took place in the context of a faunal turnover across the Ladinian-Carnian boundary, when it was replaced by the much more abundant Late Triassic hyperodapedontine rhynchosaurs.
Kurzfassung
Der früher als “Mariante Rhynchosaur” bezeichnete Rhynchosaurier wird hier, anhand zweier Exemplare (ein unterkieferloser kompletter Schädel mit den drei ersten Halswirbeln sowie ein Satz rechter Oberkiefer und Dentale), formell als neue Gattung und Art beschrieben. Beide Exemplare wurden in der selben Lagerstätte in Rio Grande do Sul, Brasilien, gefunden, in Ablagerungen der Santa Maria Formation aus dem Zeitalter des Ladinium (Mittlere Trias). Diagnostische Merkmale beinhalten den Kontakt zwischen Pre- und Postfrontale, ein Paar tiefer frontaler Furchen, und einen sehr tiefen Schädel. Eine neue phylogenetische Analyse positionierte das neue Taxon als Mitglied der Stenaulorhynchinae, eine relative vielfältige Klade an Rhynchosauriern des Mittleren Trias, mit Funden aus Indien, Ostafrika und den Amerikas. Hinweise deuten darauf, dass das Aussterben der Klade im Zusammenhang eines Faunenaustausches an der Ladinium-Karnium Grenze stattfand, als sie durch die viel häufigeren hyperodapedontinen Rhynchosaurier des Späten Trias ersetzt wurden.
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References
Abdala, F., and A.M. Ribeiro. 2010. Distribution and diversity patterns of Triassic cynodonts (Therapsida, Cynodontia) in Gondwana. Palaeogeography, Palaeoclimatology, Palaeoecology 286: 202–217.
Abdala, F., and A.M. Sá-Teixeira. 2004. A traversodontid cynodont of African affinity in the South American Triassic. Palaeontologia Africana 40: 11–22.
Abdala, F., A.M. Ribeiro, and C.L. Schultz. 2001. A rich cynodont fauna of Santa Cruz do Sul, Santa Maria Formation (Middle-Late Triassic), southern Brazil. Neues Jahrbuch für Geologie und Paläontologie Monatshefte 11: 669–687.
Abdala, F., A.G. Martinelli, M.B. Soares, M. de la Fuente, and A.M. Ribeiro. 2009. South American Middle Triassic continental faunas with amniotes: biostratigraphy and correlation. Palaeontologia Africana 44: 83–87.
Abdala, F., C.A. Marsicano, R.M. Smith, and R. Swart. 2013. Strengthening Western Gondwanan correlations: a Brazilian Dicynodont (Synapsida, Anomodontia) in the Middle Triassic of Namibia. Gondwana Research 23: 1151–1162.
Andreis, R. R., G.E. Bossi, and D.K. Montardo. 1980. O Grupo Rosário do Sul, Triássico no Rio Grande do Sul. In Anais do XXXI Congresso Brasileiro de Geologia. 2: 659–673. Camboriú, Siciedade Brasileira de Geologia.
Bandyopadhyay, S., T.K. Roy Chowdhury, and D.P. Sengupta. 2002. Taphonomy of some Gondwana vertebrate assemblages of India. Sedimentary Geology 147: 219–245.
Benton, M.J. 1983a. The Triassic reptile Hyperodapedon from Elgin: functional morphology and relationships. Philosophical Transaction of the Royal Society B 302: 605–717.
Benton, M.J. 1983b. Dinosaur success in the Triassic: a noncompetitive ecological model. The Quarterly Review of Biology 58: 29–55.
Benton, M.J., and A.D. Walker. 1985. Palaeoecology, taphonomy, and dating of Permo-Triassic reptiles from Elgin, north-east Scotland. Palaeontology 28: 207–234.
Benton, M.J., G. Warrington, A. Newell, and P.S. Spencer. 1994. A review of the British Mid Triassic tetrapod faunas. In In the Shadow of the Dinosaurs, ed. N.C. Fraser, and H.-D. Sues, 131–160. New York: Columbia University.
Besairie, H. 1972. Géologie de Madagascar I. Les terraines sédimentaires. Annales Géologiques de Madagascar, Service des Mines 35: 1–463.
Brazeau, M. 2011. Problematic character coding methods in morphology and their effects. Biological Journal of the Linnean Society 104: 489–498.
Bremer, K. 1994. Branch support and tree stability. Cladistics-the International Journal of the Willi Hennig Society 10: 295–304.
Butler, R.J., O.W.M. Rauhut, M.R. Stocker, and R. Bronowicz. 2014. Redescription of the phytosaurs Paleorhinus (“Francosuchus”) angustifrons and Ebrachosuchus neukami from Germany, with implications for Late Triassic biochronology. Zoological Journal of the Linnean Society 170: 155–208.
Butler, R., M. Ezcurra, F. Montefeltro, A. Samathi, and G. Sobral. 2015. A new species of basal rhynchosaur (Diapsida: Archosauromorpha) from the early Middle Triassic of South Africa, and the early evolution of Rhynchosauria. Zoological Journal of the Linnean Society 174: 571–588.
Chatterjee, S. 1980. The evolution of rhynchosaurs. Mémoires de la Société géologique de France 139: 57–65.
Da Rosa, A.A.S. 2014. Geological context of the dinosauriform-bearing outcrops from the Triassic of Brazil. Journal of South American Earth Sciences 61: 108–119.
Da Silva, L.R., and S.F. Cabreira. 2009. Novo achado de Luangwa sudamericana Abdala & Teixeira, 2004 do Triássico Médio da Formação Santa Maria, Rio Grande do Sul, Brasil. Palaeontologia em Destaque 24: 23–24.
Desojo, J.B., M.D. Ezcurra, and C.L. Schultz. 2011. An unusual new archosauriform from the Middle-Late Triassic of southern Brazil and the monophyly of Doswelliidae. Zoological Journal of the Linnean Society 161: 839–871.
Dilkes, D. 1998. The Early Triassic rhynchosaur Mesosuchus browni and the interrelationships of basal archosauromorph reptiles. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences 353: 501–541.
Ezcurra, M.D., M.J. Trotteyn, L.E. Fiorelli, M.B. von Baczko, J.R.A. Taborda, M. Iberlucea, and J.B. Desojo. 2013. The oldest rhynchosaur from Argentina: a Middle Triassic rhynchosaurid from the Chañares Formation (Ischigualasto–Villa Unión Basin, La Rioja Province). Paläontologische Zeitschrift 88: 453–460.
Ezcurra, M.D., F.C. Montefeltro, and R.J. Butler. 2016. The early evolution of rhynchosaurs. Frontiers in Ecology and Evolution 3: 142.
Fiorelli, L.E., M.D. Ezcurra, E.M. Hechenleitner, E. Argañaraz, J.R.A. Taborda, M. Jimena Trotteyn, M.B. von Baczko, and J.B. Desojo. 2013. The oldest known communal latrines provide evidence of gregarism in Triassic megaherbivores. Scientific Reports 3: 3348.
Flynn, J.J., J.M. Parrish, L. Ranivoharimanana, W.F. Simpson, and A.R. Wyss. 2000. New traversodontids (Synapsida: Eucynodontia) from the Triassic of Madagascar. Journal of Vertebrate Paleontology 20: 422–427.
Flynn, J.J., S.J. Nesbitt, J.M. Parrish, L. Ranivoharimanana, and A.R. Wyss. 2010. A new taxon of Azendohsaurus (Archosauromorpha, Diapsida, Reptilia) from the Triassic Isalo Group of southwest Madagascar: part 1, cranium. Palaeontology 53: 669–688.
Goloboff, P., J. Farris, and K. Nixon. 2008. TNT, a free program for phylogenetic analysis. Cladistics 24: 774–786.
Gradstein, F.M., J.G. Ogg, M.D. Schmitz, and G.M. Ogg. 2012. The Geologic Time Scale 2012, 1144. Oxford: Elsevier.
Horn, B.L.D., T.P. Melo, C.L. Schultz, R.P. Philipp, H.P. Kloss, and K. Goldberg. 2014. A new third-order sequence stratigraphic framework applied to the Triassic of the Paraná Basin, Rio Grande do Sul, Brazil, based on structural, stratigraphic and paleontological data. Journal of South American Earth Sciences 55: 123–132.
Hunt, A.P., and S.G. Lucas. 1991. A new rhynchosaur from West Texas (USA) and the biochronology of Late Triassic rhynchosaurs. Palaeontology 34: 927–938.
Irmis, R.B., R. Mundil, J.W. Martz, and W.G. Parker. 2011. High-resolution U–Pb ages from the Upper Triassic Chinle Formation (New Mexico, USA) support a diachronous rise of dinosaurs. Earth and Planetary Science Letters 309: 258–267.
Kammerer, C.F., J.J. Flynn, L. Ranivoharimanana, and A.R. Wyss. 2010. The first record of a probainognathian (Cynodontia: Chiniquodontidae) from the Triassic of Madagascar. Journal of Vertebrate Paleontology 30: 1889–1894.
Langer, M.C. 2005. Studies on continental Late Triassic tetrapod biochronology. II. The Ischigualastian and a Carnian global correlation. Journal of South American Earth Sciences 19: 219–239.
Langer, M.C., and C.L. Schultz. 2000a. Rincossauros- herbívoros cosmopolitas do Triássico. In Paleontologia do Rio Grande do Sul, ed. M. Holz, and L.F. Roz, 246–272. Porto Alegre: CIGO/UFRGS.
Langer, M.C., and C.L. Schultz. 2000b. A new species of the late Triassic rhynchosaur Hyperodapedon from the Santa Maria Formation of south Brazil. Palaeontology 43: 633–652.
Langer, M.C., M. Boniface, G. Cuny, and L. Barbieri. 2000. The phylogenetic position of Isalorhynchus genovefae, a Late Triassic rhynchosaur from Madagascar. Annales de Paléontologie 86: 101–127.
Langer, M.C., A.M. Ribeiro, C.L. Schultz, and J. Ferigolo. 2007. The continental tetrapod–bearing Triassic of South Brazil. Bulletin of the New Mexico Museum of Natural History and Science 41: 201–218.
Leleu, S., and A.J. Hartley. 2010. Controls on the stratigraphic development of the Triassic Fundy Basin, Nova Scotia: implications for the tectonostratigraphic evolution of Triassic. Journal of the Geological Society, London 167: 437–454.
Long, J.A., and P.A. Murry. 1995. Late Triassic (Carnian and Norian) tetrapods from the Southwestern United States. Bulletin of the New Mexico Museum of Natural History and Science 4: 1–254.
Lucas, S.G., and A.B. Heckert. 2002. The Hyperodapedon Biochron, Late Triassic of Pangea. Albertiana 27: 30–38.
Lucas, S.G. 1998. Global Triassic tetrapod biostratigraphy and biochronology. Palaeogeography, Palaeoclimatology, Palaeoecology 143: 347–384.
Lucas, S.G. 2001. Age and correlation of Triassic tetrapod assemblages from Brazil. Albertiana 26: 13–20.
Lucas, S.G., A.B. Heckert, and N. Hotton III. 2002. The rhynchosaur Hyperodapedon from the upper Triassic of Wyoming and its global biochronological significance. Bulletin of the New Mexico Museum of Natural History and Sciences 21: 149–156.
Marsicano, C.A., R.B. Irmis, A.C. Mancuso, R. Mundil, and F. Chemale. 2015. The precise temporal calibration of dinosaur origins. In Proceedings of the National Academy of Science On-line first.
Martínez, R.N., P.C. Sereno, O.A. Alcober, C.E. Colombi, P.R. Renne, I.P. Montañez, and B.S. Currie. 2011. A basal dinosaur from the dawn of the dinosaur era in southwestern Pangaea. Science 331: 206–210.
Martínez, R.N., C. Apaldetti, O.A. Alcober, C.E. Colombi, P.C. Sereno, E. Fernandez, P.S. Malnis, G.A. Correa, and D. Abelin. 2013. Vertebrate succession in the Ischigualasto Formation. Journal of Vertebrate Paleontology 32: 10–30.
Mietto, P., et al. 2012. The global boundary stratotype section and point (GSSP) of the Carnian Stage (Late Triassic) at Prati di Stuores/Stuores Wiesen section (southern Alps, NE Italy). Episodes 3: 414–430.
Montefeltro, F., M.C. Langer, and C.L. Schultz. 2010. Cranial anatomy of a new genus of hyperodapedontine rhynchosaur (Diapsida, Archosauromorpha) from the upper Triassic of southern Brazil. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 101: 27–52.
Montefeltro, F., J. Bittencourt, M.C. Langer, and C.L. Schultz. 2013. Postcranial anatomy of the hyperodapedontine rhynchosaur Teyumbaita sulcognathus (Azevedo and Schultz, 1987) from the Late Triassic of southern Brazil. Journal of Vertebrate Paleontology 33: 67–84.
Mukherjee, D., and S. Ray. 2014. A new Hyperodapedon (Archosauromorpha, Rhynchosauria) from the upper Triassic of India: implications for rhynchosaur phylogeny. Palaeontology 57: 1241–1276.
Nesbitt, S. 2005. Stratigraphy and tetrapod fauna of major quarries in the Moenkopi Formation (Early-Middle Triassic) along the Little Colorado River of northern Arizona. Bulletin of the Mesa Southwest Museum 11: 18–33.
Nesbitt, S.J., and R.L. Whatley. 2004. The first discovery of a rhynchosaur from the upper Moenkopi Formation (Middle Triassic) of northern Arizona. PalaeoBios 24: 1–10.
Nesbitt, S.J., J.J. Flynn, A.C. Pritchard, J.M. Parrish, L. Ranivoharimanana, and A.R. Wyss. 2015. Postcranial osteology of Azendohsaurus madagaskarensis (?Middle to Upper Triassic, Isalo Group, Madagascar) and its systematic position among stem archosaur reptiles. Bulletin of the American Museum of Natural History 398: 1–126.
Philipp, R.P., H. Closs, C.L. Schultz, M. Basei, B.L.D. Horn, and M.B. Soares. 2013. Proveniência por U-Pb LA-ICP-MS em zircão detrítico e idade de deposição da Formação Santa Maria, Triássico da Bacia do Paraná, RS: evidências da estruturação do Arco do Rio Grande. In Anais do VIII Symposium International on Tectonics & XIV Simpósio Nacional de Estudos Tectónicos, 154–157. Cuiabá.
Prevosti, F., and M. Chemisquy. 2010. The impact of missing data on real morphological phylogenies: influence of the number and distribution of missing entries. Cladistics 26: 326–339.
Ramezani, J., D.E. Fastovsky, and S.S. Bowring. 2014. Revised chronostratigraphy of the lower Chinle Formation strata in Arizona and New Mexico (USA): high-precision U-Pb geochronological constraints on the Late Triassic evolution of dinosaurs. American Journal of Science 314: 981–1008.
Razafimbelo, E. 1987. Le basin de Morondava (Madagascar). Synthèse géologique et structurale. Ph.D. dissertation. Strasbourg, Université Louis Pasteur. p. 189.
Schultz, C.L. 1995. Subdivisão do Triássico do RS com base em macrofósseis: problemas e perspectivas. Comunicações do Museu de Ciências e Tecnologia, UBEA/PUCRS, Série Ciências da Terra 1: 25–32.
Schultz, C.L., and S.A.K. Azevedo. 1990. Dados preliminares sobre a ocorrência de uma nova forma de rincossauro para o Triássico do Rio Grande do Sul-Brasil. Paula-Coutiana 4: 35–44.
Siddall, M.E. 2002. Measures of support. In Techniques in molecular systematics and evolution, ed. R. DeSalle, G. Giribet, and W.C. Wheeler, 80–101. Basel: Birkhauser Verlag.
Soares, M.B., C.L. Schultz, and B.L.D. Horn. 2011. New information on Riograndia guaibensis Bonaparte, Ferigolo & Ribeiro, 2001 (Eucynodontia, Tritheledontidae) from the Late Triassic of southern Brazil: anatomical and biostratigraphic implications. Anais da Academia Brasileira de Ciências 83: 329–354.
Spielmann, J.A., S.G. Lucas, and A.P. Hunt. 2013. The first Norian (Revueltian) rhynchosaur: Bull Canyon Formation, New Mexico, USA. New Mexico Museum of Natural History and Science Bulletin 61: 562–566.
Wilkinson, M. 2003. Missing entries and multiple trees: instability, relationships, and support in parsimony analysis. Journal of Vertebrate Paleontology 23: 311–323.
Zerfass, H., E.L. Lavina, C.L. Schultz, A.G.V. Garcia, U.F. Faccini, and F. Chemale Jr. 2003. Sequence stratigraphy of continental Triassic strata of southernmost Brazil: a contribution to Southwestern Gondwana palaeogeography and palaeoclimate. Sedimentary Geology 161: 85–105.
Acknowledgments
Max Langer research is supported by FAPESP Grant # 2014/03825–3). The authors thank the Paläontologische Zeitschrift reviewers Mike Benton and Martin Ezcurra for their useful comments. Photographs taken by Luiz Flávio P. Lopes, drawings by Bianca M. Mastrantonio, CLS Grant: CNPq 309995/2013-2.
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An erratum to this article can be found at http://dx.doi.org/10.1007/s12542-016-0325-5.
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Schultz, C.L., Langer, M.C. & Montefeltro, F.C. A new rhynchosaur from south Brazil (Santa Maria Formation) and rhynchosaur diversity patterns across the Middle-Late Triassic boundary. PalZ 90, 593–609 (2016). https://doi.org/10.1007/s12542-016-0307-7
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DOI: https://doi.org/10.1007/s12542-016-0307-7